/* POSIX.1 `sigaction' call for Linux/x86-64.
- Copyright (C) 2001, 2002 Free Software Foundation, Inc.
+ Copyright (C) 2001-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; if not, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <errno.h>
#include <sysdep.h>
#include <sys/syscall.h>
-#include <kernel-features.h>
-
/* The difference here is that the sigaction structure used in the
kernel is not the same as we use in the libc. Therefore we must
translate it here. */
#include <kernel_sigaction.h>
+#include "ucontext_i.h"
+
/* We do not globally define the SA_RESTORER flag so do it here. */
#define SA_RESTORER 0x04000000
-extern int __syscall_rt_sigaction (int, const struct kernel_sigaction *__unbounded,
- struct kernel_sigaction *__unbounded, size_t);
-
-static void restore_rt (void) asm ("__restore_rt");
+/* Using the hidden attribute here does not change the code but it
+ helps to avoid warnings. */
+extern void restore_rt (void) asm ("__restore_rt") attribute_hidden;
/* If ACT is not NULL, change the action for SIG to *ACT.
/* XXX The size argument hopefully will have to be changed to the
real size of the user-level sigset_t. */
result = INLINE_SYSCALL (rt_sigaction, 4,
- sig, act ? __ptrvalue (&kact) : NULL,
- oact ? __ptrvalue (&koact) : NULL, _NSIG / 8);
+ sig, act ? &kact : NULL,
+ oact ? &koact : NULL, _NSIG / 8);
if (oact && result >= 0)
{
oact->sa_handler = koact.k_sa_handler;
return result;
}
libc_hidden_def (__libc_sigaction)
-weak_alias (__libc_sigaction, __sigaction)
-libc_hidden_weak (__sigaction)
-weak_alias (__libc_sigaction, sigaction)
+
+#include <nptl/sigaction.c>
+
/* NOTE: Please think twice before making any changes to the bits of
code below. GDB needs some intimate knowledge about it to
signal handlers work right. Important are both the names
(__restore_rt) and the exact instruction sequence.
If you ever feel the need to make any changes, please notify the
- appropriate GDB maintainer. */
+ appropriate GDB maintainer.
+
+ The unwind information starts a byte before __restore_rt, so that
+ it is found when unwinding, to get an address the unwinder assumes
+ will be in the middle of a call instruction. See the Linux kernel
+ (the i386 vsyscall, in particular) for an explanation of the complex
+ unwind information used here in order to get the traditional CFA.
+ We do not restore cs - it's only stored as two bytes here so that's
+ a bit tricky. We don't use the gas cfi directives, so that we can
+ reliably add .cfi_signal_frame. */
+
+#define do_cfa_expr \
+ " .byte 0x0f\n" /* DW_CFA_def_cfa_expression */ \
+ " .uleb128 2f-1f\n" /* length */ \
+ "1: .byte 0x77\n" /* DW_OP_breg7 */ \
+ " .sleb128 " CFI_STRINGIFY (oRSP) "\n" \
+ " .byte 0x06\n" /* DW_OP_deref */ \
+ "2:"
+
+#define do_expr(regno, offset) \
+ " .byte 0x10\n" /* DW_CFA_expression */ \
+ " .uleb128 " CFI_STRINGIFY (regno) "\n" \
+ " .uleb128 2f-1f\n" /* length */ \
+ "1: .byte 0x77\n" /* DW_OP_breg7 */ \
+ " .sleb128 " CFI_STRINGIFY (offset) "\n" \
+ "2:"
#define RESTORE(name, syscall) RESTORE2 (name, syscall)
-#define RESTORE2(name, syscall) \
-asm \
- ( \
- ".align 16\n" \
- "__" #name ":\n" \
- " movq $" #syscall ", %rax\n" \
- " syscall\n" \
+# define RESTORE2(name, syscall) \
+asm \
+ ( \
+ /* `nop' for debuggers assuming `call' should not disalign the code. */ \
+ " nop\n" \
+ ".align 16\n" \
+ ".LSTART_" #name ":\n" \
+ " .type __" #name ",@function\n" \
+ "__" #name ":\n" \
+ " movq $" #syscall ", %rax\n" \
+ " syscall\n" \
+ ".LEND_" #name ":\n" \
+ ".section .eh_frame,\"a\",@progbits\n" \
+ ".LSTARTFRAME_" #name ":\n" \
+ " .long .LENDCIE_" #name "-.LSTARTCIE_" #name "\n" \
+ ".LSTARTCIE_" #name ":\n" \
+ " .long 0\n" /* CIE ID */ \
+ " .byte 1\n" /* Version number */ \
+ " .string \"zRS\"\n" /* NUL-terminated augmentation string */ \
+ " .uleb128 1\n" /* Code alignment factor */ \
+ " .sleb128 -8\n" /* Data alignment factor */ \
+ " .uleb128 16\n" /* Return address register column (rip) */ \
+ /* Augmentation value length */ \
+ " .uleb128 .LENDAUGMNT_" #name "-.LSTARTAUGMNT_" #name "\n" \
+ ".LSTARTAUGMNT_" #name ":\n" \
+ " .byte 0x1b\n" /* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */ \
+ ".LENDAUGMNT_" #name ":\n" \
+ " .align " LP_SIZE "\n" \
+ ".LENDCIE_" #name ":\n" \
+ " .long .LENDFDE_" #name "-.LSTARTFDE_" #name "\n" /* FDE len */ \
+ ".LSTARTFDE_" #name ":\n" \
+ " .long .LSTARTFDE_" #name "-.LSTARTFRAME_" #name "\n" /* CIE */ \
+ /* `LSTART_' is subtracted 1 as debuggers assume a `call' here. */ \
+ " .long (.LSTART_" #name "-1)-.\n" /* PC-relative start addr. */ \
+ " .long .LEND_" #name "-(.LSTART_" #name "-1)\n" \
+ " .uleb128 0\n" /* FDE augmentation length */ \
+ do_cfa_expr \
+ do_expr (8 /* r8 */, oR8) \
+ do_expr (9 /* r9 */, oR9) \
+ do_expr (10 /* r10 */, oR10) \
+ do_expr (11 /* r11 */, oR11) \
+ do_expr (12 /* r12 */, oR12) \
+ do_expr (13 /* r13 */, oR13) \
+ do_expr (14 /* r14 */, oR14) \
+ do_expr (15 /* r15 */, oR15) \
+ do_expr (5 /* rdi */, oRDI) \
+ do_expr (4 /* rsi */, oRSI) \
+ do_expr (6 /* rbp */, oRBP) \
+ do_expr (3 /* rbx */, oRBX) \
+ do_expr (1 /* rdx */, oRDX) \
+ do_expr (0 /* rax */, oRAX) \
+ do_expr (2 /* rcx */, oRCX) \
+ do_expr (7 /* rsp */, oRSP) \
+ do_expr (16 /* rip */, oRIP) \
+ /* libgcc-4.1.1 has only `DWARF_FRAME_REGISTERS == 17'. */ \
+ /* do_expr (49 |* rflags *|, oEFL) */ \
+ /* `cs'/`ds'/`fs' are unaligned and a different size. */ \
+ /* gas: Error: register save offset not a multiple of 8 */ \
+ " .align " LP_SIZE "\n" \
+ ".LENDFDE_" #name ":\n" \
+ " .previous\n" \
);
-
/* The return code for realtime-signals. */
RESTORE (restore_rt, __NR_rt_sigreturn)
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