This patch contains the actual JIT implementation, all in one file.
Signed-off-by: Johan Almbladh <johan.almbladh@xxxxxxxxxxxxxxxxx>
---
arch/mips/net/Makefile | 7 +-
arch/mips/net/ebpf_jit_32.c | 2207 +++++++++++++++++++++++++++++++++++
2 files changed, 2213 insertions(+), 1 deletion(-)
create mode 100644 arch/mips/net/ebpf_jit_32.c
diff --git a/arch/mips/net/Makefile b/arch/mips/net/Makefile
index d55912349039..9acd70473575 100644
--- a/arch/mips/net/Makefile
+++ b/arch/mips/net/Makefile
@@ -2,4 +2,9 @@
# MIPS networking code
obj-$(CONFIG_MIPS_CBPF_JIT) += bpf_jit.o bpf_jit_asm.o
-obj-$(CONFIG_MIPS_EBPF_JIT) += ebpf_jit.o
+
+ifeq ($(CONFIG_32BIT),y)
+ obj-$(CONFIG_MIPS_EBPF_JIT) += ebpf_jit_32.o
+else
+ obj-$(CONFIG_MIPS_EBPF_JIT) += ebpf_jit.o
+endif
diff --git a/arch/mips/net/ebpf_jit_32.c b/arch/mips/net/ebpf_jit_32.c
new file mode 100644
index 000000000000..95b71321e6e7
--- /dev/null
+++ b/arch/mips/net/ebpf_jit_32.c
@@ -0,0 +1,2207 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Just-In-Time compiler for eBPF bytecode on MIPS I-V and MIPS32.
+ *
+ * Copyright (c) 2021 Anyfi Networks AB.
+ * Author: Johan Almbladh <johan.almbladh@xxxxxxxxx>
+ *
+ * Based on code and ideas from
+ * Copyright (c) 2017 Cavium, Inc.
+ * Copyright (c) 2017 Shubham Bansal <illusionist.neo@xxxxxxxxx>
+ * Copyright (c) 2011 Mircea Gherzan <mgherzan@xxxxxxxxx>
+ */
+
+#include <linux/bitops.h>
+#include <linux/math64.h>
+#include <linux/errno.h>
+#include <linux/filter.h>
+#include <linux/bpf.h>
+#include <linux/slab.h>
+#include <asm/bitops.h>
+#include <asm/cacheflush.h>
+#include <asm/cpu-features.h>
+#include <asm/isa-rev.h>
+#include <asm/uasm.h>
+
+/* MIPS 32-bit registers */
+#define MIPS_R_ZERO 0 /* Const zero */
+#define MIPS_R_AT 1 /* Asm temp */
+#define MIPS_R_V0 2 /* Result */
+#define MIPS_R_V1 3 /* Result */
+#define MIPS_R_A0 4 /* Argument */
+#define MIPS_R_A1 5 /* Argument */
+#define MIPS_R_A2 6 /* Argument */
+#define MIPS_R_A3 7 /* Argument */
+#define MIPS_R_T0 8 /* Temporary */
+#define MIPS_R_T1 9 /* Temporary */
+#define MIPS_R_T2 10 /* Temporary */
+#define MIPS_R_T3 11 /* Temporary */
+#define MIPS_R_T4 12 /* Temporary */
+#define MIPS_R_T5 13 /* Temporary */
+#define MIPS_R_T6 14 /* Temporary */
+#define MIPS_R_T7 15 /* Temporary */
+#define MIPS_R_S0 16 /* Saved */
+#define MIPS_R_S1 17 /* Saved */
+#define MIPS_R_S2 18 /* Saved */
+#define MIPS_R_S3 19 /* Saved */
+#define MIPS_R_S4 20 /* Saved */
+#define MIPS_R_S5 21 /* Saved */
+#define MIPS_R_S6 22 /* Saved */
+#define MIPS_R_S7 23 /* Saved */
+#define MIPS_R_T8 24 /* Temporary */
+#define MIPS_R_T9 25 /* Temporary */
+/* MIPS_R_K0 26 Reserved */
+/* MIPS_R_K1 27 Reserved */
+#define MIPS_R_GP 28 /* Global ptr */
+#define MIPS_R_SP 29 /* Stack ptr */
+#define MIPS_R_FP 30 /* Frame ptr */
+#define MIPS_R_RA 31 /* Return */
+
+/* Stack is 8-byte aligned in O32 ABI */
+#define MIPS_STACK_ALIGNMENT 8
+
+/*
+ * Jump address mask for immediate jumps. The four most significant bits
+ * must be equal to PC.
+ */
+#define MIPS_JMP_MASK 0x0fffffff
+
+/* Maximum number of iterations in offset table computation */
+#define JIT_MAX_ITERATIONS 64
+
+/* Jump pseudo-instruction used internally */
+#define JIT_JNSET 0xf0
+
+/* Temporary 64-bit registers used by JIT */
+#define JIT_REG_T0 (MAX_BPF_JIT_REG + 0)
+#define JIT_REG_T1 (MAX_BPF_JIT_REG + 1)
+
+/*
+ * Number of prologue bytes to skip when doing a tail call.
+ * Tail call count (TCC) initialization (8 bytes) always, plus
+ * R0-to-v0 assignment (4 bytes) if big endian.
+ */
+#ifdef __BIG_ENDIAN
+#define JIT_TCALL_SKIP 12
+#else
+#define JIT_TCALL_SKIP 8
+#endif
+
+/*
+ * The top 16 bytes of a stack frame is reserved for the callee.
+ * This corresponds to stack space for register arguments a0-a3.
+ */
+#define JIT_RESERVED_STACK 16
+
+/* CPU registers holding the callee return value */
+#define JIT_RETURN_REGS \
+ (BIT(MIPS_R_V0) | \
+ BIT(MIPS_R_V1))
+
+/* CPU registers arguments passed to callee directly */
+#define JIT_ARG_REGS \
+ (BIT(MIPS_R_A0) | \
+ BIT(MIPS_R_A1) | \
+ BIT(MIPS_R_A2) | \
+ BIT(MIPS_R_A3))
+
+/* CPU register arguments passed to callee on stack */
+#define JIT_STACK_REGS \
+ (BIT(MIPS_R_T0) | \
+ BIT(MIPS_R_T1) | \
+ BIT(MIPS_R_T2) | \
+ BIT(MIPS_R_T3) | \
+ BIT(MIPS_R_T4) | \
+ BIT(MIPS_R_T5))
+
+/* Caller-saved CPU registers */
+#define JIT_CALLER_REGS \
+ (JIT_RETURN_REGS | \
+ JIT_ARG_REGS | \
+ JIT_STACK_REGS)
+
+/* Callee-saved CPU registers */
+#define JIT_CALLEE_REGS \
+ (BIT(MIPS_R_S0) | \
+ BIT(MIPS_R_S1) | \
+ BIT(MIPS_R_S2) | \
+ BIT(MIPS_R_S3) | \
+ BIT(MIPS_R_S4) | \
+ BIT(MIPS_R_S5) | \
+ BIT(MIPS_R_S6) | \
+ BIT(MIPS_R_S7) | \
+ BIT(MIPS_R_GP) | \
+ BIT(MIPS_R_FP) | \
+ BIT(MIPS_R_RA))
+
+/*
+ * Mapping of 64-bit eBPF registers to 32-bit native MIPS registers.
+ *
+ * 1) Native register pairs are ordered according to CPU endiannes, following
+ * the MIPS convention for passing 64-bit arguments and return values.
+ * 2) The eBPF return value, arguments and callee-saved registers are mapped
+ * to their native MIPS equivalents.
+ * 3) Since the 32 highest bits in the eBPF FP register are always zero,
+ * only one general-purpose register is actually needed for the mapping.
+ * We use the fp register for this purpose, and map the highest bits to
+ * the MIPS register r0 (zero).
+ * 4) We use the MIPS gp and at registers as internal temporary registers
+ * for constant blinding. The gp register is callee-saved.
+ * 5) Two 64-bit temporary registers are available for use when performing
+ * more complex operations.
+ *
+ * With this scheme all eBPF registers are being mapped to native MIPS
+ * registers without having to use any stack scratch space. The direct
+ * register mapping (2) simplifies the handling of function calls.
+ */
+static const u8 bpf2mips32[][2] = {
+ /* Return value from in-kernel function, and exit value from eBPF */
+ [BPF_REG_0] = {MIPS_R_V1, MIPS_R_V0},
+ /* Arguments from eBPF program to in-kernel function */
+ [BPF_REG_1] = {MIPS_R_A1, MIPS_R_A0},
+ [BPF_REG_2] = {MIPS_R_A3, MIPS_R_A2},
+ /* Remaining arguments, to be passed on the stack per O32 ABI */
+ [BPF_REG_3] = {MIPS_R_T1, MIPS_R_T0},
+ [BPF_REG_4] = {MIPS_R_T3, MIPS_R_T2},
+ [BPF_REG_5] = {MIPS_R_T5, MIPS_R_T4},
+ /* Callee-saved registers that in-kernel function will preserve */
+ [BPF_REG_6] = {MIPS_R_S1, MIPS_R_S0},
+ [BPF_REG_7] = {MIPS_R_S3, MIPS_R_S2},
+ [BPF_REG_8] = {MIPS_R_S5, MIPS_R_S4},
+ [BPF_REG_9] = {MIPS_R_S7, MIPS_R_S6},
+ /* Read-only frame pointer to access the eBPF stack */
+#ifdef __BIG_ENDIAN
+ [BPF_REG_FP] = {MIPS_R_FP, MIPS_R_ZERO},
+#else
+ [BPF_REG_FP] = {MIPS_R_ZERO, MIPS_R_FP},
+#endif
+ /* Temporary register for blinding constants */
+ [BPF_REG_AX] = {MIPS_R_GP, MIPS_R_AT},
+ /* Temporary registers for internal JIT use */
+ [JIT_REG_T0] = {MIPS_R_T7, MIPS_R_T6},
+ [JIT_REG_T1] = {MIPS_R_T9, MIPS_R_T8},
+};
+
+/* JIT descriptor for an eBPF instruction */
+struct jit_desc {
+ u32 convert : 1; /* PC-relative branch converted to absolute jump */
+ u32 offset : 31; /* Index of (first) native instruction generated */
+};
+
+/* JIT context for an eBPF program */
+struct jit_context {
+ struct bpf_prog *program; /* The eBPF program being JITed */
+ struct jit_desc *descriptors; /* Per-eBPF insn offset descriptors */
+ u32 *target; /* JITed code buffer */
+ u32 bpf_index; /* Index of current BPF program instruction */
+ u32 jit_index; /* Index of current JIT target instruction */
+ u32 changes; /* Number of PC-relative branch conversions */
+ u32 clobbered; /* Bit mask of clobbered callee-saved regs */
+ u32 stack_size; /* Total allocated stack size in bytes */
+ u32 saved_size; /* Total size of callee-saved registers */
+ u32 stack_used; /* Total stack size used for function calls */
+};
+
+/* Simply emit the instruction if the JIT memory space has been allocated */
+#define emit(ctx, func, ...) \
+do { \
+ if ((ctx)->target != NULL) { \
+ u32 *p = &(ctx)->target[ctx->jit_index]; \
+ uasm_i_##func(&p, ##__VA_ARGS__); \
+ } \
+ (ctx)->jit_index++; \
+} while (0)
+
+/* Get low CPU register for a 64-bit eBPF register mapping */
+static inline u8 lo(const u8 reg[])
+{
+#ifdef __BIG_ENDIAN
+ return reg[0];
+#else
+ return reg[1];
+#endif
+}
+
+/* Get high CPU register for a 64-bit eBPF register mapping */
+static inline u8 hi(const u8 reg[])
+{
+#ifdef __BIG_ENDIAN
+ return reg[1];
+#else
+ return reg[0];
+#endif
+}
+
+/* Test if a value is within the signed 16-bit range */
+static inline bool is_16bit(int value)
+{
+ return value >= -0x8000 && value <= 0x7fff;
+}
+
+/* Test if a value is within the signed 18-bit range */
+static inline bool is_18bit(int value)
+{
+ return value >= -0x20000 && value <= 0x1ffff;
+}
+
+/*
+ * Mark a 32-bit CPU register as clobbered, it needs to be
+ * saved/restored by the program if callee-saved.
