![Oleg Nesterov](/assets/img/avatar_default.png)
save_xstate_sig()->drop_init_fpu() doesn't look right. setup_rt_frame() can fail after that, in this case the next setup_rt_frame() triggered by SIGSEGV won't save fpu simply because the old state was lost. This obviously mean that fpu won't be restored after sys_rt_sigreturn() from SIGSEGV handler. Shift drop_init_fpu() into !failed branch in handle_signal(). Test-case (needs -O2): #include <stdio.h> #include <signal.h> #include <unistd.h> #include <sys/syscall.h> #include <sys/mman.h> #include <pthread.h> #include <assert.h> volatile double D; void test(double d) { int pid = getpid(); for (D = d; D == d; ) { /* sys_tkill(pid, SIGHUP); asm to avoid save/reload * fp regs around "C" call */ asm ("" : : "a"(200), "D"(pid), "S"(1)); asm ("syscall" : : : "ax"); } printf("ERR!!\n"); } void sigh(int sig) { } char altstack[4096 * 10] __attribute__((aligned(4096))); void *tfunc(void *arg) { for (;;) { mprotect(altstack, sizeof(altstack), PROT_READ); mprotect(altstack, sizeof(altstack), PROT_READ|PROT_WRITE); } } int main(void) { stack_t st = { .ss_sp = altstack, .ss_size = sizeof(altstack), .ss_flags = SS_ONSTACK, }; struct sigaction sa = { .sa_handler = sigh, }; pthread_t pt; sigaction(SIGSEGV, &sa, NULL); sigaltstack(&st, NULL); sa.sa_flags = SA_ONSTACK; sigaction(SIGHUP, &sa, NULL); pthread_create(&pt, NULL, tfunc, NULL); test(123.456); return 0; } Reported-by: Bean Anderson <bean@azulsystems.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Link: http://lkml.kernel.org/r/20140902175713.GA21646@redhat.com Cc: <stable@kernel.org> # v3.7+ Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
813 lines
20 KiB
C
813 lines
20 KiB
C
/*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
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*
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* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
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* 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
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* 2000-2002 x86-64 support by Andi Kleen
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/wait.h>
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#include <linux/tracehook.h>
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#include <linux/unistd.h>
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#include <linux/stddef.h>
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#include <linux/personality.h>
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#include <linux/uaccess.h>
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#include <linux/user-return-notifier.h>
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#include <linux/uprobes.h>
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#include <linux/context_tracking.h>
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#include <asm/processor.h>
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#include <asm/ucontext.h>
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#include <asm/i387.h>
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#include <asm/fpu-internal.h>
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#include <asm/vdso.h>
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#include <asm/mce.h>
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#include <asm/sighandling.h>
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#ifdef CONFIG_X86_64
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#include <asm/proto.h>
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#include <asm/ia32_unistd.h>
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#include <asm/sys_ia32.h>
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#endif /* CONFIG_X86_64 */
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#include <asm/syscall.h>
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#include <asm/syscalls.h>
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#include <asm/sigframe.h>
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#define COPY(x) do { \
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get_user_ex(regs->x, &sc->x); \
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} while (0)
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#define GET_SEG(seg) ({ \
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unsigned short tmp; \
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get_user_ex(tmp, &sc->seg); \
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tmp; \
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})
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#define COPY_SEG(seg) do { \
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regs->seg = GET_SEG(seg); \
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} while (0)
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#define COPY_SEG_CPL3(seg) do { \
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regs->seg = GET_SEG(seg) | 3; \
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} while (0)
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int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
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unsigned long *pax)
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{
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void __user *buf;
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unsigned int tmpflags;
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unsigned int err = 0;
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/* Always make any pending restarted system calls return -EINTR */
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current_thread_info()->restart_block.fn = do_no_restart_syscall;
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get_user_try {
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#ifdef CONFIG_X86_32
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set_user_gs(regs, GET_SEG(gs));
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COPY_SEG(fs);
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COPY_SEG(es);
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COPY_SEG(ds);
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#endif /* CONFIG_X86_32 */
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COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
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COPY(dx); COPY(cx); COPY(ip);
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#ifdef CONFIG_X86_64
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COPY(r8);
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COPY(r9);
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COPY(r10);
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COPY(r11);
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COPY(r12);
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COPY(r13);
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COPY(r14);
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COPY(r15);
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#endif /* CONFIG_X86_64 */
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#ifdef CONFIG_X86_32
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COPY_SEG_CPL3(cs);
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COPY_SEG_CPL3(ss);
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#else /* !CONFIG_X86_32 */
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/* Kernel saves and restores only the CS segment register on signals,
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* which is the bare minimum needed to allow mixed 32/64-bit code.
