[thirdparty/glibc.git] / sysdeps / unix / sysv / linux / x86_64 / sigaction.c

/* POSIX.1 `sigaction' call for Linux/x86-64.
   Copyright (C) 2001-2019 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
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   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, see
   <http://www.gnu.org/licenses/>.  */

#include <signal.h>
#define SA_RESTORER 0x04000000

extern void restore_rt (void) asm ("__restore_rt") attribute_hidden;

#define SET_SA_RESTORER(kact, act)			\
  (kact)->sa_flags = (act)->sa_flags | SA_RESTORER;	\
  (kact)->sa_restorer = &restore_rt

#define RESET_SA_RESTORER(act, kact) 			\
  (act)->sa_restorer = (kact)->sa_restorer

#include <kernel_sigaction.h>

#include <sysdeps/unix/sysv/linux/sigaction.c>

/* NOTE: Please think twice before making any changes to the bits of
   code below.  GDB needs some intimate knowledge about it to
   recognize them as signal trampolines, and make backtraces through
   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.

   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.  */

#include "ucontext_i.h"

#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									\
  (									\
   /* `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)
Commit	Line	Data
c9cf6dde	1	/* POSIX.1 `sigaction' call for Linux/x86-64.
04277e02	2	Copyright (C) 2001-2019 Free Software Foundation, Inc.
c9cf6dde AJ	3	This file is part of the GNU C Library.
	4
	5	The GNU C Library is free software; you can redistribute it and/or
	6	modify it under the terms of the GNU Lesser General Public
	7	License as published by the Free Software Foundation; either
	8	version 2.1 of the License, or (at your option) any later version.
	9
	10	The GNU C Library is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	Lesser General Public License for more details.
	14
	15	You should have received a copy of the GNU Lesser General Public
59ba27a6 PE	16	License along with the GNU C Library; if not, see
59ba27a6 PE	17	<http://www.gnu.org/licenses/>. */
c9cf6dde	18
c9cf6dde	19	#include <signal.h>
c9cf6dde AJ	20	#define SA_RESTORER 0x04000000
c9cf6dde AJ	21
a7a2ea5a	22	extern void restore_rt (void) asm ("__restore_rt") attribute_hidden;
c9cf6dde	23
b4a5d26d AZ	24	#define SET_SA_RESTORER(kact, act) \
	25	(kact)->sa_flags = (act)->sa_flags \| SA_RESTORER; \
	26	(kact)->sa_restorer = &restore_rt
c9cf6dde	27
b4a5d26d AZ	28	#define RESET_SA_RESTORER(act, kact) \
b4a5d26d AZ	29	(act)->sa_restorer = (kact)->sa_restorer
08192659	30
43a45c2d AZ	31	#include <kernel_sigaction.h>
43a45c2d AZ	32
b4a5d26d	33	#include <sysdeps/unix/sysv/linux/sigaction.c>
c9cf6dde AJ	34
	35	/* NOTE: Please think twice before making any changes to the bits of
	36	code below. GDB needs some intimate knowledge about it to
	37	recognize them as signal trampolines, and make backtraces through
	38	signal handlers work right. Important are both the names
	39	(__restore_rt) and the exact instruction sequence.
	40	If you ever feel the need to make any changes, please notify the
11bf311e UD	41	appropriate GDB maintainer.
	42
	43	The unwind information starts a byte before __restore_rt, so that
	44	it is found when unwinding, to get an address the unwinder assumes
	45	will be in the middle of a call instruction. See the Linux kernel
	46	(the i386 vsyscall, in particular) for an explanation of the complex
	47	unwind information used here in order to get the traditional CFA.
	48	We do not restore cs - it's only stored as two bytes here so that's
