To be consistent with other VDSO functions, the function is called __kernel_getrandom() __arch_chacha20_blocks_nostack() fonction is implemented basically with 32 bits operations. It performs 4 QUARTERROUND operations in parallele. There are enough registers to avoid using the stack: On input: r3: output bytes r4: 32-byte key input r5: 8-byte counter input/output r6: number of 64-byte blocks to write to output During operation: stack: pointer to counter (r5) and non-volatile registers (r14-131) r0: counter of blocks (initialised with r6) r4: Value '4' after key has been read, used for indexing r5-r12: key r14-r15: block counter r16-r31: chacha state At the end: r0, r6-r12: Zeroised r5, r14-r31: Restored Performance on powerpc 885 (using kernel selftest): ~# ./vdso_test_getrandom bench-single vdso: 25000000 times in 62.938002291 seconds libc: 25000000 times in 535.581916866 seconds syscall: 25000000 times in 531.525042806 seconds Performance on powerpc 8321 (using kernel selftest): ~# ./vdso_test_getrandom bench-single vdso: 25000000 times in 16.899318858 seconds libc: 25000000 times in 131.050596522 seconds syscall: 25000000 times in 129.794790389 seconds This first patch adds support for PPC32. As selftests cannot easily be generated only for PPC32, and because the following patch brings support for PPC64 anyway, this patch opts out all code in __arch_chacha20_blocks_nostack() so that vdso_test_chacha will not fail to compile and will not crash on PPC64/PPC64LE, allthough the selftest itself will fail. This patch also adds a dummy __kernel_getrandom() function that returns ENOSYS on PPC64 so that vdso_test_getrandom returns KSFT_SKIP instead of KSFT_FAIL. Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx> --- v4: - Counter has native byte order - Fix selftest build on ppc64le until implemented. - On ppc64, for now implement __kernel_getrandom to return ENOSYS error - Use stwbrx directly, not compat macro. v3: - Preserve r13, implies saving r5 on stack - Split PPC64 implementation out. --- arch/powerpc/Kconfig | 1 + arch/powerpc/include/asm/vdso/getrandom.h | 54 +++++ arch/powerpc/include/asm/vdso/vsyscall.h | 6 + arch/powerpc/include/asm/vdso_datapage.h | 2 + arch/powerpc/kernel/asm-offsets.c | 1 + arch/powerpc/kernel/vdso/Makefile | 13 +- arch/powerpc/kernel/vdso/getrandom.S | 58 ++++++ arch/powerpc/kernel/vdso/vdso32.lds.S | 1 + arch/powerpc/kernel/vdso/vdso64.lds.S | 1 + arch/powerpc/kernel/vdso/vgetrandom-chacha.S | 207 +++++++++++++++++++ arch/powerpc/kernel/vdso/vgetrandom.c | 16 ++ tools/testing/selftests/vDSO/Makefile | 2 +- 12 files changed, 359 insertions(+), 3 deletions(-) create mode 100644 arch/powerpc/include/asm/vdso/getrandom.h create mode 100644 arch/powerpc/kernel/vdso/getrandom.S create mode 100644 arch/powerpc/kernel/vdso/vgetrandom-chacha.S create mode 100644 