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Re: [Qemu-devel] [PATCH] Add signal handling support for x86_64.
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From: |
Peter Maydell |
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Subject: |
Re: [Qemu-devel] [PATCH] Add signal handling support for x86_64. |
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Date: |
Mon, 25 Jul 2016 15:29:37 +0100 |
On 9 July 2016 at 21:07, Wirth, Allan <address@hidden> wrote:
> Note that x86_64 has only _rt signal handlers. This implementation
> attempts to share code with the x86_32 implementation.
>
> Reported-by: Timothy Pearson <address@hidden>
> Suggested-by: Peter Maydell <address@hidden>
> Signed-off-by: Allan Wirth <address@hidden>
Thanks. This mostly looks good; I have one comment below about
a definite bug, and the rest are minor style comments.
The commit message subject line should start with a "linux-user: " prefix.
> ---
> linux-user/signal.c | 344
> ++++++++++++++++++++++++++++++++++++-----------
> target-i386/cpu.h | 2 +
> target-i386/fpu_helper.c | 12 ++
> 3 files changed, 282 insertions(+), 76 deletions(-)
>
> diff --git a/linux-user/signal.c b/linux-user/signal.c
> index 9d98045..edca9e4 100644
> --- a/linux-user/signal.c
> +++ b/linux-user/signal.c
> @@ -253,8 +253,7 @@ int do_sigprocmask(int how, const sigset_t *set, sigset_t
> *oldset)
> return 0;
> }
>
> -#if !defined(TARGET_OPENRISC) && !defined(TARGET_UNICORE32) && \
> - !defined(TARGET_X86_64)
> +#if !defined(TARGET_OPENRISC) && !defined(TARGET_UNICORE32)
> /* Just set the guest's signal mask to the specified value; the
> * caller is assumed to have called block_signals() already.
> */
> @@ -789,9 +788,8 @@ int do_sigaction(int sig, const struct target_sigaction
> *act,
> return ret;
> }
>
> -#if defined(TARGET_I386) && TARGET_ABI_BITS == 32
> -
> -/* from the Linux kernel */
> +#if defined(TARGET_I386)
> +/* from the Linux kernel - /arch/x86/include/uapi/asm/sigcontext.h */
>
> struct target_fpreg {
> uint16_t significand[4];
> @@ -805,7 +803,7 @@ struct target_fpxreg {
> };
>
> struct target_xmmreg {
> - abi_ulong element[4];
> + uint32_t element[4];
> };
>
> struct target_fpstate {
> @@ -830,33 +828,117 @@ struct target_fpstate {
> abi_ulong padding[56];
> };
>
> -#define X86_FXSR_MAGIC 0x0000
> +struct target_fpstate_32 {
> + /* Regular FPU environment */
> + uint32_t cw;
> + uint32_t sw;
> + uint32_t tag;
> + uint32_t ipoff;
> + uint32_t cssel;
> + uint32_t dataoff;
> + uint32_t datasel;
> + struct target_fpreg _st[8];
Better to avoid the leading underscores.
> + uint16_t status;
> + uint16_t magic; /* 0xffff = regular FPU data only */
>
> -struct target_sigcontext {
> + /* FXSR FPU environment */
> + uint32_t _fxsr_env[6]; /* FXSR FPU env is ignored */
> + uint32_t mxcsr;
> + uint32_t reserved;
> + struct target_fpxreg _fxsr_st[8]; /* FXSR FPU reg data is ignored */
