![Hiroshi Shimamoto](/assets/img/avatar_default.png)
remove braces and indent for flags and fpstate in restore_sigcontext(). Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
517 lines
13 KiB
C
517 lines
13 KiB
C
/*
|
|
* Copyright (C) 1991, 1992 Linus Torvalds
|
|
* Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
|
|
*
|
|
* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
|
|
* 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
|
|
* 2000-2002 x86-64 support by Andi Kleen
|
|
*/
|
|
|
|
#include <linux/sched.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/signal.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/wait.h>
|
|
#include <linux/ptrace.h>
|
|
#include <linux/tracehook.h>
|
|
#include <linux/unistd.h>
|
|
#include <linux/stddef.h>
|
|
#include <linux/personality.h>
|
|
#include <linux/compiler.h>
|
|
#include <linux/uaccess.h>
|
|
|
|
#include <asm/processor.h>
|
|
#include <asm/ucontext.h>
|
|
#include <asm/i387.h>
|
|
#include <asm/proto.h>
|
|
#include <asm/ia32_unistd.h>
|
|
#include <asm/mce.h>
|
|
#include <asm/syscall.h>
|
|
#include <asm/syscalls.h>
|
|
#include "sigframe.h"
|
|
|
|
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
|
|
|
|
#define __FIX_EFLAGS (X86_EFLAGS_AC | X86_EFLAGS_OF | \
|
|
X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \
|
|
X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \
|
|
X86_EFLAGS_CF)
|
|
|
|
#ifdef CONFIG_X86_32
|
|
# define FIX_EFLAGS (__FIX_EFLAGS | X86_EFLAGS_RF)
|
|
#else
|
|
# define FIX_EFLAGS __FIX_EFLAGS
|
|
#endif
|
|
|
|
asmlinkage long
|
|
sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
|
|
struct pt_regs *regs)
|
|
{
|
|
return do_sigaltstack(uss, uoss, regs->sp);
|
|
}
|
|
|
|
#define COPY(x) { \
|
|
err |= __get_user(regs->x, &sc->x); \
|
|
}
|
|
|
|
#define COPY_SEG_STRICT(seg) { \
|
|
unsigned short tmp; \
|
|
err |= __get_user(tmp, &sc->seg); \
|
|
regs->seg = tmp | 3; \
|
|
}
|
|
|
|
/*
|
|
* Do a signal return; undo the signal stack.
|
|
*/
|
|
static int
|
|
restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
|
|
unsigned long *pax)
|
|
{
|
|
void __user *buf;
|
|
unsigned int tmpflags;
|
|
unsigned int err = 0;
|
|
|
|
/* Always make any pending restarted system calls return -EINTR */
|
|
current_thread_info()->restart_block.fn = do_no_restart_syscall;
|
|
|
|
COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
|
|
COPY(dx); COPY(cx); COPY(ip);
|
|
COPY(r8);
|
|
COPY(r9);
|
|
COPY(r10);
|
|
COPY(r11);
|
|
COPY(r12);
|
|
COPY(r13);
|
|
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. */
|
|
COPY_SEG_STRICT(cs);
|
|
|
|
err |= __get_user(tmpflags, &sc->flags);
|
|
regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
|
|
regs->orig_ax = -1; /* disable syscall checks */
|
|
|
|
err |= __get_user(buf, &sc->fpstate);
|
|
err |= restore_i387_xstate(buf);
|
|
|
|
err |= __get_user(*pax, &sc->ax);
|
|
return err;
|
|
}
|
|
|
|
static long do_rt_sigreturn(struct pt_regs *regs)
|
|
{
|
|
struct rt_sigframe __user *frame;
|
|
unsigned long ax;
|
|
sigset_t set;
|
|
|
|
frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
|
|
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, &ax))
|
|
goto badframe;
|
|
|
|
if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
|
|
goto badframe;
|
|
|
|
return ax;
|
|
|
|
badframe:
|
|
signal_fault(regs, frame, "rt_sigreturn");
|
|
return 0;
|
|
}
|
|
|
|
asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
|
|
{
|
|
return do_rt_sigreturn(regs);
|
|
}
|
|
|
|
/*
|
|
* Set up a signal frame.
