The state beyond what is present on the running cpu will be zero. Signed-off-by: Richard Henderson <richard.hender...@linaro.org> --- risu_reginfo_i386.h | 15 ++++ risu_reginfo_i386.c | 194 ++++++++++++++++++++++++++++++++++++++++++-- test_i386.S | 39 +++++++++ 3 files changed, 243 insertions(+), 5 deletions(-)
diff --git a/risu_reginfo_i386.h b/risu_reginfo_i386.h index 755283a..1d13e41 100644 --- a/risu_reginfo_i386.h +++ b/risu_reginfo_i386.h @@ -12,14 +12,29 @@ #ifndef RISU_REGINFO_I386_H #define RISU_REGINFO_I386_H +struct avx512_reg { + uint64_t q[8]; +}; + /* * This is the data structure we pass over the socket. * It is a simplified and reduced subset of what can * be obtained with a ucontext_t* */ struct reginfo { + uint16_t nvecregs; + uint16_t nvecquads; uint32_t faulting_insn; + uint32_t mxcsr; + gregset_t gregs; + +#ifdef __x86_64__ + struct avx512_reg vregs[32]; +#else + struct avx512_reg vregs[8]; +#endif + uint64_t kregs[8]; }; /* diff --git a/risu_reginfo_i386.c b/risu_reginfo_i386.c index c4dc14a..e1974ec 100644 --- a/risu_reginfo_i386.c +++ b/risu_reginfo_i386.c @@ -11,13 +11,17 @@ #include <stdio.h> #include <stdlib.h> +#include <stddef.h> #include <string.h> #include <ucontext.h> #include <assert.h> +#include <cpuid.h> #include "risu.h" #include "risu_reginfo_i386.h" +#include <asm/sigcontext.h> + const struct option * const arch_long_opts; const char * const arch_extra_help; @@ -31,10 +35,30 @@ const int reginfo_size(void) return sizeof(struct reginfo); } +static void *xsave_feature_buf(struct _xstate *xs, int feature) +{ + unsigned int eax, ebx, ecx, edx; + int ok; + + /* + * Get the location of the XSAVE feature from the cpuid leaf. + * Given that we know the xfeature bit is set, this must succeed. + */ + ok = __get_cpuid_count(0xd, feature, &eax, &ebx, &ecx, &edx); + assert(ok); + + /* Sanity check that the frame stored by the kernel contains the data. */ + assert(xs->fpstate.sw_reserved.extended_size >= eax + ebx); + + return (void *)xs + ebx; +} + /* reginfo_init: initialize with a ucontext */ void reginfo_init(struct reginfo *ri, ucontext_t *uc) { - int i; + int i, nvecregs, nvecquads; + struct _fpstate *fp; + struct _xstate *xs; memset(ri, 0, sizeof(*ri)); @@ -79,12 +103,100 @@ void reginfo_init(struct reginfo *ri, ucontext_t *uc) * distinguish 'do compare' from 'stop'. */ ri->faulting_insn = *(uint32_t *)uc->uc_mcontext.gregs[REG_E(IP)]; + + /* + * FP state is omitted if unused (aka in init state). + * Use the <asm/sigcontext.h> struct for access to AVX state. + */ + fp = (struct _fpstate *)uc->uc_mcontext.fpregs; + if (fp == NULL) { + return; + } + +#ifdef __x86_64__ + nvecregs = 16; +#else + /* We don't (currently) care about the 80387 state, only SSE+. */ + if (fp->magic != X86_FXSR_MAGIC) { + return; + } + nvecregs = 8; +#endif + nvecquads = 2; + + /* + * Now we know that _fpstate contains FXSAVE data. + */ + ri->mxcsr = fp->mxcsr; + + for (i = 0; i < nvecregs; ++i) { +#ifdef __x86_64__ + memcpy(&ri->vregs[i], &fp->xmm_space[i], 16); +#else + memcpy(&ri->vregs[i], &fp->_xmm[i * 4], 16); +#endif + } + + if (fp->sw_reserved.magic1 != FP_XSTATE_MAGIC1) { + return; + } + xs = (struct _xstate *)fp; + + /* + * Now we know that _fpstate contains XSAVE data. + */ + + if (xs->xstate_hdr.xfeatures & (1 << 2)) { + /* YMM_Hi128 state */ + void *buf = xsave_feature_buf(xs, 2); + for (i = 0; i < nvecregs; ++i) { + memcpy(&ri->vregs[i].q[2], buf + 16 * i, 16); + } + nvecquads = 4; + } + + if (xs->xstate_hdr.xfeatures & (1 << 5)) { + /* Opmask state */ + uint64_t *buf = xsave_feature_buf(xs, 5); + for (i = 0; i < 8; ++i) { + ri->kregs[i] = buf[i]; + } + } + + if (xs->xstate_hdr.xfeatures & (1 << 6)) { + /* ZMM_Hi256 state */ + void *buf = xsave_feature_buf(xs, 6); + for (i = 0; i < nvecregs; ++i) { + memcpy(&ri->vregs[i].q[4], buf + 32 * i, 32); + } + nvecquads = 8; + } + +#ifdef __x86_64__ + if (xs->xstate_hdr.xfeatures & (1 << 7)) { + /* Hi16_ZMM state */ + void *buf = xsave_feature_buf(xs, 7); + for (i = 0; i < 16; ++i) { + memcpy(&ri->vregs[i + 16], buf + 64 * i, 64); + } + nvecregs = 32; + } +#endif + + ri->nvecregs = nvecregs; + ri->nvecquads = nvecquads; } /* reginfo_is_eq: compare the reginfo structs, returns nonzero if equal */ int reginfo_is_eq(struct reginfo *m, struct reginfo *a) { - return 0 == memcmp(m, a, sizeof(*m)); + /* + * Do not compare nvecregs & nvecquads. This allows master + * and apprentice to have different vector widths, so long + * as we're only interested in the low N bits of the register. + */ + return !memcmp(&m->faulting_insn, &a->faulting_insn, + sizeof(*m) - offsetof(struct reginfo, faulting_insn)); } static const char *const regname[NGREG] = { @@ -129,25 +241,97 @@ static const char *const regname[NGREG] = { /* reginfo_dump: print state to a stream, returns nonzero on success */ int reginfo_dump(struct reginfo *ri, FILE *f) { - int i; + int i, j, n, w; + char r; + fprintf(f, " faulting insn %x\n", ri->faulting_insn); for (i = 0; i < NGREG; i++) { if (regname[i]) { fprintf(f, " %-6s: " PRIxREG "\n", regname[i], ri->gregs[i]); } } + + fprintf(f, " mxcsr : %x\n", ri->mxcsr); + + n = ri->nvecregs; + w = ri->nvecquads; + r = (w <= 2 ? 'x' : w <= 4 ? 'y' : 'z'); + + for (i = 0; i < n; i++) { + fprintf(f, " %cmm%-3d: ", r, i); + for (j = w - 1; j >= 0; j--) { + fprintf(f, "%016" PRIx64 "%c", + ri->vregs[i].q[j], j == 0 ? '\n' : ' '); + } + } + + if (n >= 32 || w >= 8) { + for (i = 0; i < 8; i++) { + fprintf(f, " k%-5d: %016" PRIx64 "\n", i, ri->kregs[i]); + } + } + return !ferror(f); } +static void reginfo_dump_mismatch_vreg(struct reginfo *m, struct reginfo *a, + FILE *f, int i, int w) +{ + char r = (w <= 2 ? 'x' : w <= 4 ? 'y' : 'z'); + int j; + + fprintf(f, " %cmm%-3d: ", r, i); + for (j = w - 1; j >= 0; j--) { + fprintf(f, "%016" PRIx64 "%c", + m->vregs[i].q[j], j == 0 ? '\n' : ' '); + } + fprintf(f, " vs: "); + for (j = w - 1; j >= 0; j--) { + fprintf(f, "%016" PRIx64 "%c", + a->vregs[i].q[j], j == 0 ? '\n' : ' '); + } +} + int reginfo_dump_mismatch(struct reginfo *m, struct reginfo *a, FILE *f) { - int i; + int i, n, wmin, wmax; + + fprintf(f, "Mismatch (master v apprentice):\n"); + for (i = 0; i < NGREG; i++) { if (m->gregs[i] != a->gregs[i]) { assert(regname[i]); - fprintf(f, "Mismatch: %s: " PRIxREG " v " PRIxREG "\n", + fprintf(f, " %-6s: " PRIxREG " v " PRIxREG "\n", regname[i], m->gregs[i], a->gregs[i]); } } + + if (m->mxcsr != a->mxcsr) { + fprintf(f, " mxcsr : %x v %x\n", m->mxcsr, a->mxcsr); + } + + n = sizeof(m->vregs) / sizeof(m->vregs[0]); + wmax = sizeof(m->vregs[0]) / sizeof(m->vregs[0].q[0]); + wmin = m->nvecquads; + + for (i = 0; i < n; i++) { + if (memcmp(&m->vregs[i], &a->vregs[i], wmax * 8)) { + if (memcmp(&m->vregs[i], &a->vregs[i], wmin * 8)) { + /* This is expected behaviour. */ + reginfo_dump_mismatch_vreg(m, a, f, i, wmin); + } else { + /* This probably means different vector widths. */ + reginfo_dump_mismatch_vreg(m, a, f, i, wmax); + } + } + } + + for (i = 0; i < 8; i++) { + if (m->kregs[i] != a->kregs[i]) { + fprintf(f, " k%-5d: %016" PRIx64 " v %016" PRIx64 "\n", + i, m->kregs[i], a->kregs[i]); + } + } + return !ferror(f); } diff --git a/test_i386.S b/test_i386.S index 456b99c..05344d7 100644 --- a/test_i386.S +++ b/test_i386.S @@ -12,6 +12,37 @@ /* A trivial test image for x86 */ /* Initialise the registers to avoid spurious mismatches */ + +#ifdef __x86_64__ +#define BASE %rax + lea 2f(%rip), BASE +#else +#define BASE %eax + call 1f +1: pop BASE + add $2f-1b, BASE +#endif + + movdqa 0(BASE), %xmm0 + movdqa 1*16(BASE), %xmm1 + movdqa 2*16(BASE), %xmm2 + movdqa 3*16(BASE), %xmm3 + movdqa 4*16(BASE), %xmm4 + movdqa 5*16(BASE), %xmm5 + movdqa 6*16(BASE), %xmm6 + movdqa 7*16(BASE), %xmm7 + +#ifdef __x86_64__ + movdqa 8*16(BASE), %xmm8 + movdqa 9*16(BASE), %xmm9 + movdqa 10*16(BASE), %xmm10 + movdqa 11*16(BASE), %xmm11 + movdqa 12*16(BASE), %xmm12 + movdqa 13*16(BASE), %xmm13 + movdqa 14*16(BASE), %xmm14 + movdqa 15*16(BASE), %xmm15 +#endif + xor %eax, %eax sahf /* init eflags */ @@ -39,3 +70,11 @@ /* exit test */ ud1 %ecx, %eax + + .p2align 16 +2: + .set i, 0 + .rept 256 + .byte i + .set i, i + 1 + .endr -- 2.17.1