| /* |
| * 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/random.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/traps.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)) |
| |
| static 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) |
| { |
| sigset_t blocked; |
| |
| current->saved_sigmask = current->blocked; |
| |
| mask &= _BLOCKABLE; |
| siginitset(&blocked, mask); |
| set_current_blocked(&blocked); |
| |
| 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; |
| } |
| |
| static unsigned long signal_return_offset; |
| |
| #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) |
| { |
| const unsigned long magic = VFP_MAGIC; |
| const unsigned long size = VFP_STORAGE_SIZE; |
| int err = 0; |
| |
| __put_user_error(magic, &frame->magic, err); |
| __put_user_error(size, &frame->size, err); |
| |
| if (err) |
| return -EFAULT; |
| |
| return vfp_preserve_user_clear_hwstate(&frame->ufp, &frame->ufp_exc); |
| } |
| |
| static int restore_vfp_context(struct vfp_sigframe __user *frame) |
| { |
| unsigned long magic; |
| unsigned long size; |
| 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; |
| |
| return vfp_restore_user_hwstate(&frame->ufp, &frame->ufp_exc); |
| } |
| |
| #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); |
| set_current_blocked(&set); |
| } |
| |
| __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 __LINUX_ARM_ARCH__ >= 7 |
| /* |
| * Clear the If-Then Thumb-2 execution state |
| * ARM spec requires this to be all 000s in ARM mode |
| * Snapdragon S4/Krait misbehaves on a Thumb=>ARM |
| * signal transition without this. |
| */ |
| cpsr &= ~PSR_IT_MASK; |
| #endif |
| |
| if (thumb) { |
| cpsr |= PSR_T_BIT; |
| } 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; |
| |
| #ifdef CONFIG_MMU |
| if (cpsr & MODE32_BIT) { |
| struct mm_struct *mm = current->mm; |
| |
| /* |
| * 32-bit code can use the signal return page |
| * except when the MPU has protected the vectors |
| * page from PL0 |
| */ |
| retcode = mm->context.sigpage + signal_return_offset + |
| (idx << 2) + thumb; |
| } else |
| #endif |
| { |
| /* |
| * 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. |
| */ |
| block_sigmask(ka, sig); |
| |
| 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(); |
| } |
| } |
| |
| struct page *get_signal_page(void) |
| { |
| unsigned long ptr; |
| unsigned offset; |
| struct page *page; |
| void *addr; |
| |
| page = alloc_pages(GFP_KERNEL, 0); |
| |
| if (!page) |
| return NULL; |
| |
| addr = page_address(page); |
| |
| /* Give the signal return code some randomness */ |
| offset = 0x200 + (get_random_int() & 0x7fc); |
| signal_return_offset = offset; |
| |
| /* |
| * Copy signal return handlers into the vector page, and |
| * set sigreturn to be a pointer to these. |
| */ |
| memcpy(addr + offset, sigreturn_codes, sizeof(sigreturn_codes)); |
| |
| ptr = (unsigned long)addr + offset; |
| flush_icache_range(ptr, ptr + sizeof(sigreturn_codes)); |
| |
| return page; |
| } |