arch/powerpc/kernel/vdso/vgetrandom.c diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index d7b09b064a8a..54b270ef18b1 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -311,6 +311,7 @@ config PPC select SYSCTL_EXCEPTION_TRACE select THREAD_INFO_IN_TASK select TRACE_IRQFLAGS_SUPPORT + select VDSO_GETRANDOM if PPC32 # # Please keep this list sorted alphabetically. # diff --git a/arch/powerpc/include/asm/vdso/getrandom.h b/arch/powerpc/include/asm/vdso/getrandom.h new file mode 100644 index 000000000000..501d6bb14e8a --- /dev/null +++ b/arch/powerpc/include/asm/vdso/getrandom.h @@ -0,0 +1,54 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2024 Christophe Leroy <christophe.leroy@xxxxxxxxxx>, CS GROUP France + */ +#ifndef _ASM_POWERPC_VDSO_GETRANDOM_H +#define _ASM_POWERPC_VDSO_GETRANDOM_H + +#ifndef __ASSEMBLY__ + +static __always_inline int do_syscall_3(const unsigned long _r0, const unsigned long _r3, + const unsigned long _r4, const unsigned long _r5) +{ + register long r0 asm("r0") = _r0; + register unsigned long r3 asm("r3") = _r3; + register unsigned long r4 asm("r4") = _r4; + register unsigned long r5 asm("r5") = _r5; + register int ret asm ("r3"); + + asm volatile( + " sc\n" + " bns+ 1f\n" + " neg %0, %0\n" + "1:\n" + : "=r" (ret), "+r" (r4), "+r" (r5), "+r" (r0) + : "r" (r3) + : "memory", "r6", "r7", "r8", "r9", "r10", "r11", "r12", "cr0", "ctr"); + + return ret; +} + +/** + * getrandom_syscall - Invoke the getrandom() syscall. + * @buffer: Destination buffer to fill with random bytes. + * @len: Size of @buffer in bytes. + * @flags: Zero or more GRND_* flags. + * Returns: The number of bytes written to @buffer, or a negative value indicating an error. + */ +static __always_inline ssize_t getrandom_syscall(void *buffer, size_t len, unsigned int flags) +{ + return do_syscall_3(__NR_getrandom, (unsigned long)buffer, + (unsigned long)len, (unsigned long)flags); +} + +static __always_inline struct vdso_rng_data *__arch_get_vdso_rng_data(void) +{ + return NULL; +} + +ssize_t __c_kernel_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, + size_t opaque_len, const struct vdso_rng_data *vd); + +#endif /* !__ASSEMBLY__ */ + +#endif /* _ASM_POWERPC_VDSO_GETRANDOM_H */ diff --git a/arch/powerpc/include/asm/vdso/vsyscall.h b/arch/powerpc/include/asm/vdso/vsyscall.h index 48cf23f1e273..92f480d8cc6d 100644 --- a/arch/powerpc/include/asm/vdso/vsyscall.h +++ b/arch/powerpc/include/asm/vdso/vsyscall.h @@ -17,6 +17,12 @@ struct vdso_data *__arch_get_k_vdso_data(void) } #define __arch_get_k_vdso_data __arch_get_k_vdso_data +static __always_inline +struct vdso_rng_data *__arch_get_k_vdso_rng_data(void) +{ + return &vdso_data->rng_data; +} + /* The asm-generic header needs to be included after the definitions above */ #include <asm-generic/vdso/vsyscall.h> diff --git a/arch/powerpc/include/asm/vdso_datapage.h