Le 21/09/2021 à 15:29, Hari Bathini a écrit :
Refactor powerpc LDX JITing code to simplify adding BPF_PROBE_MEM
support.
Signed-off-by: Hari Bathini <hbathini@xxxxxxxxxxxxx>
---
Changes in v3:
* Dropped ST(X) JITing coderefactoring and ensured the changes are
minimal and relevant to BPF_PROBE_MEM support.
* Added a default for size switch case to ensure compiler would
not complain.
arch/powerpc/net/bpf_jit_comp32.c | 42 ++++++++++++++++++++-----------
arch/powerpc/net/bpf_jit_comp64.c | 40 +++++++++++++++++++----------
2 files changed, 55 insertions(+), 27 deletions(-)
diff --git a/arch/powerpc/net/bpf_jit_comp32.c b/arch/powerpc/net/bpf_jit_comp32.c
index b60b59426a24..6e4956cd52e7 100644
--- a/arch/powerpc/net/bpf_jit_comp32.c
+++ b/arch/powerpc/net/bpf_jit_comp32.c
@@ -282,6 +282,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
u32 src_reg = bpf_to_ppc(ctx, insn[i].src_reg);
u32 src_reg_h = src_reg - 1;
u32 tmp_reg = bpf_to_ppc(ctx, TMP_REG);
+ u32 size = BPF_SIZE(code);
s16 off = insn[i].off;
s32 imm = insn[i].imm;
bool func_addr_fixed;
@@ -810,23 +811,36 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
* BPF_LDX
*/
case BPF_LDX | BPF_MEM | BPF_B: /* dst = *(u8 *)(ul) (src + off) */
- EMIT(PPC_RAW_LBZ(dst_reg, src_reg, off));
- if (!fp->aux->verifier_zext)
- EMIT(PPC_RAW_LI(dst_reg_h, 0));
- break;
+ fallthrough;
case BPF_LDX | BPF_MEM | BPF_H: /* dst = *(u16 *)(ul) (src + off) */
- EMIT(PPC_RAW_LHZ(dst_reg, src_reg, off));
- if (!fp->aux->verifier_zext)
- EMIT(PPC_RAW_LI(dst_reg_h, 0));
- break;
+ fallthrough;
case BPF_LDX | BPF_MEM | BPF_W: /* dst = *(u32 *)(ul) (src + off) */
- EMIT(PPC_RAW_LWZ(dst_reg, src_reg, off));
- if (!fp->aux->verifier_zext)
- EMIT(PPC_RAW_LI(dst_reg_h, 0));
- break;
+ fallthrough;
case BPF_LDX | BPF_MEM | BPF_DW: /* dst = *(u64 *)(ul) (src + off) */
- EMIT(PPC_RAW_LWZ(dst_reg_h, src_reg, off));
- EMIT(PPC_RAW_LWZ(dst_reg, src_reg, off + 4));
+ switch (size) {
+ case BPF_B:
+ EMIT(PPC_RAW_LBZ(dst_reg, src_reg, off));
+ break;
+ case BPF_H:
+ EMIT(PPC_RAW_LHZ(dst_reg, src_reg, off));
+ break;
+ case BPF_W:
+ EMIT(PPC_RAW_LWZ(dst_reg, src_reg, off));
+ break;
+ case BPF_DW:
+ EMIT(PPC_RAW_LWZ(dst_reg_h, src_reg, off));
+ EMIT(PPC_RAW_LWZ(dst_reg, src_reg, off + 4));
+ break;
+ /*
+ * With size not being an enum and BPF_B/H/W/DW being macros, ensure no
+ * compiler warning/error by adding a default case that never reaches.
+ */
Thinking about it once more, in fact this is already bounded by the
upper switch/case, so there is no possibility to end up here with
something else than the 4 cases and that's probably the reason why GCC
says nothing about it, so I now think that a default is unnecessary and
should not be added. Sorry for that.
+ default:
+ break;
+ }
+
+ if (size != BPF_DW && !fp->aux->verifier_zext)
+ EMIT(PPC_RAW_LI(dst_reg_h, 0));
break;
/*
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index 2a87da50d9a4..991eb43d4cd2 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -285,6 +285,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
u32 code = insn[i].code;
u32 dst_reg = b2p[insn[i].dst_reg];
u32 src_reg = b2p[insn[i].src_reg];
+ u32 size = BPF_SIZE(code);
s16 off = insn[i].off;
s32 imm = insn[i].imm;
bool func_addr_fixed;
@@ -716,25 +717,38 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
*/
/* dst = *(u8 *)(ul) (src + off) */
case BPF_LDX | BPF_MEM | BPF_B:
- EMIT(PPC_RAW_LBZ(dst_reg, src_reg, off));
- if (insn_is_zext(&insn[i + 1]))
- addrs[++i] = ctx->idx * 4;
- break;
+ fallthrough;
/* dst = *(u16 *)(ul) (src + off) */
case BPF_LDX | BPF_MEM | BPF_H:
- EMIT(PPC_RAW_LHZ(dst_reg, src_reg, off));
- if (insn_is_zext(&insn[i + 1]))
- addrs[++i] = ctx->idx * 4;
- break;
+ fallthrough;
/* dst = *(u32 *)(ul) (src + off) */
case BPF_LDX | BPF_MEM | BPF_W:
- EMIT(PPC_RAW_LWZ(dst_reg, src_reg, off));
- if (insn_is_zext(&insn[i + 1]))
- addrs[++i] = ctx->idx * 4;
- break;
+ fallthrough;
/* dst = *(u64 *)(ul) (src + off) */
case BPF_LDX | BPF_MEM | BPF_DW:
- PPC_BPF_LL(dst_reg, src_reg, off);
+ switch (size) {
+ case BPF_B:
+ EMIT(PPC_RAW_LBZ(dst_reg, src_reg, off));
+ break;
+ case BPF_H:
+ EMIT(PPC_RAW_LHZ(dst_reg, src_reg, off));
+ break;
+ case BPF_W:
+ EMIT(PPC_RAW_LWZ(dst_reg, src_reg, off));
+ break;
+ case BPF_DW:
+ PPC_BPF_LL(dst_reg, src_reg, off);
+ break;
+ /*
+ * With size not being an enum and BPF_B/H/W/DW being macros, ensure no
+ * compiler warning/error by adding a default case that never reaches.
+ */
Same
+ default:
+ break;
+ }
+
+ if (size != BPF_DW && insn_is_zext(&insn[i + 1]))
+ addrs[++i] = ctx->idx * 4;
break;
/*
