[PATCH v5 5/5] powerpc/vdso: Wire up getrandom() vDSO implementation on VDSO64
Madhavan Srinivasan
maddy at linux.ibm.com
Wed Sep 4 21:46:21 AEST 2024
On 9/3/24 12:47 AM, Christophe Leroy wrote:
> Extend getrandom() vDSO implementation to VDSO64
>
> 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
Tried the patchset on top of
https://kernel.googlesource.com/pub/scm/linux/kernel/git/crng/random.git
(commit 963233ff013377bc2aa0d641b9efbb7fd4c2b72c (origin/master,
origin/HEAD, master))
Results from a Power9 (PowerNV)
# ./vdso_test_getrandom bench-single
vdso: 25000000 times in 0.787943615 seconds
libc: 25000000 times in 14.101887252 seconds
syscall: 25000000 times in 14.047475082 seconds
Impressive, thanks for enabling it.
Tested-by: Madhavan Srinivasan <maddy at linux.ibm.com>
> Signed-off-by: Christophe Leroy <christophe.leroy at csgroup.eu>
> ---
> v5:
> - VDSO32 for both PPC32 and PPC64 is in previous patch. This patch have the logic for VDSO64.
>
> 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/kernel/vdso/Makefile | 8 ++-
> arch/powerpc/kernel/vdso/getrandom.S | 8 +++
> arch/powerpc/kernel/vdso/vdso64.lds.S | 1 +
> arch/powerpc/kernel/vdso/vgetrandom-chacha.S | 53 ++++++++++++++++++++
> 5 files changed, 69 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index e500a59ddecc..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 VDSO32
> + select VDSO_GETRANDOM
> #
> # Please keep this list sorted alphabetically.
> #
> diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile
> index 7a4a935406d8..56fb1633529a 100644
> --- a/arch/powerpc/kernel/vdso/Makefile
> +++ b/arch/powerpc/kernel/vdso/Makefile
> @@ -9,6 +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 vgetrandom-chacha-64.o
>
> ifneq ($(c-gettimeofday-y),)
> CFLAGS_vgettimeofday-32.o += -include $(c-gettimeofday-y)
> @@ -21,6 +22,7 @@ endif
>
> ifneq ($(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
> @@ -34,7 +36,7 @@ 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 -DBUILD_VDSO
> @@ -71,7 +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
> @@ -87,6 +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 21773ef3fc1d..a957cd2b2b03 100644
> --- a/arch/powerpc/kernel/vdso/getrandom.S
> +++ b/arch/powerpc/kernel/vdso/getrandom.S
> @@ -27,10 +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
> 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
> index ac85788205cb..7f9061a9e8b4 100644
> --- a/arch/powerpc/kernel/vdso/vgetrandom-chacha.S
> +++ b/arch/powerpc/kernel/vdso/vgetrandom-chacha.S
> @@ -124,6 +124,26 @@
> */
> SYM_FUNC_START(__arch_chacha20_blocks_nostack)
> #ifdef __powerpc64__
> + std counter, -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 counter, 20(r1)
> @@ -149,9 +169,13 @@ SYM_FUNC_START(__arch_chacha20_blocks_nostack)
> stw r30, 88(r1)
> stw r31, 92(r1)
> #endif
> +#endif /* __powerpc64__ */
>
> lwz counter0, 0(counter)
> lwz counter1, 4(counter)
> +#ifdef __powerpc64__
> + rldimi counter0, counter1, 32, 0
> +#endif
> mr idx_r0, nblocks
> subi dst_bytes, dst_bytes, 4
>
> @@ -267,12 +291,21 @@ SYM_FUNC_START(__arch_chacha20_blocks_nostack)
>
> subic. idx_r0, idx_r0, 1 /* subi. can't use r0 as source */
>
> +#ifdef __powerpc64__
> + addi counter0, counter0, 1
> + srdi counter1, counter0, 32
> +#else
> addic counter0, counter0, 1
> addze counter1, counter1
> +#endif
>
> bne .Lblock
>
> +#ifdef __powerpc64__
> + ld counter, -216(r1)
> +#else
> lwz counter, 20(r1)
> +#endif
> stw counter0, 0(counter)
> stw counter1, 4(counter)
>
> @@ -284,6 +317,26 @@ 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
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