+ */
+static void clobber_reg(struct jit_context *ctx, u8 reg)
+{
+ ctx->clobbered |= BIT(reg);
+}
+
+/*
+ * Mark a 64-bit CPU register pair as clobbered, it needs to be
+ * saved/restored by the program if callee-saved.
+ */
+static void clobber_reg64(struct jit_context *ctx, const u8 reg[])
+{
+ clobber_reg(ctx, reg[0]);
+ clobber_reg(ctx, reg[1]);
+}
+
+/*
+ * Push registers on the stack, starting at a given depth from the stack
+ * pointer and increasing. The next depth to be written is returned.
+ */
+static int push_regs(struct jit_context *ctx, u32 mask, u32 excl, int depth)
+{
+ int reg;
+
+ for (reg = 0; reg < BITS_PER_BYTE * sizeof(u32); reg++)
+ if (mask & BIT(reg)) {
+ if ((excl & BIT(reg)) == 0)
+ emit(ctx, sw, reg, depth, MIPS_R_SP);
+ depth += sizeof(u32);
+ }
+
+ ctx->stack_used = max((int)ctx->stack_used, depth);
+ return depth;
+}
+
+/*
+ * Pop registers from the stack, starting at a given depth from the stack
+ * pointer and increasing. The next depth to be read is returned.
+ */
+static int pop_regs(struct jit_context *ctx, u32 mask, u32 excl, int depth)
+{
+ int reg;
+
+ for (reg = 0; reg < BITS_PER_BYTE * sizeof(u32); reg++)
+ if (mask & BIT(reg)) {
+ if ((excl & BIT(reg)) == 0)
+ emit(ctx, lw, reg, depth, MIPS_R_SP);
+ depth += sizeof(u32);
+ }
+
+ return depth;
+}
+
+/* Compute the 28-bit jump target address from a BPF program location */
+static int get_target(struct jit_context *ctx, u32 loc)
+{
+ u32 offset = ctx->descriptors[loc].offset;
+ u32 addr = (u32)&ctx->target[offset];
+ u32 pc = (u32)&ctx->target[ctx->jit_index];
+
+ if (!ctx->target)
+ return 0;
+
+ if ((addr ^ pc) & ~MIPS_JMP_MASK)
+ return -1;
+
+ return addr & MIPS_JMP_MASK;
+}
+
+/* Compute the PC-relative offset to relative BPF program offset */
+static inline int get_offset(const struct jit_context *ctx, int off)
+{
+ return (ctx->descriptors[ctx->bpf_index + 1].offset -
+ ctx->jit_index - 1) * sizeof(u32);
+}
+
+/* Build program prologue to set up the stack and registers */
+static void build_prologue(struct jit_context *ctx)
+{
+ const u8 *r1 = bpf2mips32[BPF_REG_1];
+ int stack, saved, locals, reserved;
+
+ /*
+ * The first two instructions initialize TCC in the reserved (for us)
+ * 16-byte area in the parent's stack frame. On a tail call, the
+ * calling function jumps into the prologue after these instructions.
+ */
+ emit(ctx, ori, MIPS_R_T9, MIPS_R_ZERO, min(MAX_TAIL_CALL_CNT, 0xffff));
+ emit(ctx, sw, MIPS_R_T9, 0, MIPS_R_SP);
+
+ /*
+ * Register eBPF R1 contains the 32-bit context pointer argument.
+ * A 32-bit argument is always passed in MIPS register a0, regardless
+ * of CPU endianness. Initalize R1 accordingly and zero-extend.
+ */
+#ifdef __BIG_ENDIAN
+ emit(ctx, addiu, lo(r1), MIPS_R_A0, 0);
+#endif
+
+ /* === Entry-point for tail calls === */
+
+ /* Zero-extend the 32-bit argument */
+ emit(ctx, addiu, hi(r1), MIPS_R_ZERO, 0);
+
+ /* Compute the stack space needed for callee-saved registers */
+ saved = hweight32(ctx->clobbered & JIT_CALLEE_REGS) * sizeof(u32);
+ saved = ALIGN(saved, MIPS_STACK_ALIGNMENT);
+
+ /* Stack space used by eBPF program local data */
+ locals = ALIGN(ctx->program->aux->stack_depth, MIPS_STACK_ALIGNMENT);
+
+ /*
+ * If we are emitting function calls, reserve extra stack space for
+ * caller-saved registers and function arguments passed on the stack.
+ * The required space is computed automatically during resource
+ * usage discovery (pass 1).
+ */
+ reserved = ctx->stack_used;
+
+ /* Allocate the stack frame */
+ stack = ALIGN(saved + locals + reserved, MIPS_STACK_ALIGNMENT);
+ emit(ctx, addiu, MIPS_R_SP, MIPS_R_SP, -stack);
+
+ /* Store callee-saved registers on stack */
+ push_regs(ctx, ctx->clobbered & JIT_CALLEE_REGS, 0, stack - saved);
+
+ /* Set up the eBPF stack pointer */
+ emit(ctx, addiu, MIPS_R_FP, MIPS_R_SP, stack - saved);
+ ctx->saved_size = saved;
+ ctx->stack_size = stack;
+}
+
+/* Build the program epilogue to restore the stack and registers */
+static void build_epilogue(struct jit_context *ctx, int dest_reg)
+{
+ /* Restore callee-saved registers from stack */
+ pop_regs(ctx, ctx->clobbered & JIT_CALLEE_REGS, 0,
+ ctx->stack_size - ctx->saved_size);
+ /*
+ * A 32-bit return value is always passed in MIPS register v0,
+ * but on big-endian targets the low part of R0 is mapped to v1.
+ */
+#ifdef __BIG_ENDIAN
+ emit(ctx, addiu, MIPS_R_V0, MIPS_R_V1, 0);
+#endif
+
+ /* Jump to the return address and adjust the stack pointer */
+ emit(ctx, jr, dest_reg);
+ emit(ctx, addiu, MIPS_R_SP, MIPS_R_SP, ctx->stack_size);
+}
+
+/* dst = imm (4 bytes) */
+static inline void emit_mov_i(struct jit_context *ctx, u8 dst, s32 imm)
+{
+ if (is_16bit(imm)) {
+ emit(ctx, addiu, dst, MIPS_R_ZERO, imm);
+ } else {
+ emit(ctx, lui, dst, (s16)((u32)imm >> 16));
+ emit(ctx, ori, dst, dst, (u16)(imm & 0xffff));
+ }
+ clobber_reg(ctx, dst);
+}
+
+/* dst = src (4 bytes) */
+static inline void emit_mov_r(struct jit_context *ctx, u8 dst, u8 src)
+{
+ emit(ctx, addiu, dst, src, 0);
+ clobber_reg(ctx, dst);
+}
+
+/* dst = imm (sign-extended) */
+static inline void emit_mov_se_i64(struct jit_context *ctx,
+ const u8 dst[], s32 imm)
+{
+ emit_mov_i(ctx, lo(dst), imm);
+ if (imm < 0)
+ emit(ctx, addiu, hi(dst), MIPS_R_ZERO, -1);
+ else
+ emit(ctx, addiu, hi(dst), MIPS_R_ZERO, 0);
+ clobber_reg64(ctx, dst);
+}
+
+/* dst = 0 */
+static inline void emit_zext(struct jit_context *ctx, u8 dst)
+{
+ if (!ctx->program->aux->verifier_zext)
+ emit_mov_i(ctx, dst, 0);
+}
+
+/* ALU register operation (32 bit) */
+static inline void emit_alu_r(struct jit_context *ctx, u8 dst, u8 src, u8 op)
+{
+ switch (BPF_OP(op)) {
+ /* dst = dst + src */
+ case BPF_ADD:
+ emit(ctx, addu, dst, dst, src);
+ break;
+ /* dst = dst - src */
+ case BPF_SUB:
+ emit(ctx, subu, dst, dst, src);
+ break;
+ /* dst = dst | src */
+ case BPF_OR:
+ emit(ctx, or, dst, dst, src);
+ break;
+ /* dst = dst & src */
+ case BPF_AND:
+ emit(ctx, and, dst, dst, src);
+ break;
+ /* dst = dst ^ src */
+ case BPF_XOR:
+ emit(ctx, xor, dst, dst, src);
+ break;
+ /* dst = dst * src */
+ case BPF_MUL:
+ if (cpu_has_mips32r1) {
+ emit(ctx, mul, dst, dst, src);
+ } else {
+ emit(ctx, multu, dst, src);
+ emit(ctx, mflo, dst);
+ }
+ break;
+ /* dst = dst << src */
+ case BPF_LSH:
+ emit(ctx, sllv, dst, dst, src);
+ break;
+ /* dst = dst >> src */
+ case BPF_RSH:
+ emit(ctx, srlv, dst, dst, src);
+ break;
+ /* dst = dst >> src (arithmetic) */
+ case BPF_ARSH:
+ emit(ctx, srav, dst, dst, src);
+ break;
+ }
+ clobber_reg(ctx, dst);
+}
+
+/* ALU immediate operation (32 bit) */
+static inline void emit_alu_i(struct jit_context *ctx, u8 dst, s16 imm, u8 op)
+{
+ u8 tmp = bpf2mips32[JIT_REG_T1][0];
+
+ switch (BPF_OP(op)) {
+ /* dst = -dst */
+ case BPF_NEG:
+ emit(ctx, subu, dst, MIPS_R_ZERO, dst);
+ break;
+ /* dst = dst + imm */
+ case BPF_ADD:
+ emit(ctx, addiu, dst, dst, imm);
+ break;
+ /* dst = dst - imm */
+ case BPF_SUB:
+ emit(ctx, addiu, dst, dst, -imm);
+ break;
+ /* dst = dst | imm */
+ case BPF_OR:
+ emit(ctx, ori, dst, dst, (u16)imm);
+ break;
+ /* dst = dst & imm */
+ case BPF_AND:
+ emit(ctx, andi, dst, dst, (u16)imm);
+ break;
+ /* dst = dst ^ imm */
+ case BPF_XOR:
+ emit(ctx, xori, dst, dst, (u16)imm);
+ break;
+ /* dst = dst * imm */
+ case BPF_MUL:
+ emit_mov_i(ctx, tmp, imm);
+ if (cpu_has_mips32r1) {
+ emit(ctx, mul, dst, dst, tmp);
+ } else {
+ emit(ctx, multu, dst, tmp);
+ emit(ctx, mflo, dst);
+ }
+ break;
+ /* dst = dst << imm */
+ case BPF_LSH:
+ emit(ctx, sll, dst, dst, imm);
+ break;
+ /* dst = dst >> imm */
+ case BPF_RSH:
+ emit(ctx, srl, dst, dst, imm);
+ break;
+ /* dst = dst >> imm (arithmetic) */
+ case BPF_ARSH:
+ emit(ctx, sra, dst, dst, imm);
+ break;
+ }
+ clobber_reg(ctx, dst);
+}
+
+/* ALU register operation (64 bit) */
+static inline void emit_alu_r64(struct jit_context *ctx,
+ const u8 dst[], const u8 src[], u8 op)
+{
+ u8 tmp = bpf2mips32[JIT_REG_T1][0];
+
+ switch (BPF_OP(op)) {
+ /* dst = dst + src */
+ case BPF_ADD:
+ emit(ctx, addu, lo(dst), lo(dst), lo(src));
+ emit(ctx, sltu, tmp, lo(dst), lo(src));
+ emit(ctx, addu, hi(dst), hi(dst), hi(src));
+ emit(ctx, addu, hi(dst), hi(dst), tmp);
+ break;
