diff options
Diffstat (limited to 'arch/arm/kernel/signal.c')
| -rw-r--r-- | arch/arm/kernel/signal.c | 748 |
1 files changed, 748 insertions, 0 deletions
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c new file mode 100644 index 00000000000..931919fd512 --- /dev/null +++ b/arch/arm/kernel/signal.c @@ -0,0 +1,748 @@ +/* + * linux/arch/arm/kernel/signal.c + * + * Copyright (C) 1995-2002 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/config.h> +#include <linux/errno.h> +#include <linux/signal.h> +#include <linux/ptrace.h> +#include <linux/personality.h> + +#include <asm/cacheflush.h> +#include <asm/ucontext.h> +#include <asm/uaccess.h> +#include <asm/unistd.h> + +#include "ptrace.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)) +#define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)) + +/* + * 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 retcodes[4] = { + SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN, + SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN +}; + +static int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall); + +/* + * 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, struct pt_regs *regs) +{ + sigset_t saveset; + + mask &= _BLOCKABLE; + spin_lock_irq(¤t->sighand->siglock); + saveset = current->blocked; + siginitset(¤t->blocked, mask); + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + regs->ARM_r0 = -EINTR; + + while (1) { + current->state = TASK_INTERRUPTIBLE; + schedule(); + if (do_signal(&saveset, regs, 0)) + return regs->ARM_r0; + } +} + +asmlinkage int +sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, struct pt_regs *regs) +{ + sigset_t saveset, newset; + + /* XXX: Don't preclude handling different sized sigset_t's. */ + if (sigsetsize != sizeof(sigset_t)) + return -EINVAL; + + if (copy_from_user(&newset, unewset, sizeof(newset))) + return -EFAULT; + sigdelsetmask(&newset, ~_BLOCKABLE); + + spin_lock_irq(¤t->sighand->siglock); + saveset = current->blocked; + current->blocked = newset; + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + regs->ARM_r0 = -EINTR; + + while (1) { + current->state = TASK_INTERRUPTIBLE; + schedule(); + if (do_signal(&saveset, regs, 0)) + return regs->ARM_r0; + } +} + +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_IWMMXT + +/* iwmmxt_area is 0x98 bytes long, preceeded by 8 bytes of signature */ +#define IWMMXT_STORAGE_SIZE (0x98 + 8) +#define IWMMXT_MAGIC0 0x12ef842a +#define IWMMXT_MAGIC1 0x1c07ca71 + +struct iwmmxt_sigframe { + unsigned long magic0; + unsigned long magic1; + unsigned long storage[0x98/4]; +}; + +static int page_present(struct mm_struct *mm, void __user *uptr, int wr) +{ + unsigned long addr = (unsigned long)uptr; + pgd_t *pgd = pgd_offset(mm, addr); + if (pgd_present(*pgd)) { + pmd_t *pmd = pmd_offset(pgd, addr); + if (pmd_present(*pmd)) { + pte_t *pte = pte_offset_map(pmd, addr); + return (pte_present(*pte) && (!wr || pte_write(*pte))); + } + } + return 0; +} + +static int copy_locked(void __user *uptr, void *kptr, size_t size, int write, + void (*copyfn)(void *, void __user *)) +{ + unsigned char v, __user *userptr = uptr; + int err = 0; + + do { + struct mm_struct *mm; + + if (write) { + __put_user_error(0, userptr, err); + __put_user_error(0, userptr + size - 1, err); + } else { + __get_user_error(v, userptr, err); + __get_user_error(v, userptr + size - 1, err); + } + + if (err) + break; + + mm = current->mm; + spin_lock(&mm->page_table_lock); + if (page_present(mm, userptr, write) && + page_present(mm, userptr + size - 1, write)) { + copyfn(kptr, uptr); + } else + err = 1; + spin_unlock(&mm->page_table_lock); + } while (err); + + return err; +} + +static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame) +{ + int err = 0; + + /* the iWMMXt context must be 64 bit aligned */ + WARN_ON((unsigned long)frame & 7); + + __put_user_error(IWMMXT_MAGIC0, &frame->magic0, err); + __put_user_error(IWMMXT_MAGIC1, &frame->magic1, err); + + /* + * iwmmxt_task_copy() doesn't check user permissions. + * Let's do a dummy write on the upper boundary to ensure + * access to user mem is OK all way up. + */ + err |= copy_locked(&frame->storage, current_thread_info(), + sizeof(frame->storage), 1, iwmmxt_task_copy); + return err; +} + +static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame) +{ + unsigned long magic0, magic1; + int err = 0; + + /* the iWMMXt context is 64 bit aligned */ + WARN_ON((unsigned long)frame & 7); + + /* + * Validate iWMMXt context signature. + * Also, iwmmxt_task_restore() doesn't check user permissions. + * Let's do a dummy write on the upper boundary to ensure + * access to user mem is OK all