b/arch/powerpc/include/asm/vdso_datapage.h index a585c8e538ff..e17500c5237e 100644 --- a/arch/powerpc/include/asm/vdso_datapage.h +++ b/arch/powerpc/include/asm/vdso_datapage.h @@ -83,6 +83,7 @@ struct vdso_arch_data { __u32 compat_syscall_map[SYSCALL_MAP_SIZE]; /* Map of compat syscalls */ struct vdso_data data[CS_BASES]; + struct vdso_rng_data rng_data; }; #else /* CONFIG_PPC64 */ @@ -95,6 +96,7 @@ struct vdso_arch_data { __u32 syscall_map[SYSCALL_MAP_SIZE]; /* Map of syscalls */ __u32 compat_syscall_map[0]; /* No compat syscalls on PPC32 */ struct vdso_data data[CS_BASES]; + struct vdso_rng_data rng_data; }; #endif /* CONFIG_PPC64 */ diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 23733282de4d..eedb2e04c785 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -335,6 +335,7 @@ int main(void) /* datapage offsets for use by vdso */ OFFSET(VDSO_DATA_OFFSET, vdso_arch_data, data); + OFFSET(VDSO_RNG_DATA_OFFSET, vdso_arch_data, rng_data); OFFSET(CFG_TB_TICKS_PER_SEC, vdso_arch_data, tb_ticks_per_sec); #ifdef CONFIG_PPC64 OFFSET(CFG_ICACHE_BLOCKSZ, vdso_arch_data, icache_block_size); diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile index 67fe79d26fae..af3ba61b022e 100644 --- a/arch/powerpc/kernel/vdso/Makefile +++ b/arch/powerpc/kernel/vdso/Makefile @@ -8,6 +8,9 @@ include $(srctree)/lib/vdso/Makefile obj-vdso32 = sigtramp32-32.o gettimeofday-32.o datapage-32.o cacheflush-32.o note-32.o getcpu-32.o obj-vdso64 = sigtramp64-64.o gettimeofday-64.o datapage-64.o cacheflush-64.o note-64.o getcpu-64.o +obj-vdso32 += getrandom-32.o vgetrandom-chacha-32.o +obj-vdso64 += getrandom-64.o + ifneq ($(c-gettimeofday-y),) CFLAGS_vgettimeofday-32.o += -include $(c-gettimeofday-y) # Go prior to 1.16.x assumes r30 is not clobbered by any VDSO code. That used to be true @@ -17,6 +20,10 @@ ifneq ($(c-gettimeofday-y),) CFLAGS_vgettimeofday-64.o += -include $(c-gettimeofday-y) $(call cc-option, -ffixed-r30) endif +ifneq ($(c-getrandom-y),) + CFLAGS_vgetrandom-32.o += -include $(c-getrandom-y) +endif + # Build rules ifdef CROSS32_COMPILE @@ -25,7 +32,7 @@ else VDSOCC := $(CC) endif -targets := $(obj-vdso32) vdso32.so.dbg vgettimeofday-32.o +targets := $(obj-vdso32) vdso32.so.dbg vgettimeofday-32.o vgetrandom-32.o targets += crtsavres-32.o obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32)) targets += $(obj-vdso64) vdso64.so.dbg vgettimeofday-64.o @@ -63,7 +70,7 @@ targets += vdso64.lds CPPFLAGS_vdso64.lds += -P -C # link rule for the .so file, .lds has to be first -$(obj)/vdso32.so.dbg: $(obj)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday-32.o $(obj)/crtsavres-32.o FORCE +$(obj)/vdso32.so.dbg: $(obj)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday-32.o $(obj)/vgetrandom-32.o $(obj)/crtsavres-32.o FORCE $(call if_changed,vdso32ld_and_check) $(obj)/vdso64.so.dbg: $(obj)/vdso64.lds $(obj-vdso64) $(obj)/vgettimeofday-64.o FORCE $(call if_changed,vdso64ld_and_check) @@ -75,6 +82,8 @@ $(obj)/crtsavres-32.o: %-32.o: $(srctree)/arch/powerpc/lib/crtsavres.S FORCE $(call if_changed_dep,vdso32as) $(obj)/vgettimeofday-32.o: %-32.o: %.c FORCE $(call if_changed_dep,vdso32cc) +$(obj)/vgetrandom-32.o: %-32.o: %.c FORCE + $(call if_changed_dep,vdso32cc) $(obj-vdso64): %-64.o: %.S FORCE $(call if_changed_dep,vdso64as) $(obj)/vgettimeofday-64.o: %-64.o: %.c FORCE diff --git a/arch/powerpc/kernel/vdso/getrandom.S b/arch/powerpc/kernel/vdso/getrandom.S new file mode 100644 index 000000000000..7db51c0635a5 --- /dev/null +++ b/arch/powerpc/kernel/vdso/getrandom.S @@ -0,0 +1,58 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Userland implementation of getrandom() for processes + * for use in the vDSO + * + * Copyright (C) 2024 Christophe Leroy <christophe.leroy@xxxxxxxxxx>, CS GROUP France + */ +#include <linux/errno.h> + +#include <asm/processor.h> +#include <asm/ppc_asm.h> +#include <asm/vdso.h> +#include <asm/vdso_datapage.h> +#include <asm/asm-offsets.h> +#include <asm/unistd.h> + +/* + * The macro sets two stack frames, one for the caller and one for the callee + * because there are no requirement for the caller to set a stack frame when + * calling VDSO so it may have omitted to set one, especially on PPC64 + */ + +.macro cvdso_call funct + .cfi_startproc + PPC_STLU r1, -PPC_MIN_STKFRM(r1) + .cfi_adjust_cfa_offset PPC_MIN_STKFRM + mflr r0 + PPC_STLU r1, -PPC_MIN_STKFRM(r1) + .cfi_adjust_cfa_offset PPC_MIN_STKFRM + PPC_STL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) + .cfi_rel_offset lr, PPC_MIN_STKFRM + PPC_LR_STKOFF + get_datapage r8 + addi r8, r8, VDSO_RNG_DATA_OFFSET + bl CFUNC(DOTSYM(\funct)) + PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) + cmpwi r3, 0 + mtlr r0 + addi r1, r1, 2 * PPC_MIN_STKFRM + .cfi_restore lr + .cfi_def_cfa_offset 0 + crclr so + bgelr+ + crset so + neg r3, r3 + blr + .cfi_endproc +.endm + + .text +V_FUNCTION_BEGIN(__kernel_getrandom) +#ifdef CONFIG_PPC64 + li r3, ENOSYS + crset so + blr +#else + cvdso_call __c_kernel_getrandom +#endif +V_FUNCTION_END(__kernel_getrandom) diff --git a/arch/powerpc/kernel/vdso/vdso32.lds.S b/arch/powerpc/kernel/vdso/vdso32.lds.S index 8f57107000a2..7b41d5d256e8 100644 --- a/arch/powerpc/kernel/vdso/vdso32.lds.S +++ b/arch/powerpc/kernel/vdso/vdso32.lds.S @@ -130,6 +130,7 @@ VERSION #if defined(CONFIG_PPC64) || !defined(CONFIG_SMP) __kernel_getcpu; #endif + __kernel_getrandom; local: *; }; diff --git a/arch/powerpc/kernel/vdso/vdso64.lds.S b/arch/powerpc/kernel/vdso/vdso64.lds.S index 400819258c06..9481e4b892ed 100644 --- a/arch/powerpc/kernel/vdso/vdso64.lds.S +++ b/arch/powerpc/kernel/vdso/vdso64.lds.S @@ -123,6 +123,7 @@ VERSION __kernel_sigtramp_rt64; __kernel_getcpu; __kernel_time; + __kernel_getrandom; local: *; }; diff --git a/arch/powerpc/kernel/vdso/vgetrandom-chacha.S b/arch/powerpc/kernel/vdso/vgetrandom-chacha.S new file mode 100644 index 000000000000..17a2f586223a --- /dev/null +++ b/arch/powerpc/kernel/vdso/vgetrandom-chacha.S @@ -0,0 +1,207 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2024 Christophe Leroy <christophe.leroy@xxxxxxxxxx>, CS GROUP France + */ + +#include <linux/linkage.h> + +#include <asm/ppc_asm.h> + +.macro quarterround4 a1 b1 c1 d1 a2 b2 c2 d2 a3 b3 c3 d3 a4 b4 c4 d4 + add \a1, \a1, \b1 + add \a2, \a2, \b2 + add \a3, \a3, \b3 + add \a4, \a4, \b4 + xor \d1, \d1, \a1 + xor \d2, \d2, \a2 + xor \d3, \d3, \a3 + xor \d4, \d4, \a4 + rotlwi \d1, \d1, 16 + rotlwi \d2, \d2, 16 + rotlwi \d3, \d3, 16 + rotlwi \d4, \d4, 16 + add \c1, \c1, \d1 + add \c2, \c2, \d2 + add \c3, \c3, \d3 + add \c4, \c4, \d4 + xor \b1, \b1, \c1 + xor \b2, \b2, \c2 + xor \b3, \b3, \c3 + xor \b4, \b4, \c4 + rotlwi \b1, \b1, 12 + rotlwi \b2, \b2, 12 + rotlwi \b3, \b3, 12 + rotlwi \b4, \b4, 12 + add \a1, \a1, \b1 + add \a2, \a2, \b2 + add \a3, \a3, \b3 + add \a4, \a4, \b4 + xor \d1, \d1, \a1 + xor \d2, \d2, \a2 + xor \d3, \d3, \a3 + xor \d4, \d4, \a4 + rotlwi \d1, \d1, 8 + rotlwi \d2, \d2, 8 + rotlwi \d3, \d3, 8 + rotlwi \d4, \d4, 8 + add \c1, \c1, \d1 + add \c2, \c2, \d2 + add \c3, \c3, \d3 + add \c4, \c4, \d4 + xor \b1, \b1, \c1 + xor \b2, \b2, \c2 + xor \b3, \b3, \c3 + xor \b4, \b4, \c4 + rotlwi \b1, \b1, 7 + rotlwi \b2, \b2, 7 + rotlwi \b3, \b3, 7 + rotlwi \b4, \b4, 7 +.endm + +#define QUARTERROUND4(a1,b1,c1,d1,a2,b2,c2,d2,a3,b3,c3,d3,a4,b4,c4,d4) \ + quarterround4 16+a1 16+b1 16+c1 16+d1 16+a2 16+b2 16+c2 16+d2 \ + 16+a3 16+b3 16+c3 16+d3 16+a4 16+b4 16+c4 16+d4 + +/* + * Very basic 32 bits implementation of ChaCha20. Produces a given positive number + * of blocks of output with a nonce of 0, taking an input key and 8-byte + * counter. Importantly does not spill to the stack. Its arguments are: + * + * r3: output bytes + * r4: 32-byte key input + * r5: 8-byte counter input/output (saved on stack) + * r6: number of 64-byte blocks to write to output + * + * r0: counter of blocks (initialised with r6) + * r4: Value '4' after key has been read. + * r5-r12: key + * r14-r15: counter + * r16-r31: state + */ +SYM_FUNC_START(__arch_chacha20_blocks_nostack) +#ifdef __powerpc64__ + blr +#else + stwu r1, -96(r1) + stw r5, 20(r1) + stmw r14, 24(r1) + + lwz r14, 0(r5) + lwz r15, 4(r5) + mr r0, r6 + subi r3, r3, 4 + + lwz r5, 0(r4) + lwz r6, 4(r4) + lwz r7, 8(r4) + lwz r8, 12(r4) + lwz r9, 16(r4) + lwz r10, 20(r4) + lwz r11, 24(r4) + lwz r12, 28(r4) + + li r4, 4 +.Lblock: + li r31, 10 + + lis r16, 0x6170 + lis r17, 0x3320 + lis r18, 0x7962 + lis r19, 0x6b20 + addi r16, r16, 0x7865 + addi r17, r17, 0x646e + addi r18, r18, 0x2d32 + addi r19, r19, 0x6574 + + mtctr r31 + + mr r20, r5 + mr r21, r6 + mr r22, r7 + mr r23, r8 + mr r24, r9 + mr r25, r10 + mr r26, r11 + mr r27, r12 + + mr r28, r14 + mr r29, r15 + li r30, 0 + li r31, 0 + +.Lpermute: + QUARTERROUND4( 0, 4, 8,12, 1, 5, 9,13, 2, 6,10,14, 3, 7,11,15) + QUARTERROUND4( 0, 5,10,15, 1, 6,11,12, 2, 7, 8,13, 3, 4, 9,14) + + bdnz .Lpermute + + addis r16, r16, 0x6170 + addis r17, r17, 0x3320 + addis r18, r18, 0x7962 + addis r19, r19, 0x6b20 + addi r16, r16, 0x7865 + addi r17, r17, 0x646e + addi r18, r18, 0x2d32 + addi r19, r19, 0x6574 + + add r20, r20, r5 + add r21, r21, r6 + add r22, r22, r7 + add r23, r23, r8 + add r24, r24, r9 + add r25, r25, r10 + add r26, r26, r11 + add r27, r27, r12 + + add r28, r28, r14 + add r29, r29, r15 + + stwbrx r16, r4, r3 + addi r3, r3, 8 + stwbrx r17, 0, r3 + stwbrx r18, r4, r3 + addi r3, r3, 8 + stwbrx r19, 0, r3 + stwbrx r20, r4, r3 + addi r3, r3, 8 + stwbrx r21, 0, r3 + stwbrx r22, r4, r3 + addi r3, r3, 8 + stwbrx r23, 0, r3 + stwbrx r24, r4, r3 + addi r3, r3, 8 + stwbrx r25, 0, r3 + stwbrx r26, r4, r3 + addi r3, r3, 8 + stwbrx r27, 0, r3 + stwbrx r28, r4, r3 + addi r3, r3, 8 + stwbrx r29, 0, r3 + stwbrx r30, r4, r3 + addi r3, r3, 8 + stwbrx r31, 0, r3 + + subic. r0, r0, 1 /* subi. can't use r0 as source */ + + addic r14, r14, 1 + addze r15, r15 + + bne .Lblock + + lwz r5, 20(r1) + stw r14, 0(r5) + stw r15, 4(r5) + + li r6, 0 + li r7, 0 + li r8, 0 + li r9, 0 + li r10, 0 + li r11, 0 + li r12, 0 + + lmw r14, 24(r1) + addi r1, r1, 96 + blr +#endif +SYM_FUNC_END(__arch_chacha20_blocks_nostack) diff --git a/arch/powerpc/kernel/vdso/vgetrandom.c b/arch/powerpc/kernel/vdso/vgetrandom.c new file mode 100644 index 000000000000..923330845b2c --- /dev/null +++ b/arch/powerpc/kernel/vdso/vgetrandom.c @@ -0,0 +1,16 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Powerpc userspace implementation of getrandom() + * + * Copyright (C) 2024 Christophe Leroy <christophe.leroy@xxxxxxxxxx>, CS GROUP France + */ +#include <linux/time.h> +#include <linux/types.h> + +#ifndef CONFIG_PPC64 +ssize_t __c_kernel_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, + size_t opaque_len, const struct vdso_rng_data *vd) +{ + return __cvdso_getrandom_data(vd, buffer, len, flags, opaque_state, opaque_len); +} +#endif diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile index 04930125035e..853e669d8643 100644 --- a/tools/testing/selftests/vDSO/Makefile +++ b/tools/testing/selftests/vDSO/Makefile @@ -9,7 +9,7 @@ ifeq ($(ARCH),$(filter $(ARCH),x86 x86_64)) TEST_GEN_PROGS += vdso_standalone_test_x86 endif TEST_GEN_PROGS += vdso_test_correctness -ifeq ($(ARCH)$(CONFIG_X86_32),$(filter $(ARCH)$(CONFIG_X86_32),x86 x86_64 loongarch)) +ifeq ($(ARCH)$(CONFIG_X86_32),$(filter $(ARCH)$(CONFIG_X86_32),x86 x86_64 loongarch powerpc)) TEST_GEN_PROGS += vdso_test_getrandom TEST_GEN_PROGS += vdso_test_chacha endif -- 2.44.0