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@ -27,6 +27,7 @@ |
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#include "regcache.h" |
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#include "regset.h" |
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#include "osabi.h" |
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#include "target.h" |
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#include "gdb_assert.h" |
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#include "gdb_string.h" |
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@ -35,6 +36,81 @@ |
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#include "i387-tdep.h" |
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#include "solib-svr4.h" |
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/* Support for signal handlers. */ |
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/* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
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in virtual memory. The randomness makes it somewhat tricky to |
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detect it, but fortunately we can rely on the fact that the start |
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of the sigtramp routine is page-aligned. By the way, the mapping |
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is read-only, so you cannot place a breakpoint in the signal |
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trampoline. */ |
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/* Default page size. */ |
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static const int i386obsd_page_size = 4096; |
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/* Return whether PC is in an OpenBSD sigtramp routine. */ |
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static int |
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i386obsd_pc_in_sigtramp (CORE_ADDR pc, char *name) |
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{ |
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CORE_ADDR start_pc = (pc & ~(i386obsd_page_size - 1)); |
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const char sigreturn[] = |
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{ |
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0xb8, |
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0x67, 0x00, 0x00, 0x00, /* movl $SYS_sigreturn, %eax */ |
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0xcd, 0x80 /* int $0x80 */ |
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}; |
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char *buf; |
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/* Avoid reading memory from the target if possible. If we're in a
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named function, we're certainly not in a sigtramp routine |
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provided by the kernel. Take synthetic function names into |
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account though. */ |
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if (name && name[0] != '<') |
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return 0; |
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/* If we can't read the instructions at START_PC, return zero. */ |
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buf = alloca (sizeof sigreturn); |
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if (target_read_memory (start_pc + 0x14, buf, sizeof sigreturn)) |
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return 0; |
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/* Check for sigreturn(2). */ |
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if (memcmp (buf, sigreturn, sizeof sigreturn) == 0) |
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return 1; |
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/* Check for a traditional BSD sigtramp routine. */ |
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return i386bsd_pc_in_sigtramp (pc, name); |
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} |
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/* Return the start address of the sigtramp routine. */ |
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static CORE_ADDR |
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i386obsd_sigtramp_start (CORE_ADDR pc) |
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{ |
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CORE_ADDR start_pc = (pc & ~(i386obsd_page_size - 1)); |
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if (i386bsd_pc_in_sigtramp (pc, NULL)) |
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return i386bsd_sigtramp_start (pc); |
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return start_pc; |
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} |
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/* Return the end address of the sigtramp routine. */ |
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static CORE_ADDR |
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i386obsd_sigtramp_end (CORE_ADDR pc) |
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{ |
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CORE_ADDR start_pc = (pc & ~(i386obsd_page_size - 1)); |
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if (i386bsd_pc_in_sigtramp (pc, NULL)) |
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return i386bsd_sigtramp_end (pc); |
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return start_pc + 0x22; |
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} |
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/* Mapping between the general-purpose registers in `struct reg'
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format and GDB's register cache layout. */ |
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/* From <machine/reg.h>. */ |
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static int i386obsd_r_reg_offset[] = |
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{ |
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@ -95,8 +171,9 @@ i386obsd_aout_regset_from_core_section (struct gdbarch *gdbarch, |
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} |
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CORE_ADDR i386obsd_sigtramp_start = 0xbfbfdf20; |
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CORE_ADDR i386obsd_sigtramp_end = 0xbfbfdff0; |
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/* Sigtramp routine location for OpenBSD 3.1 and earlier releases. */ |
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CORE_ADDR i386obsd_sigtramp_start_addr = 0xbfbfdf20; |
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CORE_ADDR i386obsd_sigtramp_end_addr = 0xbfbfdff0; |
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/* From <machine/signal.h>. */ |
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int i386obsd_sc_reg_offset[I386_NUM_GREGS] = |
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@ -136,8 +213,11 @@ i386obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
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tdep->struct_return = reg_struct_return; |
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/* OpenBSD uses a different memory layout. */ |
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tdep->sigtramp_start = i386obsd_sigtramp_start; |
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tdep->sigtramp_end = i386obsd_sigtramp_end; |
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tdep->sigtramp_start = i386obsd_sigtramp_start_addr; |
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tdep->sigtramp_end = i386obsd_sigtramp_end_addr; |
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set_gdbarch_pc_in_sigtramp (gdbarch, i386obsd_pc_in_sigtramp); |
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set_gdbarch_sigtramp_start (gdbarch, i386obsd_sigtramp_start); |
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set_gdbarch_sigtramp_end (gdbarch, i386obsd_sigtramp_end); |
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/* OpenBSD has a `struct sigcontext' that's different from the
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origional 4.3 BSD. */ |
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Mark Kettenis
23 years ago