+ /* dst = dst - src */
+ case BPF_SUB:
+ emit(ctx, sltu, tmp, lo(dst), lo(src));
+ emit(ctx, subu, lo(dst), lo(dst), lo(src));
+ emit(ctx, subu, hi(dst), hi(dst), hi(src));
+ emit(ctx, subu, hi(dst), hi(dst), tmp);
+ break;
+ /* dst = dst | src */
+ case BPF_OR:
+ emit(ctx, or, lo(dst), lo(dst), lo(src));
+ emit(ctx, or, hi(dst), hi(dst), hi(src));
+ break;
+ /* dst = dst & src */
+ case BPF_AND:
+ emit(ctx, and, lo(dst), lo(dst), lo(src));
+ emit(ctx, and, hi(dst), hi(dst), hi(src));
+ break;
+ /* dst = dst ^ src */
+ case BPF_XOR:
+ emit(ctx, xor, lo(dst), lo(dst), lo(src));
+ emit(ctx, xor, hi(dst), hi(dst), hi(src));
+ break;
+ }
+ clobber_reg64(ctx, dst);
+}
+
+/* ALU invert (64 bit) */
+static inline void emit_neg_i64(struct jit_context *ctx, const u8 dst[])
+{
+ u8 tmp = bpf2mips32[JIT_REG_T1][0];
+
+ emit(ctx, sltu, tmp, MIPS_R_ZERO, lo(dst));
+ emit(ctx, subu, lo(dst), MIPS_R_ZERO, lo(dst));
+ emit(ctx, subu, hi(dst), MIPS_R_ZERO, hi(dst));
+ emit(ctx, subu, hi(dst), hi(dst), tmp);
+
+ clobber_reg64(ctx, dst);
+}
+
+/* ALU shift immediate (64 bit) */
+static inline void emit_shift_i64(struct jit_context *ctx,
+ const u8 dst[], u32 imm, u8 op)
+{
+ u8 tmp = bpf2mips32[JIT_REG_T1][0];
+
+ switch (BPF_OP(op)) {
+ /* dst = dst << imm */
+ case BPF_LSH:
+ if (imm < 32) {
+ emit(ctx, srl, tmp, lo(dst), 32 - imm);
+ emit(ctx, sll, lo(dst), lo(dst), imm);
+ emit(ctx, sll, hi(dst), hi(dst), imm);
+ emit(ctx, or, hi(dst), hi(dst), tmp);
+ } else {
+ emit(ctx, sll, hi(dst), lo(dst), imm - 32);
+ emit(ctx, addiu, lo(dst), MIPS_R_ZERO, 0);
+ }
+ break;
+ /* dst = dst >> imm */
+ case BPF_RSH:
+ if (imm < 32) {
+ emit(ctx, sll, tmp, hi(dst), 32 - imm);
+ emit(ctx, srl, lo(dst), lo(dst), imm);
+ emit(ctx, srl, hi(dst), hi(dst), imm);
+ emit(ctx, or, lo(dst), lo(dst), tmp);
+ } else {
+ emit(ctx, srl, lo(dst), hi(dst), imm - 32);
+ emit(ctx, addiu, hi(dst), MIPS_R_ZERO, 0);
+ }
+ break;
+ /* dst = dst >> imm (arithmetic) */
+ case BPF_ARSH:
+ if (imm < 32) {
+ emit(ctx, sll, tmp, hi(dst), 32 - imm);
+ emit(ctx, srl, lo(dst), lo(dst), imm);
+ emit(ctx, sra, hi(dst), hi(dst), imm);
+ emit(ctx, or, lo(dst), lo(dst), tmp);
+ } else {
+ emit(ctx, sra, lo(dst), hi(dst), imm - 32);
+ emit(ctx, sra, hi(dst), hi(dst), 31);
+ }
+ break;
+ }
+ clobber_reg64(ctx, dst);
+}
+
+/* ALU shift register (64 bit) */
+static inline void emit_shift_r64(struct jit_context *ctx,
+ const u8 dst[], u8 src, u8 op)
+{
+ u8 t1 = bpf2mips32[JIT_REG_T1][0];
+ u8 t2 = bpf2mips32[JIT_REG_T1][1];
+
+ emit(ctx, andi, t1, src, 32); /* t1 = src & 32 */
+ emit(ctx, beqz, t1, 16); /* PC += 16 if t1 == 0 */
+ emit(ctx, nor, t2, src, MIPS_R_ZERO); /* t2 = ~src (delay slot) */
+
+ switch (BPF_OP(op)) {
+ /* dst = dst << src */
+ case BPF_LSH:
+ /* Next: shift >= 32 */
+ emit(ctx, sllv, hi(dst), lo(dst), src); /* dh = dl << src */
+ emit(ctx, addiu, lo(dst), MIPS_R_ZERO, 0); /* dl = 0 */
+ emit(ctx, b, 20); /* PC += 20 */
+ /* +16: shift < 32 */
+ emit(ctx, srl, t1, lo(dst), 1); /* t1 = dl >> 1 */
+ emit(ctx, srlv, t1, t1, t2); /* t1 = t1 >> t2 */
+ emit(ctx, sllv, lo(dst), lo(dst), src); /* dl = dl << src */
+ emit(ctx, sllv, hi(dst), hi(dst), src); /* dh = dh << src */
+ emit(ctx, or, hi(dst), hi(dst), t1); /* dh = dh | t1 */
+ break;
+ /* dst = dst >> src */
+ case BPF_RSH:
+ /* Next: shift >= 32 */
+ emit(ctx, srlv, lo(dst), hi(dst), src); /* dl = dh >> src */
+ emit(ctx, addiu, hi(dst), MIPS_R_ZERO, 0); /* dh = 0 */
+ emit(ctx, b, 20); /* PC += 20 */
+ /* +16: shift < 32 */
+ emit(ctx, sll, t1, hi(dst), 1); /* t1 = dl << 1 */
+ emit(ctx, sllv, t1, t1, t2); /* t1 = t1 << t2 */
+ emit(ctx, srlv, lo(dst), lo(dst), src); /* dl = dl >> src */
+ emit(ctx, srlv, hi(dst), hi(dst), src); /* dh = dh >> src */
+ emit(ctx, or, lo(dst), lo(dst), t1); /* dl = dl | t1 */
+ break;
+ /* dst = dst >> src (arithmetic) */
+ case BPF_ARSH:
+ /* Next: shift >= 32 */
+ emit(ctx, srav, lo(dst), hi(dst), src); /* dl = dh >>a src */
+ emit(ctx, sra, hi(dst), hi(dst), 31); /* dh = dh >>a 31 */
+ emit(ctx, b, 20); /* PC += 20 */
+ /* +16: shift < 32 */
+ emit(ctx, sll, t1, hi(dst), 1); /* t1 = dl << 1 */
+ emit(ctx, sllv, t1, t1, t2); /* t1 = t1 << t2 */
+ emit(ctx, srlv, lo(dst), lo(dst), src); /* dl = dl >>a src */
+ emit(ctx, srav, hi(dst), hi(dst), src); /* dh = dh >> src */
+ emit(ctx, or, lo(dst), lo(dst), t1); /* dl = dl | t1 */
+ break;
+ }
+
+ /* +20: Done */
+ clobber_reg64(ctx, dst);
+}
+
+/* ALU mul register (64 bit) */
+static inline void emit_mul_r64(struct jit_context *ctx,
+ const u8 dst[], const u8 src[])
+{
+ u8 tmp = bpf2mips32[JIT_REG_T1][0];
+
+ emit(ctx, multu, hi(dst), lo(src)); /* hi,lo = dh * sl */
+ emit(ctx, mflo, hi(dst)); /* dh = lo */
+ emit(ctx, multu, lo(dst), hi(src)); /* hi,lo = dl * sh */
+ emit(ctx, mflo, tmp); /* tmp = lo */
+ emit(ctx, addu, hi(dst), hi(dst), tmp); /* dh = dh + tmp */
+ emit(ctx, multu, lo(dst), lo(src)); /* hi,lo = dl * sl */
+ emit(ctx, mflo, lo(dst)); /* dl = lo */
+ emit(ctx, mfhi, tmp); /* tmp = hi */
+ emit(ctx, addu, hi(dst), hi(dst), tmp); /* dh = dh + tmp */
+
+ clobber_reg64(ctx, dst);
+}
+
+/* ALU div/mod register */
+static inline void emit_divmod_r(struct jit_context *ctx,
+ u8 dst, u8 src, u8 op)
+{
+ emit(ctx, divu, dst, src);
+ switch (BPF_OP(op)) {
+ /* dst = dst / src */
+ case BPF_DIV:
+ emit(ctx, mflo, dst);
+ break;
+ /* dst = dst % src */
+ case BPF_MOD:
+ emit(ctx, mfhi, dst);
+ break;
+ }
+ clobber_reg(ctx, dst);
+}
+
+/* Helper function for 64-bit modulo */
+static u64 jit_mod64(u64 a, u64 b)
+{
+ u64 rem;
+ div64_u64_rem(a, b, &rem);
+ return rem;
+}
+
+/* Helper function for 64-bit atomic exchange */
+static s64 jit_xchg64(s64 a, atomic64_t *v)
+{
+ return atomic64_xchg(v, a);
+}
+
+/* ALU div/mod register (64-bit) */
+static void emit_divmod_r64(struct jit_context *ctx,
+ const u8 dst[], const u8 src[], u8 op)
+{
+ const u8 *r0 = bpf2mips32[BPF_REG_0]; /* Mapped to v0-v1 */
+ const u8 *r1 = bpf2mips32[BPF_REG_1]; /* Mapped to a0-a1 */
+ const u8 *r2 = bpf2mips32[BPF_REG_2]; /* Mapped to a2-a3 */
+ u8 tmp = bpf2mips32[JIT_REG_T1][0];
+ u32 addr = 0;
+ int exclude, k;
+
+ /* Push caller-saved registers on stack */
+ push_regs(ctx, ctx->clobbered & JIT_CALLER_REGS,
+ 0, JIT_RESERVED_STACK);
+
+ /* Put 64-bit arguments 1 and 2 in registers a0-a3 */
+ for (k = 0; k < 2; k++) {
+ emit(ctx, addiu, tmp, src[k], 0);
+ emit(ctx, addiu, r1[k], dst[k], 0);
+ emit(ctx, addiu, r2[k], tmp, 0);
+ }
+
+ /* Emit function call */
+ switch (BPF_OP(op)) {
+ /* dst = dst / src */
+ case BPF_DIV:
+ addr = (u32)&div64_u64;
+ break;
+ /* dst = dst % src */
+ case BPF_MOD:
+ addr = (u32)&jit_mod64;
+ break;
+ }
+ emit_mov_i(ctx, tmp, addr);
+ emit(ctx, jalr, MIPS_R_RA, tmp);
+ emit(ctx, nop); /* Delay slot */
+
+ /* Store the 64-bit result in dst */
+ emit(ctx, addiu, dst[0], r0[0], 0);
+ emit(ctx, addiu, dst[1], r0[1], 0);
+
+ /* Restore caller-saved registers, excluding the computed result */
+ exclude = BIT(lo(dst)) | BIT(hi(dst));
+ pop_regs(ctx, ctx->clobbered & JIT_CALLER_REGS,
+ exclude, JIT_RESERVED_STACK);
+
+ clobber_reg64(ctx, dst);
+ clobber_reg(ctx, MIPS_R_V0);
+ clobber_reg(ctx, MIPS_R_V1);
+ clobber_reg(ctx, MIPS_R_RA);
+}
+
+/* Byteswap (64-bit) */
+static inline void emit_bswap_i64(struct jit_context *ctx,
+ const u8 dst[], u32 imm)
+{
+/* Load constant 0x00ff00ff in a register */
+#define MASK8(ctx, mask) \
+ emit(ctx, lui, mask, 0xff); \
+ emit(ctx, ori, mask, mask, 0xff)
+
+/* Swap bytes in a register word */
+#define SWAP8(ctx, dst, src, mask, tmp) \
+ emit(ctx, and, tmp, src, mask); /* tmp = src & 0x00ff00ff */ \
+ emit(ctx, sll, tmp, tmp, 8); /* tmp = tmp << 8 */ \
+ emit(ctx, srl, dst, src, 8); /* dst = src >> 8 */ \
+ emit(ctx, and, dst, dst, mask); /* dst = dst & 0x00ff00ff */ \
+ emit(ctx, or, dst, dst, tmp) /* dst = dst | tmp */
+
+/* Swap half words in a register word */
+#define SWAP16(ctx, dst, src, tmp) \
+ emit(ctx, sll, tmp, src, 16); /* tmp = src << 16 */ \
+ emit(ctx, srl, dst, src, 16); /* dst = src >> 16 */ \
+ emit(ctx, or, dst, dst, tmp) /* dst = dst | tmp */
+
+ u8 t1 = bpf2mips32[JIT_REG_T1][0];
+ u8 t2 = bpf2mips32[JIT_REG_T1][1];
+
+ switch (imm) {
+ case 64:
