/* Target-dependent code for GNU/Linux on MIPS processors.
- Copyright 2001, 2002 Free Software Foundation, Inc.
+ Copyright 2001, 2002, 2004 Free Software Foundation, Inc.
This file is part of GDB.
#include "mips-tdep.h"
#include "gdb_string.h"
#include "gdb_assert.h"
+#include "frame.h"
/* Copied from <asm/elf.h>. */
#define ELF_NGREG 45
return 0;
}
+/* Check the code at PC for a dynamic linker lazy resolution stub. Because
+ they aren't in the .plt section, we pattern-match on the code generated
+ by GNU ld. They look like this:
+
+ lw t9,0x8010(gp)
+ addu t7,ra
+ jalr t9,ra
+ addiu t8,zero,INDEX
+
+ (with the appropriate doubleword instructions for N64). Also return the
+ dynamic symbol index used in the last instruction. */
+
+static int
+mips_linux_in_dynsym_stub (CORE_ADDR pc, char *name)
+{
+ unsigned char buf[28], *p;
+ ULONGEST insn, insn1;
+ int n64 = (mips_abi (current_gdbarch) == MIPS_ABI_N64);
+
+ read_memory (pc - 12, buf, 28);
+
+ if (n64)
+ {
+ /* ld t9,0x8010(gp) */
+ insn1 = 0xdf998010;
+ }
+ else
+ {
+ /* lw t9,0x8010(gp) */
+ insn1 = 0x8f998010;
+ }
+
+ p = buf + 12;
+ while (p >= buf)
+ {
+ insn = extract_unsigned_integer (p, 4);
+ if (insn == insn1)
+ break;
+ p -= 4;
+ }
+ if (p < buf)
+ return 0;
+
+ insn = extract_unsigned_integer (p + 4, 4);
+ if (n64)
+ {
+ /* daddu t7,ra */
+ if (insn != 0x03e0782d)
+ return 0;
+ }
+ else
+ {
+ /* addu t7,ra */
+ if (insn != 0x03e07821)
+ return 0;
+ }
+
+ insn = extract_unsigned_integer (p + 8, 4);
+ /* jalr t9,ra */
+ if (insn != 0x0320f809)
+ return 0;
+
+ insn = extract_unsigned_integer (p + 12, 4);
+ if (n64)
+ {
+ /* daddiu t8,zero,0 */
+ if ((insn & 0xffff0000) != 0x64180000)
+ return 0;
+ }
+ else
+ {
+ /* addiu t8,zero,0 */
+ if ((insn & 0xffff0000) != 0x24180000)
+ return 0;
+ }
+
+ return (insn & 0xffff);
+}
+
+/* Return non-zero iff PC belongs to the dynamic linker resolution code
+ or to a stub. */
+
+int
+mips_linux_in_dynsym_resolve_code (CORE_ADDR pc)
+{
+ /* Check whether PC is in the dynamic linker. This also checks whether
+ it is in the .plt section, which MIPS does not use. */
+ if (in_solib_dynsym_resolve_code (pc))
+ return 1;
+
+ /* Pattern match for the stub. It would be nice if there were a more
+ efficient way to avoid this check. */
+ if (mips_linux_in_dynsym_stub (pc, NULL))
+ return 1;
+
+ return 0;
+}
+
+/* See the comments for SKIP_SOLIB_RESOLVER at the top of infrun.c,
+ and glibc_skip_solib_resolver in glibc-tdep.c. The normal glibc
+ implementation of this triggers at "fixup" from the same objfile as
+ "_dl_runtime_resolve"; MIPS GNU/Linux can trigger at
+ "__dl_runtime_resolve" directly. An unresolved PLT entry will
+ point to _dl_runtime_resolve, which will first call
+ __dl_runtime_resolve, and then pass control to the resolved
+ function. */
+
+static CORE_ADDR
+mips_linux_skip_resolver (struct gdbarch *gdbarch, CORE_ADDR pc)
+{
+ struct minimal_symbol *resolver;
+
+ resolver = lookup_minimal_symbol ("__dl_runtime_resolve", NULL, NULL);
+
+ if (resolver && SYMBOL_VALUE_ADDRESS (resolver) == pc)
+ return frame_pc_unwind (get_current_frame ());
+
+ return 0;
+}
+
static void
mips_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
internal_error (__FILE__, __LINE__, "can't handle ABI");
break;
}
+
+ set_gdbarch_skip_solib_resolver (gdbarch, mips_linux_skip_resolver);
+
+ /* This overrides the MIPS16 stub support from mips-tdep. But no
+ one uses MIPS16 on GNU/Linux yet, so this isn't much of a loss. */
+ set_gdbarch_in_solib_call_trampoline (gdbarch, mips_linux_in_dynsym_stub);
}
void