From e7ee86a99a02694c6bcac22f53b09680ad6c5f86 Mon Sep 17 00:00:00 2001 From: Jim Blandy Date: Mon, 20 Mar 2000 20:38:29 +0000 Subject: [PATCH] * i386-linux-nat.c: No need to #include "frame.h" any more. (LINUX_SIGTRAMP_INSN0, LINUX_SIGTRAMP_OFFSET0, LINUX_SIGTRAMP_INSN1, LINUX_SIGTRAMP_OFFSET1, LINUX_SIGTRAMP_INSN2, LINUX_SIGTRAMP_OFFSET2, linux_sigtramp_code, LINUX_SIGTRAMP_LEN, i386_linux_sigtramp_start, LINUX_RT_SIGTRAMP_INSN0, LINUX_RT_SIGTRAMP_OFFSET0, LINUX_RT_SIGTRAMP_INSN1, LINUX_RT_SIGTRAMP_OFFSET1, linux_rt_sigtramp_code, LINUX_RT_SIGTRAMP_LEN, i386_linux_rt_sigtramp_start, i386_linux_in_sigtramp, i386_linux_sigcontext_addr, LINUX_SIGCONTEXT_PC_OFFSET, i386_linux_sigtramp_saved_pc, LINUX_SIGCONTEXT_SP_OFFSET, i386_linux_sigtramp_saved_sp): Deleted. Folks rightly pointed out that these are target-dependent, and useful in non-native configurations. Moved to... * i386-linux-tdep.c: ... Here, a new file. * Makefile.in (ALLDEPFILES): Add i386-linux-tdep.c. (i386-linux-tdep.o): New rule. (i386-linux-nat.o): We no longer depend on frame.h. * config/i386/linux.mt (TDEPFILES): Add i386-linux-tdep.o. --- gdb/ChangeLog | 42 +++--- gdb/Makefile.in | 6 +- gdb/config/i386/linux.mt | 2 +- gdb/i386-linux-nat.c | 258 ----------------------------------- gdb/i386-linux-tdep.c | 281 +++++++++++++++++++++++++++++++++++++++ 5 files changed, 309 insertions(+), 280 deletions(-) create mode 100644 gdb/i386-linux-tdep.c diff --git a/gdb/ChangeLog b/gdb/ChangeLog index bd1b1427fd8..b715b301dd6 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,25 @@ +2000-03-20 Jim Blandy + + * i386-linux-nat.c: No need to #include "frame.h" any more. + (LINUX_SIGTRAMP_INSN0, LINUX_SIGTRAMP_OFFSET0, + LINUX_SIGTRAMP_INSN1, LINUX_SIGTRAMP_OFFSET1, + LINUX_SIGTRAMP_INSN2, LINUX_SIGTRAMP_OFFSET2, linux_sigtramp_code, + LINUX_SIGTRAMP_LEN, i386_linux_sigtramp_start, + LINUX_RT_SIGTRAMP_INSN0, LINUX_RT_SIGTRAMP_OFFSET0, + LINUX_RT_SIGTRAMP_INSN1, LINUX_RT_SIGTRAMP_OFFSET1, + linux_rt_sigtramp_code, LINUX_RT_SIGTRAMP_LEN, + i386_linux_rt_sigtramp_start, i386_linux_in_sigtramp, + i386_linux_sigcontext_addr, LINUX_SIGCONTEXT_PC_OFFSET, + i386_linux_sigtramp_saved_pc, LINUX_SIGCONTEXT_SP_OFFSET, + i386_linux_sigtramp_saved_sp): Deleted. Folks rightly pointed + out that these are target-dependent, and useful in non-native + configurations. Moved to... + * i386-linux-tdep.c: ... Here, a new file. + * Makefile.in (ALLDEPFILES): Add i386-linux-tdep.c. + (i386-linux-tdep.o): New rule. + (i386-linux-nat.o): We no longer depend on frame.h. + * config/i386/linux.mt (TDEPFILES): Add i386-linux-tdep.o. + 2000-03-04 Eli Zaretskii * event-loop.c (top-level) [NO_FD_SET]: Deprecate this branch. @@ -64,26 +86,6 @@ Mon Mar 20 17:33:32 2000 Andrew Cagney * gdb_wait.h (WSETSTOP): Pass the appropriate number of arguments to W_STOPCODE. - * i386-linux-nat.c: No need to #include "frame.h" any