| Message ID | 1f49c2ce009f8b007ab0676fb41187b2d54f28b2.1725304404.git.christophe.leroy@csgroup.eu (mailing list archive) |
|---|---|
| State | Handled Elsewhere, archived |
| Headers | show |
| Series | Wire up getrandom() vDSO implementation on powerpc | expand |
> +/* > + * 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 You wrote in an earlier email that this worked with time namespaces, but in my testing that doesn't seem to be the case. From my test harness [1]: Normal single thread vdso: 25000000 times in 12.494133131 seconds libc: 25000000 times in 69.594625188 seconds syscall: 25000000 times in 67.349243972 seconds Time namespace single thread vdso: 25000000 times in 71.673057436 seconds libc: 25000000 times in 71.712774121 seconds syscall: 25000000 times in 66.902318080 seconds I'm seeing this on ppc, ppc64, and ppc64le. Can you figure out what's going on and send a fix, which I'll squash into this commit? Jason [1] https://git.zx2c4.com/linux-rng/commit/?h=jd/vdso-test-harness
On Thu, Sep 05, 2024 at 06:13:29PM +0200, Jason A. Donenfeld wrote: > > +/* > > + * 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 > > You wrote in an earlier email that this worked with time namespaces, but > in my testing that doesn't seem to be the case. > > From my test harness [1]: > > Normal single thread > vdso: 25000000 times in 12.494133131 seconds > libc: 25000000 times in 69.594625188 seconds > syscall: 25000000 times in 67.349243972 seconds > Time namespace single thread > vdso: 25000000 times in 71.673057436 seconds > libc: 25000000 times in 71.712774121 seconds > syscall: 25000000 times in 66.902318080 seconds > > I'm seeing this on ppc, ppc64, and ppc64le. > > Can you figure out what's going on and send a fix, which I'll squash > into this commit? Also, FYI, I've verified that things do work on x86_64, loongarch64, arm64, and arm64_be. It's just the ppc archs that are broken. So this test _is_ a good one.
Le 05/09/2024 à 18:13, Jason A. Donenfeld a écrit : >> +/* >> + * 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 > > You wrote in an earlier email that this worked with time namespaces, but > in my testing that doesn't seem to be the case. Did I write that ? I can't remember and neither can I remember testing it with time namespaces. > > From my test harness [1]: > > Normal single thread > vdso: 25000000 times in 12.494133131 seconds > libc: 25000000 times in 69.594625188 seconds > syscall: 25000000 times in 67.349243972 seconds > Time namespace single thread > vdso: 25000000 times in 71.673057436 seconds > libc: 25000000 times in 71.712774121 seconds > syscall: 25000000 times in 66.902318080 seconds > > I'm seeing this on ppc, ppc64, and ppc64le. What is the command to use to test with time namespace ? > > Can you figure out what's going on and send a fix, which I'll squash > into this commit? Sure > > Jason > > [1] https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.zx2c4.com%2Flinux-rng%2Fcommit%2F%3Fh%3Djd%2Fvdso-test-harness&data=05%7C02%7Cchristophe.leroy%40csgroup.eu%7C59fa9061064945c73a1608dccdc5b51c%7C8b87af7d86474dc78df45f69a2011bb5%7C0%7C0%7C638611496253413014%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=ZUJqhcnZL7SYkuXUIt9Nlo46sZj26VYW%2F8I%2BrBLRpBE%3D&reserved=0
On Thu, 2024-09-05 at 18:55 +0200, Christophe Leroy wrote: > > Normal single thread > > vdso: 25000000 times in 12.494133131 seconds > > libc: 25000000 times in 69.594625188 seconds > > syscall: 25000000 times in 67.349243972 seconds > > Time namespace single thread > > vdso: 25000000 times in 71.673057436 seconds > > libc: 25000000 times in 71.712774121 seconds > > syscall: 25000000 times in 66.902318080 seconds > > > > I'm seeing this on ppc, ppc64, and ppc64le. > > What is the command to use to test with time namespace ? Assuming user namespace and time namespace are available: $ unshare -r -T --boottime $((365*24*3600)) It'll start a new shell where you are pretended to be the root (i.e. the root in the separated user namespace). Then: # uptime 00:57:17 up 365 days, 57 min, 2 users, load average: 0.19, 0.30, 0.32 So in the separated time namespace the system is pretended to have been booted for 1 year. Now: # /path/to/linux.git/tools/testing/selftests/vDSO/vdso_test_getrandom bench_single vdso: 25000000 times in 0.419125373 seconds libc: 25000000 times in 5.985498234 seconds syscall: 25000000 times in 5.993506773 seconds This is on x86_64, indicating vDSO getrandom is fine for x86_64 in a separated time namespace. If user namespace isn't available (disabled building the kernel or disabled by the security policy of some distros) use $ sudo unshare -T --boottime $((365*24*3600)) to create the time namespace instead. But note that with this approach you'll be operating as the real root user and be careful not to break things.
