@@ -1,3 +1,27 @@
+2015-02-25 John Baldwin <jhb@FreeBSD.org>
+
+ * amd64fbsd-nat.c: Include sys/user.h.
+ (_initialize_amd64fbsd_nat): Use the KERN_PROC_SIGTRAMP sysctl
+ instead of KERN_PS_STRINGS to locate the signal trampoline.
+ * i386fbsd-nat.c: Include sys/user.h.
+ (_initialize_i386fbsd_nat): Use the KERN_PROC_SIGTRAMP sysctl
+ instead of KERN_PS_STRINGS to locate the signal trampoline.
+ * amd64fbsd-tdep.c (amd64fbsd_sigtramp_code): New.
+ (amd64fbsd_sigtramp_p): New.
+ (amd64fbsd_sigtramp_start_addr, amd64fbsd_sigtramp_end_addr): No
+ longer set default values.
+ (amd64fbsd_init_abi): Set "sigtramp_p" to "amd64fbsd_sigtramp_p".
+ * i386fbsd-tdep.c (i386fbsd_sigtramp_start)
+ (i386fbsd_sigtramp_middle, i386fbsd_sigtramp_end)
+ (i386fbsd_freebsd4_sigtramp_start)
+ (i386fbsd_freebsd4_sigtramp_middle)
+ (i386fbsd_freebsd4_sigtramp_end, i386fbsd_osigtramp_start)
+ (i386fbsd_osigtramp_middle, i386fbsd_osigtramp_end): New.
+ (i386fbsd_sigtramp_p): New.
+ (i386fbsd_sigtramp_start_addr, i386fbsd_sigtramp_end_addr): No
+ longer set default values.
+ (i386fbsd_init_abi): Set "sigtramp_p" to "i386fbsd_sigtramp_p".
+
2015-02-25 John Baldwin <jhb@freebsd.org>
* amd64fbsd-tdep.c (amd64fbsd_sigcontext_addr): Use
@@ -26,6 +26,7 @@
#include <sys/types.h>
#include <sys/ptrace.h>
#include <sys/sysctl.h>
+#include <sys/user.h>
#include <machine/reg.h>
#include "fbsd-nat.h"
@@ -244,24 +245,31 @@ Please report this to <bug-gdb@gnu.org>."),
SC_RBP_OFFSET = offset;
- /* FreeBSD provides a kern.ps_strings sysctl that we can use to
- locate the sigtramp. That way we can still recognize a sigtramp
- if its location is changed in a new kernel. Of course this is
- still based on the assumption that the sigtramp is placed
- directly under the location where the program arguments and
- environment can be found. */
+#ifdef KERN_PROC_SIGTRAMP
+ /* Normally signal frames are detected via amd64fbsd_sigtramp_p.
+ However, FreeBSD 9.2 through 10.1 do not include the page holding
+ the signal code in core dumps. These releases do provide a
+ kern.proc.sigtramp.<pid> sysctl that returns the location of the
+ signal trampoline for a running process. We fetch the location
+ of the current (gdb) process and use this to identify signal
+ frames in core dumps from these releases. Note that this only
+ works for core dumps of 64-bit (FreeBSD/amd64) processes and does
+ not handle core dumps of 32-bit (FreeBSD/i386) processes. */
{
- int mib[2];
- long ps_strings;
+ int mib[4];
+ struct kinfo_sigtramp kst;
size_t len;
mib[0] = CTL_KERN;
- mib[1] = KERN_PS_STRINGS;
- len = sizeof (ps_strings);
- if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)
+ mib[1] = KERN_PROC;
+ mib[2] = KERN_PROC_SIGTRAMP;
+ mib[3] = getpid ();
+ len = sizeof (kst);
+ if (sysctl (mib, 4, &kst, &len, NULL, 0) == 0)
{
- amd64fbsd_sigtramp_start_addr = ps_strings - 32;
- amd64fbsd_sigtramp_end_addr = ps_strings;
+ amd64fbsd_sigtramp_start_addr = (uintptr_t) kst.ksigtramp_start;
+ amd64fbsd_sigtramp_end_addr = (uintptr_t) kst.ksigtramp_end;
}
}
+#endif
}
@@ -31,6 +31,33 @@
/* Support for signal handlers. */
+/* Return whether THIS_FRAME corresponds to a FreeBSD sigtramp
+ routine. */
+
