This series wires up getrandom() vDSO implementation on powerpc.
Tested on PPC32 on real hardware. Tested on PPC64 (both BE and LE) on QEMU:
Performance on powerpc 885: ~# ./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: ~# ./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
Performance on QEMU pseries: ~ # ./vdso_test_getrandom bench-single vdso: 25000000 times in 4.977777162 seconds libc: 25000000 times in 75.516749981 seconds syscall: 25000000 times in 86.842242014 seconds
Changes in v4: - Rebased on recent random git tree (963233ff0133) (The new tree includes selftests fixes) - Read/write counter in native byte order - Don't use anymore compat macros to write output - Fixed selftests build failure with patch 4 (without patch 5) on little endian on PPC64 - Implement a __kernel_getrandom() stub returning ENOSYS on ppc64 in patch 4 (without patch 5) to make selftests happy.
Changes in v3: - Rebased on recent random git tree (0c7e00e22c21) - Fixed build failures reported by robots around VM_DROPPABLE - Fixed crash on PPC64 due to clobbered r13 by not using r13 anymore (saving it was not enough for signals). - Split final patch in two, first for PPC32, second for PPC64 - Moved selftest fixes out of this series
Changes in v2: - Define VM_DROPPABLE for powerpc/32 - Fixes generic vDSO getrandom headers to enable CONFIG_COMPAT build. - Fixed size of generation counter - Fixed selftests to work on non x86 architectures
Christophe Leroy (5): mm: Define VM_DROPPABLE for powerpc/32 powerpc/vdso32: Add crtsavres powerpc/vdso: Refactor CFLAGS for CVDSO build powerpc/vdso: Wire up getrandom() vDSO implementation on PPC32 powerpc/vdso: Wire up getrandom() vDSO implementation on PPC64
arch/powerpc/Kconfig | 1 + arch/powerpc/include/asm/mman.h | 2 +- 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 | 57 ++-- arch/powerpc/kernel/vdso/getrandom.S | 58 ++++ arch/powerpc/kernel/vdso/gettimeofday.S | 13 - arch/powerpc/kernel/vdso/vdso32.lds.S | 1 + arch/powerpc/kernel/vdso/vdso64.lds.S | 1 + arch/powerpc/kernel/vdso/vgetrandom-chacha.S | 320 +++++++++++++++++++ arch/powerpc/kernel/vdso/vgetrandom.c | 14 + fs/proc/task_mmu.c | 4 +- include/linux/mm.h | 4 +- include/trace/events/mmflags.h | 4 +- tools/testing/selftests/vDSO/Makefile | 2 +- 17 files changed, 501 insertions(+), 43 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
Commit 9651fcedf7b9 ("mm: add MAP_DROPPABLE for designating always lazily freeable mappings") only adds VM_DROPPABLE for 64 bits architectures.
In order to also use the getrandom vDSO implementation on powerpc/32, use VM_ARCH_1 for VM_DROPPABLE on powerpc/32. This is possible because VM_ARCH_1 is used for VM_SAO on powerpc and VM_SAO is only for powerpc/64. It is used in combination with PROT_SAO in some parts of code that are restricted to CONFIG_PPC64 through #ifdefs, it is therefore possible to define VM_SAO for CONFIG_PPC64 only.
Signed-off-by: Christophe Leroy christophe.leroy@csgroup.eu --- v4: Added more details in commit message following comment from Michael. v3: Fixed build failure reported by robots. --- fs/proc/task_mmu.c | 4 +++- include/linux/mm.h | 4 +++- include/trace/events/mmflags.h | 4 ++-- 3 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 5f171ad7b436..3a07e13e2f81 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -987,8 +987,10 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) #ifdef CONFIG_X86_USER_SHADOW_STACK [ilog2(VM_SHADOW_STACK)] = "ss", #endif -#ifdef CONFIG_64BIT +#if defined(CONFIG_64BIT) || defined(CONFIG_PPC32) [ilog2(VM_DROPPABLE)] = "dp", +#endif +#ifdef CONFIG_64BIT [ilog2(VM_SEALED)] = "sl", #endif }; diff --git a/include/linux/mm.h b/include/linux/mm.h index 6549d0979b28..028847f39442 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -359,7 +359,7 @@ extern unsigned int kobjsize(const void *objp);
#if defined(CONFIG_X86) # define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */ -#elif defined(CONFIG_PPC) +#elif defined(CONFIG_PPC64) # define VM_SAO VM_ARCH_1 /* Strong Access Ordering (powerpc) */ #elif defined(CONFIG_PARISC) # define VM_GROWSUP VM_ARCH_1 @@ -409,6 +409,8 @@ extern unsigned int kobjsize(const void *objp); #ifdef CONFIG_64BIT #define VM_DROPPABLE_BIT 40 #define VM_DROPPABLE BIT(VM_DROPPABLE_BIT) +#elif defined(CONFIG_PPC32) +#define VM_DROPPABLE VM_ARCH_1 #else #define VM_DROPPABLE VM_NONE #endif diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h index b63d211bd141..37265977d524 100644 --- a/include/trace/events/mmflags.h +++ b/include/trace/events/mmflags.h @@ -143,7 +143,7 @@ IF_HAVE_PG_ARCH_X(arch_3)
#if defined(CONFIG_X86) #define __VM_ARCH_SPECIFIC_1 {VM_PAT, "pat" } -#elif defined(CONFIG_PPC) +#elif defined(CONFIG_PPC64) #define __VM_ARCH_SPECIFIC_1 {VM_SAO, "sao" } #elif defined(CONFIG_PARISC) #define __VM_ARCH_SPECIFIC_1 {VM_GROWSUP, "growsup" } @@ -165,7 +165,7 @@ IF_HAVE_PG_ARCH_X(arch_3) # define IF_HAVE_UFFD_MINOR(flag, name) #endif
-#ifdef CONFIG_64BIT +#if defined(CONFIG_64BIT) || defined(CONFIG_PPC32) # define IF_HAVE_VM_DROPPABLE(flag, name) {flag, name}, #else # define IF_HAVE_VM_DROPPABLE(flag, name)
Commit 08c18b63d965 ("powerpc/vdso32: Add missing _restgpr_31_x to fix build failure") added _restgpr_31_x to the vdso for gettimeofday, but the work on getrandom shows that we will need more of those functions.