more. - (LINUX_SIGTRAMP_INSN0, LINUX_SIGTRAMP_OFFSET0, - LINUX_SIGTRAMP_INSN1, LINUX_SIGTRAMP_OFFSET1, - LINUX_SIGTRAMP_INSN2, LINUX_SIGTRAMP_OFFSET2, linux_sigtramp_code, - LINUX_SIGTRAMP_LEN, i386_linux_sigtramp_start, - LINUX_RT_SIGTRAMP_INSN0, LINUX_RT_SIGTRAMP_OFFSET0, - LINUX_RT_SIGTRAMP_INSN1, LINUX_RT_SIGTRAMP_OFFSET1, - linux_rt_sigtramp_code, LINUX_RT_SIGTRAMP_LEN, - i386_linux_rt_sigtramp_start, i386_linux_in_sigtramp, - i386_linux_sigcontext_addr, LINUX_SIGCONTEXT_PC_OFFSET, - i386_linux_sigtramp_saved_pc, LINUX_SIGCONTEXT_SP_OFFSET, - i386_linux_sigtramp_saved_sp): Deleted. Folks rightly pointed - out that these are target-dependent, and useful in non-native - configurations. Moved to... - * i386-linux-tdep.c: ... Here, a new file. - * Makefile.in (ALLDEPFILES): Add i386-linux-tdep.c. - (i386-linux-tdep.o): New rule. - (i386-linux-nat.o): We no longer depend on frame.h. - * config/i386/linux.mt (TDEPFILES): Add i386-linux-tdep.o. - * solib.c (solib_add): Delete debugging code. 2000-03-17 Mark Kettenis diff --git a/gdb/Makefile.in b/gdb/Makefile.in index 72441caa3de..60464323897 100644 --- a/gdb/Makefile.in +++ b/gdb/Makefile.in @@ -1063,6 +1063,7 @@ ALLDEPFILES = 29k-share/udi/udip2soc.c 29k-share/udi/udr.c \ i386-tdep.c i386b-nat.c i386mach-nat.c i386v-nat.c i386-linux-nat.c \ i386aix-nat.c i386m3-nat.c i386v4-nat.c i386ly-tdep.c \ i387-tdep.c \ + i386-linux-tdep.c \ i960-tdep.c \ infptrace.c inftarg.c irix4-nat.c irix5-nat.c isi-xdep.c \ lynx-nat.c m3-nat.c \ @@ -1395,7 +1396,10 @@ i386v-nat.o: i386v-nat.c $(floatformat_h) $(defs_h) $(gdbcore_h) \ $(inferior_h) language.h target.h i386-linux-nat.o: i386-linux-nat.c $(defs_h) $(inferior_h) $(gdbcore_h) \ - $(symtab_h) $(frame_h) symfile.h objfiles.h + $(symtab_h) symfile.h objfiles.h + +i386-linux-tdep.o: i386-linux-tdep.c $(defs_h) $(gdbcore_h) $(frame_h) \ + $(value_h) i386v4-nat.o: i386v4-nat.c $(defs_h) diff --git a/gdb/config/i386/linux.mt b/gdb/config/i386/linux.mt index 66cc97dbde5..df17b184369 100644 --- a/gdb/config/i386/linux.mt +++ b/gdb/config/i386/linux.mt @@ -1,5 +1,5 @@ # Target: Intel 386 running GNU/Linux -TDEPFILES= i386-tdep.o i387-tdep.o +TDEPFILES= i386-tdep.o i386-linux-tdep.o i387-tdep.o TM_FILE= tm-linux.h GDBSERVER_DEPFILES= low-linux.o diff --git a/gdb/i386-linux-nat.c b/gdb/i386-linux-nat.c index bf5e821a279..2e46ead746c 100644 --- a/gdb/i386-linux-nat.c +++ b/gdb/i386-linux-nat.c @@ -23,7 +23,6 @@ /* For i386_linux_skip_solib_resolver. */ #include "symtab.h" -#include "frame.h" #include "symfile.h" #include "objfiles.h" @@ -1043,263 +1042,6 @@ i386_linux_skip_solib_resolver (CORE_ADDR pc) return 0; } - -/* Recognizing signal handler frames. */ - -/* Linux has two flavors of signals. Normal signal handlers, and - "realtime" (RT) signals. The RT signals can provide additional - information to the signal handler if the SA_SIGINFO flag is set - when establishing a signal handler using `sigaction'. It is not - unlikely that future versions of Linux will support SA_SIGINFO for - normal signals too. */ - -/* When the i386 Linux kernel calls a signal handler and the - SA_RESTORER flag isn't set, the return address points to a bit of - code on the stack. This function returns whether the PC appears to - be within this bit of code. - - The instruction sequence for normal signals is - pop %eax - mov $0x77,%eax - int $0x80 - or 0x58 0xb8 