diff options
Diffstat (limited to 'gdb/i386fbsd-tdep.c')
| -rw-r--r-- | gdb/i386fbsd-tdep.c | 154 |
1 files changed, 152 insertions, 2 deletions
diff --git a/gdb/i386fbsd-tdep.c b/gdb/i386fbsd-tdep.c index 8d237f0ee2e..d4516ee137b 100644 --- a/gdb/i386fbsd-tdep.c +++ b/gdb/i386fbsd-tdep.c @@ -29,6 +29,154 @@ #include "fbsd-tdep.h" #include "solib-svr4.h" +/* Support for signal handlers. */ + +/* Return whether THIS_FRAME corresponds to a FreeBSD sigtramp + routine. */ + +/* FreeBSD/i386 supports three different signal trampolines, one for + versions before 4.0, a second for 4.x, and a third for 5.0 and + later. To complicate matters, FreeBSD/i386 binaries running under + an amd64 kernel use a different set of trampolines. These + trampolines differ from the i386 kernel trampolines in that they + omit a middle section that conditionally restores %gs. */ + +static const gdb_byte i386fbsd_sigtramp_start[] = +{ + 0x8d, 0x44, 0x24, 0x20, /* lea SIGF_UC(%esp),%eax */ + 0x50 /* pushl %eax */ +}; + +static const gdb_byte i386fbsd_sigtramp_middle[] = +{ + 0xf7, 0x40, 0x54, 0x00, 0x00, 0x02, 0x00, + /* testl $PSL_VM,UC_EFLAGS(%eax) */ + 0x75, 0x03, /* jne +3 */ + 0x8e, 0x68, 0x14 /* mov UC_GS(%eax),%gs */ +}; + +static const gdb_byte i386fbsd_sigtramp_end[] = +{ + 0xb8, 0xa1, 0x01, 0x00, 0x00, /* movl $SYS_sigreturn,%eax */ + 0x50, /* pushl %eax */ + 0xcd, 0x80 /* int $0x80 */ +}; + +static const gdb_byte i386fbsd_freebsd4_sigtramp_start[] = +{ + 0x8d, 0x44, 0x24, 0x14, /* lea SIGF_UC4(%esp),%eax */ + 0x50 /* pushl %eax */ +}; + +static const gdb_byte i386fbsd_freebsd4_sigtramp_middle[] = +{ + 0xf7, 0x40, 0x54, 0x00, 0x00, 0x02, 0x00, + /* testl $PSL_VM,UC4_EFLAGS(%eax) */ + 0x75, 0x03, /* jne +3 */ + 0x8e, 0x68, 0x14 /* mov UC4_GS(%eax),%gs */ +}; + +static const gdb_byte i386fbsd_freebsd4_sigtramp_end[] = +{ + 0xb8, 0x58, 0x01, 0x00, 0x00, /* movl $344,%eax */ + 0x50, /* pushl %eax */ + 0xcd, 0x80 /* int $0x80 */ +}; + +static const gdb_byte i386fbsd_osigtramp_start[] = +{ + 0x8d, 0x44, 0x24, 0x14, /* lea SIGF_SC(%esp),%eax */ + 0x50 /* pushl %eax */ +}; + +static const gdb_byte i386fbsd_osigtramp_middle[] = +{ + 0xf7, 0x40, 0x18, 0x00, 0x00, 0x02, 0x00, + /* testl $PSL_VM,SC_PS(%eax) */ + 0x75, 0x03, /* jne +3 */ + 0x8e, 0x68, 0x44 /* mov SC_GS(%eax),%gs */ +}; + +static const gdb_byte i386fbsd_osigtramp_end[] = +{ + 0xb8, 0x67, 0x00, 0x00, 0x00, /* movl $103,%eax */ + 0x50, /* pushl %eax */ + 0xcd, 0x80 /* int $0x80 */ +}; + +/* The three different trampolines are all the same size. */ +gdb_static_assert (sizeof i386fbsd_sigtramp_start == + sizeof i386fbsd_freebsd4_sigtramp_start); +gdb_static_assert (sizeof i386fbsd_sigtramp_start == + sizeof i386fbsd_osigtramp_start); +gdb_static_assert (sizeof i386fbsd_sigtramp_middle == + sizeof i386fbsd_freebsd4_sigtramp_middle); +gdb_static_assert (sizeof i386fbsd_sigtramp_middle == + sizeof