On Thu, Sep 05, 2024 at 06:55:27PM +0200, Christophe Leroy wrote: > > > Le 05/09/2024 à 18:13, Jason A. Donenfeld a écrit : > >> +/* > >> + * 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 > > > > You wrote in an earlier email that this worked with time namespaces, but > > in my testing that doesn't seem to be the case. > > Did I write that ? I can't remember and neither can I remember testing > it with time namespaces. It's possible I confused you with someone else? Hum. Anyway... > > From my test harness [1]: > > > > Normal single thread > > vdso: 25000000 times in 12.494133131 seconds > > libc: 25000000 times in 69.594625188 seconds > > syscall: 25000000 times in 67.349243972 seconds > > Time namespace single thread > > vdso: 25000000 times in 71.673057436 seconds > > libc: 25000000 times in 71.712774121 seconds > > syscall: 25000000 times in 66.902318080 seconds > > > > I'm seeing this on ppc, ppc64, and ppc64le. > > What is the command to use to test with time namespace ? Look at the C in the commit I linked.
On Thu, Sep 05, 2024 at 07:03:34PM +0200, Jason A. Donenfeld wrote: > On Thu, Sep 05, 2024 at 06:55:27PM +0200, Christophe Leroy wrote: > > > > > > Le 05/09/2024 à 18:13, Jason A. Donenfeld a écrit : > > >> +/* > > >> + * 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 > > > > > > You wrote in an earlier email that this worked with time namespaces, but > > > in my testing that doesn't seem to be the case. > > > > Did I write that ? I can't remember and neither can I remember testing > > it with time namespaces. > > It's possible I confused you with someone else? Hum. Anyway... > > > > From my test harness [1]: > > > > > > Normal single thread > > > vdso: 25000000 times in 12.494133131 seconds > > > libc: 25000000 times in 69.594625188 seconds > > > syscall: 25000000 times in 67.349243972 seconds > > > Time namespace single thread > > > vdso: 25000000 times in 71.673057436 seconds > > > libc: 25000000 times in 71.712774121 seconds > > > syscall: 25000000 times in 66.902318080 seconds > > > > > > I'm seeing this on ppc, ppc64, and ppc64le. > > > > What is the command to use to test with time namespace ? > > Look at the C in the commit I linked. The below also seems to work well for testing on x86. I'll clean that up and send a patch to the list. diff --git a/tools/testing/selftests/vDSO/vdso_test_getrandom.c b/tools/testing/selftests/vDSO/vdso_test_getrandom.c index 8866b65a4605..4df80f769aa7 100644 --- a/tools/testing/selftests/vDSO/vdso_test_getrandom.c +++ b/tools/testing/selftests/vDSO/vdso_test_getrandom.c @@ -16,8 +16,11 @@ #include <sys/mman.h> #include <sys/random.h> #include <sys/syscall.h> +#include <sys/ptrace.h> +#include <sys/wait.h> #include <sys/types.h> #include <linux/random.h> +#include <linux/ptrace.h> #include "../kselftest.h" #include "parse_vdso.h" @@ -239,9 +242,10 @@ static void fill(void) static void kselftest(void) { uint8_t weird_size[1263]; + pid_t child; ksft_print_header(); - ksft_set_plan(1); + ksft_set_plan(2); for (size_t i = 0; i < 1000; ++i) { ssize_t ret = vgetrandom(weird_size, sizeof(weird_size), 0); @@ -250,6 +254,39 @@ static void kselftest(void) } ksft_test_result_pass("getrandom: PASS\n"); + + assert(unshare(CLONE_NEWTIME) == 0); + child = fork(); + assert(child >= 0); + + if (!child) { + vgetrandom_init(); + child = getpid(); + assert(ptrace(PTRACE_TRACEME, 0, NULL, NULL) == 0); + assert(kill(child, SIGSTOP) == 0); + assert(vgetrandom(weird_size, sizeof(weird_size), 0) == sizeof(weird_size)); + _exit(0); + } + for (;;) { + struct