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* App's signal handler can save/restore other segments if needed. */
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COPY_SEG_CPL3(cs);
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#endif /* CONFIG_X86_32 */
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get_user_ex(tmpflags, &sc->flags);
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regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
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regs->orig_ax = -1; /* disable syscall checks */
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get_user_ex(buf, &sc->fpstate);
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get_user_ex(*pax, &sc->ax);
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} get_user_catch(err);
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err |= restore_xstate_sig(buf, config_enabled(CONFIG_X86_32));
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return err;
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}
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int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
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struct pt_regs *regs, unsigned long mask)
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{
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int err = 0;
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put_user_try {
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#ifdef CONFIG_X86_32
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put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
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put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
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put_user_ex(regs->es, (unsigned int __user *)&sc->es);
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put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
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#endif /* CONFIG_X86_32 */
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put_user_ex(regs->di, &sc->di);
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put_user_ex(regs->si, &sc->si);
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put_user_ex(regs->bp, &sc->bp);
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put_user_ex(regs->sp, &sc->sp);
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put_user_ex(regs->bx, &sc->bx);
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put_user_ex(regs->dx, &sc->dx);
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put_user_ex(regs->cx, &sc->cx);
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put_user_ex(regs->ax, &sc->ax);
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#ifdef CONFIG_X86_64
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put_user_ex(regs->r8, &sc->r8);
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put_user_ex(regs->r9, &sc->r9);
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put_user_ex(regs->r10, &sc->r10);
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put_user_ex(regs->r11, &sc->r11);
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put_user_ex(regs->r12, &sc->r12);
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put_user_ex(regs->r13, &sc->r13);
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put_user_ex(regs->r14, &sc->r14);
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put_user_ex(regs->r15, &sc->r15);
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#endif /* CONFIG_X86_64 */
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put_user_ex(current->thread.trap_nr, &sc->trapno);
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put_user_ex(current->thread.error_code, &sc->err);
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put_user_ex(regs->ip, &sc->ip);
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#ifdef CONFIG_X86_32
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put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
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put_user_ex(regs->flags, &sc->flags);
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put_user_ex(regs->sp, &sc->sp_at_signal);
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put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
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#else /* !CONFIG_X86_32 */
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put_user_ex(regs->flags, &sc->flags);
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put_user_ex(regs->cs, &sc->cs);
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put_user_ex(0, &sc->gs);
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put_user_ex(0, &sc->fs);
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#endif /* CONFIG_X86_32 */
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put_user_ex(fpstate, &sc->fpstate);
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/* non-iBCS2 extensions.. */
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put_user_ex(mask, &sc->oldmask);
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put_user_ex(current->thread.cr2, &sc->cr2);
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} put_user_catch(err);
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return err;
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}
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/*
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* Set up a signal frame.
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*/
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/*
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* Determine which stack to use..
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*/
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static unsigned long align_sigframe(unsigned long sp)
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{
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#ifdef CONFIG_X86_32
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/*
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* Align the stack pointer according to the i386 ABI,
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* i.e. so that on function entry ((sp + 4) & 15) == 0.