Remove _restgpr_31_x and link in crtsavres.o so that we get all save/restore functions when optimising the kernel for size.
Signed-off-by: Christophe Leroy christophe.leroy@csgroup.eu --- arch/powerpc/kernel/vdso/Makefile | 5 ++++- arch/powerpc/kernel/vdso/gettimeofday.S | 13 ------------- 2 files changed, 4 insertions(+), 14 deletions(-)
diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile index 1425b6edc66b..c07a425b8f78 100644 --- a/arch/powerpc/kernel/vdso/Makefile +++ b/arch/powerpc/kernel/vdso/Makefile @@ -43,6 +43,7 @@ else endif
targets := $(obj-vdso32) vdso32.so.dbg vgettimeofday-32.o +targets += crtsavres-32.o obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32)) targets += $(obj-vdso64) vdso64.so.dbg vgettimeofday-64.o obj-vdso64 := $(addprefix $(obj)/, $(obj-vdso64)) @@ -68,7 +69,7 @@ targets += vdso64.lds CPPFLAGS_vdso64.lds += -P -C
# link rule for the .so file, .lds has to be first -$(obj)/vdso32.so.dbg: $(obj)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday-32.o FORCE +$(obj)/vdso32.so.dbg: $(obj)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday-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) @@ -76,6 +77,8 @@ $(obj)/vdso64.so.dbg: $(obj)/vdso64.lds $(obj-vdso64) $(obj)/vgettimeofday-64.o # assembly rules for the .S files $(obj-vdso32): %-32.o: %.S FORCE $(call if_changed_dep,vdso32as) +$(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) $(obj-vdso64): %-64.o: %.S FORCE diff --git a/arch/powerpc/kernel/vdso/gettimeofday.S b/arch/powerpc/kernel/vdso/gettimeofday.S index 48fc6658053a..67254ac9c8bb 100644 --- a/arch/powerpc/kernel/vdso/gettimeofday.S +++ b/arch/powerpc/kernel/vdso/gettimeofday.S @@ -118,16 +118,3 @@ V_FUNCTION_END(__kernel_clock_getres) V_FUNCTION_BEGIN(__kernel_time) cvdso_call __c_kernel_time call_time=1 V_FUNCTION_END(__kernel_time) - -/* Routines for restoring integer registers, called by the compiler. */ -/* Called with r11 pointing to the stack header word of the caller of the */ -/* function, just beyond the end of the integer restore area. */ -#ifndef __powerpc64__ -_GLOBAL(_restgpr_31_x) -_GLOBAL(_rest32gpr_31_x) - lwz r0,4(r11) - lwz r31,-4(r11) - mtlr r0 - mr r1,r11 - blr -#endif
In order to avoid two much duplication when we add new VDSO functionnalities in C like getrandom, refactor common CFLAGS.
