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Diffstat (limited to 'arch/powerpc/kernel/signal.c')
| -rw-r--r-- | arch/powerpc/kernel/signal.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c new file mode 100644 index 000000000..cf8c7e4e0 --- /dev/null +++ b/arch/powerpc/kernel/signal.c @@ -0,0 +1,197 @@ +/* + * Common signal handling code for both 32 and 64 bits + * + * Copyright (c) 2007 Benjamin Herrenschmidt, IBM Coproration + * Extracted from signal_32.c and signal_64.c + * + * This file is subject to the terms and conditions of the GNU General + * Public License. See the file README.legal in the main directory of + * this archive for more details. + */ + +#include <linux/tracehook.h> +#include <linux/signal.h> +#include <linux/uprobes.h> +#include <linux/key.h> +#include <linux/context_tracking.h> +#include <asm/hw_breakpoint.h> +#include <asm/uaccess.h> +#include <asm/unistd.h> +#include <asm/debug.h> +#include <asm/tm.h> + +#include "signal.h" + +/* Log an error when sending an unhandled signal to a process. Controlled + * through debug.exception-trace sysctl. + */ + +int show_unhandled_signals = 1; + +/* + * Allocate space for the signal frame + */ +void __user *get_sigframe(struct ksignal *ksig, unsigned long sp, + size_t frame_size, int is_32) +{ + unsigned long oldsp, newsp; + + /* Default to using normal stack */ + oldsp = get_clean_sp(sp, is_32); + oldsp = sigsp(oldsp, ksig); + newsp = (oldsp - frame_size) & ~0xFUL; + + /* Check access */ + if (!access_ok(VERIFY_WRITE, (void __user *)newsp, oldsp - newsp)) + return NULL; + + return (void __user *)newsp; +} + +static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka, + int has_handler) +{ + unsigned long ret = regs->gpr[3]; + int restart = 1; + + /* syscall ? */ + if (TRAP(regs) != 0x0C00) + return; + + /* error signalled ? */ + if (!(regs->ccr & 0x10000000)) + return; + + switch (ret) { + case ERESTART_RESTARTBLOCK: + case ERESTARTNOHAND: + /* ERESTARTNOHAND means that the syscall should only be + * restarted if there was no handler for the signal, and since + * we only get here if there is a handler, we dont restart. + */ + restart = !has_handler; + break; + case ERESTARTSYS: + /* ERESTARTSYS means to restart the syscall if there is no + * handler or the handler was registered with SA_RESTART + */ + restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0; + break; + case ERESTARTNOINTR: + /* ERESTARTNOINTR means that the syscall should be + * called again after the signal handler returns. + */ + break; + default: + return; + } + if (restart) { + if (ret == ERESTART_RESTARTBLOCK) + regs->gpr[0] = __NR_restart_syscall; + else + regs->gpr[3] = regs->orig_gpr3; + regs->nip -= 4; + regs->result = 0; + } else { + regs->result = -EINTR; + regs->gpr[3] = EINTR; + regs->ccr |= 0x10000000; + } +} + +static void do_signal(struct pt_regs *regs) +{ + sigset_t *oldset = sigmask_to_save(); + struct ksignal ksig; + int ret; + int is32 = is_32bit_task(); + + get_signal(&ksig); + + /* Is there any syscall restart business here ? */ + check_syscall_restart(regs, &ksig.ka, ksig.sig > 0); + + if (ksig.sig <= 0) { + /* No signal to deliver -- put the saved sigmask back */ + restore_saved_sigmask(); + regs->trap = 0; + return; /* no signals delivered */ + } + +#ifndef CONFIG_PPC_ADV_DEBUG_REGS + /* + * Reenable the DABR before delivering the signal to + * user space. The DABR will have been cleared if it + * triggered inside the kernel. + */ + if (current->thread.hw_brk.address && + current->thread.hw_brk.type) + __set_breakpoint(¤t->thread.hw_brk); +#endif + /* Re-enable the breakpoints for the signal stack */ + thread_change_pc(current, regs); + + if (is32) { + if (ksig.ka.sa.sa_flags & SA_SIGINFO) + ret = handle_rt_signal32(&ksig, oldset, regs); + else + ret = handle_signal32(&ksig, oldset, regs); + } else { + ret = handle_rt_signal64(&ksig, oldset, regs); + } + + regs->trap = 0; + signal_setup_done(ret, &ksig, test_thread_flag(TIF_SINGLESTEP)); +} + +void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags) +{ + user_exit(); + + if (thread_info_flags & _TIF_UPROBE) + uprobe_notify_resume(regs); + + if (thread_info_flags & _TIF_SIGPENDING) + do_signal(regs); + + if (thread_info_flags & _TIF_NOTIFY_RESUME) { + clear_thread_flag(TIF_NOTIFY_RESUME); + tracehook_notify_resume(regs); + } + + user_enter(); +} + +unsigned long get_tm_stackpointer(struct pt_regs *regs) +{ + /* When in an active transaction that takes a signal, we need to be + * careful with the stack. It's possible that the stack has moved back + * up after the tbegin. The obvious case here is when the tbegin is + * called inside a function that returns before a tend. In this case, + * the stack is part of the checkpointed transactional memory state. + * If we write over this non transactionally or in suspend, we are in + * trouble because if we get a tm abort, the program counter and stack + * pointer will be back at the tbegin but our in memory stack won't be + * valid anymore. + * + * To avoid this, when taking a signal in an active transaction, we + * need to use the stack pointer from the checkpointed state, rather + * than the speculated state. This ensures that the signal context + * (written tm suspended) will be written below the stack required for + * the rollback. The transaction is aborted becuase of the treclaim, + * so any memory written between the tbegin and the signal will be + * rolled back anyway. + * + * For signals taken in non-TM or suspended mode, we use the + * normal/non-checkpointed stack pointer. + */ + +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM + if (MSR_TM_ACTIVE(regs->msr)) { + tm_reclaim_current(TM_CAUSE_SIGNAL); + if (MSR_TM_TRANSACTIONAL(regs->msr)) + return current->thread.ckpt_regs.gpr[1]; + } +#endif + return regs->gpr[1]; +} |