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*/
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sp = ((sp + 4) & -16ul) - 4;
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#else /* !CONFIG_X86_32 */
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sp = round_down(sp, 16) - 8;
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#endif
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return sp;
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}
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static inline void __user *
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get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
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void __user **fpstate)
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{
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/* Default to using normal stack */
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unsigned long math_size = 0;
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unsigned long sp = regs->sp;
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unsigned long buf_fx = 0;
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int onsigstack = on_sig_stack(sp);
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/* redzone */
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if (config_enabled(CONFIG_X86_64))
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sp -= 128;
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if (!onsigstack) {
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/* This is the X/Open sanctioned signal stack switching. */
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if (ka->sa.sa_flags & SA_ONSTACK) {
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if (current->sas_ss_size)
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sp = current->sas_ss_sp + current->sas_ss_size;
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} else if (config_enabled(CONFIG_X86_32) &&
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(regs->ss & 0xffff) != __USER_DS &&
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!(ka->sa.sa_flags & SA_RESTORER) &&
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ka->sa.sa_restorer) {
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/* This is the legacy signal stack switching. */
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sp = (unsigned long) ka->sa.sa_restorer;
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}
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}
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if (used_math()) {
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sp = alloc_mathframe(sp, config_enabled(CONFIG_X86_32),
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&buf_fx, &math_size);
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*fpstate = (void __user *)sp;
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}
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sp = align_sigframe(sp - frame_size);
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/*
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* If we are on the alternate signal stack and would overflow it, don't.
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* Return an always-bogus address instead so we will die with SIGSEGV.
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*/
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if (onsigstack && !likely(on_sig_stack(sp)))
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return (void __user *)-1L;
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/* save i387 and extended state */
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if (used_math() &&
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save_xstate_sig(*fpstate, (void __user *)buf_fx, math_size) < 0)
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return (void __user *)-1L;
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return (void __user *)sp;
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}
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#ifdef CONFIG_X86_32
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static const struct {
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u16 poplmovl;
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u32 val;
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u16 int80;
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} __attribute__((packed)) retcode = {
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0xb858, /* popl %eax; movl $..., %eax */
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__NR_sigreturn,
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0x80cd, /* int $0x80 */
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};
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static const struct {
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u8 movl;
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u32 val;
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u16 int80;
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u8 pad;
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} __attribute__((packed)) rt_retcode = {
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0xb8, /* movl $..., %eax */
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__NR_rt_sigreturn,
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0x80cd, /* int $0x80 */
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0
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};
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static int
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__setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
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struct pt_regs *regs)
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{
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struct sigframe __user *frame;
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void __user *restorer;
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int err = 0;
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void __user *fpstate = NULL;
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frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
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if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
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return -EFAULT;
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if (__put_user(sig, &frame->sig))
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return -EFAULT;
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if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
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return -EFAULT;
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if (_NSIG_WORDS > 1) {
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if (__copy_to_user(&frame->extramask, &set->sig[1],
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sizeof(frame->extramask)))
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return -EFAULT;
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}
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if (current->mm->context.vdso)
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restorer = current->mm->context.vdso +
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selected_vdso32->sym___kernel_sigreturn;
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else
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restorer = &frame->retcode;
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if (ksig->ka.sa.sa_flags & SA_RESTORER)
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restorer = ksig->ka.sa.sa_restorer;
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/* Set up to return from userspace. */
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err |= __put_user(restorer, &frame->pretcode);
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/*
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* This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
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*
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* WE DO NOT USE IT ANY MORE! It's only left here for historical
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* reasons and because gdb uses it as a signature to notice
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* signal handler stack frames.