way up. + */ + __get_user_error(magic0, &frame->magic0, err); + __get_user_error(magic1, &frame->magic1, err); + if (!err && magic0 == IWMMXT_MAGIC0 && magic1 == IWMMXT_MAGIC1) + err = copy_locked(&frame->storage, current_thread_info(), + sizeof(frame->storage), 0, iwmmxt_task_restore); + return err; +} + +#endif + +/* + * Auxiliary signal frame. This saves stuff like FP state. + * The layout of this structure is not part of the user ABI. + */ +struct aux_sigframe { +#ifdef CONFIG_IWMMXT + struct iwmmxt_sigframe iwmmxt; +#endif +#ifdef CONFIG_VFP + union vfp_state vfp; +#endif +}; + +/* + * Do a signal return; undo the signal stack. These are aligned to 64-bit. + */ +struct sigframe { + struct sigcontext sc; + unsigned long extramask[_NSIG_WORDS-1]; + unsigned long retcode; + struct aux_sigframe aux __attribute__((aligned(8))); +}; + +struct rt_sigframe { + struct siginfo __user *pinfo; + void __user *puc; + struct siginfo info; + struct ucontext uc; + unsigned long retcode; + struct aux_sigframe aux __attribute__((aligned(8))); +}; + +static int +restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, + struct aux_sigframe __user *aux) +{ + int err = 0; + + __get_user_error(regs->ARM_r0, &sc->arm_r0, err); + __get_user_error(regs->ARM_r1, &sc->arm_r1, err); + __get_user_error(regs->ARM_r2, &sc->arm_r2, err); + __get_user_error(regs->ARM_r3, &sc->arm_r3, err); + __get_user_error(regs->ARM_r4, &sc->arm_r4, err); + __get_user_error(regs->ARM_r5, &sc->arm_r5, err); + __get_user_error(regs->ARM_r6, &sc->arm_r6, err); + __get_user_error(regs->ARM_r7, &sc->arm_r7, err); + __get_user_error(regs->ARM_r8, &sc->arm_r8, err); + __get_user_error(regs->ARM_r9, &sc->arm_r9, err); + __get_user_error(regs->ARM_r10, &sc->arm_r10, err); + __get_user_error(regs->ARM_fp, &sc->arm_fp, err); + __get_user_error(regs->ARM_ip, &sc->arm_ip, err); + __get_user_error(regs->ARM_sp, &sc->arm_sp, err); + __get_user_error(regs->ARM_lr, &sc->arm_lr, err); + __get_user_error(regs->ARM_pc, &sc->arm_pc, err); + __get_user_error(regs->ARM_cpsr, &sc->arm_cpsr, err); + + err |= !valid_user_regs(regs); + +#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 |= vfp_restore_state(&aux->vfp); +#endif + + return err; +} + +asmlinkage int sys_sigreturn(struct pt_regs *regs) +{ + struct sigframe __user *frame; + sigset_t set; + + /* 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 (__get_user(set.sig[0], &frame->sc.oldmask) + || (_NSIG_WORDS > 1 + && __copy_from_user(&set.sig[1], &frame->extramask, + sizeof(frame->extramask)))) + goto badframe; + + sigdelsetmask(&set, ~_BLOCKABLE); + spin_lock_irq(¤t->sighand->siglock); + current->blocked = set; + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + if (restore_sigcontext(regs, &frame->sc, &frame->aux)) + goto badframe; + + /* Send SIGTRAP if we're single-stepping */ + if (current->ptrace & PT_SINGLESTEP) { + ptrace_cancel_bpt(current); + send_sig(SIGTRAP, current, 1); + } + + 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; + sigset_t set; + + /* 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 (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) + goto badframe; + + sigdelsetmask(&set, ~_BLOCKABLE); + spin_lock_irq(¤t->sighand->siglock); + current->blocked = set; + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &frame->aux)) + goto badframe; + + if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT) + goto badframe; + + /* Send SIGTRAP if we're single-stepping */ + if (current->ptrace & PT_SINGLESTEP) { + ptrace_cancel_bpt(current); + send_sig(SIGTRAP, current, 1); + } + + return regs->ARM_r0; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +static int +setup_sigcontext(struct sigcontext __user *sc, struct aux_sigframe __user *aux, + struct pt_regs *regs, unsigned long mask) +{ + int err = 0; + + __put_user_error(regs->ARM_r0, &sc->arm_r0, err); + __put_user_error(regs->ARM_r1, &sc->arm_r1, err); + __put_user_error(regs->ARM_r2, &sc->arm_r2, err); + __put_user_error(regs->ARM_r3, &sc->arm_r3, err); + __put_user_error(regs->ARM_r4, &sc->arm_r4, err); + __put_user_error(regs->ARM_r5, &sc->arm_r5, err); + __put_user_error(regs->ARM_r6, &sc->arm_r6, err); + __put_user_error(regs->ARM_r7, &sc->arm_r7, err); + __put_user_error(regs->ARM_r8, &sc->arm_r8, err); + __put_user_error(regs->ARM_r9, &sc->arm_r9, err); + __put_user_error(regs->ARM_r10, &sc->arm_r10, err); + __put_user_error(regs->ARM_fp, &sc->arm_fp, err); + __put_user_error(regs->ARM_ip, &sc->arm_ip, err); + __put_user_error(regs->ARM_sp, &sc->arm_sp, err); + __put_user_error(regs->ARM_lr, &sc->arm_lr, err); + __put_user_error(regs->ARM_pc, &sc->arm_pc, err); + __put_user_error(regs->ARM_cpsr, &sc->arm_cpsr, err); + + __put_user_error(current->thread.trap_no, &sc->trap_no, err); + __put_user_error(current->thread.error_code, &sc->error_code, err); + __put_user_error(current->thread.address, &sc->fault_address, err); + __put_user_error(mask, &sc->oldmask, err); + +#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 |= vfp_save_state(&aux->vfp); +#endif + + 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; + + /* + * 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; + 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; + + if (ka->sa.sa_flags & SA_SIGINFO) + idx += 2; + + if (__put_user(retcodes[idx], rc)) + return 1; + + /* + * Ensure that the instruction cache sees + * the return code written onto the stack. + */ + flush_icache_range((unsigned long)rc, + (unsigned long)(rc + 1)); + + 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; + + err |= setup_sigcontext(&frame->sc, &frame->aux, regs, set->sig[0]); + + if (_NSIG_WORDS > 1) { + err |= __copy_to_user(frame->extramask, &set->sig[1], + sizeof(frame->extramask)); + } + + 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; + + __put_user_error(&frame->info, &frame->pinfo, err); + __put_user_error(&frame->uc, &frame->puc, err); + err |= copy_siginfo_to_user(&frame->info, info); + + __put_user_error(0, &frame->uc.uc_flags, err); + __put_user_error(NULL, &frame->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->uc.uc_stack, &stack, sizeof(stack)); + + err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->aux, + regs, set->sig[0]); + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); + + if (err == 0) + err = setup_return(regs, ka, &frame->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->uc; + } + + return err; +} + +static inline void restart_syscall(struct pt_regs *regs) +{ + regs->ARM_r0 = regs->ARM_ORIG_r0; + regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; +} + +/* + * OK, we're invoking a handler + */ +static void +handle_signal(unsigned long sig, struct k_sigaction *ka, + siginfo_t *info, sigset_t *oldset, + struct pt_regs * regs, int syscall) +{ + struct thread_info *thread = current_thread_info(); + struct task_struct *tsk = current; + int usig = sig; + int ret; + + /* + * If we were from a system call, check for system call restarting... + */ + if (syscall) { + switch (regs->ARM_r0) { + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + regs->ARM_r0 = -EINTR; + break; + case -ERESTARTSYS: + if (!(ka->sa.sa_flags & SA_RESTART)) { + regs->ARM_r0 = -EINTR; + break; + } + /* fallthrough */ + case -ERESTARTNOINTR: + restart_syscall(regs); + } + } + + /* + * 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); + + /* + * Block the signal if we were unsuccessful. + */ + if (ret != 0 || !(ka->sa.sa_flags & SA_NODEFER)) { + spin_lock_irq(&tsk->sighand->siglock); + sigorsets(&tsk->blocked, &tsk->blocked, + &ka->sa.sa_mask); + sigaddset(&tsk->blocked, sig); + recalc_sigpending(); + spin_unlock_irq(&tsk->sighand->siglock); + } + + if (ret == 0) + return; + + force_sigsegv(sig, tsk); +} + +/* + * 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 int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall) +{ + 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 0; + + if (try_to_freeze(0)) + goto no_signal; + + if (current->ptrace & PT_SINGLESTEP) + ptrace_cancel_bpt(current); + + signr = get_signal_to_deliver(&info, &ka, regs, NULL); + if (signr > 0) { + handle_signal(signr, &ka, &info, oldset, regs, syscall); + if (current->ptrace & PT_SINGLESTEP) + ptrace_set_bpt(current); + return 1; + } + + no_signal: + /* + * No signal to deliver to the process - restart the syscall. + */ + if (syscall) { + if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) { + if (thumb_mode(regs)) { + regs->ARM_r7 = __NR_restart_syscall; + regs->ARM_pc -= 2; + } else { + u32 __user *usp; + + regs->ARM_sp -= 12; + usp = (u32 __user *)regs->ARM_sp; + + put_user(regs->ARM_pc, &usp[0]); + /* swi __NR_restart_syscall */ + put_user(0xef000000 | __NR_restart_syscall, &usp[1]); + /* ldr pc, [sp], #12 */ + put_user(0xe49df00c, &usp[2]); + + flush_icache_range((unsigned long)usp, + (unsigned long)(usp + 3)); + + regs->ARM_pc = regs->ARM_sp + 4; + } + } + if (regs->ARM_r0 == -ERESTARTNOHAND || + regs->ARM_r0 == -ERESTARTSYS || + regs->ARM_r0 == -ERESTARTNOINTR) { + restart_syscall(regs); + } + } + if (current->ptrace & PT_SINGLESTEP) + ptrace_set_bpt(current); + return 0; +} + +asmlinkage void +do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall) +{ + if (thread_flags & _TIF_SIGPENDING) + do_signal(¤t->blocked, regs, syscall); +} |