+ if (cpu_has_mips32r2) {
+ emit(ctx, rotr, t1, hi(dst), 16);
+ emit(ctx, rotr, hi(dst), lo(dst), 16);
+ emit(ctx, wsbh, lo(dst), t1);
+ emit(ctx, wsbh, hi(dst), hi(dst));
+ } else {
+ SWAP16(ctx, t1, lo(dst), t2);
+ SWAP16(ctx, lo(dst), hi(dst), t2);
+ emit(ctx, addiu, hi(dst), t1, 0);
+
+ MASK8(ctx, t1);
+ SWAP8(ctx, lo(dst), lo(dst), t1, t2);
+ SWAP8(ctx, hi(dst), hi(dst), t1, t2);
+ }
+ clobber_reg64(ctx, dst);
+ break;
+
+ case 32:
+ if (cpu_has_mips32r2) {
+ emit(ctx, rotr, lo(dst), lo(dst), 16);
+ emit(ctx, wsbh, lo(dst), lo(dst));
+ } else {
+ SWAP16(ctx, lo(dst), lo(dst), t2);
+ MASK8(ctx, t1);
+ SWAP8(ctx, lo(dst), lo(dst), t1, t2);
+ }
+ clobber_reg(ctx, lo(dst));
+ break;
+
+ case 16:
+ if (cpu_has_mips32r2) {
+ emit(ctx, wsbh, lo(dst), lo(dst));
+ } else {
+ emit(ctx, andi, t1, lo(dst), 0xff00);
+ emit(ctx, srl, t1, t1, 8);
+ emit(ctx, andi, lo(dst), lo(dst), 0x00ff);
+ emit(ctx, sll, lo(dst), lo(dst), 8);
+ emit(ctx, or, lo(dst), lo(dst), t1);
+ }
+ clobber_reg(ctx, lo(dst));
+ break;
+ }
+}
+
+/* Zero-extend imm bits of dst */
+static inline void emit_zext_i64(struct jit_context *ctx,
+ const u8 dst[], u32 imm)
+{
+ switch (imm) {
+ case 64:
+ break;
+
+ case 32:
+ emit_zext(ctx, hi(dst));
+ break;
+
+ case 16:
+ emit_zext(ctx, hi(dst));
+ emit(ctx, andi, lo(dst), lo(dst), 0xffff);
+ clobber_reg(ctx, lo(dst));
+ break;
+ }
+}
+
+/* Load operation: dst = *(size*)(src + off) */
+static inline void emit_ldx_r(struct jit_context *ctx,
+ const u8 dst[], u8 src, s16 off, u8 size)
+{
+ switch (size) {
+ /* Load a byte */
+ case BPF_B:
+ emit(ctx, lbu, lo(dst), off, src);
+ clobber_reg(ctx, lo(dst));
+ break;
+ /* Load a half word */
+ case BPF_H:
+ emit(ctx, lhu, lo(dst), off, src);
+ clobber_reg(ctx, lo(dst));
+ break;
+ /* Load a word */
+ case BPF_W:
+ emit(ctx, lw, lo(dst), off, src);
+ clobber_reg(ctx, lo(dst));
+ break;
+ /* Load a double word */
+ case BPF_DW:
+ emit(ctx, lw, dst[1], off, src);
+ emit(ctx, lw, dst[0], off + 4, src);
+ clobber_reg64(ctx, dst);
+ break;
+ }
+}
+
+/* Store operation: *(size *)(dst + off) = src */
+static inline void emit_stx_r(struct jit_context *ctx,
+ const u8 dst, const u8 src[], s16 off, u8 size)
+{
+ switch (size) {
+ /* Store a byte */
+ case BPF_B:
+ emit(ctx, sb, lo(src), off, dst);
+ break;
+ /* Store a half word */
+ case BPF_H:
+ emit(ctx, sh, lo(src), off, dst);
+ break;
+ /* Store a word */
+ case BPF_W:
+ emit(ctx, sw, lo(src), off, dst);
+ break;
+ /* Store a double word */
+ case BPF_DW:
+ emit(ctx, sw, src[1], off, dst);
+ emit(ctx, sw, src[0], off + 4, dst);
+ break;
+ }
+}
+
+/* Atomic read-modify-write */
+static inline void emit_atomic_r(struct jit_context *ctx,
+ u8 dst, u8 src, s16 off, u8 code)
+{
+ u8 t1 = bpf2mips32[JIT_REG_T1][0];
+ u8 t2 = bpf2mips32[JIT_REG_T1][1];
+
+ emit(ctx, ll, t1, off, dst);
+ switch (code) {
+ case BPF_ADD:
+ case BPF_ADD | BPF_FETCH:
+ emit(ctx, addu, t2, t1, src);
+ break;
+ case BPF_SUB:
+ case BPF_SUB | BPF_FETCH:
+ emit(ctx, subu, t2, t1, src);
+ break;
+ case BPF_OR:
+ case BPF_OR | BPF_FETCH:
+ emit(ctx, or, t2, t1, src);
+ break;
+ case BPF_AND:
+ case BPF_AND | BPF_FETCH:
+ emit(ctx, and, t2, t1, src);
+ break;
+ case BPF_XOR:
+ case BPF_XOR | BPF_FETCH:
+ emit(ctx, xor, t2, t1, src);
+ break;
+ case BPF_XCHG:
+ emit(ctx, addiu, t2, src, 0);
+ break;
+ }
+ emit(ctx, sc, t2, off, dst);
+ emit(ctx, beqz, t2, -16);
+ if (code & BPF_FETCH) {
+ emit(ctx, addiu, src, t1, 0);
+ clobber_reg(ctx, src);
+ } else {
+ emit(ctx, nop); /* Delay slot */
+ }
+}
+
+/* Atomic read-modify-write (64-bit) */
+static inline void emit_atomic_r64(struct jit_context *ctx,
+ u8 dst, const u8 src[], s16 off, u8 code)
+{
+ const u8 *r0 = bpf2mips32[BPF_REG_0]; /* Mapped to v0-v1 */
+ const u8 *r1 = bpf2mips32[BPF_REG_1]; /* Mapped to a0-a1 */
+ int tmp = bpf2mips32[JIT_REG_T1][0];
+ u32 exclude = 0;
+ u32 addr = 0;
+
+ /* Push caller-saved registers on stack */
+ push_regs(ctx, ctx->clobbered & JIT_CALLER_REGS,
+ 0, JIT_RESERVED_STACK);
+ /*
+ * Argument 1: 64-bit src, passed in registers a0-a1
+ * Argument 2: 32-bit dst+off, passed in register a2
+ */
+ emit(ctx, addiu, tmp, dst, 0);
+ emit(ctx, addiu, r1[0], src[0], 0);
+ emit(ctx, addiu, r1[1], src[1], 0);
+ emit(ctx, addiu, MIPS_R_A2, tmp, off);
+
+ /* Emit function call */
+ switch (code) {
+ case BPF_ADD:
+ addr = (u32)&atomic64_add;
+ break;
+ case BPF_ADD | BPF_FETCH:
+ addr = (u32)&atomic64_fetch_add;
+ break;
+ case BPF_SUB:
+ addr = (u32)&atomic64_sub;
+ break;
+ case BPF_SUB | BPF_FETCH:
+ addr = (u32)&atomic64_fetch_sub;
+ break;
+ case BPF_OR:
+ addr = (u32)&atomic64_or;
+ break;
+ case BPF_OR | BPF_FETCH:
+ addr = (u32)&atomic64_fetch_or;
+ break;
+ case BPF_AND:
+ addr = (u32)&atomic64_and;
+ break;
+ case BPF_AND | BPF_FETCH:
+ addr = (u32)&atomic64_fetch_and;
+ break;
+ case BPF_XOR:
+ addr = (u32)&atomic64_xor;
+ break;
+ case BPF_XOR | BPF_FETCH:
+ addr = (u32)&atomic64_fetch_xor;
+ break;
+ case BPF_XCHG:
+ addr = (u32)&jit_xchg64;
+ break;
+ }
+ emit_mov_i(ctx, tmp, addr);
+ emit(ctx, jalr, MIPS_R_RA, tmp);
+ emit(ctx, nop); /* Delay slot */
+
+ /* Update src register with old value, if specified */
+ if (code & BPF_FETCH) {
+ emit(ctx, addiu, lo(src), lo(r0), 0);
+ emit(ctx, addiu, hi(src), hi(r0), 0);
+ exclude = BIT(src[0]) | BIT(src[1]);
+ clobber_reg64(ctx, src);
+ }
+
+ /* Restore caller-saved registers, except any fetched value */
+ pop_regs(ctx, ctx->clobbered & JIT_CALLER_REGS,
+ exclude, JIT_RESERVED_STACK);
+ clobber_reg(ctx, MIPS_R_RA);
+}
+
+/* Atomic compare-and-exchange */
+static inline void emit_cmpxchg_r(struct jit_context *ctx,
+ u8 dst, u8 src, s16 off)
+{
+ const u8 *r0 = bpf2mips32[BPF_REG_0];
+ u8 t1 = bpf2mips32[JIT_REG_T1][0];
+ u8 t2 = bpf2mips32[JIT_REG_T1][1];
+
+ emit(ctx, ll, t1, off, dst);
+ emit(ctx, bne, t1, lo(r0), 12);
+ emit(ctx, addiu, t2, src, 0); /* Delay slot */
+ emit(ctx, sc, t2, off, dst);
+ emit(ctx, beqz, t2, -20);
+ emit(ctx, addiu, lo(r0), t1, 0);
+ emit(ctx, addiu, hi(r0), MIPS_R_ZERO, 0);
+
+ clobber_reg64(ctx, r0);
+}
+
+/* Atomic compare-and-exchange (64-bit) */
+static inline void emit_cmpxchg_r64(struct jit_context *ctx,
+ u8 dst, const u8 src[], s16 off)
+{
+ const u8 *r0 = bpf2mips32[BPF_REG_0];
+ const u8 *r2 = bpf2mips32[BPF_REG_2];
+ u8 tmp = bpf2mips32[JIT_REG_T1][0];
+
+ /* Push caller-saved registers on stack */
+ push_regs(ctx, ctx->clobbered & JIT_CALLER_REGS,
+ JIT_RETURN_REGS, JIT_RESERVED_STACK + 2 * sizeof(u32));
+ /*
+ * Argument 1: 32-bit dst+off, passed in register a0 (a1 unused)
+ * Argument 2: 64-bit r0, passed in registers a2-a3
+ * Argument 3: 64-bit src, passed on stack
+ */
+ push_regs(ctx, BIT(src[0]) | BIT(src[1]), 0, JIT_RESERVED_STACK);
+ emit(ctx, addiu, tmp, dst, off);
+ emit(ctx, addiu, r2[0], r0[0], 0);
+ emit(ctx, addiu, r2[1], r0[1], 0);
+ emit(ctx, addiu, MIPS_R_A0, tmp, 0);
+
+ /* Emit function call */
+ emit_mov_i(ctx, tmp, (u32)&atomic64_cmpxchg);
+ emit(ctx, jalr, MIPS_R_RA, tmp);
+ emit(ctx, nop); /* Delay slot */
+
+ /* Restore caller-saved registers, except the return value */
+ pop_regs(ctx, ctx->clobbered & JIT_CALLER_REGS,
+ JIT_RETURN_REGS, JIT_RESERVED_STACK + 2 * sizeof(u32));
+ clobber_reg(ctx, MIPS_R_V0);
+ clobber_reg(ctx, MIPS_R_V1);
+ clobber_reg(ctx, MIPS_R_RA);
+}
+
+/* Invert a conditional jump operation */
+static inline u8 invert_jmp(u8 op)
+{
+ switch (op) {
+ case BPF_JEQ: return BPF_JNE;
+ case BPF_JNE: return BPF_JEQ;
+ case BPF_JSET: return JIT_JNSET;
+ case BPF_JGT: return BPF_JLE;
+ case BPF_JGE: return BPF_JLT;
+ case BPF_JLT: return BPF_JGE;
+ case BPF_JLE: return BPF_JGT;
+ case BPF_JSGT: return BPF_JSLE;
+ case BPF_JSGE: return BPF_JSLT;
+ case BPF_JSLT: return BPF_JSGE;
+ case BPF_JSLE: return BPF_JSGT;
+ }
+ return 0;
+}
+
+/* Prepare a PC-relative jump operation */
+static inline void setup_jmp(struct jit_context *ctx,
+ u8 bpf_op, s16 bpf_off,
+ u8 *jit_op, s16 *jit_off)
+{
+ struct jit_desc *desc = &ctx->descriptors[ctx->bpf_index];
+ int offset = 0;
+ int op = bpf_op;
+
+ /* Do not compute offsets on the first pass */
+ if (desc->offset == 0)
+ goto done;
+ /*
+ * Current ctx->jit_index points to the start of the branch preamble.