0x77 0x00 0x00 0x00 0xcd 0x80. - - Checking for the code sequence should be somewhat reliable, because - the effect is to call the system call sigreturn. This is unlikely - to occur anywhere other than a signal trampoline. - - It kind of sucks that we have to read memory from the process in - order to identify a signal trampoline, but there doesn't seem to be - any other way. The IN_SIGTRAMP macro in tm-linux.h arranges to - only call us if no function name could be identified, which should - be the case since the code is on the stack. - - Detection of signal trampolines for handlers that set the - SA_RESTORER flag is in general not possible. Unfortunately this is - what the GNU C Library has been doing for quite some time now. - However, as of version 2.1.2, the GNU C Library uses signal - trampolines (named __restore and __restore_rt) that are identical - to the ones used by the kernel. Therefore, these trampolines are - supported too. */ - -#define LINUX_SIGTRAMP_INSN0 (0x58) /* pop %eax */ -#define LINUX_SIGTRAMP_OFFSET0 (0) -#define LINUX_SIGTRAMP_INSN1 (0xb8) /* mov $NNNN,%eax */ -#define LINUX_SIGTRAMP_OFFSET1 (1) -#define LINUX_SIGTRAMP_INSN2 (0xcd) /* int */ -#define LINUX_SIGTRAMP_OFFSET2 (6) - -static const unsigned char linux_sigtramp_code[] = -{ - LINUX_SIGTRAMP_INSN0, /* pop %eax */ - LINUX_SIGTRAMP_INSN1, 0x77, 0x00, 0x00, 0x00, /* mov $0x77,%eax */ - LINUX_SIGTRAMP_INSN2, 0x80 /* int $0x80 */ -}; - -#define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code) - -/* If PC is in a sigtramp routine, return the address of the start of - the routine. Otherwise, return 0. */ - -static CORE_ADDR -i386_linux_sigtramp_start (CORE_ADDR pc) -{ - unsigned char buf[LINUX_SIGTRAMP_LEN]; - - /* We only recognize a signal trampoline if PC is at the start of - one of the three instructions. We optimize for finding the PC at - the start, as will be the case when the trampoline is not the - first frame on the stack. We assume that in the case where the - PC is not at the start of the instruction sequence, there will be - a few trailing readable bytes on the stack. */ - - if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) - return 0; - - if (buf[0] != LINUX_SIGTRAMP_INSN0) - { - int adjust; - - switch (buf[0]) - { - case LINUX_SIGTRAMP_INSN1: - adjust = LINUX_SIGTRAMP_OFFSET1; - break; - case LINUX_SIGTRAMP_INSN2: - adjust = LINUX_SIGTRAMP_OFFSET2; - break; - default: - return 0; - } - - pc -= adjust; - - if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) - return 0; - } - - if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0) - return 0; - - return pc; -} - -/* This function does the same for RT signals. Here the instruction - sequence is - mov $0xad,%eax - int $0x80 - or 0xb8 0xad 0x00 0x00 0x00 0xcd 0x80. - - The effect is to call the system call rt_sigreturn. */ - -#define LINUX_RT_SIGTRAMP_INSN0 (0xb8) /* mov $NNNN,%eax */ -#define LINUX_RT_SIGTRAMP_OFFSET0 (0) -#define LINUX_RT_SIGTRAMP_INSN1 (0xcd) /* int */ -#define LINUX_RT_SIGTRAMP_OFFSET1 (5) - -static const unsigned char linux_rt_sigtramp_code[] = -{ - LINUX_RT_SIGTRAMP_INSN0, 0xad, 0x00, 0x00, 