	49	a bit tricky. We don't use the gas cfi directives, so that we can
	50	reliably add .cfi_signal_frame. */
	51
b4a5d26d AZ	52	#include "ucontext_i.h"
b4a5d26d AZ	53
11bf311e UD	54	#define do_cfa_expr \
	55	" .byte 0x0f\n" /* DW_CFA_def_cfa_expression */ \
	56	" .uleb128 2f-1f\n" /* length */ \
	57	"1: .byte 0x77\n" /* DW_OP_breg7 */ \
	58	" .sleb128 " CFI_STRINGIFY (oRSP) "\n" \
	59	" .byte 0x06\n" /* DW_OP_deref */ \
	60	"2:"
	61
	62	#define do_expr(regno, offset) \
	63	" .byte 0x10\n" /* DW_CFA_expression */ \
	64	" .uleb128 " CFI_STRINGIFY (regno) "\n" \
	65	" .uleb128 2f-1f\n" /* length */ \
	66	"1: .byte 0x77\n" /* DW_OP_breg7 */ \
	67	" .sleb128 " CFI_STRINGIFY (offset) "\n" \
	68	"2:"
c9cf6dde AJ	69
c9cf6dde AJ	70	#define RESTORE(name, syscall) RESTORE2 (name, syscall)
2b1c0eea	71	# define RESTORE2(name, syscall) \
11bf311e UD	72	asm \
	73	( \
	74	/* `nop' for debuggers assuming `call' should not disalign the code. */ \
	75	" nop\n" \
	76	".align 16\n" \
	77	".LSTART_" #name ":\n" \
	78	" .type __" #name ",@function\n" \
	79	"__" #name ":\n" \
	80	" movq $" #syscall ", %rax\n" \
	81	" syscall\n" \
	82	".LEND_" #name ":\n" \
	83	".section .eh_frame,\"a\",@progbits\n" \
	84	".LSTARTFRAME_" #name ":\n" \
	85	" .long .LENDCIE_" #name "-.LSTARTCIE_" #name "\n" \
	86	".LSTARTCIE_" #name ":\n" \
	87	" .long 0\n" /* CIE ID */ \
	88	" .byte 1\n" /* Version number */ \
	89	" .string \"zRS\"\n" /* NUL-terminated augmentation string */ \
	90	" .uleb128 1\n" /* Code alignment factor */ \
	91	" .sleb128 -8\n" /* Data alignment factor */ \
	92	" .uleb128 16\n" /* Return address register column (rip) */ \
	93	/* Augmentation value length */ \
	94	" .uleb128 .LENDAUGMNT_" #name "-.LSTARTAUGMNT_" #name "\n" \
	95	".LSTARTAUGMNT_" #name ":\n" \
	96	" .byte 0x1b\n" /* DW_EH_PE_pcrel\|DW_EH_PE_sdata4. */ \
	97	".LENDAUGMNT_" #name ":\n" \
890d8bd8	98	" .align " LP_SIZE "\n" \
11bf311e UD	99	".LENDCIE_" #name ":\n" \
	100	" .long .LENDFDE_" #name "-.LSTARTFDE_" #name "\n" /* FDE len */ \
	101	".LSTARTFDE_" #name ":\n" \
	102	" .long .LSTARTFDE_" #name "-.LSTARTFRAME_" #name "\n" /* CIE */ \
	103	/* `LSTART_' is subtracted 1 as debuggers assume a `call' here. */ \
	104	" .long (.LSTART_" #name "-1)-.\n" /* PC-relative start addr. */ \
	105	" .long .LEND_" #name "-(.LSTART_" #name "-1)\n" \
	106	" .uleb128 0\n" /* FDE augmentation length */ \
	107	do_cfa_expr \
	108	do_expr (8 /* r8 */, oR8) \
	109	do_expr (9 /* r9 */, oR9) \
	110	do_expr (10 /* r10 */, oR10) \
	111	do_expr (11 /* r11 */, oR11) \
	112	do_expr (12 /* r12 */, oR12) \
	113	do_expr (13 /* r13 */, oR13) \
	114	do_expr (14 /* r14 */, oR14) \
	115	do_expr (15 /* r15 */, oR15) \
	116	do_expr (5 /* rdi */, oRDI) \
	117	do_expr (4 /* rsi */, oRSI) \
	118	do_expr (6 /* rbp */, oRBP) \
	119	do_expr (3 /* rbx */, oRBX) \
	120	do_expr (1 /* rdx */, oRDX) \
	121	do_expr (0 /* rax */, oRAX) \
	122	do_expr (2 /* rcx */, oRCX) \
	123	do_expr (7 /* rsp */, oRSP) \
	124	do_expr (16 /* rip */, oRIP) \
	125	/* libgcc-4.1.1 has only `DWARF_FRAME_REGISTERS == 17'. */ \
	126	/* do_expr (49 \|* rflags \|, oEFL) / \
	127	/* `cs'/`ds'/`fs' are unaligned and a different size. */ \
	128	/* gas: Error: register save offset not a multiple of 8 */ \
890d8bd8	129	" .align " LP_SIZE "\n" \
11bf311e UD	130	".LENDFDE_" #name ":\n" \
11bf311e UD	131	" .previous\n" \
c9cf6dde	132	);
c9cf6dde AJ	133	/* The return code for realtime-signals. */
c9cf6dde AJ	134	RESTORE (restore_rt, __NR_rt_sigreturn)