/* Target-dependent code for GNU/Linux on Alpha.
- Copyright 2002 Free Software Foundation, Inc.
+ Copyright 2002, 2003 Free Software Foundation, Inc.
This file is part of GDB.
Boston, MA 02111-1307, USA. */
#include "defs.h"
-#include "gdbcore.h"
-#include "value.h"
+#include "frame.h"
+#include "gdb_assert.h"
+#include "osabi.h"
#include "alpha-tdep.h"
-/* Under GNU/Linux, signal handler invocations can be identified by the
- designated code sequence that is used to return from a signal
+/* Under GNU/Linux, signal handler invocations can be identified by
+ the designated code sequence that is used to return from a signal
handler. In particular, the return address of a signal handler
- points to the following sequence (the first instruction is quadword
- aligned):
-
- bis $30,$30,$16
- addq $31,0x67,$0
- call_pal callsys
-
- Each instruction has a unique encoding, so we simply attempt to
- match the instruction the pc is pointing to with any of the above
- instructions. If there is a hit, we know the offset to the start
- of the designated sequence and can then check whether we really are
- executing in a designated sequence. If not, -1 is returned,
- otherwise the offset from the start of the desingated sequence is
- returned.
-
- There is a slight chance of false hits: code could jump into the
- middle of the designated sequence, in which case there is no
- guarantee that we are in the middle of a sigreturn syscall. Don't
- think this will be a problem in praxis, though. */
-LONGEST
-alpha_linux_sigtramp_offset (CORE_ADDR pc)
-{
- unsigned int i[3], w;
- long off;
+ points to a sequence that copies $sp to $16, loads $0 with the
+ appropriate syscall number, and finally enters the kernel.
- if (read_memory_nobpt (pc, (char *) &w, 4) != 0)
- return -1;
+ This is somewhat complicated in that:
+ (1) the expansion of the "mov" assembler macro has changed over
+ time, from "bis src,src,dst" to "bis zero,src,dst",
+ (2) the kernel has changed from using "addq" to "lda" to load the
+ syscall number,
+ (3) there is a "normal" sigreturn and an "rt" sigreturn which
+ has a different stack layout.
+*/
- off = -1;
- switch (w)
+static long
+alpha_linux_sigtramp_offset_1 (CORE_ADDR pc)
+{
+ switch (alpha_read_insn (pc))
{
- case 0x47de0410:
- off = 0;
- break; /* bis $30,$30,$16 */
- case 0x43ecf400:
- off = 4;
- break; /* addq $31,0x67,$0 */
- case 0x00000083:
- off = 8;
- break; /* call_pal callsys */
+ case 0x47de0410: /* bis $30,$30,$16 */
+ case 0x47fe0410: /* bis $31,$30,$16 */
+ return 0;
+
+ case 0x43ecf400: /* addq $31,103,$0 */
+ case 0x201f0067: /* lda $0,103($31) */
+ case 0x201f015f: /* lda $0,351($31) */
+ return 4;
+
+ case 0x00000083: /* call_pal callsys */
+ return 8;
+
default:
return -1;
}
+}
+
+static LONGEST
+alpha_linux_sigtramp_offset (CORE_ADDR pc)
+{
+ long i, off;
+
+ if (pc & 3)
+ return -1;
+
+ /* Guess where we might be in the sequence. */
+ off = alpha_linux_sigtramp_offset_1 (pc);
+ if (off < 0)
+ return -1;
+
+ /* Verify that the other two insns of the sequence are as we expect. */
pc -= off;
- if (pc & 0x7)
+ for (i = 0; i < 12; i += 4)
{
- /* designated sequence is not quadword aligned */
- return -1;
+ if (i == off)
+ continue;
+ if (alpha_linux_sigtramp_offset_1 (pc + i) != i)
+ return -1;
}
- if (read_memory_nobpt (pc, (char *) i, sizeof (i)) != 0)
- return -1;
- if (i[0] == 0x47de0410 && i[1] == 0x43ecf400 && i[2] == 0x00000083)
- return off;
+ return off;
+}
+
+static int
+alpha_linux_pc_in_sigtramp (CORE_ADDR pc, char *func_name)
+{
+ return alpha_linux_sigtramp_offset (pc) >= 0;
+}
+
+static CORE_ADDR
+alpha_linux_sigcontext_addr (struct frame_info *next_frame)
+{
+ CORE_ADDR pc;
+ ULONGEST sp;
+ long off;
+
+ pc = frame_pc_unwind (next_frame);
+ frame_unwind_unsigned_register (next_frame, ALPHA_SP_REGNUM, &sp);
+
+ off = alpha_linux_sigtramp_offset (pc);
+ gdb_assert (off >= 0);
+
+ /* __NR_rt_sigreturn has a couple of structures on the stack. This is:
- return -1;
+ struct rt_sigframe {
+ struct siginfo info;
+ struct ucontext uc;
+ };
+
+ offsetof (struct rt_sigframe, uc.uc_mcontext);
+ */
+ if (alpha_read_insn (pc - off + 4) == 0x201f015f)
+ return sp + 176;
+
+ /* __NR_sigreturn has the sigcontext structure at the top of the stack. */
+ return sp;
}
static void
-alpha_linux_init_abi (struct gdbarch_info info,
- struct gdbarch *gdbarch)
+alpha_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
- struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+ struct gdbarch_tdep *tdep;
+
+ /* Hook into the DWARF CFI frame unwinder. */
+ alpha_dwarf2_init_abi (info, gdbarch);
+
+ /* Hook into the MDEBUG frame unwinder. */
+ alpha_mdebug_init_abi (info, gdbarch);
+ tdep = gdbarch_tdep (gdbarch);
tdep->dynamic_sigtramp_offset = alpha_linux_sigtramp_offset;
+ tdep->sigcontext_addr = alpha_linux_sigcontext_addr;
+ tdep->pc_in_sigtramp = alpha_linux_pc_in_sigtramp;
+ tdep->jb_pc = 2;
+ tdep->jb_elt_size = 8;
}
void
_initialize_alpha_linux_tdep (void)
{
- alpha_gdbarch_register_os_abi (ALPHA_ABI_LINUX, alpha_linux_init_abi);
+ gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_LINUX,
+ alpha_linux_init_abi);
}
projects / deliverable / binutils-gdb.git / blobdiff