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*/
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err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
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if (err)
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return -EFAULT;
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/* Set up registers for signal handler */
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regs->sp = (unsigned long)frame;
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regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
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regs->ax = (unsigned long)sig;
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regs->dx = 0;
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regs->cx = 0;
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regs->ds = __USER_DS;
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regs->es = __USER_DS;
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regs->ss = __USER_DS;
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regs->cs = __USER_CS;
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return 0;
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}
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static int __setup_rt_frame(int sig, struct ksignal *ksig,
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sigset_t *set, struct pt_regs *regs)
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{
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struct rt_sigframe __user *frame;
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void __user *restorer;
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int err = 0;
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void __user *fpstate = NULL;
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frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
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if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
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return -EFAULT;
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put_user_try {
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put_user_ex(sig, &frame->sig);
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put_user_ex(&frame->info, &frame->pinfo);
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put_user_ex(&frame->uc, &frame->puc);
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/* Create the ucontext. */
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if (cpu_has_xsave)
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put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
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else
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put_user_ex(0, &frame->uc.uc_flags);
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put_user_ex(0, &frame->uc.uc_link);
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save_altstack_ex(&frame->uc.uc_stack, regs->sp);
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/* Set up to return from userspace. */
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restorer = current->mm->context.vdso +
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selected_vdso32->sym___kernel_rt_sigreturn;
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if (ksig->ka.sa.sa_flags & SA_RESTORER)
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restorer = ksig->ka.sa.sa_restorer;
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put_user_ex(restorer, &frame->pretcode);
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/*
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* This is movl $__NR_rt_sigreturn, %ax ; int $0x80
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*
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* WE DO NOT USE IT ANY MORE! It's only left here for historical
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* reasons and because gdb uses it as a signature to notice
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* signal handler stack frames.
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*/
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put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
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} put_user_catch(err);
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err |= copy_siginfo_to_user(&frame->info, &ksig->info);
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err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
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regs, set->sig[0]);
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err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
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if (err)
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return -EFAULT;
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/* Set up registers for signal handler */
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regs->sp = (unsigned long)frame;
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regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
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regs->ax = (unsigned long)sig;
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regs->dx = (unsigned long)&frame->info;
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regs->cx = (unsigned long)&frame->uc;
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regs->ds = __USER_DS;
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regs->es = __USER_DS;
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regs->ss = __USER_DS;
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regs->cs = __USER_CS;
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return 0;
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}
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#else /* !CONFIG_X86_32 */
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static int __setup_rt_frame(int sig, struct ksignal *ksig,
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sigset_t *set, struct pt_regs *regs)
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{
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struct rt_sigframe __user *frame;
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void __user *fp = NULL;
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int err = 0;
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frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);
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if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
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return -EFAULT;
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if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
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if (copy_siginfo_to_user(&frame->info, &ksig->info))
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return -EFAULT;
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}
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put_user_try {