0x00, /* mov $0xad,%eax */ - LINUX_RT_SIGTRAMP_INSN1, 0x80 /* int $0x80 */ -}; - -#define LINUX_RT_SIGTRAMP_LEN (sizeof linux_rt_sigtramp_code) - -/* If PC is in a RT sigtramp routine, return the address of the start - of the routine. Otherwise, return 0. */ - -static CORE_ADDR -i386_linux_rt_sigtramp_start (CORE_ADDR pc) -{ - unsigned char buf[LINUX_RT_SIGTRAMP_LEN]; - - /* We only recognize a signal trampoline if PC is at the start of - one of the two instructions. We optimize for finding the PC at - the start, as will be the case when the trampoline is not the - first frame on the stack. We assume that in the case where the - PC is not at the start of the instruction sequence, there will be - a few trailing readable bytes on the stack. */ - - if (read_memory_nobpt (pc, (char *) buf, LINUX_RT_SIGTRAMP_LEN) != 0) - return 0; - - if (buf[0] != LINUX_RT_SIGTRAMP_INSN0) - { - if (buf[0] != LINUX_RT_SIGTRAMP_INSN1) - return 0; - - pc -= LINUX_RT_SIGTRAMP_OFFSET1; - - if (read_memory_nobpt (pc, (char *) buf, LINUX_RT_SIGTRAMP_LEN) != 0) - return 0; - } - - if (memcmp (buf, linux_rt_sigtramp_code, LINUX_RT_SIGTRAMP_LEN) != 0) - return 0; - - return pc; -} - -/* Return whether PC is in a Linux sigtramp routine. */ - -int -i386_linux_in_sigtramp (CORE_ADDR pc, char *name) -{ - if (name) - return STREQ ("__restore", name) || STREQ ("__restore_rt", name); - - return (i386_linux_sigtramp_start (pc) != 0 - || i386_linux_rt_sigtramp_start (pc) != 0); -} - -/* Assuming FRAME is for a Linux sigtramp routine, return the address - of the associated sigcontext structure. */ - -CORE_ADDR -i386_linux_sigcontext_addr (struct frame_info *frame) -{ - CORE_ADDR pc; - - pc = i386_linux_sigtramp_start (frame->pc); - if (pc) - { - CORE_ADDR sp; - - if (frame->next) - /* If this isn't the top frame, the next frame must be for the - signal handler itself. The sigcontext structure lives on - the stack, right after the signum argument. */ - return frame->next->frame + 12; - - /* This is the top frame. We'll have to find the address of the - sigcontext structure by looking at the stack pointer. Keep - in mind that the first instruction of the sigtramp code is - "pop %eax". If the PC is at this instruction, adjust the - returned value accordingly. */ - sp = read_register (SP_REGNUM); - if (pc == frame->pc) - return sp + 4; - return sp; - } - - pc = i386_linux_rt_sigtramp_start (frame->pc); - if (pc) - { - if (frame->next) - /* If this isn't the top frame, the next frame must be for the - signal handler itself. The sigcontext structure is part of - the user context. A pointer to the user context is passed - as the third argument to the signal handler. */ - return read_memory_integer (frame->next->frame + 16, 4) + 20; - - /* This is the top frame. Again, use the stack pointer to find - the address of the sigcontext structure. */ - return read_memory_integer (read_register (SP_REGNUM) + 8, 4) + 20; - } - - error ("Couldn't recognize signal trampoline."); - return 0; -} - -/* Offset to saved PC in sigcontext, from . */ -#define LINUX_SIGCONTEXT_PC_OFFSET (56) - -/* Assuming FRAME is for a Linux sigtramp