> + struct target_xmmreg _xmm[8];
> + uint32_t padding[56];
> +};
> +
> +struct target_fpstate_64 {
> + /* FXSAVE format */
> + uint16_t cw;
> + uint16_t sw;
> + uint16_t twd;
> + uint16_t fop;
> + uint64_t rip;
> + uint64_t rdp;
> + uint32_t mxcsr;
> + uint32_t mxcsr_mask;
> + uint32_t st_space[32];
> + uint32_t xmm_space[64];
> + uint32_t reserved[24];
> +};
> +
> +#ifndef TARGET_X86_64
> +# define target_fpstate target_fpstate_32
> +#else
> +# define target_fpstate target_fpstate_64
> +#endif
> +
> +struct target_sigcontext_32 {
> uint16_t gs, __gsh;
> uint16_t fs, __fsh;
> uint16_t es, __esh;
> uint16_t ds, __dsh;
> - abi_ulong edi;
> - abi_ulong esi;
> - abi_ulong ebp;
> - abi_ulong esp;
> - abi_ulong ebx;
> - abi_ulong edx;
> - abi_ulong ecx;
> - abi_ulong eax;
> - abi_ulong trapno;
> - abi_ulong err;
> - abi_ulong eip;
> + uint32_t edi;
> + uint32_t esi;
> + uint32_t ebp;
> + uint32_t esp;
> + uint32_t ebx;
> + uint32_t edx;
> + uint32_t ecx;
> + uint32_t eax;
> + uint32_t trapno;
> + uint32_t err;
> + uint32_t eip;
> uint16_t cs, __csh;
> - abi_ulong eflags;
> - abi_ulong esp_at_signal;
> + uint32_t eflags;
> + uint32_t esp_at_signal;
> uint16_t ss, __ssh;
> - abi_ulong fpstate; /* pointer */
> - abi_ulong oldmask;
> - abi_ulong cr2;
> + uint32_t fpstate; /* pointer */
> + uint32_t oldmask;
> + uint32_t cr2;
> };
>
> +struct target_sigcontext_64 {
> + uint64_t r8;
> + uint64_t r9;
> + uint64_t r10;
> + uint64_t r11;
> + uint64_t r12;
> + uint64_t r13;
> + uint64_t r14;
> + uint64_t r15;
> +
> + uint64_t rdi;
> + uint64_t rsi;
> + uint64_t rbp;
> + uint64_t rbx;
> + uint64_t rdx;
> + uint64_t rax;
> + uint64_t rcx;
> + uint64_t rsp;
> + uint64_t rip;
> +
> + uint64_t eflags;
> +
> + uint16_t cs;
> + uint16_t gs;
> + uint16_t fs;
> + uint16_t ss;
> +
> + uint64_t err;
> + uint64_t trapno;
> + uint64_t oldmask;
> + uint64_t cr2;
> +
> + uint64_t fpstate; /* pointer */
> + uint64_t padding[8];
> +};
> +
> +#ifndef TARGET_X86_64
> +# define target_sigcontext target_sigcontext_32
> +#else
> +# define target_sigcontext target_sigcontext_64
> +#endif
> +
> +/* see Linux/include/uapi/asm-generic/ucontext.h */
> struct target_ucontext {
> abi_ulong tuc_flags;
> abi_ulong tuc_link;
> @@ -865,6 +947,7 @@ struct target_ucontext {
> target_sigset_t tuc_sigmask; /* mask last for extensibility */
> };
>
> +#ifndef TARGET_X86_64
> struct sigframe
> {
> abi_ulong pretcode;
> @@ -887,6 +970,18 @@ struct rt_sigframe
> char retcode[8];
> };
>
> +#else
> +
> +struct rt_sigframe
> +{
This brace should be on the line before. If you run your patch
through scripts/checkpatch.pl it will catch this nit (and
another ten coding style issues that I'm not going to bother
to list out below).
> + abi_ulong pretcode;
> + struct target_ucontext uc;
> + struct target_siginfo info;
> + struct target_fpstate fpstate;
> +};
> +
> +#endif
> +
> /*
> * Set up a signal frame.