ptrace_syscall_info info = { 0 }; + int status, ret; + assert(waitpid(child, &status, 0) >= 0); + if (WIFEXITED(status)) + break; + assert(WIFSTOPPED(status)); + if (WSTOPSIG(status) == SIGSTOP) + assert(ptrace(PTRACE_SETOPTIONS, child, 0, PTRACE_O_TRACESYSGOOD) == 0); + else if (WSTOPSIG(status) == SIGTRAP | 0x80) { + assert(ptrace(PTRACE_GET_SYSCALL_INFO, child, sizeof(info), &info) > 0); + if (info.entry.nr == __NR_getrandom && + ((void *)info.entry.args[0] == &weird_size && info.entry.args[1] == sizeof(weird_size))) + exit(KSFT_FAIL); + } + assert(ptrace(PTRACE_SYSCALL, child, 0, 0) == 0); + } + + ksft_test_result_pass("getrandom timens: PASS\n"); + exit(KSFT_PASS); }
On Thu, Sep 05, 2024 at 06:13:29PM +0200, Jason A. Donenfeld wrote: > > +/* > > + * 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 > > Can you figure out what's going on and send a fix, which I'll squash > into this commit? This doesn't work, but I wonder if something like it is what we want. I need to head out for the day, but here's what I've got. It's all wrong but might be of interest. diff --git a/arch/powerpc/include/asm/vdso/getrandom.h b/arch/powerpc/include/asm/vdso/getrandom.h index 501d6bb14e8a..acb271709d30 100644 --- a/arch/powerpc/include/asm/vdso/getrandom.h +++ b/arch/powerpc/include/asm/vdso/getrandom.h @@ -47,7 +47,8 @@ static __always_inline struct vdso_rng_data *__arch_get_vdso_rng_data(void) } 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); + size_t opaque_len, const struct vdso_data *vd, + const struct vdso_rng_data *vrd); #endif /* !__ASSEMBLY__ */ diff --git a/arch/powerpc/kernel/vdso/getrandom.S b/arch/powerpc/kernel/vdso/getrandom.S index a957cd2b2b03..bc49eb87cfd1 100644 --- a/arch/powerpc/kernel/vdso/getrandom.S +++ b/arch/powerpc/kernel/vdso/getrandom.S @@ -32,7 +32,7 @@ .cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT #endif get_datapage r8 - addi r8, r8, VDSO_RNG_DATA_OFFSET + addi r9, r8, VDSO_RNG_DATA_OFFSET bl CFUNC(DOTSYM(\funct)) PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) #ifdef __powerpc64__ diff --git a/arch/powerpc/kernel/vdso/vgetrandom.c b/arch/powerpc/kernel/vdso/vgetrandom.c index 5f855d45fb7b..408c76036868 100644 --- a/arch/powerpc/kernel/vdso/vgetrandom.c +++ b/arch/powerpc/kernel/vdso/vgetrandom.c @@ -8,7 +8,10 @@ #include <linux/types.h> 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) + size_t opaque_len, const struct vdso_data *vd, + const struct vdso_rng_data *vrd) { - return __cvdso_getrandom_data(vd, buffer, len, flags, opaque_state, opaque_len); + if (IS_ENABLED(CONFIG_TIME_NS) && vd->clock_mode == VDSO_CLOCKMODE_TIMENS) + vrd = (void *)vrd + (1UL << CONFIG_PAGE_SHIFT); + return __cvdso_getrandom_data(vrd, buffer, len, flags, opaque_state, opaque_len); }
On Thu, Sep 05, 2024 at 10:41:40PM +0200, Jason A. Donenfeld wrote: > On Thu, Sep 05, 2024 at 06:13:29PM +0200, Jason A. Donenfeld wrote: > > > +/* > > > + * 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 > > > > Can you figure out what's going on and send a fix, which I'll squash > > into this commit? > > This doesn't work, but I wonder if something like it is what we want. I > need to head out for the day, but here's what I've got. It's all wrong > but might be of interest. Oh, I just got one small detail wrong before. The below actually works, and uses the same strategy as on arm64. Let me know if you'd like me to fix up this commit with the below patch, or if you have another way you'd like to go about it. diff --git a/arch/powerpc/include/asm/vdso/getrandom.h b/arch/powerpc/include/asm/vdso/getrandom.h index 501d6bb14e8a..acb271709d30 100644 --- a/arch/powerpc/include/asm/vdso/getrandom.h +++ b/arch/powerpc/include/asm/vdso/getrandom.h @@ -47,7 +47,8 @@ static __always_inline struct vdso_rng_data *__arch_get_vdso_rng_data(void) } 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); + size_t opaque_len, const struct vdso_data *vd, + const struct vdso_rng_data *vrd); #endif /* !