|
|
*/
|
|
|
|
static inline int
|
|
setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
|
|
unsigned long mask, struct task_struct *me)
|
|
{
|
|
int err = 0;
|
|
|
|
err |= __put_user(regs->cs, &sc->cs);
|
|
err |= __put_user(0, &sc->gs);
|
|
err |= __put_user(0, &sc->fs);
|
|
|
|
err |= __put_user(regs->di, &sc->di);
|
|
err |= __put_user(regs->si, &sc->si);
|
|
err |= __put_user(regs->bp, &sc->bp);
|
|
err |= __put_user(regs->sp, &sc->sp);
|
|
err |= __put_user(regs->bx, &sc->bx);
|
|
err |= __put_user(regs->dx, &sc->dx);
|
|
err |= __put_user(regs->cx, &sc->cx);
|
|
err |= __put_user(regs->ax, &sc->ax);
|
|
err |= __put_user(regs->r8, &sc->r8);
|
|
err |= __put_user(regs->r9, &sc->r9);
|
|
err |= __put_user(regs->r10, &sc->r10);
|
|
err |= __put_user(regs->r11, &sc->r11);
|
|
err |= __put_user(regs->r12, &sc->r12);
|
|
err |= __put_user(regs->r13, &sc->r13);
|
|
err |= __put_user(regs->r14, &sc->r14);
|
|
err |= __put_user(regs->r15, &sc->r15);
|
|
err |= __put_user(me->thread.trap_no, &sc->trapno);
|
|
err |= __put_user(me->thread.error_code, &sc->err);
|
|
err |= __put_user(regs->ip, &sc->ip);
|
|
err |= __put_user(regs->flags, &sc->flags);
|
|
err |= __put_user(mask, &sc->oldmask);
|
|
err |= __put_user(me->thread.cr2, &sc->cr2);
|
|
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Determine which stack to use..
|
|
*/
|
|
|
|
static void __user *
|
|
get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size)
|
|
{
|
|
unsigned long sp;
|
|
|
|
/* Default to using normal stack - redzone*/
|
|
sp = regs->sp - 128;
|
|
|
|
/* This is the X/Open sanctioned signal stack switching. */
|
|
if (ka->sa.sa_flags & SA_ONSTACK) {
|
|
if (sas_ss_flags(sp) == 0)
|
|
sp = current->sas_ss_sp + current->sas_ss_size;
|
|
}
|
|
|
|
return (void __user *)round_down(sp - size, 64);
|
|
}
|
|
|
|
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;
|
|
void __user *fp = NULL;
|
|
int err = 0;
|
|
struct task_struct *me = current;
|
|
|
|
if (used_math()) {
|
|
fp = get_stack(ka, regs, sig_xstate_size);
|
|
frame = (void __user *)round_down(
|
|
(unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;
|
|
|
|
if (save_i387_xstate(fp) < 0)
|
|
return -EFAULT;
|
|
} else
|
|
frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;
|
|
|
|
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
|
|
return -EFAULT;
|
|
|
|
if (ka->sa.sa_flags & SA_SIGINFO) {
|
|
if (copy_siginfo_to_user(&frame->info, info))
|
|
return -EFAULT;
|
|
}
|
|
|
|
/* Create the ucontext. */
|
|
if (cpu_has_xsave)
|
|
err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
|
|
else
|
|
err |= __put_user(0, &frame->uc.uc_flags);
|
|
err |= __put_user(0, &frame->uc.uc_link);
|
|
err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
|
|
err |= __put_user(sas_ss_flags(regs->sp),
|
|
&frame->uc.uc_stack.ss_flags);
|
|
err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
|
|
err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0], me);
|
|
err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
|
|
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));
|
|
|
|
/* Set up to return from userspace. If provided, use a stub
|
|