+ * Since the preamble differs among different branch conditionals,
+ * the current index cannot be used to compute the branch offset.
+ * Instead, we use the offset table value for the next instruction,
+ * which gives the index immediately after the branch delay slot.
+ */
+ if (!desc->convert) {
+ int origin = ctx->bpf_index + 1;
+ int target = ctx->bpf_index + bpf_off + 1;
+ offset = (ctx->descriptors[target].offset -
+ ctx->descriptors[origin].offset) * sizeof(u32);
+ }
+
+ /*
+ * The PC-relative branch offset field on MIPS is 18 bits signed,
+ * so if the computed offset is larger than this we generate a an
+ * absolute jump that we skip with an inverted conditional branch.
+ */
+ if (desc->convert || is_18bit(offset)) {
+ offset = 2 * sizeof(u32);
+ op = invert_jmp(bpf_op);
+ ctx->changes += !desc->convert;
+ desc->convert = true;
+ }
+
+done:
+ *jit_off = offset;
+ *jit_op = op;
+}
+
+/* Finish a PC-relative jump operation */
+static inline int finish_jmp(struct jit_context *ctx, s16 bpf_off)
+{
+ struct jit_desc *desc = &ctx->descriptors[ctx->bpf_index];
+
+ /*
+ * Add an absolute long jump with delay slot,
+ * if the PC-relative branch was converted.
+ */
+ if (desc->convert) {
+ int target = get_target(ctx, ctx->bpf_index + bpf_off + 1);
+ if (target < 0)
+ return -1;
+ emit(ctx, j, target);
+ emit(ctx, nop);
+ }
+ return 0;
+}
+
+/* Jump immediate */
+static inline void emit_jmp_i(struct jit_context *ctx,
+ u8 dst, s16 imm, s16 off, u8 op)
+{
+ u8 tmp = bpf2mips32[JIT_REG_T1][0];
+
+ switch (op) {
+ /* PC += off if dst == imm */
+ case BPF_JEQ:
+ emit(ctx, addiu, tmp, dst, -imm);
+ emit(ctx, beqz, tmp, off);
+ break;
+ /* PC += off if dst != imm */
+ case BPF_JNE:
+ emit(ctx, addiu, tmp, dst, -imm);
+ emit(ctx, bnez, tmp, off);
+ break;
+ /* PC += off if dst & imm */
+ case BPF_JSET:
+ emit(ctx, andi, tmp, dst, (u16)imm);
+ emit(ctx, bnez, tmp, off);
+ break;
+ /* PC += off if (dst & imm) == 0 (not in BPF, used for long jumps) */
+ case JIT_JNSET:
+ emit(ctx, andi, tmp, dst, (u16)imm);
+ emit(ctx, beqz, tmp, off);
+ break;
+ /* PC += off if dst > imm */
+ case BPF_JGT:
+ emit(ctx, addiu, tmp, MIPS_R_ZERO, imm);
+ emit(ctx, sltu, tmp, tmp, dst);
+ emit(ctx, bnez, tmp, off);
+ break;
+ /* PC += off if dst >= imm */
+ case BPF_JGE:
+ emit(ctx, addiu, tmp, MIPS_R_ZERO, imm);
+ emit(ctx, sltu, tmp, dst, tmp);
+ emit(ctx, beqz, tmp, off);
+ break;
+ /* PC += off if dst < imm */
+ case BPF_JLT:
+ emit(ctx, addiu, tmp, MIPS_R_ZERO, imm);
+ emit(ctx, sltu, tmp, dst, tmp);
+ emit(ctx, bnez, tmp, off);
+ break;
+ /* PC += off if dst <= imm */
+ case BPF_JLE:
+ emit(ctx, addiu, tmp, MIPS_R_ZERO, imm);
+ emit(ctx, sltu, tmp, tmp, dst);
+ emit(ctx, beqz, tmp, off);
+ break;
+ /* PC += off if dst > imm (signed) */
+ case BPF_JSGT:
+ emit(ctx, addiu, tmp, dst, -imm);
+ emit(ctx, bgtz, tmp, off);
+ break;
+ /* PC += off if dst >= imm (signed) */
+ case BPF_JSGE:
+ emit(ctx, addiu, tmp, dst, -imm);
+ emit(ctx, bgez, tmp, off);
+ break;
+ /* PC += off if dst < imm (signed) */
+ case BPF_JSLT:
+ emit(ctx, addiu, tmp, dst, -imm);
+ emit(ctx, bltz, tmp, off);
+ break;
+ /* PC += off if dst <= imm (signed) */
+ case BPF_JSLE:
+ emit(ctx, addiu, tmp, dst, -imm);
+ emit(ctx, blez, tmp, off);
+ break;
+ }
+
+ emit(ctx, nop); /* Delay slot */
+}
+
+/* Jump register */
+static inline void emit_jmp_r(struct jit_context *ctx,
+ u8 dst, u8 src, s16 off, u8 op)
+{
+ u8 tmp = bpf2mips32[JIT_REG_T1][0];
+
+ switch (op) {
+ /* PC += off if dst == src */
+ case BPF_JEQ:
+ emit(ctx, subu, tmp, dst, src);
+ emit(ctx, beqz, tmp, off);
+ break;
+ /* PC += off if dst != src */
+ case BPF_JNE:
+ emit(ctx, subu, tmp, dst, src);
+ emit(ctx, bnez, tmp, off);
+ break;
+ /* PC += off if dst & src */
+ case BPF_JSET:
+ emit(ctx, and, tmp, dst, src);
+ emit(ctx, bnez, tmp, off);
+ break;
+ /* PC += off if (dst & imm) == 0 (not in BPF, used for long jumps) */
+ case JIT_JNSET:
+ emit(ctx, and, tmp, dst, src);
+ emit(ctx, beqz, tmp, off);
+ break;
+ /* PC += off if dst > src */
+ case BPF_JGT:
+ emit(ctx, sltu, tmp, src, dst);
+ emit(ctx, bnez, tmp, off);
+ break;
+ /* PC += off if dst >= src */
+ case BPF_JGE:
+ emit(ctx, sltu, tmp, dst, src);
+ emit(ctx, beqz, tmp, off);
+ break;
+ /* PC += off if dst < src */
+ case BPF_JLT:
+ emit(ctx, sltu, tmp, dst, src);
+ emit(ctx, bnez, tmp, off);
+ break;
+ /* PC += off if dst <= src */
+ case BPF_JLE:
+ emit(ctx, sltu, tmp, src, dst);
+ emit(ctx, beqz, tmp, off);
+ break;
+ /* PC += off if dst > src (signed) */
+ case BPF_JSGT:
+ emit(ctx, subu, tmp, dst, src);
+ emit(ctx, bgtz, tmp, off);
+ break;
+ /* PC += off if dst >= src (signed) */
+ case BPF_JSGE:
+ emit(ctx, subu, tmp, dst, src);
+ emit(ctx, bgez, tmp, off);
+ break;
+ /* PC += off if dst < src (signed) */
+ case BPF_JSLT:
+ emit(ctx, subu, tmp, dst, src);
+ emit(ctx, bltz, tmp, off);
+ break;
+ /* PC += off if dst <= src (signed) */
+ case BPF_JSLE:
+ emit(ctx, subu, tmp, dst, src);
+ emit(ctx, blez, tmp, off);
+ break;
+ }
+
+ emit(ctx, nop); /* Delay slot */
+}
+
+/* Jump register (64-bit) */
+static inline void emit_jmp_r64(struct jit_context *ctx,
+ const u8 dst[], const u8 src[], s16 off, u8 op)
+{
+ u8 t1 = bpf2mips32[JIT_REG_T1][0];
+ u8 t2 = bpf2mips32[JIT_REG_T1][1];
+
+ switch (op) {
+ /* PC += off if dst == src */
+ /* PC += off if dst != src */
+ case BPF_JEQ:
+ case BPF_JNE:
+ emit(ctx, subu, t1, lo(dst), lo(src));
+ emit(ctx, subu, t2, hi(dst), hi(src));
+ emit(ctx, or, t1, t1, t2);
+ if (op == BPF_JEQ)
+ emit(ctx, beqz, t1, off);
+ else
+ emit(ctx, bnez, t1, off);
+ break;
+ /* PC += off if dst & src */
+ /* PC += off if (dst & imm) == 0 (not in BPF, used for long jumps) */
+ case BPF_JSET:
+ case JIT_JNSET:
+ emit(ctx, and, t1, lo(dst), lo(src));
+ emit(ctx, and, t2, hi(dst), hi(src));
+ emit(ctx, or, t1, t1, t2);
+ if (op == BPF_JSET)
+ emit(ctx, bnez, t1, off);
+ else
+ emit(ctx, beqz, t1, off);
+ break;
+ /* PC += off if dst > src */
+ /* PC += off if dst <= src */
+ case BPF_JGT:
+ case BPF_JLE:
+ emit(ctx, sltu, t1, lo(src), lo(dst)); /* t1 = sl < dl */
+ emit(ctx, subu, t2, hi(src), hi(dst)); /* t2 = sh - dh */
+ emit(ctx, movn, t1, MIPS_R_ZERO, t2); /* t1 = 0 if t2 != 0 */
+ emit(ctx, sltu, t2, hi(src), hi(dst)); /* t2 = sh < dh */
+ emit(ctx, or, t1, t1, t2); /* t1 = t1 | t2 */
+ if (op == BPF_JGT)
+ emit(ctx, bnez, t1, off);
+ else
+ emit(ctx, beqz, t1, off);
+ break;
+ /* PC += off if dst >= src */
+ /* PC += off if dst < src */
+ case BPF_JLT:
+ case BPF_JGE:
+ emit(ctx, sltu, t1, lo(dst), lo(src)); /* t1 = dl < sl */
+ emit(ctx, subu, t2, hi(dst), hi(src)); /* t2 = dh - sh */
+ emit(ctx, movn, t1, MIPS_R_ZERO, t2); /* t1 = 0 if t2 != 0 */
+ emit(ctx, sltu, t2, hi(dst), hi(src)); /* t2 = dh < sh */
+ emit(ctx, or, t1, t1, t2); /* t1 = t1 | t2 */
+ if (op == BPF_JLT)
+ emit(ctx, bnez, t1, off);
+ else
+ emit(ctx, beqz, t1, off);
+ break;
+ /* PC += off if dst > src (signed) */
+ /* PC += off if dst <= src (signed) */
+ case BPF_JSGT:
+ case BPF_JSLE:
+ emit(ctx, sltu, t1, lo(src), lo(dst)); /* t1 = sl < dl */