Signed-off-by: Christophe Leroy christophe.leroy@csgroup.eu --- v3: Also refactor removed flags --- arch/powerpc/kernel/vdso/Makefile | 32 +++++++++++++------------------ 1 file changed, 13 insertions(+), 19 deletions(-)
diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile index c07a425b8f78..67fe79d26fae 100644 --- a/arch/powerpc/kernel/vdso/Makefile +++ b/arch/powerpc/kernel/vdso/Makefile @@ -10,28 +10,11 @@ obj-vdso64 = sigtramp64-64.o gettimeofday-64.o datapage-64.o cacheflush-64.o not
ifneq ($(c-gettimeofday-y),) CFLAGS_vgettimeofday-32.o += -include $(c-gettimeofday-y) - CFLAGS_vgettimeofday-32.o += $(DISABLE_LATENT_ENTROPY_PLUGIN) - CFLAGS_vgettimeofday-32.o += $(call cc-option, -fno-stack-protector) - CFLAGS_vgettimeofday-32.o += -DDISABLE_BRANCH_PROFILING - CFLAGS_vgettimeofday-32.o += -ffreestanding -fasynchronous-unwind-tables - CFLAGS_REMOVE_vgettimeofday-32.o = $(CC_FLAGS_FTRACE) - CFLAGS_REMOVE_vgettimeofday-32.o += -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc - # This flag is supported by clang for 64-bit but not 32-bit so it will cause - # an unused command line flag warning for this file. - ifdef CONFIG_CC_IS_CLANG - CFLAGS_REMOVE_vgettimeofday-32.o += -fno-stack-clash-protection - endif - CFLAGS_vgettimeofday-64.o += -include $(c-gettimeofday-y) - CFLAGS_vgettimeofday-64.o += $(DISABLE_LATENT_ENTROPY_PLUGIN) - CFLAGS_vgettimeofday-64.o += $(call cc-option, -fno-stack-protector) - CFLAGS_vgettimeofday-64.o += -DDISABLE_BRANCH_PROFILING - CFLAGS_vgettimeofday-64.o += -ffreestanding -fasynchronous-unwind-tables - CFLAGS_REMOVE_vgettimeofday-64.o = $(CC_FLAGS_FTRACE) # Go prior to 1.16.x assumes r30 is not clobbered by any VDSO code. That used to be true # by accident when the VDSO was hand-written asm code, but may not be now that the VDSO is # compiler generated. To avoid breaking Go tell GCC not to use r30. Impact on code # generation is minimal, it will just use r29 instead. - CFLAGS_vgettimeofday-64.o += $(call cc-option, -ffixed-r30) + CFLAGS_vgettimeofday-64.o += -include $(c-gettimeofday-y) $(call cc-option, -ffixed-r30) endif
# Build rules @@ -49,6 +32,11 @@ targets += $(obj-vdso64) vdso64.so.dbg vgettimeofday-64.o obj-vdso64 := $(addprefix $(obj)/, $(obj-vdso64))
ccflags-y := -fno-common -fno-builtin +ccflags-y += $(DISABLE_LATENT_ENTROPY_PLUGIN) +ccflags-y += $(call cc-option, -fno-stack-protector) +ccflags-y += -DDISABLE_BRANCH_PROFILING +ccflags-y += -ffreestanding -fasynchronous-unwind-tables +ccflags-remove-y := $(CC_FLAGS_FTRACE) ldflags-y := -Wl,--hash-style=both -nostdlib -shared -z noexecstack $(CLANG_FLAGS) ldflags-$(CONFIG_LD_IS_LLD) += $(call cc-option,--ld-path=$(LD),-fuse-ld=lld) ldflags-$(CONFIG_LD_ORPHAN_WARN) += -Wl,--orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL) @@ -57,6 +45,12 @@ ldflags-$(CONFIG_LD_ORPHAN_WARN) += -Wl,--orphan-handling=$(CONFIG_LD_ORPHAN_WAR ldflags-y += $(filter-out $(CC_AUTO_VAR_INIT_ZERO_ENABLER) $(CC_FLAGS_FTRACE) -Wa$(comma)%, $(KBUILD_CFLAGS))
CC32FLAGS := -m32 +CC32FLAGSREMOVE := -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc + # This flag is supported by clang for 64-bit but not 32-bit so it will cause + # an unused command line flag warning for this file. +ifdef CONFIG_CC_IS_CLANG +CC32FLAGSREMOVE += -fno-stack-clash-protection +endif LD32FLAGS := -Wl,-soname=linux-vdso32.so.1 AS32FLAGS := -D__VDSO32__
@@ -105,7 +99,7 @@ quiet_cmd_vdso32ld_and_check = VDSO32L $@ quiet_cmd_vdso32as = VDSO32A $@ cmd_vdso32as = $(VDSOCC) $(a_flags) $(CC32FLAGS) $(AS32FLAGS) -c -o $@ $< quiet_cmd_vdso32cc = VDSO32C $@ - cmd_vdso32cc = $(VDSOCC) $(c_flags) $(CC32FLAGS) -c -o $@ $< + cmd_vdso32cc = $(VDSOCC) $(filter-out $(CC32FLAGSREMOVE), $(c_flags)) $(CC32FLAGS) -c -o $@ $<
quiet_cmd_vdso64ld_and_check = VDSO64L $@ cmd_vdso64ld_and_check = $(VDSOCC) $(ldflags-y) $(LD64FLAGS) -o $@ -Wl,-T$(filter %.lds,$^) $(filter %.o,$^); $(cmd_vdso_check)
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@csgroup.eu --- 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@csgroup.eu, 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@csgroup.eu, 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@csgroup.eu, 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@csgroup.eu, 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
On Mon, Sep 02, 2024 at 02:04:41PM +0200, Christophe Leroy wrote:
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.
Why not just wire up the selftests in the next patch like you did for v3? This seems like extra stuff for no huge reason?
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
I think you might have forgotten to add the symlink in this commit (or the next one, per my comment above, if you agree with it).
+/*
- 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)
If you don't want to do this, don't worry about it, but while I'm commenting on things, I think it's worth noting that x86, loongarch, and arm64 implementations all use the preprocessor or macros to give names to these registers -- state1,2,3,...copy1,2,3 and so forth. Might be worth doing the same if you think there's an easy and obvious way of doing it. If not -- or if that kind of work abhors you -- don't worry about it, as I'm confident enough that this code works fine. But it might be "nice to have". Up to you.
- li r4, 4
+.Lblock:
- li r31, 10
Maybe a comment here, "expand 32-byte k" or similar.
