diff options
Diffstat (limited to 'arch/arm/kernel/signal.c')
| -rw-r--r-- | arch/arm/kernel/signal.c | 796 |
1 files changed, 796 insertions, 0 deletions
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c new file mode 100644 index 00000000..9e617bd4 --- /dev/null +++ b/arch/arm/kernel/signal.c @@ -0,0 +1,796 @@ +/* + * linux/arch/arm/kernel/signal.c + * + * Copyright (C) 1995-2009 Russell King + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include <linux/errno.h> +#include <linux/signal.h> +#include <linux/personality.h> +#include <linux/freezer.h> +#include <linux/uaccess.h> +#include <linux/tracehook.h> + +#include <asm/elf.h> +#include <asm/cacheflush.h> +#include <asm/ucontext.h> +#include <asm/unistd.h> +#include <asm/vfp.h> + +#include "signal.h" + +#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) + +/* + * For ARM syscalls, we encode the syscall number into the instruction. + */ +#define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE)) +#define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE)) +#define SWI_SYS_RESTART (0xef000000|__NR_restart_syscall|__NR_OABI_SYSCALL_BASE) + +/* + * With EABI, the syscall number has to be loaded into r7. + */ +#define MOV_R7_NR_SIGRETURN (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE)) +#define MOV_R7_NR_RT_SIGRETURN (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE)) + +/* + * For Thumb syscalls, we pass the syscall number via r7. We therefore + * need two 16-bit instructions. + */ +#define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE)) +#define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE)) + +const unsigned long sigreturn_codes[7] = { + MOV_R7_NR_SIGRETURN, SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN, + MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN, +}; + +/* + * Either we support OABI only, or we have EABI with the OABI + * compat layer enabled. In the later case we don't know if + * user space is EABI or not, and if not we must not clobber r7. + * Always using the OABI syscall solves that issue and works for + * all those cases. + */ +const unsigned long syscall_restart_code[2] = { + SWI_SYS_RESTART, /* swi __NR_restart_syscall */ + 0xe49df004, /* ldr pc, [sp], #4 */ +}; + +/* + * atomically swap in the new signal mask, and wait for a signal. + */ +asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask) +{ + mask &= _BLOCKABLE; + spin_lock_irq(¤t->sighand->siglock); + current->saved_sigmask = current->blocked; + siginitset(¤t->blocked, mask); + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + current->state = TASK_INTERRUPTIBLE; + schedule(); + set_restore_sigmask(); + return -ERESTARTNOHAND; +} + +asmlinkage int +sys_sigaction(int sig, const struct old_sigaction __user *act, + struct old_sigaction __user *oact) +{ + struct k_sigaction new_ka, old_ka; + int ret; + + if (act) { + old_sigset_t mask; + if (!access_ok(VERIFY_READ, act, sizeof(*act)) || + __get_user(new_ka.sa.sa_handler, &act->sa_handler) || + __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) + return -EFAULT; + __get_user(new_ka.sa.sa_flags, &act->sa_flags); + __get_user(mask, &act->sa_mask); + siginitset(&new_ka.sa.sa_mask, mask); + } + + ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); + + if (!ret && oact) { + if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || + __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || + __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) + return -EFAULT; + __put_user(old_ka.sa.sa_flags, &oact->sa_flags); + __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); + } + + return ret; +} + +#ifdef CONFIG_CRUNCH +static int preserve_crunch_context(struct crunch_sigframe __user *frame) +{ + char kbuf[sizeof(*frame) + 8]; + struct crunch_sigframe *kframe; + + /* the crunch context must be 64 bit aligned */ + kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); + kframe->magic = CRUNCH_MAGIC; + kframe->size = CRUNCH_STORAGE_SIZE; + crunch_task_copy(current_thread_info(), &kframe->storage); + return __copy_to_user(frame, kframe, sizeof(*frame)); +} + +static int restore_crunch_context(struct crunch_sigframe __user *frame) +{ + char kbuf[sizeof(*frame) + 8]; + struct crunch_sigframe *kframe; + + /* the crunch context must be 64 bit aligned */ + kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); + if (__copy_from_user(kframe, frame, sizeof(*frame))) + return -1; + if (kframe->magic != CRUNCH_MAGIC || + kframe->size != CRUNCH_STORAGE_SIZE) + return -1; + crunch_task_restore(current_thread_info(), &kframe->storage); + return 0; +} +#endif + +#ifdef CONFIG_IWMMXT + +static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame) +{ + char kbuf[sizeof(*frame) + 8]; + struct iwmmxt_sigframe *kframe; + + /* the iWMMXt context must be 64 bit aligned */ + kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7); + kframe->magic = IWMMXT_MAGIC; + kframe->size = IWMMXT_STORAGE_SIZE; + iwmmxt_task_copy(current_thread_info(), &kframe->storage); + return __copy_to_user(frame, kframe, sizeof(*frame)); +} + +static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame) +{ + char kbuf[sizeof(*frame) + 8]; + struct iwmmxt_sigframe *kframe; + + /* the iWMMXt context must be 64 bit aligned */ + kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7); + if (__copy_from_user(kframe, frame, sizeof(*frame))) + return -1; + if (kframe->magic != IWMMXT_MAGIC || + kframe->size != IWMMXT_STORAGE_SIZE) + return -1; + iwmmxt_task_restore(current_thread_info(), &kframe->storage); + return 0; +} + +#endif + +#ifdef CONFIG_VFP + +static int preserve_vfp_context(struct vfp_sigframe __user *frame) +{ + struct thread_info *thread = current_thread_info(); + struct vfp_hard_struct *h = &thread->vfpstate.hard; + const unsigned long magic = VFP_MAGIC; + const unsigned long size = VFP_STORAGE_SIZE; + int err = 0; + + vfp_sync_hwstate(thread); + __put_user_error(magic, &frame->magic, err); + __put_user_error(size, &frame->size, err); + + /* + * Copy the floating point registers. There can be unused + * registers see asm/hwcap.h for details. + */ + err |= __copy_to_user(&frame->ufp.fpregs, &h->fpregs, + sizeof(h->fpregs)); + /* + * Copy the status and control register. + */ + __put_user_error(h->fpscr, &frame->ufp.fpscr, err); + + /* + * Copy the exception registers. + */ + __put_user_error(h->fpexc, &frame->ufp_exc.fpexc, err); + __put_user_error(h->fpinst, &frame->ufp_exc.fpinst, err); + __put_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err); + + return err ? -EFAULT : 0; +} + +static int restore_vfp_context(struct vfp_sigframe __user *frame) +{ + struct thread_info *thread = current_thread_info(); + struct vfp_hard_struct *h = &thread->vfpstate.hard; + unsigned long magic; + unsigned long size; + unsigned long fpexc; + int err = 0; + + __get_user_error(magic, &frame->magic, err); + __get_user_error(size, &frame->size, err); + + if (err) + return -EFAULT; + if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE) + return -EINVAL; + + vfp_flush_hwstate(thread); + + /* + * Copy the floating point registers. There can be unused + * registers see asm/hwcap.h for details. + */ + err |= __copy_from_user(&h->fpregs, &frame->ufp.fpregs, + sizeof(h->fpregs)); + /* + * Copy the status and control register. + */ + __get_user_error(h->fpscr, &frame->ufp.fpscr, err); + + /* + * Sanitise and restore the exception registers. + */ + __get_user_error(fpexc, &frame->ufp_exc.fpexc, err); + /* Ensure the VFP is enabled. */ + fpexc |= FPEXC_EN; + /* Ensure FPINST2 is invalid and the exception flag is cleared. */ + fpexc &= ~(FPEXC_EX | FPEXC_FP2V); + h->fpexc = fpexc; + + __get_user_error(h->fpinst, &frame->ufp_exc.fpinst, err); + __get_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err); + + return err ? -EFAULT : 0; +} + +#endif + +/* + * Do a signal return; undo the signal stack. These are aligned to 64-bit. + */ +struct sigframe { + struct ucontext uc; + unsigned long retcode[2]; +}; + +struct rt_sigframe { + struct siginfo info; + struct sigframe sig; +}; + +static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf) +{ + struct aux_sigframe __user *aux; + sigset_t set; + int err; + + err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set)); + if (err == 0) { + sigdelsetmask(&set, ~_BLOCKABLE); + spin_lock_irq(¤t->sighand->siglock); + current->blocked = set; + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + } + + __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); + __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); + __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); + __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); + __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); + __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); + __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); + __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); + __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); + __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); + __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); + __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); + __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); + __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); + __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); + __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); + __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); + + err |= !valid_user_regs(regs); + + aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; +#ifdef CONFIG_CRUNCH + if (err == 0) + err |= restore_crunch_context(&aux->crunch); +#endif +#ifdef CONFIG_IWMMXT + if (err == 0 && test_thread_flag(TIF_USING_IWMMXT)) + err |= restore_iwmmxt_context(&aux->iwmmxt); +#endif +#ifdef CONFIG_VFP + if (err == 0) + err |= restore_vfp_context(&aux->vfp); +#endif + + return err; +} + +asmlinkage int sys_sigreturn(struct pt_regs *regs) +{ + struct sigframe __user *frame; + + /* Always make any pending restarted system calls return -EINTR */ + current_thread_info()->restart_block.fn = do_no_restart_syscall; + + /* + * Since we stacked the signal on a 64-bit boundary, + * then 'sp' should be word aligned here. If it's + * not, then the user is trying to mess with us. + */ + if (regs->ARM_sp & 7) + goto badframe; + + frame = (struct sigframe __user *)regs->ARM_sp; + + if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) + goto badframe; + + if (restore_sigframe(regs, frame)) + goto badframe; + + return regs->ARM_r0; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) +{ + struct rt_sigframe __user *frame; + + /* Always make any pending restarted system calls return -EINTR */ + current_thread_info()->restart_block.fn = do_no_restart_syscall; + + /* + * Since we stacked the signal on a 64-bit boundary, + * then 'sp' should be word aligned here. If it's + * not, then the user is trying to mess with us. + */ + if (regs->ARM_sp & 7) + goto badframe; + + frame = (struct rt_sigframe __user *)regs->ARM_sp; + + if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) + goto badframe; + + if (restore_sigframe(regs, &frame->sig)) + goto badframe; + + if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT) + goto badframe; + + return regs->ARM_r0; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +static int +setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set) +{ + struct aux_sigframe __user *aux; + int err = 0; + + __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); + __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); + __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); + __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); + __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); + __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); + __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); + __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); + __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); + __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); + __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); + __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); + __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); + __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); + __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); + __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); + __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); + + __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err); + __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err); + __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err); + __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err); + + err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set)); + + aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; +#ifdef CONFIG_CRUNCH + if (err == 0) + err |= preserve_crunch_context(&aux->crunch); +#endif +#ifdef CONFIG_IWMMXT + if (err == 0 && test_thread_flag(TIF_USING_IWMMXT)) + err |= preserve_iwmmxt_context(&aux->iwmmxt); +#endif +#ifdef CONFIG_VFP + if (err == 0) + err |= preserve_vfp_context(&aux->vfp); +#endif + __put_user_error(0, &aux->end_magic, err); + + return