> */
> @@ -897,6 +992,7 @@ static void setup_sigcontext(struct target_sigcontext *sc,
> abi_ulong fpstate_addr)
> {
> CPUState *cs = CPU(x86_env_get_cpu(env));
> +#ifndef TARGET_X86_64
> uint16_t magic;
>
> /* already locked in setup_frame() */
> @@ -929,12 +1025,49 @@ static void setup_sigcontext(struct target_sigcontext
> *sc,
> /* non-iBCS2 extensions.. */
> __put_user(mask, &sc->oldmask);
> __put_user(env->cr[2], &sc->cr2);
> +#else
> + __put_user(env->regs[8], &sc->r8);
> + __put_user(env->regs[9], &sc->r9);
> + __put_user(env->regs[10], &sc->r10);
> + __put_user(env->regs[11], &sc->r11);
> + __put_user(env->regs[12], &sc->r12);
> + __put_user(env->regs[13], &sc->r13);
> + __put_user(env->regs[14], &sc->r14);
> + __put_user(env->regs[15], &sc->r15);
> +
> + __put_user(env->regs[R_EDI], &sc->rdi);
> + __put_user(env->regs[R_ESI], &sc->rsi);
> + __put_user(env->regs[R_EBP], &sc->rbp);
> + __put_user(env->regs[R_EBX], &sc->rbx);
> + __put_user(env->regs[R_EDX], &sc->rdx);
> + __put_user(env->regs[R_EAX], &sc->rax);
> + __put_user(env->regs[R_ECX], &sc->rcx);
> + __put_user(env->regs[R_ESP], &sc->rsp);
> + __put_user(env->eip, &sc->rip);
> +
> + __put_user(env->eflags, &sc->eflags);
> +
> + __put_user(env->segs[R_CS].selector, &sc->cs);
> + __put_user((uint16_t)0, &sc->gs);
> + __put_user((uint16_t)0, &sc->fs);
> + __put_user(env->segs[R_SS].selector, &sc->ss);
> +
> + __put_user(env->error_code, &sc->err);
> + __put_user(cs->exception_index, &sc->trapno);
> + __put_user(mask, &sc->oldmask);
> + __put_user(env->cr[2], &sc->cr2);
> +
> + /* fpstate_addr must be 16 byte aligned for fxsave */
> + assert (! (fpstate_addr & 0xf));
> +
> + cpu_x86_fxsave(env, fpstate_addr);
> + __put_user(fpstate_addr, &sc->fpstate);
> +#endif
> }
>
> /*
> * Determine which stack to use..
> */
> -
Stray whitespace change.
> static inline abi_ulong
> get_sigframe(struct target_sigaction *ka, CPUX86State *env, size_t
> frame_size)
> {
> @@ -942,63 +1075,98 @@ get_sigframe(struct target_sigaction *ka, CPUX86State
> *env, size_t frame_size)
>
> /* Default to using normal stack */
> esp = env->regs[R_ESP];
> +#ifdef TARGET_X86_64
> + esp -= 128; /* this is the redzone */
> +#endif
> +
> /* This is the X/Open sanctioned signal stack switching. */
> if (ka->sa_flags & TARGET_SA_ONSTACK) {
> if (sas_ss_flags(esp) == 0) {
> esp = target_sigaltstack_used.ss_sp +
> target_sigaltstack_used.ss_size;
> }
> +#ifndef TARGET_X86_64
This would be better after the "} else {" so we don't have mismatched
nesting of #if..#endif and if..else...
> } else {
> -
> /* This is the legacy signal stack switching. */
> if ((env->segs[R_SS].selector & 0xffff) != __USER_DS &&
> !(ka->sa_flags & TARGET_SA_RESTORER) &&
> ka->sa_restorer) {
> esp = (unsigned long) ka->sa_restorer;
> }
> +#endif
> }
> +
> +#ifndef TARGET_X86_64
> return (esp - frame_size) & -8ul;
> +#else
> + return ((esp - frame_size) & (~15ul)) - 8;
> +#endif
> }
>
> -/* compare linux/arch/i386/kernel/signal.c:setup_frame() */
> -static void setup_frame(int sig, struct target_sigaction *ka,
> - target_sigset_t *set, CPUX86State *env)
> +/* compare linux/arch/i386/kernel/signal.c:setup_rt_frame() */
> +static void setup_rt_frame(int sig, struct target_sigaction *ka,
> + target_siginfo_t *info,
> + target_sigset_t *set, CPUX86State *env)
Why have you switched the order of these two functions? It makes the
diff very hard to read :-(
> {
> abi_ulong frame_addr;
> - struct sigframe *frame;
> +#ifndef TARGET_X86_64
> + abi_ulong addr;
> +#endif
> + struct rt_sigframe *frame;
> int i;
>
> frame_addr = get_sigframe(ka, env, sizeof(*frame));
> - trace_user_setup_frame(env, frame_addr);
> + trace_user_setup_rt_frame(env, frame_addr);
>
> if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
> goto give_sigsegv;
>
> + /* These fields are only in rt_sigframe on 32 bit...? */
Yes; you can remove the "?" from the comment. (They correspond
to setting up arguments on the stack for the signal handler.
x86-64's ABI passes arguments in registers; see later.)