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/* Create the ucontext. */
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if (cpu_has_xsave)
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put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
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else
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put_user_ex(0, &frame->uc.uc_flags);
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put_user_ex(0, &frame->uc.uc_link);
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save_altstack_ex(&frame->uc.uc_stack, regs->sp);
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/* Set up to return from userspace. If provided, use a stub
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already in userspace. */
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/* x86-64 should always use SA_RESTORER. */
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if (ksig->ka.sa.sa_flags & SA_RESTORER) {
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put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode);
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} else {
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/* could use a vstub here */
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err |= -EFAULT;
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}
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} put_user_catch(err);
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err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
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err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
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if (err)
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return -EFAULT;
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/* Set up registers for signal handler */
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regs->di = sig;
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/* In case the signal handler was declared without prototypes */
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regs->ax = 0;
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/* This also works for non SA_SIGINFO handlers because they expect the
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next argument after the signal number on the stack. */
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regs->si = (unsigned long)&frame->info;
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regs->dx = (unsigned long)&frame->uc;
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regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
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|
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;
|
|
}
|
|
#endif /* CONFIG_X86_32 */
|
|
|
|
static int x32_setup_rt_frame(struct ksignal *ksig,
|
|
compat_sigset_t *set,
|
|
struct pt_regs *regs)
|
|
{
|
|
#ifdef CONFIG_X86_X32_ABI
|
|
struct rt_sigframe_x32 __user *frame;
|
|
void __user *restorer;
|
|
int err = 0;
|
|
void __user *fpstate = NULL;
|
|
|
|
frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
|
|
|
|
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
|
|
return -EFAULT;
|
|
|
|
if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
|
|
if (copy_siginfo_to_user32(&frame->info, &ksig->info))
|
|
return -EFAULT;
|
|
}
|
|
|
|
put_user_try {
|
|
/* Create the ucontext. */
|
|
if (cpu_has_xsave)
|
|
put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
|
|
else
|
|
put_user_ex(0, &frame->uc.uc_flags);
|
|
put_user_ex(0, &frame->uc.uc_link);
|
|
compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
|
|
put_user_ex(0, &frame->uc.uc__pad0);
|
|
|
|
if (ksig->ka.sa.sa_flags & SA_RESTORER) {
|
|
restorer = ksig->ka.sa.sa_restorer;
|
|
} else {
|
|
/* could use a vstub here */
|
|
restorer = NULL;
|
|
err |= -EFAULT;
|
|
}
|
|
put_user_ex(restorer, &frame->pretcode);
|
|
} put_user_catch(err);
|
|
|
|
err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
|
|
regs, set->sig[0]);
|
|
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
|
|
|
|
if (err)
|
|
return -EFAULT;
|
|
|
|
/* Set up registers for signal handler */
|
|
regs->sp = (unsigned long) frame;
|
|
regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
|
|
|
|
/* We use the x32 calling convention here... */
|
|
regs->di = ksig->sig;
|
|
regs->si = (unsigned long) &frame->info;
|
|
regs->dx = (unsigned long) &frame->uc;
|
|
|
|
loadsegment(ds, __USER_DS);
|
|
loadsegment(es, __USER_DS);
|
|
|
|
regs->cs = __USER_CS;
|
|
regs->ss = __USER_DS;
|
|
#endif /* CONFIG_X86_X32_ABI */
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Do a signal return; undo the signal stack.
|
|
*/
|
|
#ifdef CONFIG_X86_32
|
|
asmlinkage unsigned long sys_sigreturn(void)
|
|
{
|
|
struct pt_regs *regs = current_pt_regs();
|
|
struct sigframe __user *frame;
|
|
unsigned long ax;
|
|
sigset_t set;
|
|
|
|
frame = (struct sigframe __user *)(regs->sp - 8);
|
|
|
|
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;
|
|
|
|
set_current_blocked(&set);
|
|
|
|
if (restore_sigcontext(regs, &frame->sc, &ax))
|
|
goto badframe;
|
|
return ax;
|
|
|
|
badframe:
|
|
signal_fault(regs, frame, "sigreturn");
|
|
|
|
return 0;
|
|
}
|
|
#endif /* CONFIG_X86_32 */
|
|
|
|
asmlinkage long sys_rt_sigreturn(void)
|
|
{
|
|
struct pt_regs *regs = current_pt_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;
|
|
|
|
set_current_blocked(&set);
|
|
|
|
if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
|
|
goto badframe;
|
|
|
|
if (restore_altstack(&frame->uc.uc_stack))
|
|
goto badframe;
|
|
|
|
return ax;
|
|
|
|
badframe:
|
|
signal_fault(regs, frame, "rt_sigreturn");
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* OK, we're invoking a handler:
|
|
*/
|
|
static int signr_convert(int sig)
|
|
{
|
|
#ifdef CONFIG_X86_32
|
|
struct thread_info *info = current_thread_info();
|
|
|
|
if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
|
|
return info->exec_domain->signal_invmap[sig];
|
|
#endif /* CONFIG_X86_32 */
|
|
return sig;
|
|
}
|
|
|
|
static int
|
|
setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
|
|
{
|
|
int usig = signr_convert(ksig->sig);
|
|
sigset_t *set = sigmask_to_save();
|
|
compat_sigset_t *cset = (compat_sigset_t *) set;
|
|
|
|
/* Set up the stack frame */
|
|
if (is_ia32_frame()) {
|
|
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
|
|
return ia32_setup_rt_frame(usig, ksig, cset, regs);
|
|
else
|
|
return ia32_setup_frame(usig, ksig, cset, regs);
|
|
} else if (is_x32_frame()) {
|
|
return x32_setup_rt_frame(ksig, cset, regs);
|
|
} else {
|
|
return __setup_rt_frame(ksig->sig, ksig, set, regs);
|
|
}
|
|
}
|
|
|
|
static void
|
|
handle_signal(struct ksignal *ksig, struct pt_regs *regs)
|
|
{
|
|
bool failed;
|
|
/* 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 (!(ksig->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;
|
|
|
|
failed = (setup_rt_frame(ksig, regs) < 0);
|
|
if (!failed) {
|
|
/*
|
|
* Clear the direction flag as per the ABI for function entry.