err; +} + +static inline void __user * +get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize) +{ + unsigned long sp = regs->ARM_sp; + void __user *frame; + + /* + * This is the X/Open sanctioned signal stack switching. + */ + if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) + sp = current->sas_ss_sp + current->sas_ss_size; + + /* + * ATPCS B01 mandates 8-byte alignment + */ + frame = (void __user *)((sp - framesize) & ~7); + + /* + * Check that we can actually write to the signal frame. + */ + if (!access_ok(VERIFY_WRITE, frame, framesize)) + frame = NULL; + + return frame; +} + +static int +setup_return(struct pt_regs *regs, struct k_sigaction *ka, + unsigned long __user *rc, void __user *frame, int usig) +{ + unsigned long handler = (unsigned long)ka->sa.sa_handler; + unsigned long retcode; + int thumb = 0; + unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT); + + cpsr |= PSR_ENDSTATE; + + /* + * Maybe we need to deliver a 32-bit signal to a 26-bit task. + */ + if (ka->sa.sa_flags & SA_THIRTYTWO) + cpsr = (cpsr & ~MODE_MASK) | USR_MODE; + +#ifdef CONFIG_ARM_THUMB + if (elf_hwcap & HWCAP_THUMB) { + /* + * The LSB of the handler determines if we're going to + * be using THUMB or ARM mode for this signal handler. + */ + thumb = handler & 1; + + if (thumb) { + cpsr |= PSR_T_BIT; +#if __LINUX_ARM_ARCH__ >= 7 + /* clear the If-Then Thumb-2 execution state */ + cpsr &= ~PSR_IT_MASK; +#endif + } else + cpsr &= ~PSR_T_BIT; + } +#endif + + if (ka->sa.sa_flags & SA_RESTORER) { + retcode = (unsigned long)ka->sa.sa_restorer; + } else { + unsigned int idx = thumb << 1; + + if (ka->sa.sa_flags & SA_SIGINFO) + idx += 3; + + if (__put_user(sigreturn_codes[idx], rc) || + __put_user(sigreturn_codes[idx+1], rc+1)) + return 1; + + if (cpsr & MODE32_BIT) { + /* + * 32-bit code can use the new high-page + * signal return code support. + */ + retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb; + } else { + /* + * Ensure that the instruction cache sees + * the return code written onto the stack. + */ + flush_icache_range((unsigned long)rc, + (unsigned long)(rc + 2)); + + retcode = ((unsigned long)rc) + thumb; + } + } + + regs->ARM_r0 = usig; + regs->ARM_sp = (unsigned long)frame; + regs->ARM_lr = retcode; + regs->ARM_pc = handler; + regs->ARM_cpsr = cpsr; + + return 0; +} + +static int +setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs) +{ + struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); + int err = 0; + + if (!frame) + return 1; + + /* + * Set uc.uc_flags to a value which sc.trap_no would never have. + */ + __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); + + err |= setup_sigframe(frame, regs, set); + if (err == 0) + err = setup_return(regs, ka, frame->retcode, frame, usig); + + return err; +} + +static int +setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info, + sigset_t *set, struct pt_regs *regs) +{ + struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); + stack_t stack; + int err = 0; + + if (!frame) + return 1; + + err |= copy_siginfo_to_user(&frame->info, info); + + __put_user_error(0, &frame->sig.uc.uc_flags, err); + __put_user_error(NULL, &frame->sig.uc.uc_link, err); + + memset(&stack, 0, sizeof(stack)); + stack.ss_sp = (void __user *)current->sas_ss_sp; + stack.ss_flags = sas_ss_flags(regs->ARM_sp); + stack.ss_size = current->sas_ss_size; + err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack)); + + err |= setup_sigframe(&frame->sig, regs, set); + if (err == 0) + err = setup_return(regs, ka, frame->sig.retcode, frame, usig); + + if (err == 0) { + /* + * For realtime signals we must also set the second and third + * arguments for the signal handler. + * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06 + */ + regs->ARM_r1 = (unsigned long)&frame->info; + regs->ARM_r2 = (unsigned long)&frame->sig.uc; + } + + return err; +} + +/* + * OK, we're invoking a handler + */ +static int +handle_signal(unsigned long sig, struct k_sigaction *ka, + siginfo_t *info, sigset_t *oldset, + struct pt_regs * regs) +{ + struct thread_info *thread = current_thread_info(); + struct task_struct *tsk = current; + int usig = sig; + int ret; + + /* + * translate the signal + */ + if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap) + usig = thread->exec_domain->signal_invmap[usig]; + + /* + * Set up the stack frame + */ + if (ka->sa.sa_flags & SA_SIGINFO) + ret = setup_rt_frame(usig, ka, info, oldset, regs); + else + ret = setup_frame(usig, ka, oldset, regs); + + /* + * Check that the resulting registers are actually sane. + */ + ret |= !valid_user_regs(regs); + + if (ret != 0) { + force_sigsegv(sig, tsk); + return ret; + } + + /* + * Block the signal if we were successful. + */ + spin_lock_irq(&tsk->sighand->siglock); + sigorsets(&tsk->blocked, &tsk->blocked, + &ka->sa.sa_mask); + if (!