> +#ifndef TARGET_X86_64
> __put_user(sig, &frame->sig);
> + addr = frame_addr + offsetof(struct rt_sigframe, info);
> + __put_user(addr, &frame->pinfo);
> + addr = frame_addr + offsetof(struct rt_sigframe, uc);
> + __put_user(addr, &frame->puc);
> +#endif
> + if (info) {
> + tswap_siginfo(&frame->info, info);
> + }
>
> - setup_sigcontext(&frame->sc, &frame->fpstate, env, set->sig[0],
> - frame_addr + offsetof(struct sigframe, fpstate));
> + /* Create the ucontext. */
> + __put_user(0, &frame->uc.tuc_flags);
> + __put_user(0, &frame->uc.tuc_link);
> + __put_user(target_sigaltstack_used.ss_sp, &frame->uc.tuc_stack.ss_sp);
> + __put_user(sas_ss_flags(get_sp_from_cpustate(env)),
> + &frame->uc.tuc_stack.ss_flags);
> + __put_user(target_sigaltstack_used.ss_size,
> + &frame->uc.tuc_stack.ss_size);
> + setup_sigcontext(&frame->uc.tuc_mcontext, &frame->fpstate, env,
> + set->sig[0], frame_addr + offsetof(struct rt_sigframe, fpstate));
>
> - for(i = 1; i < TARGET_NSIG_WORDS; i++) {
> - __put_user(set->sig[i], &frame->extramask[i - 1]);
> + for(i = 0; i < TARGET_NSIG_WORDS; i++) {
> + __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
> }
>
> /* Set up to return from userspace. If provided, use a stub
> already in userspace. */
> +#ifndef TARGET_X86_64
> if (ka->sa_flags & TARGET_SA_RESTORER) {
> __put_user(ka->sa_restorer, &frame->pretcode);
> } else {
> uint16_t val16;
> - abi_ulong retcode_addr;
> - retcode_addr = frame_addr + offsetof(struct sigframe, retcode);
> - __put_user(retcode_addr, &frame->pretcode);
> - /* This is popl %eax ; movl $,%eax ; int $0x80 */
> - val16 = 0xb858;
> - __put_user(val16, (uint16_t *)(frame->retcode+0));
> - __put_user(TARGET_NR_sigreturn, (int *)(frame->retcode+2));
> + addr = frame_addr + offsetof(struct rt_sigframe, retcode);
> + __put_user(addr, &frame->pretcode);
> + /* This is movl $,%eax ; int $0x80 */
> + __put_user(0xb8, (char *)(frame->retcode+0));
> + __put_user(TARGET_NR_rt_sigreturn, (int *)(frame->retcode+1));
> val16 = 0x80cd;
> - __put_user(val16, (uint16_t *)(frame->retcode+6));
> + __put_user(val16, (uint16_t *)(frame->retcode+5));
> }
> -
> +#else
> + /// XXX: Would be slightly better to return -EFAULT here if test fails
> + assert(ka->sa_flags & TARGET_SA_RESTORER);
Don't assert() on things the guest can provoke, please.
> + __put_user(ka->sa_restorer, &frame->pretcode);
> +#endif
>
> /* Set up registers for signal handler */
> env->regs[R_ESP] = frame_addr;
If you try a test program that registers a handler and prints
the arguments to the signal handler (either just the signal
number, or all 3 arguments if you use sigaction and set SA_SIGINFO)
you will find that your code doesn't correctly pass the parameters
for x86-64, because you aren't setting the necessary registers here.
Compare
http://lxr.free-electrons.com/source/arch/x86/kernel/signal.c#L496
where we set EAX, EDI, ESI, and EDX.