- 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 */
Never seen the period suffix. Just looked this up. Neat.
Le 02/09/2024 à 14:34, Jason A. Donenfeld a écrit :
On Mon, Sep 02, 2024 at 02:04:41PM +0200, Christophe Leroy wrote:
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.
Why not just wire up the selftests in the next patch like you did for v3? This seems like extra stuff for no huge reason?
In v3 selftests were already wired up in v3, and there was the following build failure:
$ make ARCH=powerpc CROSS_COMPILE=powerpc64le-linux- CC vdso_test_gettimeofday CC vdso_test_getcpu CC vdso_test_abi CC vdso_test_clock_getres CC vdso_test_correctness CC vdso_test_getrandom CC vdso_test_chacha /home/chleroy/linux-powerpc/tools/testing/selftests/../../../tools/arch/powerpc/vdso/vgetrandom-chacha.S: Assembler messages: /home/chleroy/linux-powerpc/tools/testing/selftests/../../../tools/arch/powerpc/vdso/vgetrandom-chacha.S:84: Error: `stmw' invalid when little-endian /home/chleroy/linux-powerpc/tools/testing/selftests/../../../tools/arch/powerpc/vdso/vgetrandom-chacha.S:198: Error: `lmw' invalid when little-endian make: *** [../lib.mk:222: /home/chleroy/linux-powerpc/tools/testing/selftests/vDSO/vdso_test_chacha] Error 1
So I did this change to get a clean PPC32 implementation before going into PPC64. I thought it was easier to go in two steps for reviews, bisectability, etc .... for just a very little extra stuff.
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
I think you might have forgotten to add the symlink in this commit (or the next one, per my comment above, if you agree with it).
???? That's odd. All CI tests on github went ok !!! Looks like the CI tests for selftests are broken. Argh ! And of course on my computer the link was there so I didn't notice.
+/*
- 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)
If you don't want to do this, don't worry about it, but while I'm commenting on things, I think it's worth noting that x86, loongarch, and arm64 implementations all use the preprocessor or macros to give names to these registers -- state1,2,3,...copy1,2,3 and so forth. Might be worth doing the same if you think there's an easy and obvious way of doing it. If not -- or if that kind of work abhors you -- don't worry about it, as I'm confident enough that this code works fine. But it might be "nice to have". Up to you.
I'll have a look.
- li r4, 4
+.Lblock:
- li r31, 10
Maybe a comment here, "expand 32-byte k" or similar.
ok
- 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
- subic. r0, r0, 1 /* subi. can't use r0 as source */
Never seen the period suffix. Just looked this up. Neat.
Not sure what your comment is. Are you talking about the dot suffix after subic ?
That dot means I want CR register to be updated by the instruction. It is equivalent to doing a comparision of the result with 0. It is used by the bne (branch if not equal) a few lines later.
Extend getrandom() vDSO implementation to powerpc64.
Tested on QEMU on both ppc64_defconfig and ppc64le_defconfig.
The results are not precise as it is QEMU on an x86 laptop, but no need to be precise to see the benefit.
~ # ./vdso_test_getrandom bench-single vdso: 25000000 times in 4.977777162 seconds libc: 25000000 times in 75.516749981 seconds syscall: 25000000 times in 86.842242014 seconds
~ # ./vdso_test_getrandom bench-single vdso: 25000000 times in 6.473814156 seconds libc: 25000000 times in 73.875109463 seconds syscall: 25000000 times in 71.805066229 seconds
Signed-off-by: Christophe Leroy christophe.leroy@csgroup.eu --- v4: - Use __BIG_ENDIAN__ which is defined by GCC instead of CONFIG_CPU_BIG_ENDIAN which is unknown by selftests - Implement a cleaner/smaller output copy for little endian instead of keeping compat macro.