already in userspace. */
|
|
/* x86-64 should always use SA_RESTORER. */
|
|
if (ka->sa.sa_flags & SA_RESTORER) {
|
|
err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
|
|
} else {
|
|
/* could use a vstub here */
|
|
return -EFAULT;
|
|
}
|
|
|
|
if (err)
|
|
return -EFAULT;
|
|
|
|
/* Set up registers for signal handler */
|
|
regs->di = sig;
|
|
/* In case the signal handler was declared without prototypes */
|
|
regs->ax = 0;
|
|
|
|
/* This also works for non SA_SIGINFO handlers because they expect the
|
|
next argument after the signal number on the stack. */
|
|
regs->si = (unsigned long)&frame->info;
|
|
regs->dx = (unsigned long)&frame->uc;
|
|
regs->ip = (unsigned long) ka->sa.sa_handler;
|
|
|
|
regs->sp = (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;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* OK, we're invoking a handler
|
|
*/
|
|
static int signr_convert(int sig)
|
|
{
|
|
return sig;
|
|
}
|
|
|
|
#ifdef CONFIG_IA32_EMULATION
|
|
#define is_ia32 test_thread_flag(TIF_IA32)
|
|
#else
|
|
#define is_ia32 0
|
|
#endif
|
|
|
|
static int
|
|
setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
|
|
sigset_t *set, struct pt_regs *regs)
|
|
{
|
|
int usig = signr_convert(sig);
|
|
int ret;
|
|
|
|
/* Set up the stack frame */
|
|
if (is_ia32) {
|
|
if (ka->sa.sa_flags & SA_SIGINFO)
|
|
ret = ia32_setup_rt_frame(usig, ka, info, set, regs);
|
|
else
|
|
ret = ia32_setup_frame(usig, ka, set, regs);
|
|
} else
|
|
ret = __setup_rt_frame(sig, ka, info, set, regs);
|
|
|
|
if (ret) {
|
|
force_sigsegv(sig, current);
|
|
return -EFAULT;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int
|
|
handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
|
|
sigset_t *oldset, struct pt_regs *regs)
|
|
{
|
|
int ret;
|
|
|
|
/* Are we from a system call? */
|
|
if (syscall_get_nr(current, regs) >= 0) {
|
|
/* If so, check system call restarting.. */
|
|
switch (syscall_get_error(current, regs)) {
|
|
case -ERESTART_RESTARTBLOCK:
|
|
case -ERESTARTNOHAND:
|
|
regs->ax = -EINTR;
|
|
break;
|
|
|
|
case -ERESTARTSYS:
|
|
if (!(ka->sa.sa_flags & SA_RESTART)) {
|
|
regs->ax = -EINTR;
|
|
break;
|
|
}
|
|
/* fallthrough */
|
|
case -ERESTARTNOINTR:
|
|
regs->ax = regs->orig_ax;
|
|
regs->ip -= 2;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
|
|
* flag so that register information in the sigcontext is correct.
|
|
*/
|
|
if (unlikely(regs->flags & X86_EFLAGS_TF) &&
|
|
likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
|
|
regs->flags &= ~X86_EFLAGS_TF;
|
|
|
|
ret = setup_rt_frame(sig, ka, info, oldset, regs);
|
|
|
|
if (ret)
|
|
return ret;
|
|
|
|
#ifdef CONFIG_X86_64
|
|
/*
|
|
* This has nothing to do with segment registers,
|
|
* despite the name. This magic affects uaccess.h
|
|
* macros' behavior. Reset it to the normal setting.
|
|
*/
|
|
set_fs(USER_DS);
|
|
#endif
|
|
|
|
/*
|
|
* Clear the direction flag as per the ABI for function entry.
|
|
*/
|
|
regs->flags &= ~X86_EFLAGS_DF;
|
|
|
|
/*
|
|
* Clear TF when entering the signal handler, but
|
|
* notify any tracer that was single-stepping it.
|
|
* The tracer may want to single-step inside the
|
|
* handler too.