> @@ -1021,41 +1189,28 @@ give_sigsegv:
> force_sig(TARGET_SIGSEGV /* , current */);
> }
>
> -/* compare linux/arch/i386/kernel/signal.c:setup_rt_frame() */
> -static void setup_rt_frame(int sig, struct target_sigaction *ka,
> - target_siginfo_t *info,
> - target_sigset_t *set, CPUX86State *env)
> +/* compare linux/arch/i386/kernel/signal.c:setup_frame() */
> +static void setup_frame(int sig, struct target_sigaction *ka,
> + target_sigset_t *set, CPUX86State *env)
> {
> - abi_ulong frame_addr, addr;
> - struct rt_sigframe *frame;
> +#ifndef TARGET_X86_64
> + abi_ulong frame_addr;
> + struct sigframe *frame;
> int i;
>
> frame_addr = get_sigframe(ka, env, sizeof(*frame));
> - trace_user_setup_rt_frame(env, frame_addr);
> + trace_user_setup_frame(env, frame_addr);
>
> if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
> goto give_sigsegv;
>
> __put_user(sig, &frame->sig);
> - addr = frame_addr + offsetof(struct rt_sigframe, info);
> - __put_user(addr, &frame->pinfo);
> - addr = frame_addr + offsetof(struct rt_sigframe, uc);
> - __put_user(addr, &frame->puc);
> - tswap_siginfo(&frame->info, info);
>
> - /* Create the ucontext. */
> - __put_user(0, &frame->uc.tuc_flags);
> - __put_user(0, &frame->uc.tuc_link);
> - __put_user(target_sigaltstack_used.ss_sp, &frame->uc.tuc_stack.ss_sp);
> - __put_user(sas_ss_flags(get_sp_from_cpustate(env)),
> - &frame->uc.tuc_stack.ss_flags);
> - __put_user(target_sigaltstack_used.ss_size,
> - &frame->uc.tuc_stack.ss_size);
> - setup_sigcontext(&frame->uc.tuc_mcontext, &frame->fpstate, env,
> - set->sig[0], frame_addr + offsetof(struct rt_sigframe, fpstate));
> + setup_sigcontext(&frame->sc, &frame->fpstate, env, set->sig[0],
> + frame_addr + offsetof(struct sigframe, fpstate));
>
> - for(i = 0; i < TARGET_NSIG_WORDS; i++) {
> - __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
> + for(i = 1; i < TARGET_NSIG_WORDS; i++) {
> + __put_user(set->sig[i], &frame->extramask[i - 1]);
> }
>
> /* Set up to return from userspace. If provided, use a stub
> @@ -1064,15 +1219,18 @@ static void setup_rt_frame(int sig, struct
> target_sigaction *ka,
> __put_user(ka->sa_restorer, &frame->pretcode);
> } else {
> uint16_t val16;
> - addr = frame_addr + offsetof(struct rt_sigframe, retcode);
> - __put_user(addr, &frame->pretcode);
> - /* This is movl $,%eax ; int $0x80 */
> - __put_user(0xb8, (char *)(frame->retcode+0));
> - __put_user(TARGET_NR_rt_sigreturn, (int *)(frame->retcode+1));
> + abi_ulong retcode_addr;
> + retcode_addr = frame_addr + offsetof(struct sigframe, retcode);
> + __put_user(retcode_addr, &frame->pretcode);
> + /* This is popl %eax ; movl $,%eax ; int $0x80 */
> + val16 = 0xb858;
> + __put_user(val16, (uint16_t *)(frame->retcode+0));
> + __put_user(TARGET_NR_sigreturn, (int *)(frame->retcode+2));
> val16 = 0x80cd;
> - __put_user(val16, (uint16_t *)(frame->retcode+5));
> + __put_user(val16, (uint16_t *)(frame->retcode+6));
> }
>
> +
> /* Set up registers for signal handler */
> env->regs[R_ESP] = frame_addr;
> env->eip = ka->_sa_handler;
> @@ -1092,15 +1250,19 @@ give_sigsegv:
> ka->_sa_handler = TARGET_SIG_DFL;
> }
> force_sig(TARGET_SIGSEGV /* , current */);
> +#else
> + setup_rt_frame(sig, ka, 0, set, env);
Why is this here? setup_frame() should never be called if the
architecture doesn't implement it -- you should adjust the
#if in handle_pending_signal(), and then put the whole
setup_frame() function definition inside an #ifndef TARGET_X86_64.
