X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fx86_64%2Fkernel%2Fsignal.c;h=e5f5ce7909a32e6e0cc3e56bb8b48c1dc7882d1d;hb=43bc926fffd92024b46cafaf7350d669ba9ca884;hp=99bcd72751097d7e59219dddcf1e312f5077e977;hpb=c7b5ebbddf7bcd3651947760f423e3783bbe6573;p=linux-2.6.git diff --git a/arch/x86_64/kernel/signal.c b/arch/x86_64/kernel/signal.c index 99bcd7275..e5f5ce790 100644 --- a/arch/x86_64/kernel/signal.c +++ b/arch/x86_64/kernel/signal.c @@ -24,19 +24,19 @@ #include #include #include -#include #include #include #include #include +#include /* #define DEBUG_SIG 1 */ #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) -void ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, +int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set, struct pt_regs * regs); -void ia32_setup_frame(int sig, struct k_sigaction *ka, +int ia32_setup_frame(int sig, struct k_sigaction *ka, sigset_t *set, struct pt_regs * regs); asmlinkage long @@ -84,7 +84,7 @@ sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, struct rt_sigframe { - char *pretcode; + char __user *pretcode; struct ucontext uc; struct siginfo info; }; @@ -110,6 +110,15 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, unsigned COPY(r14); COPY(r15); + /* Kernel saves and restores only the CS segment register on signals, + * which is the bare minimum needed to allow mixed 32/64-bit code. + * App's signal handler can save/restore other segments if needed. */ + { + unsigned cs; + err |= __get_user(cs, &sc->cs); + regs->cs = cs | 3; /* Force into user mode */ + } + { unsigned int tmpflags; err |= __get_user(tmpflags, &sc->eflags); @@ -122,9 +131,15 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, unsigned err |= __get_user(buf, &sc->fpstate); if (buf) { - if (verify_area(VERIFY_READ, buf, sizeof(*buf))) + if (!access_ok(VERIFY_READ, buf, sizeof(*buf))) goto badframe; err |= restore_i387(buf); + } else { + struct task_struct *me = current; + if (used_math()) { + clear_fpu(me); + clear_used_math(); + } } } @@ -139,10 +154,10 @@ asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) { struct rt_sigframe __user *frame; sigset_t set; - long eax; + unsigned long eax; frame = (struct rt_sigframe __user *)(regs->rsp - 8); - if (verify_area(VERIFY_READ, frame, sizeof(*frame))) { + if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) { goto badframe; } if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) { @@ -155,9 +170,8 @@ asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); - if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax)) { + if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax)) goto badframe; - } #ifdef DEBUG_SIG printk("%d sigreturn rip:%lx rsp:%lx frame:%p rax:%lx\n",current->pid,regs.rip,regs.rsp,frame,eax); @@ -181,8 +195,8 @@ static inline int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask, struct task_struct *me) { int err = 0; - unsigned long eflags; + err |= __put_user(regs->cs, &sc->cs); err |= __put_user(0, &sc->gs); err |= __put_user(0, &sc->fs); @@ -205,11 +219,7 @@ setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned lo err |= __put_user(me->thread.trap_no, &sc->trapno); err |= __put_user(me->thread.error_code, &sc->err); err |= __put_user(regs->rip, &sc->rip); - eflags = regs->eflags; - if (current->ptrace & PT_PTRACED) { - eflags &= ~TF_MASK; - } - err |= __put_user(eflags, &sc->eflags); + err |= __put_user(regs->eflags, &sc->eflags); err |= __put_user(mask, &sc->oldmask); err |= __put_user(me->thread.cr2, &sc->cr2); @@ -238,7 +248,7 @@ get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size) return (void __user *)round_down(rsp - size, 16); } -static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, +static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set, struct pt_regs * regs) { struct rt_sigframe __user *frame; @@ -246,30 +256,27 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, int err = 0; struct task_struct *me = current; - if (me->used_math) { + if (used_math()) { fp = get_stack(ka, regs, sizeof(struct _fpstate)); - frame = (void __user *)round_down((unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8; + frame = (void __user *)round_down( + (unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8; - if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate))) { - goto give_sigsegv; - } + if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate))) + goto give_sigsegv; if (save_i387(fp) < 0) err |= -1; - } else { + } else frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8; - } - if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) { + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) goto give_sigsegv; - } if (ka->sa.sa_flags & SA_SIGINFO) { err |= copy_siginfo_to_user(&frame->info, info); - if (err) { + if (err) goto give_sigsegv; } - } /* Create the ucontext. */ err |= __put_user(0, &frame->uc.uc_flags); @@ -283,9 +290,8 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, if (sizeof(*set) == 16) { __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]); __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]); - } else { - err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); - } + } else + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); /* Set up to return from userspace. If provided, use a stub already in userspace. */ @@ -297,9 +303,8 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, goto give_sigsegv; } - if (err) { + if (err) goto give_sigsegv; - } #ifdef DEBUG_SIG printk("%d old rip %lx old rsp %lx old rax %lx\n", current->pid,regs->rip,regs->rsp,regs->rax); @@ -323,41 +328,47 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, regs->rsp = (unsigned long)frame; + /* Set up the CS register to run signal handlers in 64-bit mode, + even if the handler happens to be interrupting 32-bit code. */ + regs->cs = __USER_CS; + + /* This, by contrast, has nothing to do with segment registers - + see include/asm-x86_64/uaccess.h for details. */ set_fs(USER_DS); - if (regs->eflags & TF_MASK) { - if (current->ptrace & PT_PTRACED) { - ptrace_notify(SIGTRAP); - } else { - regs->eflags &= ~TF_MASK; - } - } + regs->eflags &= ~TF_MASK; + if (test_thread_flag(TIF_SINGLESTEP)) + ptrace_notify(SIGTRAP); #ifdef DEBUG_SIG printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n", current->comm, current->pid, frame, regs->rip, frame->pretcode); #endif - return; + return 1; give_sigsegv: force_sigsegv(sig, current); + return 0; } /* * OK, we're invoking a handler */ -static void +static int handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs) { + int ret; + #ifdef DEBUG_SIG - printk("handle_signal pid:%d sig:%lu rip:%lx rsp:%lx regs=%p\n", current->pid, sig, + printk("handle_signal pid:%d sig:%lu rip:%lx rsp:%lx regs=%p\n", + current->pid, sig, regs->rip, regs->rsp, regs); #endif /* Are we from a system call? */ - if (regs->orig_rax >= 0) { + if ((long)regs->orig_rax >= 0) { /* If so, check system call restarting.. */ switch (regs->rax) { case -ERESTART_RESTARTBLOCK: @@ -370,30 +381,46 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, regs->rax = -EINTR; break; } - /* fallthrough */ + /* fallthrough */ case -ERESTARTNOINTR: regs->rax = regs->orig_rax; regs->rip -= 2; + break; + } + } + + /* + * If TF is set due to a debugger (PT_DTRACE), clear the TF + * flag so that register information in the sigcontext is + * correct. + */ + if (unlikely(regs->eflags & TF_MASK)) { + if (likely(current->ptrace & PT_DTRACE)) { + current->ptrace &= ~PT_DTRACE; + regs->eflags &= ~TF_MASK; } } #ifdef CONFIG_IA32_EMULATION if (test_thread_flag(TIF_IA32)) { if (ka->sa.sa_flags & SA_SIGINFO) - ia32_setup_rt_frame(sig, ka, info, oldset, regs); + ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs); else - ia32_setup_frame(sig, ka, oldset, regs); + ret = ia32_setup_frame(sig, ka, oldset, regs); } else #endif - setup_rt_frame(sig, ka, info, oldset, regs); + ret = setup_rt_frame(sig, ka, info, oldset, regs); - if (!(ka->sa.sa_flags & SA_NODEFER)) { + if (ret) { spin_lock_irq(¤t->sighand->siglock); sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); - sigaddset(¤t->blocked,sig); + if (!(ka->sa.sa_flags & SA_NODEFER)) + sigaddset(¤t->blocked,sig); recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); } + + return ret; } /* @@ -413,14 +440,8 @@ int do_signal(struct pt_regs *regs, sigset_t *oldset) * kernel mode. Just return without doing anything * if so. */ - if ((regs->cs & 3) != 3) { + if (!user_mode(regs)) return 1; - } - - if (current->flags & PF_FREEZE) { - refrigerator(0); - goto no_signal; - } if (!oldset) oldset = ¤t->blocked; @@ -433,16 +454,14 @@ int do_signal(struct pt_regs *regs, sigset_t *oldset) * inside the kernel. */ if (current->thread.debugreg7) - asm volatile("movq %0,%%db7" : : "r" (current->thread.debugreg7)); + set_debugreg(current->thread.debugreg7, 7); /* Whee! Actually deliver the signal. */ - handle_signal(signr, &info, &ka, oldset, regs); - return 1; + return handle_signal(signr, &info, &ka, oldset, regs); } - no_signal: /* Did we come from a system call? */ - if (regs->orig_rax >= 0) { + if ((long)regs->orig_rax >= 0) { /* Restart the system call - no handlers present */ long res = regs->rax; if (res == -ERESTARTNOHAND || @@ -452,7 +471,9 @@ int do_signal(struct pt_regs *regs, sigset_t *oldset) regs->rip -= 2; } if (regs->rax == (unsigned long)-ERESTART_RESTARTBLOCK) { - regs->rax = __NR_restart_syscall; + regs->rax = test_thread_flag(TIF_IA32) ? + __NR_ia32_restart_syscall : + __NR_restart_syscall; regs->rip -= 2; } }