+static const gdb_byte amd64fbsd_sigtramp_code[] =
+{
+ 0x48, 0x8d, 0x7c, 0x24, 0x10, /* lea SIGF_UC(%rsp),%rdi */
+ 0x6a, 0x00, /* pushq $0 */
+ 0x48, 0xc7, 0xc0, 0xa1, 0x01, 0x00, 0x00,
+ /* movq $SYS_sigreturn,%rax */
+ 0x0f, 0x05 /* syscall */
+};
+
+static int
+amd64fbsd_sigtramp_p (struct frame_info *this_frame)
+{
+ CORE_ADDR pc = get_frame_pc (this_frame);
+ gdb_byte buf[sizeof amd64fbsd_sigtramp_code];
+
+ if (!safe_frame_unwind_memory (this_frame, pc, buf, sizeof buf))
+ return 0;
+ if (memcmp (buf, amd64fbsd_sigtramp_code, sizeof amd64fbsd_sigtramp_code) !=
+ 0)
+ return 0;
+
+ return 1;
+}
+
/* Assuming THIS_FRAME is for a BSD sigtramp routine, return the
address of the associated sigcontext structure. */
@@ -88,8 +115,8 @@ static int amd64fbsd_r_reg_offset[] =
};
/* Location of the signal trampoline. */
-CORE_ADDR amd64fbsd_sigtramp_start_addr = 0x7fffffffffc0ULL;
-CORE_ADDR amd64fbsd_sigtramp_end_addr = 0x7fffffffffe0ULL;
+CORE_ADDR amd64fbsd_sigtramp_start_addr;
+CORE_ADDR amd64fbsd_sigtramp_end_addr;
/* From <machine/signal.h>. */
int amd64fbsd_sc_reg_offset[] =
@@ -199,6 +226,7 @@ amd64fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
amd64_init_abi (info, gdbarch);
+ tdep->sigtramp_p = amd64fbsd_sigtramp_p;
tdep->sigtramp_start = amd64fbsd_sigtramp_start_addr;
tdep->sigtramp_end = amd64fbsd_sigtramp_end_addr;
tdep->sigcontext_addr = amd64fbsd_sigcontext_addr;
@@ -25,6 +25,7 @@
#include <sys/types.h>
#include <sys/ptrace.h>
#include <sys/sysctl.h>
+#include <sys/user.h>
#include "fbsd-nat.h"
#include "i386-tdep.h"
@@ -148,25 +149,28 @@ _initialize_i386fbsd_nat (void)
/* Support debugging kernel virtual memory images. */
bsd_kvm_add_target (i386fbsd_supply_pcb);
- /* FreeBSD provides a kern.ps_strings sysctl that we can use to
- locate the sigtramp. That way we can still recognize a sigtramp
- if its location is changed in a new kernel. Of course this is
- still based on the assumption that the sigtramp is placed
- directly under the location where the program arguments and
- environment can be found. */
-#ifdef KERN_PS_STRINGS
+#ifdef KERN_PROC_SIGTRAMP
+ /* Normally signal frames are detected via i386fbsd_sigtramp_p.
+ However, FreeBSD 9.2 through 10.1 do not include the page holding
+ the signal code in core dumps. These releases do provide a
+ kern.proc.sigtramp.<pid> sysctl that returns the location of the
+ signal trampoline for a running process. We fetch the location
+ of the current (gdb) process and use this to identify signal
+ frames in core dumps from these releases. */
{
- int mib[2];
- u_long ps_strings;
+ int mib[4];
+ struct kinfo_sigtramp kst;
size_t len;
mib[0] = CTL_KERN;
- mib[1] = KERN_PS_STRINGS;
- len = sizeof (ps_strings);
- if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)
+ mib[1] = KERN_PROC;
+ mib[2] = KERN_PROC_SIGTRAMP;
+ mib[3] = getpid ();
+ len = sizeof (kst);
+ if (sysctl (mib, 4, &kst, &len, NULL, 0) == 0)
{
- i386fbsd_sigtramp_start_addr = ps_strings - 128;
- i386fbsd_sigtramp_end_addr = ps_strings;
+ i386fbsd_sigtramp_start_addr = (uintptr_t) kst.ksigtramp_start;
+ i386fbsd_sigtramp_end_addr = (uintptr_t) kst.ksigtramp_end;
}
}
#endif
@@ -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;