__ASSEMBLY__ */ diff --git a/arch/powerpc/kernel/vdso/getrandom.S b/arch/powerpc/kernel/vdso/getrandom.S index a957cd2b2b03..64cc1fad3ccc 100644 --- a/arch/powerpc/kernel/vdso/getrandom.S +++ b/arch/powerpc/kernel/vdso/getrandom.S @@ -32,7 +32,8 @@ .cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT #endif get_datapage r8 - addi r8, r8, VDSO_RNG_DATA_OFFSET + addi r9, r8, VDSO_RNG_DATA_OFFSET + addi r8, r8, VDSO_DATA_OFFSET bl CFUNC(DOTSYM(\funct)) PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) #ifdef __powerpc64__ diff --git a/arch/powerpc/kernel/vdso/vgetrandom.c b/arch/powerpc/kernel/vdso/vgetrandom.c index 5f855d45fb7b..408c76036868 100644 --- a/arch/powerpc/kernel/vdso/vgetrandom.c +++ b/arch/powerpc/kernel/vdso/vgetrandom.c @@ -8,7 +8,10 @@ #include <linux/types.h> 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) + size_t opaque_len, const struct vdso_data *vd, + const struct vdso_rng_data *vrd) { - return __cvdso_getrandom_data(vd, buffer, len, flags, opaque_state, opaque_len); + if (IS_ENABLED(CONFIG_TIME_NS) && vd->clock_mode == VDSO_CLOCKMODE_TIMENS) + vrd = (void *)vrd + (1UL << CONFIG_PAGE_SHIFT); + return __cvdso_getrandom_data(vrd, buffer, len, flags, opaque_state, opaque_len); }
On Fri, Sep 06, 2024 at 04:48:28AM +0200, Jason A. Donenfeld wrote: > On Thu, Sep 05, 2024 at 10:41:40PM +0200, Jason A. Donenfeld wrote: > > On Thu, Sep 05, 2024 at 06:13:29PM +0200, Jason A. Donenfeld wrote: > > > > +/* > > > > + * 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 > > > > > > Can you figure out what's going on and send a fix, which I'll squash > > > into this commit? > > > > This doesn't work, but I wonder if something like it is what we want. I > > need to head out for the day, but here's what I've got. It's all wrong > > but might be of interest. > > Oh, I just got one small detail wrong before. The below actually works, > and uses the same strategy as on arm64. > > Let me know if you'd like me to fix up this commit with the below patch, > or if you have another way you'd like to go about it. And here's the much shorter version in assembly, which maybe you prefer. Also works, and is a bit less invasive than the other thing. diff --git a/arch/powerpc/kernel/vdso/getrandom.S b/arch/powerpc/kernel/vdso/getrandom.S index a957cd2b2b03..070daba2d547 100644 --- a/arch/powerpc/kernel/vdso/getrandom.S +++ b/arch/powerpc/kernel/vdso/getrandom.S @@ -32,6 +32,14 @@ .cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT #endif get_datapage r8 +#ifdef CONFIG_TIME_NS + lis r10, 0x7fff + ori r10, r10, 0xffff + lwz r9, VDSO_DATA_OFFSET + 4(r8) + cmpw r9, r10 + bne +8 + addi r8, r8, (1 << CONFIG_PAGE_SHIFT) +#endif addi r8, r8, VDSO_RNG_DATA_OFFSET bl CFUNC(DOTSYM(\funct)) PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1)