+ emit(ctx, subu, t2, hi(src), hi(dst)); /* t2 = sh - dh */
+ emit(ctx, subu, t2, t2, t1); /* t2 = t2 - t1 */
+ emit(ctx, srl, t2, t2, 31); /* t2 = t2 >> 31 */
+ if (op == BPF_JSGT)
+ emit(ctx, bnez, t2, off);
+ else
+ emit(ctx, beqz, t2, off);
+ break;
+ /* PC += off if dst < src (signed) */
+ /* PC += off if dst >= src (signed) */
+ case BPF_JSLT:
+ case BPF_JSGE:
+ emit(ctx, sltu, t1, lo(dst), lo(src)); /* t1 = sl < sl */
+ emit(ctx, subu, t2, hi(dst), hi(src)); /* t2 = sh - sh */
+ emit(ctx, subu, t2, t2, t1); /* t2 = t2 - t1 */
+ emit(ctx, srl, t2, t2, 31); /* t2 = t2 >> 31 */
+ if (op == BPF_JSLT)
+ emit(ctx, bnez, t2, off);
+ else
+ emit(ctx, beqz, t2, off);
+ break;
+ }
+
+ emit(ctx, nop); /* Delay slot */
+}
+
+/* Jump always */
+static inline int emit_ja(struct jit_context *ctx, s16 off)
+{
+ int target = get_target(ctx, ctx->bpf_index + off + 1);
+
+ if (target < 0)
+ return -1;
+ emit(ctx, j, target);
+ emit(ctx, nop);
+ return 0;
+}
+
+/* Jump to epilogue */
+static inline int emit_exit(struct jit_context *ctx)
+{
+ int target = get_target(ctx, ctx->program->len);
+
+ if (target < 0)
+ return -1;
+ emit(ctx, j, target);
+ emit(ctx, nop);
+ return 0;
+}
+
+/* Function call */
+static inline int emit_call(struct jit_context *ctx,
+ const struct bpf_insn *insn)
+{
+ u8 tmp = bpf2mips32[JIT_REG_T1][0];
+ u64 addr;
+ bool unused;
+
+ /* Decode the call address */
+ if (bpf_jit_get_func_addr(ctx->program, insn, ctx->target == NULL,
+ &addr, &unused) < 0)
+ return -1;
+
+ /* Push stack arguments */
+ push_regs(ctx, JIT_STACK_REGS, 0, JIT_RESERVED_STACK);
+
+ /* Emit function call */
+ emit_mov_i(ctx, tmp, addr);
+ emit(ctx, jalr, MIPS_R_RA, tmp);
+ emit(ctx, nop); /* Delay slot */
+
+ clobber_reg(ctx, MIPS_R_RA);
+ clobber_reg(ctx, MIPS_R_V0);
+ clobber_reg(ctx, MIPS_R_V1);
+ return 0;
+}
+
+/* Function tail call */
+static inline int emit_tail_call(struct jit_context *ctx)
+{
+ u8 ary = lo(bpf2mips32[BPF_REG_2]);
+ u8 ind = lo(bpf2mips32[BPF_REG_3]);
+ u8 t1 = bpf2mips32[JIT_REG_T1][0];
+ u8 t2 = bpf2mips32[JIT_REG_T1][1];
+ int off;
+
+ /*
+ * Tail call:
+ * eBPF R1 - function argument (context ptr), passed in a0-a1
+ * eBPF R2 - ptr to object with array of function entry points
+ * eBPF R3 - array index of function to be called
+ * stack[sz] - remaining tail call count, initialized in prologue
+ */
+
+ /* if (ind >= ary->map.max_entries) goto out */
+ off = offsetof(struct bpf_array, map.max_entries);
+ if (off > 0x7fff)
+ return -1;
+ emit(ctx, lw, t1, off, ary); /* t1 = ary->map.max_entries*/
+ emit(ctx, sltu, t1, ind, t1); /* t1 = ind < t1 */
+ emit(ctx, beqz, t1, get_offset(ctx, 1)); /* PC += off(1) if t1 == 0 */
+ /* (next insn delay slot) */
+ /* if (TCC-- < 0) goto out */
+ emit(ctx, lw, t2, ctx->stack_size, MIPS_R_SP); /* t2 = *(SP + size) */
+ emit(ctx, bltz, t2, get_offset(ctx, 1)); /* PC += off(1) if t2 < 0 */
+ emit(ctx, subu, t2, t2, 1); /* t2-- (delay slot) */
+ emit(ctx, sw, t2, ctx->stack_size, MIPS_R_SP); /* *(SP + size) = t2 */
+
+ /* prog = ary->ptrs[ind] */
+ off = offsetof(struct bpf_array, ptrs);
+ if (off > 0x7fff)
+ return -1;
+ emit(ctx, sll, t1, ind, 2); /* t1 = ind << 2 */
+ emit(ctx, addu, t1, t1, ary); /* t1 += ary */
+ emit(ctx, lw, t2, off, t1); /* t2 = *(t1 + off) */
+
+ /* if (prog == 0) goto out */
+ emit(ctx, beqz, t2, get_offset(ctx, 1)); /* PC += off(1) if t2 == 0 */
+ emit(ctx, nop); /* Delay slot */
+
+ /* func = prog->bpf_func + 8 (prologue skip offset) */
+ off = offsetof(struct bpf_prog, bpf_func);
+ if (off > 0x7fff)
+ return -1;
+ emit(ctx, lw, t1, off, t2); /* t1 = *(t2 + off) */
+ emit(ctx, addiu, t1, t1, JIT_TCALL_SKIP); /* t1 += skip (8 or 12) */
+
+ /* goto func */
+ build_epilogue(ctx, t1);
+ return 0;
+}
+
+/*
+ * Convert an eBPF instruction to native instruction, i.e
+ * JITs an eBPF instruction.
+ * Returns :
+ * 0 - Successfully JITed an 8-byte eBPF instruction
+ * >0 - Successfully JITed a 16-byte eBPF instruction
+ * <0 - Failed to JIT.
+ */
+static int build_insn(const struct bpf_insn *insn, struct jit_context *ctx)
+{
+ u8 code = insn->code;
+ const u8 *dst = bpf2mips32[insn->dst_reg];
+ const u8 *src = bpf2mips32[insn->src_reg];
+ const u8 *tmp = bpf2mips32[JIT_REG_T0];
+ s16 off = insn->off;
+ s32 imm = insn->imm;
+ s16 rel;
+ u8 jmp;
+
+ switch (code) {
+ /* ALU operations */
+ /* dst = imm */
+ case BPF_ALU | BPF_MOV | BPF_K:
+ emit_mov_i(ctx, lo(dst), imm);
+ emit_zext(ctx, hi(dst));
+ break;
+ /* dst = src */
+ case BPF_ALU | BPF_MOV | BPF_X:
+ if (imm == 1) {
+ /* Special mov32 for zext */
+ emit_mov_i(ctx, hi(dst), 0);
+ } else {
+ emit_mov_r(ctx, lo(dst), lo(src));
+ emit_zext(ctx, hi(dst));
+ }
+ break;
+ /* dst = imm */
+ case BPF_ALU64 | BPF_MOV | BPF_K:
+ emit_mov_se_i64(ctx, dst, imm);
+ break;
+ /* dst = src */
+ case BPF_ALU64 | BPF_MOV | BPF_X:
+ emit_mov_r(ctx, lo(dst), lo(src));
+ emit_mov_r(ctx, hi(dst), hi(src));
+ break;
+ /* dst = dst + imm */
+ /* dst = dst - imm */
+ /* dst = dst * imm */
+ case BPF_ALU | BPF_ADD | BPF_K:
+ case BPF_ALU | BPF_SUB | BPF_K:
+ case BPF_ALU | BPF_MUL | BPF_K:
+ if (is_16bit(imm)) {
+ emit_alu_i(ctx, lo(dst), imm, BPF_OP(code));
+ } else {
+ emit_mov_i(ctx, tmp[0], imm);
+ emit_alu_r(ctx, lo(dst), tmp[0], BPF_OP(code));
+ }
+ emit_zext(ctx, hi(dst));
+ break;
+ /* dst = dst | imm */
+ /* dst = dst & imm */
+ /* dst = dst ^ imm */
+ case BPF_ALU | BPF_OR | BPF_K:
+ case BPF_ALU | BPF_AND | BPF_K:
+ case BPF_ALU | BPF_XOR | BPF_K:
+ if ((u32)imm <= 0xffff) {
+ emit_alu_i(ctx, lo(dst), imm, BPF_OP(code));
+ } else {
+ emit_mov_i(ctx, tmp[0], imm);
+ emit_alu_r(ctx, lo(dst), tmp[0], BPF_OP(code));
+ }
+ emit_zext(ctx, hi(dst));
+ break;
+ /* dst = dst << imm */
+ /* dst = dst >> imm */
+ /* dst = dst >> imm (signed) */
+ case BPF_ALU | BPF_LSH | BPF_K:
+ case BPF_ALU | BPF_RSH | BPF_K:
+ case BPF_ALU | BPF_ARSH | BPF_K:
+ if (unlikely(imm > 31))
+ return -EINVAL;
+ if (imm)
+ emit_alu_i(ctx, lo(dst), imm, BPF_OP(code));
+ emit_zext(ctx, hi(dst));
+ break;
+ /* dst = dst + src */
+ /* dst = dst - src */
+ /* dst = dst | src */
+ /* dst = dst & src */
+ /* dst = dst ^ src */
+ /* dst = dst * src */
+ /* dst = dst << src */
+ /* dst = dst >> src */
+ case BPF_ALU | BPF_ADD | BPF_X:
+ case BPF_ALU | BPF_SUB | BPF_X:
+ case BPF_ALU | BPF_OR | BPF_X:
+ case BPF_ALU | BPF_AND | BPF_X:
+ case BPF_ALU | BPF_XOR | BPF_X:
+ case BPF_ALU | BPF_MUL | BPF_X:
+ case BPF_ALU | BPF_LSH | BPF_X:
+ case BPF_ALU | BPF_RSH | BPF_X:
+ case BPF_ALU | BPF_ARSH | BPF_X:
+ emit_alu_r(ctx, lo(dst), lo(src), BPF_OP(code));
+ emit_zext(ctx, hi(dst));
+ break;
+ /* dst = dst + imm */
+ /* dst = dst - imm */
+ /* dst = dst | imm */
+ /* dst = dst & imm */
+ /* dst = dst ^ imm */
+ case BPF_ALU64 | BPF_ADD | BPF_K:
+ case BPF_ALU64 | BPF_SUB | BPF_K:
+ case BPF_ALU64 | BPF_OR | BPF_K:
+ case BPF_ALU64 | BPF_AND | BPF_K:
+ case BPF_ALU64 | BPF_XOR | BPF_K:
+ /*
+ * Sign-extend the immediate value into a temporary register,
+ * and then do the operation on this register.
