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Re: [Qemu-devel] [PATCH v3] linux-user: Add signal handling support for


From: Laurent Vivier
Subject: Re: [Qemu-devel] [PATCH v3] linux-user: Add signal handling support for x86_64
Date: Sun, 26 Feb 2017 18:36:03 +0100
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0

Le 26/02/2017 à 17:53, Pranith Kumar a écrit :
> Note that x86_64 has only _rt signal handlers. This implementation
> attempts to share code with the x86_32 implementation.
> 
> CC: Laurent Vivier <address@hidden>
> Signed-off-by: Allan Wirth <address@hidden>
> Reviewed-by: Peter Maydell <address@hidden>
> Signed-off-by: Pranith Kumar <address@hidden>
> ---
>  linux-user/signal.c      | 278 
> ++++++++++++++++++++++++++++++++++++++---------
>  target/i386/cpu.h        |   2 +
>  target/i386/fpu_helper.c |  12 ++
>  3 files changed, 241 insertions(+), 51 deletions(-)
> 
> diff --git a/linux-user/signal.c b/linux-user/signal.c
> index 8209539555..5dae87e3f4 100644
> --- a/linux-user/signal.c
> +++ b/linux-user/signal.c
> @@ -254,7 +254,7 @@ int do_sigprocmask(int how, const sigset_t *set, sigset_t 
> *oldset)
>  }
>  
>  #if !defined(TARGET_OPENRISC) && !defined(TARGET_UNICORE32) && \
> -    !defined(TARGET_X86_64) && !defined(TARGET_NIOS2)
> +    !defined(TARGET_NIOS2)
>  /* Just set the guest's signal mask to the specified value; the
>   * caller is assumed to have called block_signals() already.
>   */
> @@ -512,7 +512,7 @@ void signal_init(void)
>      }
>  }
>  
> -#if !(defined(TARGET_X86_64) || defined(TARGET_UNICORE32))
> +#ifndef TARGET_UNICORE32
>  /* Force a synchronously taken signal. The kernel force_sig() function
>   * also forces the signal to "not blocked, not ignored", but for QEMU
>   * that work is done in process_pending_signals().
> @@ -819,9 +819,8 @@ 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];
> @@ -835,58 +834,120 @@ struct target_fpxreg {
>  };
>  
>  struct target_xmmreg {
> -    abi_ulong element[4];
> +    uint32_t element[4];
>  };
>  
> -struct target_fpstate {
> +struct target_fpstate_32 {
>      /* Regular FPU environment */
> -    abi_ulong cw;
> -    abi_ulong sw;
> -    abi_ulong tag;
> -    abi_ulong ipoff;
> -    abi_ulong cssel;
> -    abi_ulong dataoff;
> -    abi_ulong datasel;
> -    struct target_fpreg _st[8];
> +    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];
>      uint16_t  status;
>      uint16_t  magic;          /* 0xffff = regular FPU data only */
>  
>      /* FXSR FPU environment */
> -    abi_ulong _fxsr_env[6];   /* FXSR FPU env is ignored */
> -    abi_ulong mxcsr;
> -    abi_ulong reserved;
> -    struct target_fpxreg _fxsr_st[8]; /* FXSR FPU reg data is ignored */
> -    struct target_xmmreg _xmm[8];
> -    abi_ulong padding[56];
> +    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];
>  };
>  
> -#define X86_FXSR_MAGIC               0x0000
> +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];
> +};
>  
> -struct target_sigcontext {
> +#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;
> @@ -895,8 +956,8 @@ struct target_ucontext {
>      target_sigset_t   tuc_sigmask;  /* mask last for extensibility */
>  };
>  
> -struct sigframe
> -{
> +#ifndef TARGET_X86_64
> +struct sigframe {
>      abi_ulong pretcode;
>      int sig;
>      struct target_sigcontext sc;
> @@ -905,8 +966,7 @@ struct sigframe
>      char retcode[8];
>  };
>  
> -struct rt_sigframe
> -{
> +struct rt_sigframe {
>      abi_ulong pretcode;
>      int sig;
>      abi_ulong pinfo;
> @@ -917,6 +977,17 @@ struct rt_sigframe
>      char retcode[8];
>  };
>  
> +#else
> +
> +struct rt_sigframe {
> +    abi_ulong pretcode;
> +    struct target_ucontext uc;
> +    struct target_siginfo info;
> +    struct target_fpstate fpstate;
> +};
> +
> +#endif
> +
>  /*
>   * Set up a signal frame.
>   */
> @@ -927,6 +998,7 @@ 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() */
> @@ -959,6 +1031,44 @@ 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[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_ESP], &sc->rsp);
> +    __put_user(env->regs[R_EBX], &sc->rbx);
> +    __put_user(env->regs[R_EDX], &sc->rdx);
> +    __put_user(env->regs[R_ECX], &sc->rcx);
> +    __put_user(env->regs[R_EAX], &sc->rax);
> +
> +    __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(cs->exception_index, &sc->trapno);
> +    __put_user(env->error_code, &sc->err);
> +    __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(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