Hi Jason, Le 06/09/2024 à 05:24, Jason A. Donenfeld a écrit : > On Fri, Sep 06, 2024 at 04:48:28AM +0200, Jason A. Donenfeld wrote: >> On Thu, Sep 05, 2024 at 10:41:40PM +0200, Jason A. Donenfeld wrote: >>> On Thu, Sep 05, 2024 at 06:13:29PM +0200, Jason A. Donenfeld wrote: >>>>> +/* >>>>> + * 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 >>>> >>>> Can you figure out what's going on and send a fix, which I'll squash >>>> into this commit? >>> >>> This doesn't work, but I wonder if something like it is what we want. I >>> need to head out for the day, but here's what I've got. It's all wrong >>> but might be of interest. >> >> Oh, I just got one small detail wrong before. The below actually works, >> and uses the same strategy as on arm64. >> >> Let me know if you'd like me to fix up this commit with the below patch, >> or if you have another way you'd like to go about it. > > And here's the much shorter version in assembly, which maybe you prefer. > Also works, and is a bit less invasive than the other thing. > > diff --git a/arch/powerpc/kernel/vdso/getrandom.S b/arch/powerpc/kernel/vdso/getrandom.S > index a957cd2b2b03..070daba2d547 100644 > --- a/arch/powerpc/kernel/vdso/getrandom.S > +++ b/arch/powerpc/kernel/vdso/getrandom.S > @@ -32,6 +32,14 @@ > .cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT > #endif > get_datapage r8 > +#ifdef CONFIG_TIME_NS > + lis r10, 0x7fff > + ori r10, r10, 0xffff > + lwz r9, VDSO_DATA_OFFSET + 4(r8) > + cmpw r9, r10 > + bne +8 > + addi r8, r8, (1 << CONFIG_PAGE_SHIFT) > +#endif > addi r8, r8, VDSO_RNG_DATA_OFFSET > bl CFUNC(DOTSYM(\funct)) > PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) > Thanks for looking. I came to more or less the same solutions thnt you with the following that seems to work: diff --git a/arch/powerpc/kernel/vdso/vgetrandom.c b/arch/powerpc/kernel/vdso/vgetrandom.c index 5f855d45fb7b..9705344d39d0 100644 --- a/arch/powerpc/kernel/vdso/vgetrandom.c +++ b/arch/powerpc/kernel/vdso/vgetrandom.c @@ -4,11 +4,19 @@ * * Copyright (C) 2024 Christophe Leroy <christophe.leroy@csgroup.eu>, CS GROUP France */ +#include <linux/container_of.h> #include <linux/time.h> #include <linux/types.h> +#include <asm/vdso_datapage.h> + 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) { + struct vdso_arch_data *arch_data = container_of(vd, struct vdso_arch_data, rng_data); + + if (IS_ENABLED(CONFIG_TIME_NS) && arch_data->data[0].clock_mode == VDSO_CLOCKMODE_TIMENS) + vd = (void *)vd + (1UL << CONFIG_PAGE_SHIFT); + return __cvdso_getrandom_data(vd, buffer, len, flags, opaque_state, opaque_len); } However, if we have this problem with __kernel_getrandom, don't we also have it with: ? __kernel_get_syscall_map; __kernel_get_tbfreq; __kernel_sync_dicache; If they are also affected, then get_page macro is the place to fix. I will check all of this now and keep you updated before noon (Paris Time). Christophe
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index d7b09b064a8a..e500a59ddecc 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 VDSO32 # # 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/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..7a4a935406d8 100644 --- a/arch/powerpc/kernel/vdso/Makefile +++ b/arch/powerpc/kernel/vdso/Makefile @@ -8,6 +8,8 @@ include $(srctree)/lib/vdso/Makefile obj-vdso32 = sigtramp32-32.o gettimeofday-32.o datapage-32.o cacheflush-32.o note-32.o getcpu-32.o obj-vdso64 = sigtramp64-64.o gettimeofday-64.o datapage-64.o cacheflush-64.o note-64.o getcpu-64.o +obj-vdso32 += getrandom-32.o vgetrandom-chacha-32.o + ifneq ($(c-gettimeofday-y),) CFLAGS_vgettimeofday-32.o += -include $(c-gettimeofday-y) # Go prior to 1.16.x assumes r30 is not clobbered by any VDSO code. That used to be true @@ -17,6 +19,10 @@ ifneq ($(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 @@ -25,13 +31,13 @@ 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 