i386fbsd_osigtramp_middle); +gdb_static_assert (sizeof i386fbsd_sigtramp_end == + sizeof i386fbsd_freebsd4_sigtramp_end); +gdb_static_assert (sizeof i386fbsd_sigtramp_end == + sizeof i386fbsd_osigtramp_end); + +/* We assume that the middle is the largest chunk below. */ +gdb_static_assert (sizeof i386fbsd_sigtramp_middle > + sizeof i386fbsd_sigtramp_start); +gdb_static_assert (sizeof i386fbsd_sigtramp_middle > + sizeof i386fbsd_sigtramp_end); + +static int +i386fbsd_sigtramp_p (struct frame_info *this_frame) +{ + CORE_ADDR pc = get_frame_pc (this_frame); + gdb_byte buf[sizeof i386fbsd_sigtramp_middle]; + const gdb_byte *middle, *end; + + /* Look for a matching start. */ + if (!safe_frame_unwind_memory (this_frame, pc, buf, + sizeof i386fbsd_sigtramp_start)) + return 0; + if (memcmp (buf, i386fbsd_sigtramp_start, sizeof i386fbsd_sigtramp_start) == + 0) { + middle = i386fbsd_sigtramp_middle; + end = i386fbsd_sigtramp_end; + } else if (memcmp (buf, i386fbsd_freebsd4_sigtramp_start, + sizeof i386fbsd_freebsd4_sigtramp_start) == 0) { + middle = i386fbsd_freebsd4_sigtramp_middle; + end = i386fbsd_freebsd4_sigtramp_end; + } else if (memcmp (buf, i386fbsd_osigtramp_start, + sizeof i386fbsd_osigtramp_start) == 0) { + middle = i386fbsd_osigtramp_middle; + end = i386fbsd_osigtramp_end; + } else + return 0; + + /* Since the end is shorter than the middle, check for a matching end + next. */ + pc += sizeof i386fbsd_sigtramp_start; + if (!safe_frame_unwind_memory (this_frame, pc, buf, + sizeof i386fbsd_sigtramp_end)) + return 0; + if (memcmp (buf, end, sizeof i386fbsd_sigtramp_end) == 0) + return 1; + + /* If the end didn't match, check for a matching middle. */ + if (!safe_frame_unwind_memory (this_frame, pc, buf, + sizeof i386fbsd_sigtramp_middle)) + return 0; + if (memcmp (buf, middle, sizeof i386fbsd_sigtramp_middle) != 0) + return 0; + + /* The middle matched, check for a matching end. */ + pc += sizeof i386fbsd_sigtramp_middle; + if (!safe_frame_unwind_memory (this_frame, pc, buf, + sizeof i386fbsd_sigtramp_end)) + return 0; + if (memcmp (buf, end, sizeof i386fbsd_sigtramp_end) != 0) + return 0; + + return 1; +} + /* FreeBSD 3.0-RELEASE or later. */ /* From <machine/reg.h>. */ @@ -43,8 +191,8 @@ static int i386fbsd_r_reg_offset[] = }; /* Sigtramp routine location. */ -CORE_ADDR i386fbsd_sigtramp_start_addr = 0xbfbfdf20; -CORE_ADDR i386fbsd_sigtramp_end_addr = 0xbfbfdff0; +CORE_ADDR i386fbsd_sigtramp_start_addr; +CORE_ADDR i386fbsd_sigtramp_end_addr; /* From <machine/signal.h>. */ int i386fbsd_sc_reg_offset[] = @@ -139,6 +287,8 @@ i386fbsdaout_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) /* FreeBSD uses -freg-struct-return by default. */ tdep->struct_return = reg_struct_return; + tdep->sigtramp_p = i386fbsd_sigtramp_p; + /* FreeBSD uses a different memory layout. */ tdep->sigtramp_start = i386fbsd_sigtramp_start_addr; tdep->sigtramp_end = i386fbsd_sigtramp_end_addr; |