routine, return the saved - program counter. */ - -CORE_ADDR -i386_linux_sigtramp_saved_pc (struct frame_info *frame) -{ - CORE_ADDR addr; - addr = i386_linux_sigcontext_addr (frame); - return read_memory_integer (addr + LINUX_SIGCONTEXT_PC_OFFSET, 4); -} - -/* Offset to saved SP in sigcontext, from . */ -#define LINUX_SIGCONTEXT_SP_OFFSET (28) - -/* Assuming FRAME is for a Linux sigtramp routine, return the saved - stack pointer. */ - -CORE_ADDR -i386_linux_sigtramp_saved_sp (struct frame_info *frame) -{ - CORE_ADDR addr; - addr = i386_linux_sigcontext_addr (frame); - return read_memory_integer (addr + LINUX_SIGCONTEXT_SP_OFFSET, 4); -} - -/* Immediately after a function call, return the saved pc. */ - -CORE_ADDR -i386_linux_saved_pc_after_call (struct frame_info *frame) -{ - if (frame->signal_handler_caller) - return i386_linux_sigtramp_saved_pc (frame); - - return read_memory_integer (read_register (SP_REGNUM), 4); -} - /* Register that we are able to handle Linux ELF core file formats. */ diff --git a/gdb/i386-linux-tdep.c b/gdb/i386-linux-tdep.c new file mode 100644 index 00000000000..38d6bcb1547 --- /dev/null +++ b/gdb/i386-linux-tdep.c @@ -0,0 +1,281 @@ +/* Target-dependent code for Linux running on i386's, for GDB. + Copyright (C) 2000 Free Software Foundation, Inc. + + This file is part of GDB. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include "defs.h" +#include "gdbcore.h" +#include "frame.h" +#include "value.h" + + +/* Recognizing signal handler frames. */ + +/* Linux has two flavors of signals. Normal signal handlers, and + "realtime" (RT) signals. The RT signals can provide additional + information to the signal handler if the SA_SIGINFO flag is set + when establishing a signal handler using `sigaction'. It is not + unlikely that future versions of Linux will support SA_SIGINFO for + normal signals too. */ + +/* When the i386 Linux kernel calls a signal handler and the + SA_RESTORER flag isn't set, the return address points to a bit of + code on the stack. This function returns whether the PC appears to + be within this bit of code. + + The instruction sequence for normal signals is + pop %eax + mov $0x77,%eax + int $0x80 + or 0x58 0xb8 0x77 0x00 0x00 0x00 0xcd 0x80. + + Checking for the code sequence should be somewhat reliable, because + the effect is to call the system call sigreturn. This is unlikely + to occur anywhere other than a signal trampoline. + + It kind of sucks that we have to read memory from the process in + order to identify a signal trampoline, but there doesn't seem to be + any other way. The IN_SIGTRAMP macro in tm-linux.h arranges to + only call us if no function name could be identified, which should + be the case since the code is on the stack. + + Detection of signal trampolines for handlers that set the + SA_RESTORER flag is in general not possible. Unfortunately this is + what the GNU C Library has been doing for quite some time now. + However, as of version 2.1.2, the GNU C Library uses signal + trampolines (named __restore and __restore_rt) that are identical + to the ones used by the kernel. Therefore, these trampolines are + supported too. */ + +#define LINUX_SIGTRAMP_INSN0 (0x58) /* pop %eax */ +#define LINUX_SIGTRAMP_OFFSET0 (0) +#define LINUX_SIGTRAMP_INSN1 (0xb8) /* mov $NNNN,%eax */ +#define LINUX_SIGTRAMP_OFFSET1 (1) +#define LINUX_SIGTRAMP_INSN2 (0xcd) /* int */ +#define LINUX_SIGTRAMP_OFFSET2 (6) + +static const unsigned char linux_sigtramp_code[] = +{ + LINUX_SIGTRAMP_INSN0, /* pop %eax */ + LINUX_SIGTRAMP_INSN1, 0x77, 0x00, 0x00, 0x00, /* mov $0x77,%eax */ + LINUX_SIGTRAMP_INSN2, 0x80 /* int $0x80 */ +}; + +#define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code) + +/* If PC is in a sigtramp routine, return the address of the start of + the routine. Otherwise, return 0. */ + +static CORE_ADDR +i386_linux_sigtramp_start (CORE_ADDR pc) +{ + unsigned char buf[LINUX_SIGTRAMP_LEN]; + + /* We only recognize a signal trampoline if PC is at the start of + one of the three instructions. We optimize for finding the PC at + the start, as will be the case when the trampoline is not the + first frame on the stack. We assume that in the case where the + PC is not at the start of the instruction sequence, there will be + a few trailing readable bytes on the stack. */ + + if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) + return 0; + + if (buf[0] != LINUX_SIGTRAMP_INSN0) + { + int adjust; + + switch (buf[0]) + { + case LINUX_SIGTRAMP_INSN1: + adjust = LINUX_SIGTRAMP_OFFSET1; + break; + case LINUX_SIGTRAMP_INSN2: + adjust = LINUX_SIGTRAMP_OFFSET2; + break; + default: + return 0; + } + + pc -= adjust; + + if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) + return 0; + } + + if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0) + return 0; + + return pc; +} + +/* This function does the same for RT signals. Here the instruction + sequence is + mov $0xad,%eax + int $0x80 + or 0xb8 0xad 0x00 0x00 0x00 0xcd 0x80. + + The effect is to call the system call rt_sigreturn. */ + +#define LINUX_RT_SIGTRAMP_INSN0 (0xb8) /* mov $NNNN,%eax */ +#define LINUX_RT_SIGTRAMP_OFFSET0 (0) +#define LINUX_RT_SIGTRAMP_INSN1 (0xcd) /* int */ +#define LINUX_RT_SIGTRAMP_OFFSET1 (5) + +static const unsigned char linux_rt_sigtramp_code[] = +{ + LINUX_RT_SIGTRAMP_INSN0, 0xad, 0x00, 0x00, 0x00, /* mov $0xad,%eax */ + LINUX_RT_SIGTRAMP_INSN1, 0x80 /* int $0x80 */ +}; + +#define LINUX_RT_SIGTRAMP_LEN (sizeof linux_rt_sigtramp_code) + +/* If PC is in a RT sigtramp routine, return the address of the start + of the routine. Otherwise, return 0. */ + +static CORE_ADDR +i386_linux_rt_sigtramp_start (CORE_ADDR pc) +{ + unsigned char buf[LINUX_RT_SIGTRAMP_LEN]; + + /* We only recognize a signal trampoline if PC is at the start of + one of the two instructions. We optimize for finding the PC at + the start, as will be the case when the trampoline is not the + first frame on the stack. We assume that in the case where the + PC is not at the start of the instruction sequence, there will be + a few trailing readable bytes on the stack. */ + + if (read_memory_nobpt (pc, (char *) buf, LINUX_RT_SIGTRAMP_LEN) != 0) + return 0; + + if (buf[0] != LINUX_RT_SIGTRAMP_INSN0) + { + if (buf[0] != LINUX_RT_SIGTRAMP_INSN1) + return 