v3: New (split out of previous patch) --- arch/powerpc/Kconfig | 2 +- arch/powerpc/include/asm/mman.h | 2 +- arch/powerpc/kernel/vdso/Makefile | 11 +- arch/powerpc/kernel/vdso/getrandom.S | 16 +-- arch/powerpc/kernel/vdso/vgetrandom-chacha.S | 117 ++++++++++++++++++- arch/powerpc/kernel/vdso/vgetrandom.c | 2 - 6 files changed, 132 insertions(+), 18 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 54b270ef18b1..b45452ac4a73 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -311,7 +311,7 @@ config PPC select SYSCTL_EXCEPTION_TRACE select THREAD_INFO_IN_TASK select TRACE_IRQFLAGS_SUPPORT - select VDSO_GETRANDOM if PPC32 + select VDSO_GETRANDOM # # Please keep this list sorted alphabetically. # diff --git a/arch/powerpc/include/asm/mman.h b/arch/powerpc/include/asm/mman.h index 17a77d47ed6d..42a51a993d94 100644 --- a/arch/powerpc/include/asm/mman.h +++ b/arch/powerpc/include/asm/mman.h @@ -6,7 +6,7 @@
#include <uapi/asm/mman.h>
-#ifdef CONFIG_PPC64 +#if defined(CONFIG_PPC64) && !defined(BUILD_VDSO)
#include <asm/cputable.h> #include <linux/mm.h> diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile index af3ba61b022e..56fb1633529a 100644 --- a/arch/powerpc/kernel/vdso/Makefile +++ b/arch/powerpc/kernel/vdso/Makefile @@ -9,7 +9,7 @@ obj-vdso32 = sigtramp32-32.o gettimeofday-32.o datapage-32.o cacheflush-32.o not 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 +obj-vdso64 += getrandom-64.o vgetrandom-chacha-64.o
ifneq ($(c-gettimeofday-y),) CFLAGS_vgettimeofday-32.o += -include $(c-gettimeofday-y) @@ -22,6 +22,7 @@ endif
ifneq ($(c-getrandom-y),) CFLAGS_vgetrandom-32.o += -include $(c-getrandom-y) + CFLAGS_vgetrandom-64.o += -include $(c-getrandom-y) $(call cc-option, -ffixed-r30) endif
# Build rules @@ -35,10 +36,10 @@ endif 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 +targets += $(obj-vdso64) vdso64.so.dbg vgettimeofday-64.o vgetrandom-64.o obj-vdso64 := $(addprefix $(obj)/, $(obj-vdso64))
-ccflags-y := -fno-common -fno-builtin +ccflags-y := -fno-common -fno-builtin -DBUILD_VDSO ccflags-y += $(DISABLE_LATENT_ENTROPY_PLUGIN) ccflags-y += $(call cc-option, -fno-stack-protector) ccflags-y += -DDISABLE_BRANCH_PROFILING @@ -72,7 +73,7 @@ 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)/vgetrandom-32.o $(obj)/crtsavres-32.o FORCE $(call if_changed,vdso32ld_and_check) -$(obj)/vdso64.so.dbg: $(obj)/vdso64.lds $(obj-vdso64) $(obj)/vgettimeofday-64.o FORCE +$(obj)/vdso64.so.dbg: $(obj)/vdso64.lds $(obj-vdso64) $(obj)/vgettimeofday-64.o $(obj)/vgetrandom-64.o FORCE $(call if_changed,vdso64ld_and_check)
# assembly rules for the .S files @@ -88,6 +89,8 @@ $(obj-vdso64): %-64.o: %.S FORCE $(call if_changed_dep,vdso64as) $(obj)/vgettimeofday-64.o: %-64.o: %.c FORCE $(call if_changed_dep,cc_o_c) +$(obj)/vgetrandom-64.o: %-64.o: %.c FORCE + $(call if_changed_dep,cc_o_c)
# Generate VDSO offsets using helper script gen-vdso32sym := $(src)/gen_vdso32_offsets.sh diff --git a/arch/powerpc/kernel/vdso/getrandom.S b/arch/powerpc/kernel/vdso/getrandom.S index 7db51c0635a5..a957cd2b2b03 100644 --- a/arch/powerpc/kernel/vdso/getrandom.S +++ b/arch/powerpc/kernel/vdso/getrandom.S @@ -5,8 +5,6 @@ * * Copyright (C) 2024 Christophe Leroy christophe.leroy@csgroup.eu, CS GROUP France */ -#include <linux/errno.h> - #include <asm/processor.h> #include <asm/ppc_asm.h> #include <asm/vdso.h> @@ -29,10 +27,18 @@ .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 +#ifdef __powerpc64__ + PPC_STL r2, PPC_MIN_STKFRM + STK_GOT(r1) + .cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT +#endif get_datapage r8 addi r8, r8, VDSO_RNG_DATA_OFFSET bl CFUNC(DOTSYM(\funct)) PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) +#ifdef __powerpc64__ + PPC_LL r2, PPC_MIN_STKFRM + STK_GOT(r1) + .cfi_restore r2 +#endif cmpwi r3, 0 mtlr r0 addi r1, r1, 2 * PPC_MIN_STKFRM @@ -48,11 +54,5 @@
.