>  }
>  
>  /*
> @@ -972,23 +1082,34 @@ 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;
>          }
>      } else {
> -
> +#ifndef TARGET_X86_64
>          /* 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
>  }
>  
> +#ifndef TARGET_X86_64
>  /* 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)
> @@ -1029,7 +1150,6 @@ static void setup_frame(int sig, struct 
> target_sigaction *ka,
>          __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;
> @@ -1047,13 +1167,17 @@ static void setup_frame(int sig, struct 
> target_sigaction *ka,
>  give_sigsegv:
>      force_sigsegv(sig);
>  }
> +#endif
>  
> -/* compare linux/arch/i386/kernel/signal.c:setup_rt_frame() */
> +/* compare linux/arch/x86/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)
>  {
> -    abi_ulong frame_addr, addr;
> +    abi_ulong frame_addr;
> +#ifndef TARGET_X86_64
> +    abi_ulong addr;
> +#endif
>      struct rt_sigframe *frame;
>      int i;
>  
> @@ -1063,12 +1187,17 @@ static void setup_rt_frame(int sig, struct 
> target_sigaction *ka,
>      if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
>          goto give_sigsegv;
>  
> +    /* These fields are only in rt_sigframe on 32 bit */
> +#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);
> -    tswap_siginfo(&frame->info, info);
> +#endif
> +    if (ka->sa_flags & TARGET_SA_SIGINFO) {
> +        tswap_siginfo(&frame->info, info);
> +    }
>  
>      /* Create the ucontext.  */
>      __put_user(0, &frame->uc.tuc_flags);
> @@ -1087,6 +1216,7 @@ static void setup_rt_frame(int sig, struct 
> target_sigaction *ka,
>  
>      /* 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 {
> @@ -1099,15 +1229,31 @@ static void setup_rt_frame(int sig, struct 
> target_sigaction *ka,
>          val16 = 0x80cd;
>          __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); */
> +    __put_user(ka->sa_restorer, &frame->pretcode);
> +#endif
>  
>      /* Set up registers for signal handler */
>      env->regs[R_ESP] = frame_addr;
>      env->eip = ka->_sa_handler;
>  
> +#ifndef TARGET_X86_64
> +    env->regs[R_EAX] = sig;
> +    env->regs[R_EDX] = (unsigned long)&frame->info;
> +    env->regs[R_ECX] = (unsigned long)&frame->uc;
> +#else
> +    env->regs[R_EAX] = 0;
> +    env->regs[R_EDI] = sig;
> +    env->regs[R_ESI] = (unsigned long)&frame->info;
> +    env->regs[R_EDX] = (unsigned long)&frame->uc;
> +#endif
> +
>      cpu_x86_load_seg(env, R_DS, __USER_DS);
>      cpu_x86_load_seg(env, R_ES, __USER_DS);
> -    cpu_x86_load_seg(env, R_SS, __USER_DS);
>      cpu_x86_load_seg(env, R_CS, __USER_CS);
> +    cpu_x86_load_seg(env, R_SS, __USER_DS);
>      env->eflags &= ~TF_MASK;
>  
>      unlock_user_struct(frame, frame_addr, 1);
> @@ -1125,6 +1271,7 @@ restore_sigcontext(CPUX86State *env, struct 
> target_sigcontext *sc)
>      abi_ulong fpstate_addr;
>      unsigned int tmpflags;
>  
> +#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));
> @@ -1138,7 +1285,29 @@ 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);
> @@ -1152,7 +1321,11 @@ 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;
> @@ -1160,6 +1333,8 @@ 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;
> @@ -1191,6 +1366,7 @@ badframe:
>      force_sig(TARGET_SIGSEGV);
>      return -TARGET_QEMU_ESIGRETURN;
>  }
> +#endif
>  
>  long do_rt_sigreturn(CPUX86State *env)
>  {
> @@ -1198,7 +1374,7 @@ 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;
> @@ -6418,7 +6594,7 @@ static void handle_pending_signal(CPUArchState 
> *cpu_env, int sig,
>  #if defined(TARGET_ABI_MIPSN32) || defined(TARGET_ABI_MIPSN64) \
>          || defined(TARGET_OPENRISC) || defined(TARGET_TILEGX) \
>          || defined(TARGET_PPC64) || defined(TARGET_HPPA) \
> -        || defined(TARGET_NIOS2)
> +        || defined(TARGET_NIOS2) || defined(TARGET_X86_64)
>          /* These targets do not have traditional signals.  */
>          setup_rt_frame(sig, sa, &k->info, &target_old_set, cpu_env);
>  #else
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index 8df124f332..573f2aa988 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -1417,6 +1417,8 @@ 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 66474ad98e..69ea33a5c2 100644
> --- a/target/i386/fpu_helper.c
> +++ b/target/i386/fpu_helper.c
> @@ -1377,6 +1377,18 @@ 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();
> 

Reviewed-by: Laurent Vivier <address@hidden>




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