> +#endif
> }
>
> static int
> restore_sigcontext(CPUX86State *env, struct target_sigcontext *sc)
> {
> - unsigned int err = 0;
> abi_ulong fpstate_addr;
> unsigned int tmpflags;
> + unsigned int err = 0;
>
> +#ifndef TARGET_X86_64
> cpu_x86_load_seg(env, R_GS, tswap16(sc->gs));
> cpu_x86_load_seg(env, R_FS, tswap16(sc->fs));
> cpu_x86_load_seg(env, R_ES, tswap16(sc->es));
> @@ -1114,7 +1276,29 @@ restore_sigcontext(CPUX86State *env, struct
> target_sigcontext *sc)
> env->regs[R_EDX] = tswapl(sc->edx);
> env->regs[R_ECX] = tswapl(sc->ecx);
> env->regs[R_EAX] = tswapl(sc->eax);
> +
> env->eip = tswapl(sc->eip);
> +#else
> + env->regs[8] = tswapl(sc->r8);
> + env->regs[9] = tswapl(sc->r9);
> + env->regs[10] = tswapl(sc->r10);
> + env->regs[11] = tswapl(sc->r11);
> + env->regs[12] = tswapl(sc->r12);
> + env->regs[13] = tswapl(sc->r13);
> + env->regs[14] = tswapl(sc->r14);
> + env->regs[15] = tswapl(sc->r15);
> +
> + env->regs[R_EDI] = tswapl(sc->rdi);
> + env->regs[R_ESI] = tswapl(sc->rsi);
> + env->regs[R_EBP] = tswapl(sc->rbp);
> + env->regs[R_EBX] = tswapl(sc->rbx);
> + env->regs[R_EDX] = tswapl(sc->rdx);
> + env->regs[R_EAX] = tswapl(sc->rax);
> + env->regs[R_ECX] = tswapl(sc->rcx);
> + env->regs[R_ESP] = tswapl(sc->rsp);
> +
> + env->eip = tswapl(sc->rip);
> +#endif
>
> cpu_x86_load_seg(env, R_CS, lduw_p(&sc->cs) | 3);
> cpu_x86_load_seg(env, R_SS, lduw_p(&sc->ss) | 3);
> @@ -1128,14 +1312,21 @@ restore_sigcontext(CPUX86State *env, struct
> target_sigcontext *sc)
> if (!access_ok(VERIFY_READ, fpstate_addr,
> sizeof(struct target_fpstate)))
> goto badframe;
> +#ifndef TARGET_X86_64
> cpu_x86_frstor(env, fpstate_addr, 1);
> +#else
> + cpu_x86_fxrstor(env, fpstate_addr);
> +#endif
> }
>
> return err;
> +
Stray whitespace change.
> badframe:
> return 1;
> }
>
> +/* Note: there is no sigreturn on x86_64, there is only rt_sigreturn */
> +#ifndef TARGET_X86_64
> long do_sigreturn(CPUX86State *env)
> {
> struct sigframe *frame;
> @@ -1167,6 +1358,7 @@ badframe:
> force_sig(TARGET_SIGSEGV);
> return 0;
> }
> +#endif
>
> long do_rt_sigreturn(CPUX86State *env)
> {
> @@ -1174,7 +1366,7 @@ long do_rt_sigreturn(CPUX86State *env)
> struct rt_sigframe *frame;
> sigset_t set;
>
> - frame_addr = env->regs[R_ESP] - 4;
> + frame_addr = env->regs[R_ESP] - sizeof(abi_ulong);
> trace_user_do_rt_sigreturn(env, frame_addr);
> if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
> goto badframe;
> diff --git a/target-i386/cpu.h b/target-i386/cpu.h
> index 474b0b9..90410d8 100644
> --- a/target-i386/cpu.h
> +++ b/target-i386/cpu.h
> @@ -1337,6 +1337,8 @@ floatx80 cpu_set_fp80(uint64_t mant, uint16_t upper);
> void cpu_x86_load_seg(CPUX86State *s, int seg_reg, int selector);
> void cpu_x86_fsave(CPUX86State *s, target_ulong ptr, int data32);
> void cpu_x86_frstor(CPUX86State *s, target_ulong ptr, int data32);
> +void cpu_x86_fxsave(CPUX86State *s, target_ulong ptr);
> +void cpu_x86_fxrstor(CPUX86State *s, target_ulong ptr);
>
> /* you can call this signal handler from your SIGBUS and SIGSEGV
> signal handlers to inform the virtual CPU of exceptions. non zero
> diff --git a/target-i386/fpu_helper.c b/target-i386/fpu_helper.c
> index 929489b..617fdf2 100644
> --- a/target-i386/fpu_helper.c
> +++ b/target-i386/fpu_helper.c
> @@ -1370,6 +1370,18 @@ void helper_fxrstor(CPUX86State *env, target_ulong ptr)
> }
> }
>
> +#if defined(CONFIG_USER_ONLY)
> +void cpu_x86_fxsave(CPUX86State *env, target_ulong ptr)
> +{
> + helper_fxsave(env, ptr);
> +}
> +
> +void cpu_x86_fxrstor(CPUX86State *env, target_ulong ptr)
> +{
> + helper_fxrstor(env, ptr);
> +}
> +#endif
> +
> void helper_xrstor(CPUX86State *env, target_ulong ptr, uint64_t rfbm)
> {
> uintptr_t ra = GETPC();
> --
> 1.9.1
thanks
-- PMM