|
|
*
|
|
* Clear RF when entering the signal handler, because
|
|
* it might disable possible debug exception from the
|
|
* signal handler.
|
|
*
|
|
* 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_DF|X86_EFLAGS_RF|X86_EFLAGS_TF);
|
|
/*
|
|
* Ensure the signal handler starts with the new fpu state.
|
|
*/
|
|
if (used_math())
|
|
drop_init_fpu(current);
|
|
}
|
|
signal_setup_done(failed, ksig, test_thread_flag(TIF_SINGLESTEP));
|
|
}
|
|
|
|
#ifdef CONFIG_X86_32
|
|
#define NR_restart_syscall __NR_restart_syscall
|
|
#else /* !CONFIG_X86_32 */
|
|
#define NR_restart_syscall \
|
|
test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
|
|
#endif /* CONFIG_X86_32 */
|
|
|
|
/*
|
|
* 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 ksignal ksig;
|
|
|
|
if (get_signal(&ksig)) {
|
|
/* Whee! Actually deliver the signal. */
|
|
handle_signal(&ksig, regs);
|
|
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.
|
|
*/
|
|
restore_saved_sigmask();
|
|
}
|
|
|
|
/*
|
|
* notification of userspace execution resumption
|
|
* - triggered by the TIF_WORK_MASK flags
|
|
*/
|
|
__visible void
|
|
do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
|
|
{
|
|
user_exit();
|
|
|
|
#ifdef CONFIG_X86_MCE
|
|
/* notify userspace of pending MCEs */
|
|
if (thread_info_flags & _TIF_MCE_NOTIFY)
|
|
mce_notify_process();
|
|
#endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
|
|
|
|
if (thread_info_flags & _TIF_UPROBE)
|
|
uprobe_notify_resume(regs);
|
|
|
|
/* 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);
|
|
}
|
|
if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
|
|
fire_user_return_notifiers();
|
|
|
|
user_enter();
|
|
}
|
|
|
|
void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
|
|
{
|
|
struct task_struct *me = current;
|
|
|
|
if (show_unhandled_signals && printk_ratelimit()) {
|
|
printk("%s"
|
|
"%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
|
|
task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
|
|
me->comm, me->pid, where, frame,
|
|
regs->ip, regs->sp, regs->orig_ax);
|
|
print_vma_addr(" in ", regs->ip);
|
|
pr_cont("\n");
|
|
}
|
|
|
|
force_sig(SIGSEGV, me);
|
|
}
|
|
|
|
#ifdef CONFIG_X86_X32_ABI
|
|
asmlinkage long sys32_x32_rt_sigreturn(void)
|
|
{
|
|
struct pt_regs *regs = current_pt_regs();
|
|
struct rt_sigframe_x32 __user *frame;
|
|
sigset_t set;
|
|
unsigned long ax;
|
|
|
|
frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
|
|
|
|
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
|
|
goto badframe;
|
|
if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
|
|
goto badframe;
|
|
|
|
set_current_blocked(&set);
|
|
|
|
if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
|
|
goto badframe;
|
|
|
|
if (compat_restore_altstack(&frame->uc.uc_stack))
|
|
goto badframe;
|
|
|
|
return ax;
|
|
|
|
badframe:
|
|
signal_fault(regs, frame, "x32 rt_sigreturn");
|
|
return 0;
|
|
}
|
|
#endif
|