+ */
+ emit_mov_se_i64(ctx, tmp, imm);
+ emit_alu_r64(ctx, dst, tmp, BPF_OP(code));
+ break;
+ /* dst = dst + src */
+ /* dst = dst - src */
+ /* dst = dst | src */
+ /* dst = dst & src */
+ /* dst = dst ^ src */
+ case BPF_ALU64 | BPF_ADD | BPF_X:
+ case BPF_ALU64 | BPF_SUB | BPF_X:
+ case BPF_ALU64 | BPF_OR | BPF_X:
+ case BPF_ALU64 | BPF_AND | BPF_X:
+ case BPF_ALU64 | BPF_XOR | BPF_X:
+ emit_alu_r64(ctx, dst, src, BPF_OP(code));
+ break;
+ /* dst = dst << imm */
+ /* dst = dst >> imm */
+ /* dst = dst >> imm (arithmetic) */
+ case BPF_ALU64 | BPF_LSH | BPF_K:
+ case BPF_ALU64 | BPF_RSH | BPF_K:
+ case BPF_ALU64 | BPF_ARSH | BPF_K:
+ if (unlikely(imm > 63))
+ return -EINVAL;
+ if (imm)
+ emit_shift_i64(ctx, dst, imm, BPF_OP(code));
+ break;
+ /* dst = dst << src */
+ /* dst = dst >> src */
+ /* dst = dst >> src (arithmetic) */
+ case BPF_ALU64 | BPF_LSH | BPF_X:
+ case BPF_ALU64 | BPF_RSH | BPF_X:
+ case BPF_ALU64 | BPF_ARSH | BPF_X:
+ emit_shift_r64(ctx, dst, lo(src), BPF_OP(code));
+ break;
+ /* dst = -dst */
+ case BPF_ALU | BPF_NEG:
+ emit_alu_i(ctx, lo(dst), 0, BPF_NEG);
+ emit_zext(ctx, hi(dst));
+ break;
+ /* dst = -dst (64 bit) */
+ case BPF_ALU64 | BPF_NEG:
+ emit_neg_i64(ctx, dst);
+ break;
+ /* dst = dst * src */
+ case BPF_ALU64 | BPF_MUL | BPF_X:
+ emit_mul_r64(ctx, dst, src);
+ break;
+ /* dst = dst * imm */
+ case BPF_ALU64 | BPF_MUL | BPF_K:
+ /*
+ * Sign-extend the immediate value into a temporary register,
+ * and then do the operation on this register.
+ */
+ emit_mov_se_i64(ctx, tmp, imm);
+ emit_mul_r64(ctx, dst, tmp);
+ break;
+ /* dst = dst / src */
+ /* dst = dst % src */
+ case BPF_ALU | BPF_DIV | BPF_X:
+ case BPF_ALU | BPF_MOD | BPF_X:
+ emit_divmod_r(ctx, lo(dst), lo(src), BPF_OP(code));
+ emit_zext(ctx, hi(dst));
+ break;
+ /* dst = dst / src */
+ /* dst = dst % src */
+ case BPF_ALU | BPF_DIV | BPF_K:
+ case BPF_ALU | BPF_MOD | BPF_K:
+ emit_mov_i(ctx, tmp[0], imm);
+ emit_divmod_r(ctx, lo(dst), tmp[0], BPF_OP(code));
+ emit_zext(ctx, hi(dst));
+ break;
+ /* dst = dst / src (64 bit) */
+ /* dst = dst % src (64 bit) */
+ case BPF_ALU64 | BPF_DIV | BPF_X:
+ case BPF_ALU64 | BPF_MOD | BPF_X:
+ emit_divmod_r64(ctx, dst, src, BPF_OP(code));
+ break;
+ /* dst = dst / imm (64 bit) */
+ /* dst = dst % imm (64 bit) */
+ case BPF_ALU64 | BPF_DIV | BPF_K:
+ case BPF_ALU64 | BPF_MOD | BPF_K:
+ /*
+ * Sign-extend the immediate value into a temporary register,
+ * and then do the operation on this register.
+ */
+ emit_mov_se_i64(ctx, tmp, imm);
+ emit_divmod_r64(ctx, dst, tmp, BPF_OP(code));
+ break;
+ /* dst = htole(dst) */
+ /* dst = htobe(dst) */
+ case BPF_ALU | BPF_END | BPF_FROM_LE:
+ case BPF_ALU | BPF_END | BPF_FROM_BE:
+ if (BPF_SRC(code) ==
+#ifdef __BIG_ENDIAN
+ BPF_FROM_LE
+#else
+ BPF_FROM_BE
+#endif
+ )
+ emit_bswap_i64(ctx, dst, imm);
+ emit_zext_i64(ctx, dst, imm);
+ break;
+ /* dst = imm64 */
+ case BPF_LD | BPF_IMM | BPF_DW:
+ emit_mov_i(ctx, lo(dst), imm);
+ emit_mov_i(ctx, hi(dst), insn[1].imm);
+ return 1;
+ /* LDX: dst = *(size *)(src + off) */
+ case BPF_LDX | BPF_MEM | BPF_W:
+ case BPF_LDX | BPF_MEM | BPF_H:
+ case BPF_LDX | BPF_MEM | BPF_B:
+ case BPF_LDX | BPF_MEM | BPF_DW:
+ emit_ldx_r(ctx, dst, lo(src), off, BPF_SIZE(code));
+ break;
+ /* ST: *(size *)(dst + off) = imm */
+ case BPF_ST | BPF_MEM | BPF_W:
+ case BPF_ST | BPF_MEM | BPF_H:
+ case BPF_ST | BPF_MEM | BPF_B:
+ case BPF_ST | BPF_MEM | BPF_DW:
+ switch (BPF_SIZE(code)) {
+ case BPF_DW:
+ /* Sign-extend immediate value into temporary reg */
+ emit_mov_se_i64(ctx, tmp, imm);
+ break;
+ case BPF_W:
+ case BPF_H:
+ case BPF_B:
+ emit_mov_i(ctx, lo(tmp), imm);
+ break;
+ }
+ emit_stx_r(ctx, lo(dst), tmp, off, BPF_SIZE(code));
+ break;
+ /* STX: *(size *)(dst + off) = src */
+ case BPF_STX | BPF_MEM | BPF_W:
+ case BPF_STX | BPF_MEM | BPF_H:
+ case BPF_STX | BPF_MEM | BPF_B:
+ case BPF_STX | BPF_MEM | BPF_DW:
+ emit_stx_r(ctx, lo(dst), src, off, BPF_SIZE(code));
+ break;
+ /* Atomics */
+ case BPF_STX | BPF_XADD | BPF_W:
+ case BPF_STX | BPF_XADD | BPF_DW:
+ switch (imm) {
+ case BPF_ADD:
+ case BPF_ADD | BPF_FETCH:
+ case BPF_SUB:
+ case BPF_SUB | BPF_FETCH:
+ case BPF_OR:
+ case BPF_OR | BPF_FETCH:
+ case BPF_AND:
+ case BPF_AND | BPF_FETCH:
+ case BPF_XOR:
+ case BPF_XOR | BPF_FETCH:
+ case BPF_XCHG:
+ if (BPF_SIZE(code) == BPF_W)
+ emit_atomic_r(ctx, lo(dst), lo(src), off, imm);
+ else
+ emit_atomic_r64(ctx, lo(dst), src, off, imm);
+ break;
+ case BPF_CMPXCHG:
+ if (BPF_SIZE(code) == BPF_W)
+ emit_cmpxchg_r(ctx, lo(dst), lo(src), off);
+ else
+ emit_cmpxchg_r64(ctx, lo(dst), src, off);
+ break;
+ default:
+ goto notyet;
+ }
+ break;
+ /* PC += off if dst == src */
+ /* PC += off if dst != src */
+ /* PC += off if dst & src */
+ /* PC += off if dst > src */
+ /* PC += off if dst >= src */
+ /* PC += off if dst > src (signed) */
+ /* PC += off if dst >= src (signed) */
+ /* PC += off if dst < src */
+ /* PC += off if dst <= src */
+ /* PC += off if dst < src (signed) */
+ /* PC += off if dst <= src (signed) */
+ case BPF_JMP32 | BPF_JEQ | BPF_X:
+ case BPF_JMP32 | BPF_JNE | BPF_X:
+ case BPF_JMP32 | BPF_JSET | BPF_X:
+ case BPF_JMP32 | BPF_JGT | BPF_X:
+ case BPF_JMP32 | BPF_JGE | BPF_X:
+ case BPF_JMP32 | BPF_JSGT | BPF_X:
+ case BPF_JMP32 | BPF_JSGE | BPF_X:
+ case BPF_JMP32 | BPF_JLE | BPF_X:
+ case BPF_JMP32 | BPF_JLT | BPF_X:
+ case BPF_JMP32 | BPF_JSLT | BPF_X:
+ case BPF_JMP32 | BPF_JSLE | BPF_X:
+ if (off == 0)
+ break;
+ setup_jmp(ctx, BPF_OP(code), off, &jmp, &rel);
+ emit_jmp_r(ctx, lo(dst), lo(src), rel, jmp);
+ if (finish_jmp(ctx, off) < 0)
+ goto toofar;
+ break;
+ /* PC += off if dst == imm */
+ /* PC += off if dst != imm */
+ /* PC += off if dst & imm */
+ /* PC += off if dst > imm */
+ /* PC += off if dst >= imm */
+ /* PC += off if dst > imm (signed) */
+ /* PC += off if dst >= imm (signed) */
+ /* PC += off if dst < imm */
+ /* PC += off if dst <= imm */
+ /* PC += off if dst < imm (signed) */
+ /* PC += off if dst <= imm (signed) */
+ case BPF_JMP32 | BPF_JEQ | BPF_K:
+ case BPF_JMP32 | BPF_JNE | BPF_K:
+ case BPF_JMP32 | BPF_JSET | BPF_K:
+ case BPF_JMP32 | BPF_JGT | BPF_K:
+ case BPF_JMP32 | BPF_JGE | BPF_K:
+ case BPF_JMP32 | BPF_JSGT | BPF_K:
+ case BPF_JMP32 | BPF_JSGE | BPF_K:
+ case BPF_JMP32 | BPF_JLE | BPF_K:
+ case BPF_JMP32 | BPF_JLT | BPF_K:
+ case BPF_JMP32 | BPF_JSLT | BPF_K:
+ case BPF_JMP32 | BPF_JSLE | BPF_K:
+ if (off == 0)
+ break;
+ setup_jmp(ctx, BPF_OP(code), off, &jmp, &rel);
+ if (is_16bit(imm)) {
+ emit_jmp_i(ctx, lo(dst), imm, rel, jmp);
+ } else {
+ /* Move large immediate to register */
+ emit_mov_i(ctx, tmp[0], imm);
+ emit_jmp_r(ctx, lo(dst), tmp[0], rel, jmp);
+ }
+ if (finish_jmp(ctx, off) < 0)
+ goto toofar;
+ break;
+ /* PC += off if dst == src */
+ /* PC += off if dst != src */
+ /* PC += off if dst & src */
+ /* PC += off if dst > src */
+ /* PC += off if dst >= src */
+ /* PC += off if dst > src (signed) */
+ /* PC += off if dst >= src (signed) */
+ /* PC += off if dst < src */
+ /* PC += off if dst <= src */
+ /* PC += off if dst < src (signed) */
+ /* PC += off if dst <= src (signed) */
+ case BPF_JMP | BPF_JEQ | BPF_X:
+ case BPF_JMP | BPF_JNE | BPF_X:
+ case BPF_JMP | BPF_JSET | BPF_X:
+ case BPF_JMP | BPF_JGT | BPF_X:
+ case BPF_JMP | BPF_JGE | BPF_X:
+ case BPF_JMP | BPF_JSGT | BPF_X:
+ case BPF_JMP | BPF_JSGE | BPF_X:
+ case BPF_JMP | BPF_JLE | BPF_X:
+ case BPF_JMP | BPF_JLT | BPF_X:
+ case BPF_JMP | BPF_JSLT | BPF_X:
+ case BPF_JMP | BPF_JSLE | BPF_X:
+ if (off == 0)
+ break;
+ setup_jmp(ctx, BPF_OP(code), off, &jmp, &rel);
+ emit_jmp_r64(ctx, dst, src, rel, jmp);
+ if (finish_jmp(ctx, off) < 0)
+ goto toofar;
+ break;
+ /* PC += off if dst == imm */
+ /* PC += off if dst != imm */
+ /* PC += off if dst & imm */
+ /* PC += off if dst > imm */
+ /* PC += off if dst >= imm */
+ /* PC += off if dst > imm (signed) */
+ /* PC += off if dst >= imm (signed) */
+ /* PC += off if dst < imm */
+ /* PC += off if dst <= imm */
+ /* PC += off if dst < imm (signed) */
+ /* PC += off if dst <= imm (signed) */
+ case BPF_JMP | BPF_JEQ | BPF_K:
+ case BPF_JMP | BPF_JNE | BPF_K:
+ case BPF_JMP | BPF_JSET | BPF_K:
+ case BPF_JMP | BPF_JGT | BPF_K:
+ case BPF_JMP | BPF_JGE | BPF_K:
+ case BPF_JMP | BPF_JSGT | BPF_K:
+ case BPF_JMP | BPF_JSGE | BPF_K:
+ case BPF_JMP | BPF_JLE | BPF_K:
+ case BPF_JMP | BPF_JLT | BPF_K:
+ case BPF_JMP | BPF_JSLT | BPF_K:
+ case BPF_JMP | BPF_JSLE | BPF_K:
+ if (off == 0)
+ break;
+ emit_mov_se_i64(ctx, tmp, imm);
+ setup_jmp(ctx, BPF_OP(code), off, &jmp, &rel);
+ emit_jmp_r64(ctx, dst, tmp, rel, jmp);
+ if (finish_jmp(ctx, off) < 0)
+ goto toofar;
+ break;
+ /* PC += off */
+ case BPF_JMP | BPF_JA:
+ if (off == 0)
+ break;
+ if (emit_ja(ctx, off) < 0)
+ goto toofar;
+ break;
+ /* Tail call */
+ case BPF_JMP | BPF_TAIL_CALL:
+ if (emit_tail_call(ctx) < 0)
+ goto invalid;
+ break;
+ /* Function call */
+ case BPF_JMP | BPF_CALL:
+ if (emit_call(ctx, insn) < 0)
+ goto invalid;
+ break;
+ /* Function return */
+ case BPF_JMP | BPF_EXIT:
+ /*
+ * Optimization: when last instruction is EXIT
+ * simply fallthrough to epilogue.
+ */
+ if (ctx->bpf_index == ctx->program->len - 1)
+ break;
+ if (emit_exit(ctx) < 0)
+ goto toofar;
+ break;
+
+ default:
+invalid:
+ pr_err_once("unknown opcode %02x\n", code);
+ return -EINVAL;
+notyet:
+ pr_info_once("*** NOT YET: opcode %02x ***\n", code);
+ return -EFAULT;
+toofar:
+ pr_info_once("*** TOO FAR: jump at %u opcode %02x ***\n",
+ ctx->bpf_index, code);
+ return -E2BIG;
+ }
+ return 0;
+}
+
+/*
+ * Stack frame layout for a JITed program (stack grows down).
+ *
+ * Higher address : Previous stack frame :
+ * : 64-bit eBPF args r3-r5 :
+ * +===========================+ <--- MIPS sp before call
+ * | Callee-saved registers, |
+ * | including RA and FP |
+ * +---------------------------+ <--- eBPF FP (MIPS zero,fp)
+ * | Local eBPF variables |
+ * | allocated by program |
+ * +---------------------------+
+ * | Reserved for caller-saved |
+ * | registers |
+ * +---------------------------+
+ * | Reserved for 64-bit eBPF |
+ * | args r3-r5 & args passed |
+ * | on stack in kernel calls |
+ * Lower address +===========================+ <--- MIPS sp
+ */
+
+/* Build the program body from eBPF bytecode */
+static int build_body(struct jit_context *ctx)
+{
+ const struct bpf_prog *prog = ctx->program;
+ unsigned int i;
+
+ /* MIPS fp and eBPF R1 (context) are always used */
+ clobber_reg(ctx, MIPS_R_FP);
+ clobber_reg64(ctx, bpf2mips32[BPF_REG_1]);
+
+ for (i = 0; i < prog->len; i++) {
+ const struct bpf_insn *insn = &prog->insnsi[i];
+ struct jit_desc *desc = &ctx->descriptors[i];
+ int ret;
+
+ ctx->bpf_index = i;
+ if (ctx->target == NULL) {
+ ctx->changes += desc->offset != ctx->jit_index;
+ desc->offset = ctx->jit_index;
+ }
+
+ ret = build_insn(insn, ctx);
+ if (ret < 0)
+ return ret;
+
+ if (ret > 0) {
+ i++;
+ if (ctx->target == NULL)
+ desc[1].offset = ctx->jit_index;
+ }
+ }
+
+ /* Store the end offset, where the epilogue begins */
+ ctx->descriptors[prog->len].offset = ctx->jit_index;
+ return 0;
+}
+
+/* Set the branch conversion flag on all instructions */
+static void set_convert_flag(struct jit_context *ctx, bool convert)
+{
+ const struct bpf_prog *prog = ctx->program;
+ unsigned int i;
+
+ for (i = 0; i <= prog->len; i++) {
+ ctx->descriptors[i].convert = convert;
+ }
+}
+
+static void jit_fill_hole(void *area, unsigned int size)
+{
+ u32 *p;
+
+ /* We are guaranteed to have aligned memory. */
+ for (p = area; size >= sizeof(u32); size -= sizeof(u32))
+ uasm_i_break(&p, BRK_BUG); /* Increments p */
+}
+
+bool bpf_jit_needs_zext(void)
+{
+ return true;
+}
+
+struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
+{
+ struct bpf_prog *tmp, *orig_prog = prog;
+ struct bpf_binary_header *header = NULL;
+ struct jit_context ctx;
+ bool tmp_blinded = false;
+ unsigned int tmp_idx;
+ unsigned int image_size;
+ u8 *image_ptr;
+ int tries;
+
+ /*
+ * If BPF JIT was not enabled then we must fall back to
+ * the interpreter.
+ */
+ if (!bpf_jit_enable)
+ return orig_prog;
+ /*
+ * If constant blinding was enabled and we failed during blinding
+ * then we must fall back to the interpreter. Otherwise, we save
+ * the new JITed code.
+ */
+ tmp = bpf_jit_blind_constants(prog);
+ if (IS_ERR(tmp))
+ return orig_prog;
+ if (tmp != prog) {
+ tmp_blinded = true;
+ prog = tmp;
+ }
+
+ memset(&ctx, 0, sizeof(ctx));
+ ctx.program = prog;
+
+ /*
+ * Not able to allocate memory for descriptors[], then
+ * we must fall back to the interpreter
+ */
+ ctx.descriptors = kcalloc(prog->len + 1, sizeof *ctx.descriptors,
+ GFP_KERNEL);
+ if (ctx.descriptors == NULL)
+ goto out_err;
+
+ /* First pass discovers used resources */
+ if (build_body(&ctx) < 0)
+ goto out_err;
+ /*
+ * Second pass computes instruction offsets.
+ * If any PC-relative branches are out of range, a sequence of
+ * a PC-relative branch + a jump is is generated, and we have
+ * to try again from the beginning to generate the new offsets.
+ * This is done until no additional conversions are necessary.
+ * The last two iterations are done with all branches being
+ * converted, to guarantee offset table convergence within a
+ * fixed number of iterations.
+ */
+ ctx.jit_index = 0;
+ build_prologue(&ctx);
+ tmp_idx = ctx.jit_index;
+
+ tries = JIT_MAX_ITERATIONS;
+ do {
+ ctx.jit_index = tmp_idx;
+ ctx.changes = 0;
+ if (tries == 2)
+ set_convert_flag(&ctx, true);
+ if (build_body(&ctx) < 0)
+ goto out_err;
+ } while (ctx.changes > 0 && --tries > 0);
+
+ if (WARN_ONCE(ctx.changes > 0, "JIT offsets failed to converge"))
+ goto out_err;
+
+ build_epilogue(&ctx, MIPS_R_RA);
+
+ /* Now we know the size of the structure to make */
+ image_size = sizeof(u32) * ctx.jit_index;
+ header = bpf_jit_binary_alloc(image_size, &image_ptr,
+ sizeof(u32), jit_fill_hole);
+ /*
+ * Not able to allocate memory for the structure then
+ * we must fall back to the interpretation
+ */
+ if (header == NULL)
+ goto out_err;
+
+ /* Actual pass to generate final JIT code */
+ ctx.target = (u32*)image_ptr;
+ ctx.jit_index = 0;
+
+ /*
+ * If building the JITed code fails somehow,
+ * we fall back to the interpretation.
+ */
+ build_prologue(&ctx);
+ if (build_body(&ctx) < 0)
+ goto out_err;
+ build_epilogue(&ctx, MIPS_R_RA);
+
+ flush_icache_range((u32)header, (u32)(ctx.target + ctx.jit_index));
+
+ if (bpf_jit_enable > 1)
+ bpf_jit_dump(prog->len, image_size, 2, ctx.target);
+
+ set_memory_ro((unsigned long)header, header->pages);
+ prog->bpf_func = (void *)ctx.target;
+ prog->jited = 1;
+ prog->jited_len = image_size;
+
+out:
+ if (tmp_blinded)
+ bpf_jit_prog_release_other(prog, prog == orig_prog ?
+ tmp : orig_prog);
+ kfree(ctx.descriptors);
+ return prog;
+
+out_err:
+ prog = orig_prog;
+ if (header)
+ bpf_jit_binary_free(header);
+ goto out;
+}
--
2.25.1