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/vgetrandom-chacha.S b/arch/powerpc/kernel/vdso/vgetrandom-chacha.S index 17a2f586223a..6b334bcef017 100644 --- a/arch/powerpc/kernel/vdso/vgetrandom-chacha.S +++ b/arch/powerpc/kernel/vdso/vgetrandom-chacha.S @@ -80,14 +80,58 @@ */ SYM_FUNC_START(__arch_chacha20_blocks_nostack) #ifdef __powerpc64__ - blr + std r5, -216(r1) + + std r14, -144(r1) + std r15, -136(r1) + std r16, -128(r1) + std r17, -120(r1) + std r18, -112(r1) + std r19, -104(r1) + std r20, -96(r1) + std r21, -88(r1) + std r22, -80(r1) + std r23, -72(r1) + std r24, -64(r1) + std r25, -56(r1) + std r26, -48(r1) + std r27, -40(r1) + std r28, -32(r1) + std r29, -24(r1) + std r30, -16(r1) + std r31, -8(r1) #else stwu r1, -96(r1) stw r5, 20(r1) +#ifdef __BIG_ENDIAN__ stmw r14, 24(r1) +#else + stw r14, 24(r1) + stw r15, 28(r1) + stw r16, 32(r1) + stw r17, 36(r1) + stw r18, 40(r1) + stw r19, 44(r1) + stw r20, 48(r1) + stw r21, 52(r1) + stw r22, 56(r1) + stw r23, 60(r1) + stw r24, 64(r1) + stw r25, 68(r1) + stw r26, 72(r1) + stw r27, 76(r1) + stw r28, 80(r1) + stw r29, 84(r1) + stw r30, 88(r1) + stw r31, 92(r1) +#endif +#endif
lwz r14, 0(r5) lwz r15, 4(r5) +#ifdef __powerpc64__ + rldimi r14, r15, 32, 0 +#endif mr r0, r6 subi r3, r3, 4
@@ -156,6 +200,7 @@ SYM_FUNC_START(__arch_chacha20_blocks_nostack) add r28, r28, r14 add r29, r29, r15
+#ifdef __BIG_ENDIAN__ stwbrx r16, r4, r3 addi r3, r3, 8 stwbrx r17, 0, r3 @@ -180,15 +225,42 @@ SYM_FUNC_START(__arch_chacha20_blocks_nostack) stwbrx r30, r4, r3 addi r3, r3, 8 stwbrx r31, 0, r3 +#else + stw r16, 4(r3) + stw r17, 8(r3) + stw r18, 12(r3) + stw r19, 16(r3) + stw r20, 20(r3) + stw r21, 24(r3) + stw r22, 28(r3) + stw r23, 32(r3) + stw r24, 36(r3) + stw r25, 40(r3) + stw r26, 44(r3) + stw r27, 48(r3) + stw r28, 52(r3) + stw r29, 56(r3) + stw r30, 60(r3) + stwu r31, 64(r3) +#endif
subic. r0, r0, 1 /* subi. can't use r0 as source */
+#ifdef __powerpc64__ + addi r14, r14, 1 + srdi r15, r14, 32 +#else addic r14, r14, 1 addze r15, r15 +#endif
bne .Lblock
+#ifdef __powerpc64__ + ld r5, -216(r1) +#else lwz r5, 20(r1) +#endif stw r14, 0(r5) stw r15, 4(r5)
@@ -200,8 +272,49 @@ SYM_FUNC_START(__arch_chacha20_blocks_nostack) li r11, 0 li r12, 0
+#ifdef __powerpc64__ + ld r14, -144(r1) + ld r15, -136(r1) + ld r16, -128(r1) + ld r17, -120(r1) + ld r18, -112(r1) + ld r19, -104(r1) + ld r20, -96(r1) + ld r21, -88(r1) + ld r22, -80(r1) + ld r23, -72(r1) + ld r24, -64(r1) + ld r25, -56(r1) + ld r26, -48(r1) + ld r27, -40(r1) + ld r28, -32(r1) + ld r29, -24(r1) + ld r30, -16(r1) + ld r31, -8(r1) +#else +#ifdef __BIG_ENDIAN__ lmw r14, 24(r1) +#else + lwz r14, 24(r1) + lwz r15, 28(r1) + lwz r16, 32(r1) + lwz r17, 36(r1) + lwz r18, 40(r1) + lwz r19, 44(r1) + lwz r20, 48(r1) + lwz r21, 52(r1) + lwz r22, 56(r1) + lwz r23, 60(r1) + lwz r24, 64(r1) + lwz r25, 68(r1) + lwz r26, 72(r1) + lwz r27, 76(r1) + lwz r28, 80(r1) + lwz r29, 84(r1) + lwz r30, 88(r1) + lwz r31, 92(r1) +#endif addi r1, r1, 96 - blr #endif + blr SYM_FUNC_END(__arch_chacha20_blocks_nostack) diff --git a/arch/powerpc/kernel/vdso/vgetrandom.c b/arch/powerpc/kernel/vdso/vgetrandom.c index 923330845b2c..5f855d45fb7b 100644 --- a/arch/powerpc/kernel/vdso/vgetrandom.c +++ b/arch/powerpc/kernel/vdso/vgetrandom.c @@ -7,10 +7,8 @@ #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
On Mon, Sep 02, 2024 at 02:04:42PM +0200, Christophe Leroy wrote:
SYM_FUNC_START(__arch_chacha20_blocks_nostack) #ifdef __powerpc64__
- blr
- std r5, -216(r1)
- std r14, -144(r1)
- std r15, -136(r1)
- std r16, -128(r1)
- std r17, -120(r1)
- std r18, -112(r1)
- std r19, -104(r1)
- std r20, -96(r1)
- std r21, -88(r1)
- std r22, -80(r1)
- std r23, -72(r1)
- std r24, -64(r1)
- std r25, -56(r1)
- std r26, -48(r1)
- std r27, -40(r1)
- std r28, -32(r1)
- std r29, -24(r1)
- std r30, -16(r1)
- std r31, -8(r1)
#else stwu r1, -96(r1) stw r5, 20(r1) +#ifdef __BIG_ENDIAN__ stmw r14, 24(r1) +#else
- stw r14, 24(r1)
- stw r15, 28(r1)
- stw r16, 32(r1)
- stw r17, 36(r1)
- stw r18, 40(r1)
- stw r19, 44(r1)
- stw r20, 48(r1)
- stw r21, 52(r1)
- stw r22, 56(r1)
- stw r23, 60(r1)
- stw r24, 64(r1)
- stw r25, 68(r1)
- stw r26, 72(r1)
- stw r27, 76(r1)
- stw r28, 80(r1)
- stw r29, 84(r1)
- stw r30, 88(r1)
- stw r31, 92(r1)
+#endif +#endif
This confuses me. Why are you adding code to the !__powerpc64__ branch in this commit? (Also, why does stmw not work on LE?)