(ka->sa.sa_flags & SA_NODEFER)) + sigaddset(&tsk->blocked, sig); + recalc_sigpending(); + spin_unlock_irq(&tsk->sighand->siglock); + + return 0; +} + +/* + * Note that 'init' is a special process: it doesn't get signals it doesn't + * want to handle. Thus you cannot kill init even with a SIGKILL even by + * mistake. + * + * Note that we go through the signals twice: once to check the signals that + * the kernel can handle, and then we build all the user-level signal handling + * stack-frames in one go after that. + */ +static void do_signal(struct pt_regs *regs, int syscall) +{ + unsigned int retval = 0, continue_addr = 0, restart_addr = 0; + struct k_sigaction ka; + siginfo_t info; + int signr; + + /* + * We want the common case to go fast, which + * is why we may in certain cases get here from + * kernel mode. Just return without doing anything + * if so. + */ + if (!user_mode(regs)) + return; + + /* + * If we were from a system call, check for system call restarting... + */ + if (syscall) { + continue_addr = regs->ARM_pc; + restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4); + retval = regs->ARM_r0; + + /* + * Prepare for system call restart. We do this here so that a + * debugger will see the already changed PSW. + */ + switch (retval) { + case -ERESTARTNOHAND: + case -ERESTARTSYS: + case -ERESTARTNOINTR: + regs->ARM_r0 = regs->ARM_ORIG_r0; + regs->ARM_pc = restart_addr; + break; + case -ERESTART_RESTARTBLOCK: + regs->ARM_r0 = -EINTR; + break; + } + } + + if (try_to_freeze()) + goto no_signal; + + /* + * Get the signal to deliver. When running under ptrace, at this + * point the debugger may change all our registers ... + */ + signr = get_signal_to_deliver(&info, &ka, regs, NULL); + if (signr > 0) { + sigset_t *oldset; + + /* + * Depending on the signal settings we may need to revert the + * decision to restart the system call. But skip this if a + * debugger has chosen to restart at a different PC. + */ + if (regs->ARM_pc == restart_addr) { + if (retval == -ERESTARTNOHAND + || (retval == -ERESTARTSYS + && !(ka.sa.sa_flags & SA_RESTART))) { + regs->ARM_r0 = -EINTR; + regs->ARM_pc = continue_addr; + } + } + + if (test_thread_flag(TIF_RESTORE_SIGMASK)) + oldset = ¤t->saved_sigmask; + else + oldset = ¤t->blocked; + if (handle_signal(signr, &ka, &info, oldset, regs) == 0) { + /* + * A signal was successfully delivered; the saved + * sigmask will have been stored in the signal frame, + * and will be restored by sigreturn, so we can simply + * clear the TIF_RESTORE_SIGMASK flag. + */ + if (test_thread_flag(TIF_RESTORE_SIGMASK)) + clear_thread_flag(TIF_RESTORE_SIGMASK); + } + return; + } + + no_signal: + if (syscall) { + /* + * Handle restarting a different system call. As above, + * if a debugger has chosen to restart at a different PC, + * ignore the restart. + */ + if (retval == -ERESTART_RESTARTBLOCK + && regs->ARM_pc == continue_addr) { + if (thumb_mode(regs)) { + regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE; + regs->ARM_pc -= 2; + } else { +#if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT) + regs->ARM_r7 = __NR_restart_syscall; + regs->ARM_pc -= 4; +#else + u32 __user *usp; + + regs->ARM_sp -= 4; + usp = (u32 __user *)regs->ARM_sp; + + if (put_user(regs->ARM_pc, usp) == 0) { + regs->ARM_pc = KERN_RESTART_CODE; + } else { + regs->ARM_sp += 4; + force_sigsegv(0, current); + } +#endif + } + } + + /* If there's no signal to deliver, we just put the saved sigmask + * back. + */ + if (test_thread_flag(TIF_RESTORE_SIGMASK)) { + clear_thread_flag(TIF_RESTORE_SIGMASK); + sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); + } + } +} + +asmlinkage void +do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall) +{ + if (thread_flags & _TIF_SIGPENDING) + do_signal(regs, syscall); + + if (thread_flags & _TIF_NOTIFY_RESUME) { + clear_thread_flag(TIF_NOTIFY_RESUME); + tracehook_notify_resume(regs); + if (current->replacement_session_keyring) + key_replace_session_keyring(); + } +} |