|
|
*/
|
|
regs->flags &= ~X86_EFLAGS_TF;
|
|
|
|
spin_lock_irq(¤t->sighand->siglock);
|
|
sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask);
|
|
if (!(ka->sa.sa_flags & SA_NODEFER))
|
|
sigaddset(¤t->blocked, sig);
|
|
recalc_sigpending();
|
|
spin_unlock_irq(¤t->sighand->siglock);
|
|
|
|
tracehook_signal_handler(sig, info, ka, regs,
|
|
test_thread_flag(TIF_SINGLESTEP));
|
|
|
|
return 0;
|
|
}
|
|
|
|
#define NR_restart_syscall \
|
|
test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
|
|
/*
|
|
* 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.
|
|
*/
|
|
static void do_signal(struct pt_regs *regs)
|
|
{
|
|
struct k_sigaction ka;
|
|
siginfo_t info;
|
|
int signr;
|
|
sigset_t *oldset;
|
|
|
|
/*
|
|
* 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.
|
|
* X86_32: vm86 regs switched out by assembly code before reaching
|
|
* here, so testing against kernel CS suffices.
|
|
*/
|
|
if (!user_mode(regs))
|
|
return;
|
|
|
|
if (current_thread_info()->status & TS_RESTORE_SIGMASK)
|
|
oldset = ¤t->saved_sigmask;
|
|
else
|
|
oldset = ¤t->blocked;
|
|
|
|
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
|
|
if (signr > 0) {
|
|
/*
|
|
* Re-enable any watchpoints before delivering the
|
|
* signal to user space. The processor register will
|
|
* have been cleared if the watchpoint triggered
|
|
* inside the kernel.
|
|
*/
|
|
if (current->thread.debugreg7)
|
|
set_debugreg(current->thread.debugreg7, 7);
|
|
|
|
/* Whee! Actually deliver the signal. */
|
|
if (handle_signal(signr, &info, &ka, 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 TS_RESTORE_SIGMASK flag.
|
|
*/
|
|
current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
|
|
}
|
|
return;
|
|
}
|
|
|
|
/* Did we come from a system call? */
|
|
if (syscall_get_nr(current, regs) >= 0) {
|
|
/* Restart the system call - no handlers present */
|
|
switch (syscall_get_error(current, regs)) {
|
|
case -ERESTARTNOHAND:
|
|
case -ERESTARTSYS:
|
|
case -ERESTARTNOINTR:
|
|
regs->ax = regs->orig_ax;
|
|
regs->ip -= 2;
|
|
break;
|
|
|
|
case -ERESTART_RESTARTBLOCK:
|
|
regs->ax = NR_restart_syscall;
|
|
regs->ip -= 2;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If there's no signal to deliver, we just put the saved sigmask
|
|
* back.
|
|
*/
|
|
if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
|
|
current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
|
|
sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* notification of userspace execution resumption
|
|
* - triggered by the TIF_WORK_MASK flags
|
|
*/
|
|
void
|
|
do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
|
|
{
|
|
#if defined(CONFIG_X86_64) && defined(CONFIG_X86_MCE)
|
|
/* notify userspace of pending MCEs */
|
|
if (thread_info_flags & _TIF_MCE_NOTIFY)
|
|
mce_notify_user();
|
|
#endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
|
|
|
|
/* deal with pending signal delivery */
|
|
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);
|
|
}
|
|
|
|
#ifdef CONFIG_X86_32
|
|
clear_thread_flag(TIF_IRET);
|
|
#endif /* CONFIG_X86_32 */
|
|
}
|
|
|
|
void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
|
|
{
|
|
struct task_struct *me = current;
|
|
|
|
if (show_unhandled_signals && printk_ratelimit()) {
|
|
printk(KERN_INFO
|
|
"%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
|
|
me->comm, me->pid, where, frame,
|
|
regs->ip, regs->sp, regs->orig_ax);
|
|
print_vma_addr(" in ", regs->ip);
|
|
printk(KERN_CONT "\n");
|
|
}
|
|
|
|
force_sig(SIGSEGV, me);
|
|
}
|