Le 02/09/2024 à 14:41, Jason A. Donenfeld a écrit :
On Mon, Sep 02, 2024 at 02:04:42PM +0200, Christophe Leroy wrote:
SYM_FUNC_START(__arch_chacha20_blocks_nostack) #ifdef __powerpc64__
- blr
- std r5, -216(r1)
- std r14, -144(r1)
- std r15, -136(r1)
- std r16, -128(r1)
- std r17, -120(r1)
- std r18, -112(r1)
- std r19, -104(r1)
- std r20, -96(r1)
- std r21, -88(r1)
- std r22, -80(r1)
- std r23, -72(r1)
- std r24, -64(r1)
- std r25, -56(r1)
- std r26, -48(r1)
- std r27, -40(r1)
- std r28, -32(r1)
- std r29, -24(r1)
- std r30, -16(r1)
- std r31, -8(r1) #else stwu r1, -96(r1) stw r5, 20(r1)
+#ifdef __BIG_ENDIAN__ stmw r14, 24(r1) +#else
- stw r14, 24(r1)
- stw r15, 28(r1)
- stw r16, 32(r1)
- stw r17, 36(r1)
- stw r18, 40(r1)
- stw r19, 44(r1)
- stw r20, 48(r1)
- stw r21, 52(r1)
- stw r22, 56(r1)
- stw r23, 60(r1)
- stw r24, 64(r1)
- stw r25, 68(r1)
- stw r26, 72(r1)
- stw r27, 76(r1)
- stw r28, 80(r1)
- stw r29, 84(r1)
- stw r30, 88(r1)
- stw r31, 92(r1)
+#endif +#endif
This confuses me. Why are you adding code to the !__powerpc64__ branch in this commit? (Also, why does stmw not work on LE?)
That's for the VDSO32 ie running 32 bits binaries on a 64 bits kernel.
"Programming Environments Manual for 32-Bit Implementations of the PowerPC™ Architecture" say: In some implementations operating with little-endian byte order, execution of an lmw or stmw instruction causes the system alignment error handler to be invoked
And GCC doesn't like it either:
tools/arch/powerpc/vdso/vgetrandom-chacha.S:84: Error: `stmw' invalid when little-endian
On Mon, Sep 02, 2024 at 03:12:47PM +0200, Christophe Leroy wrote:
Le 02/09/2024 à 14:41, Jason A. Donenfeld a écrit :
On Mon, Sep 02, 2024 at 02:04:42PM +0200, Christophe Leroy wrote:
SYM_FUNC_START(__arch_chacha20_blocks_nostack) #ifdef __powerpc64__
- blr
- std r5, -216(r1)
- std r14, -144(r1)
- std r15, -136(r1)
- std r16, -128(r1)
- std r17, -120(r1)
- std r18, -112(r1)
- std r19, -104(r1)
- std r20, -96(r1)
- std r21, -88(r1)
- std r22, -80(r1)
- std r23, -72(r1)
- std r24, -64(r1)
- std r25, -56(r1)
- std r26, -48(r1)
- std r27, -40(r1)
- std r28, -32(r1)
- std r29, -24(r1)
- std r30, -16(r1)
- std r31, -8(r1) #else stwu r1, -96(r1) stw r5, 20(r1)
+#ifdef __BIG_ENDIAN__ stmw r14, 24(r1) +#else
- stw r14, 24(r1)
- stw r15, 28(r1)
- stw r16, 32(r1)
- stw r17, 36(r1)
- stw r18, 40(r1)
- stw r19, 44(r1)
- stw r20, 48(r1)
- stw r21, 52(r1)
- stw r22, 56(r1)
- stw r23, 60(r1)
- stw r24, 64(r1)
- stw r25, 68(r1)
- stw r26, 72(r1)
- stw r27, 76(r1)
- stw r28, 80(r1)
- stw r29, 84(r1)
- stw r30, 88(r1)
- stw r31, 92(r1)
+#endif +#endif
This confuses me. Why are you adding code to the !__powerpc64__ branch in this commit? (Also, why does stmw not work on LE?)
That's for the VDSO32 ie running 32 bits binaries on a 64 bits kernel.
"Programming Environments Manual for 32-Bit Implementations of the PowerPC™ Architecture" say: In some implementations operating with little-endian byte order, execution of an lmw or stmw instruction causes the system alignment error handler to be invoked
And GCC doesn't like it either:
tools/arch/powerpc/vdso/vgetrandom-chacha.S:84: Error: `stmw' invalid when little-endian
Does it make sense to do all the 32-bit stuff in the PPC32 commit (and then you can introduce the selftests there without the error you mentioned), and then add the 64-bit stuff in this commit?