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 += $(call cc-option, -fno-stack-protector) ccflags-y += -DDISABLE_BRANCH_PROFILING @@ -63,7 +69,7 @@ targets += vdso64.lds CPPFLAGS_vdso64.lds += -P -C # link rule for the .so file, .lds has to be first -$(obj)/vdso32.so.dbg: $(obj)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday-32.o $(obj)/crtsavres-32.o FORCE +$(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 +81,8 @@ $(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..21773ef3fc1d --- /dev/null +++ b/arch/powerpc/kernel/vdso/getrandom.S @@ -0,0 +1,50 @@ +/* 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 <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) + cvdso_call __c_kernel_getrandom +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/vgetrandom-chacha.S b/arch/powerpc/kernel/vdso/vgetrandom-chacha.S new file mode 100644 index 000000000000..ac85788205cb --- /dev/null +++ b/arch/powerpc/kernel/vdso/vgetrandom-chacha.S @@ -0,0 +1,312 @@ +/* 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> + +#define dst_bytes r3 +#define key r4 +#define counter r5 +#define nblocks r6 + +#define idx_r0 r0 +#define val4 r4 + +#define const0 0x61707865 +#define const1 0x3320646e +#define const2 0x79622d32 +#define const3 0x6b206574 + +#define key0 r5 +#define key1 r6 +#define key2 r7 +#define key3 r8 +#define key4 r9 +#define key5 r10 +#define key6 r11 +#define key7 r12 + +#define counter0 r14 +#define counter1 r15 + +#define state0 r16 +#define state1 r17 +#define state2 r18 +#define state3 r19 +#define state4 r20 +#define state5 r21 +#define state6 r22 +#define state7 r23 +#define state8 r24 +#define state9 r25 +#define state10 r26 +#define state11 r27 +#define state12 r28 +#define state13 r29 +#define state14 r30 +#define state15 r31 + +.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 state##a1 state##b1 state##c1 state##d1 \ + state##a2 state##b2 state##c2 state##d2 \ + state##a3 state##b3 state##c3 state##d3 \ + state##a4 state##b4 state##c4 state##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__ +#else + stwu r1, -96(r1) + stw counter, 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 + + lwz counter0, 0(counter) + lwz counter1, 4(counter) + mr idx_r0, nblocks + subi dst_bytes, dst_bytes, 4 + + lwz key0, 0(key) + lwz key1, 4(key) + lwz key2, 8(key) + lwz key3, 12(key) + lwz key4, 16(key) + lwz key5, 20(key) + lwz key6, 24(key) + lwz key7, 28(key) + + li val4, 4 +.Lblock: + li r31, 10 + + lis state0, const0@ha + lis state1, const1@ha + lis state2, const2@ha + lis state3, const3@ha + addi state0, state0, const0@l + addi state1, state1, const1@l + addi state2, state2, const2@l + addi state3, state3, const3@l + + mtctr r31 + + mr state4, key0 + mr state5, key1 + mr state6, key2 + mr state7, key3 + mr state8, key4 + mr state9, key5 + mr state10, key6 + mr state11, key7 + + mr state12, counter0 + mr state13, counter1 + + li state14, 0 + li state15, 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 state0, state0, const0@ha + addis state1, state1, const1@ha + addis state2, state2, const2@ha + addis state3, state3, const3@ha + addi state0, state0, const0@l + addi state1, state1, const1@l + addi state2, state2, const2@l + addi state3, state3, const3@l + + add state4, state4, key0 + add state5, state5, key1 + add state6, state6, key2 + add state7, state7, key3 + add state8, state8, key4 + add state9, state9, key5 + add state10, state10, key6 + add state11, state11, key7 + + add state12, state12, counter0 + add state13, state13, counter1 + +#ifdef __BIG_ENDIAN__ + stwbrx state0, val4, dst_bytes + addi dst_bytes, dst_bytes, 8 + stwbrx state1, 0, dst_bytes + stwbrx state2, val4, dst_bytes + addi dst_bytes, dst_bytes, 8 + stwbrx state3, 0, dst_bytes + stwbrx state4, val4, dst_bytes + addi dst_bytes, dst_bytes, 8 + stwbrx state5, 0, dst_bytes + stwbrx state6, val4, dst_bytes + addi dst_bytes, dst_bytes, 8 + stwbrx state7, 0, dst_bytes + stwbrx state8, val4, dst_bytes + addi dst_bytes, dst_bytes, 8 + stwbrx state9, 0, dst_bytes + stwbrx state10, val4, dst_bytes + addi dst_bytes, dst_bytes, 8 + stwbrx state11, 0, dst_bytes + stwbrx state12, val4, dst_bytes + addi dst_bytes, dst_bytes, 8 + stwbrx state13, 0, dst_bytes + stwbrx state14, val4, dst_bytes + addi dst_bytes, dst_bytes, 8 + stwbrx state15, 0, dst_bytes +#else + stw state0, 4(dst_bytes) + stw state1, 8(dst_bytes) + stw state2, 12(dst_bytes) + stw state3, 16(dst_bytes) + stw state4, 20(dst_bytes) + stw state5, 24(dst_bytes) + stw state6, 28(dst_bytes) + stw state7, 32(dst_bytes) + stw state8, 36(dst_bytes) + stw state9, 40(dst_bytes) + stw state10, 44(dst_bytes) + stw state11, 48(dst_bytes) + stw state12, 52(dst_bytes) + stw state13, 56(dst_bytes) + stw state14, 60(dst_bytes) + stwu state15, 64(dst_bytes) +#endif + + subic. idx_r0, idx_r0, 1 /* subi. can't use r0 as source */ + + addic counter0, counter0, 1 + addze counter1, counter1 + + bne .Lblock + + lwz counter, 20(r1) + stw counter0, 0(counter) + stw counter1, 4(counter) + + li r6, 0 + li r7, 0 + li r8, 0 + li r9, 0 + li r10, 0 + li r11, 0 + li r12, 0 + +#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 +#endif /* __powerpc64__ */ + blr +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..5f855d45fb7b --- /dev/null +++ b/arch/powerpc/kernel/vdso/vgetrandom.c @@ -0,0 +1,14 @@ +// 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> + +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); +} diff --git a/tools/arch/powerpc/vdso b/tools/arch/powerpc/vdso new file mode 120000 index 000000000000..4e676d1d1cb4 --- /dev/null +++ b/tools/arch/powerpc/vdso @@ -0,0 +1 @@ +../../../arch/powerpc/kernel/vdso \ No newline at end of file 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
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 VDSO32. As selftests cannot easily be generated only for VDSO32, and because the following patch brings support for VDSO64 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. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> --- v5: - Add back vdso symlink that vanished in v4 after a rebase back and forth with rejected patch "selftests: vDSO: Do not rely on $ARCH for vdso_test_getrandom && vdso_test_chacha" - Set meaningfull names to registers and constants in chacha assembly - Add 32 bits LE logic in this patch as well allthought it is only usefull for ppc64le. - Remove the temporary ppc64 __kernel_getrandom added in v4, selftest will return KSFT_FAIL until following patch, not a big issue. - Move the -DBUILD_VDSO logic in patch 3 to allow build VDSO32 on ppc64. 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/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 | 14 +- arch/powerpc/kernel/vdso/getrandom.S | 50 +++ arch/powerpc/kernel/vdso/vdso32.lds.S | 1 + arch/powerpc/kernel/vdso/vgetrandom-chacha.S | 312 +++++++++++++++++++ arch/powerpc/kernel/vdso/vgetrandom.c | 14 + tools/arch/powerpc/vdso | 1 + tools/testing/selftests/vDSO/Makefile | 2 +- 13 files changed, 455 insertions(+), 5 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 create mode 120000 tools/arch/powerpc/vdso