0; + + pc -= LINUX_RT_SIGTRAMP_OFFSET1; + + if (read_memory_nobpt (pc, (char *) buf, LINUX_RT_SIGTRAMP_LEN) != 0) + return 0; + } + + if (memcmp (buf, linux_rt_sigtramp_code, LINUX_RT_SIGTRAMP_LEN) != 0) + return 0; + + return pc; +} + +/* Return whether PC is in a Linux sigtramp routine. */ + +int +i386_linux_in_sigtramp (CORE_ADDR pc, char *name) +{ + if (name) + return STREQ ("__restore", name) || STREQ ("__restore_rt", name); + + return (i386_linux_sigtramp_start (pc) != 0 + || i386_linux_rt_sigtramp_start (pc) != 0); +} + +/* Assuming FRAME is for a Linux sigtramp routine, return the address + of the associated sigcontext structure. */ + +CORE_ADDR +i386_linux_sigcontext_addr (struct frame_info *frame) +{ + CORE_ADDR pc; + + pc = i386_linux_sigtramp_start (frame->pc); + if (pc) + { + CORE_ADDR sp; + + if (frame->next) + /* If this isn't the top frame, the next frame must be for the + signal handler itself. The sigcontext structure lives on + the stack, right after the signum argument. */ + return frame->next->frame + 12; + + /* This is the top frame. We'll have to find the address of the + sigcontext structure by looking at the stack pointer. Keep + in mind that the first instruction of the sigtramp code is + "pop %eax". If the PC is at this instruction, adjust the + returned value accordingly. */ + sp = read_register (SP_REGNUM); + if (pc == frame->pc) + return sp + 4; + return sp; + } + + pc = i386_linux_rt_sigtramp_start (frame->pc); + if (pc) + { + if (frame->next) + /* If this isn't the top frame, the next frame must be for the + signal handler itself. The sigcontext structure is part of + the user context. A pointer to the user context is passed + as the third argument to the signal handler. */ + return read_memory_integer (frame->next->frame + 16, 4) + 20; + + /* This is the top frame. Again, use the stack pointer to find + the address of the sigcontext structure. */ + return read_memory_integer (read_register (SP_REGNUM) + 8, 4) + 20; + } + + error ("Couldn't recognize signal trampoline."); + return 0; +} + +/* Offset to saved PC in sigcontext, from . */ +#define LINUX_SIGCONTEXT_PC_OFFSET (56) + +/* Assuming FRAME is for a Linux sigtramp routine, return the saved + program counter. */ + +CORE_ADDR +i386_linux_sigtramp_saved_pc (struct frame_info *frame) +{ + CORE_ADDR addr; + addr = i386_linux_sigcontext_addr (frame); + return read_memory_integer (addr + LINUX_SIGCONTEXT_PC_OFFSET, 4); +} + +/* Offset to saved SP in sigcontext, from . */ +#define LINUX_SIGCONTEXT_SP_OFFSET (28) + +/* Assuming FRAME is for a Linux sigtramp routine, return the saved + stack pointer. */ + +CORE_ADDR +i386_linux_sigtramp_saved_sp (struct frame_info *frame) +{ + CORE_ADDR addr; + addr = i386_linux_sigcontext_addr (frame); + return read_memory_integer (addr + LINUX_SIGCONTEXT_SP_OFFSET, 4); +} + +/* Immediately after a function call, return the saved pc. */ + +CORE_ADDR +i386_linux_saved_pc_after_call (struct frame_info *frame) +{ + if (frame->signal_handler_caller) + return i386_linux_sigtramp_saved_pc (frame); + + return read_memory_integer (read_register (SP_REGNUM), 4); +} -- 2.30.2