Le 02/09/2024 à 16:00, Jason A. Donenfeld a écrit :
On Mon, Sep 02, 2024 at 03:12:47PM +0200, Christophe Leroy wrote:
Le 02/09/2024 à 14:41, Jason A. Donenfeld a écrit :
On Mon, Sep 02, 2024 at 02:04:42PM +0200, Christophe Leroy wrote:
SYM_FUNC_START(__arch_chacha20_blocks_nostack) #ifdef __powerpc64__
- blr
- std r5, -216(r1)
- std r14, -144(r1)
- std r15, -136(r1)
- std r16, -128(r1)
- std r17, -120(r1)
- std r18, -112(r1)
- std r19, -104(r1)
- std r20, -96(r1)
- std r21, -88(r1)
- std r22, -80(r1)
- std r23, -72(r1)
- std r24, -64(r1)
- std r25, -56(r1)
- std r26, -48(r1)
- std r27, -40(r1)
- std r28, -32(r1)
- std r29, -24(r1)
- std r30, -16(r1)
- std r31, -8(r1) #else stwu r1, -96(r1) stw r5, 20(r1)
+#ifdef __BIG_ENDIAN__ stmw r14, 24(r1) +#else
- stw r14, 24(r1)
- stw r15, 28(r1)
- stw r16, 32(r1)
- stw r17, 36(r1)
- stw r18, 40(r1)
- stw r19, 44(r1)
- stw r20, 48(r1)
- stw r21, 52(r1)
- stw r22, 56(r1)
- stw r23, 60(r1)
- stw r24, 64(r1)
- stw r25, 68(r1)
- stw r26, 72(r1)
- stw r27, 76(r1)
- stw r28, 80(r1)
- stw r29, 84(r1)
- stw r30, 88(r1)
- stw r31, 92(r1)
+#endif +#endif
This confuses me. Why are you adding code to the !__powerpc64__ branch in this commit? (Also, why does stmw not work on LE?)
That's for the VDSO32 ie running 32 bits binaries on a 64 bits kernel.
"Programming Environments Manual for 32-Bit Implementations of the PowerPC™ Architecture" say: In some implementations operating with little-endian byte order, execution of an lmw or stmw instruction causes the system alignment error handler to be invoked
And GCC doesn't like it either:
tools/arch/powerpc/vdso/vgetrandom-chacha.S:84: Error: `stmw' invalid when little-endian
Does it make sense to do all the 32-bit stuff in the PPC32 commit (and then you can introduce the selftests there without the error you mentioned), and then add the 64-bit stuff in this commit?
Can do that, but there will still be a problem with chacha selftests if I don't opt-out the entire function content when it is ppc64. It will build properly but if someone runs it on a ppc64 it will likely crash because only the low 32 bits of registers will be saved.
That's the reason why I really prefered the approach where I set something in vdso_config.h so that the assembly is used only for powerpc32 and when building powerpc64 the assembly part is kept out and vdso_test_chacha simply tells it is not supported.
Christophe
On Mon, Sep 02, 2024 at 04:16:48PM +0200, Christophe Leroy wrote:
Can do that, but there will still be a problem with chacha selftests if I don't opt-out the entire function content when it is ppc64. It will build properly but if someone runs it on a ppc64 it will likely crash because only the low 32 bits of registers will be saved.
What if you don't wire up the selftests _at all_ until the ppc64 commit? Then there'll be no risk.
(And I think I would prefer to see the 32-bit code all in the 32-bit commit; that'd make it more straight forward to review too.)
Hi Jason, hi Michael,
Le 02/09/2024 à 16:19, Jason A. Donenfeld a écrit :
On Mon, Sep 02, 2024 at 04:16:48PM +0200, Christophe Leroy wrote:
Can do that, but there will still be a problem with chacha selftests if I don't opt-out the entire function content when it is ppc64. It will build properly but if someone runs it on a ppc64 it will likely crash because only the low 32 bits of registers will be saved.
What if you don't wire up the selftests _at all_ until the ppc64 commit? Then there'll be no risk.
(And I think I would prefer to see the 32-bit code all in the 32-bit commit; that'd make it more straight forward to review too.)
I'd be fine with that but I'd like feedback from Michael on it: Is there a risk to only get PPC32 part merged as a first step or will both PPC32 and PPC64 go together anyway ?
I would prefer not to delay PPC32 because someone doesn't feel confident with PPC64.
Christophe
On Mon, Sep 02, 2024 at 04:27:12PM +0200, Christophe Leroy wrote:
Hi Jason, hi Michael,
Le 02/09/2024 à 16:19, Jason A. Donenfeld a écrit :
On Mon, Sep 02, 2024 at 04:16:48PM +0200, Christophe Leroy wrote:
Can do that, but there will still be a problem with chacha selftests if I don't opt-out the entire function content when it is ppc64. It will build properly but if someone runs it on a ppc64 it will likely crash because only the low 32 bits of registers will be saved.
What if you don't wire up the selftests _at all_ until the ppc64 commit? Then there'll be no risk.
(And I think I would prefer to see the 32-bit code all in the 32-bit commit; that'd make it more straight forward to review too.)
I'd be fine with that but I'd like feedback from Michael on it: Is there a risk to only get PPC32 part merged as a first step or will both PPC32 and PPC64 go together anyway ?
I would prefer not to delay PPC32 because someone doesn't feel confident with PPC64.
I have no objection to applying these at the same time.
linux-kselftest-mirror@lists.linaro.org
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Christophe Leroy -
Jason A. Donenfeld