#include "defs.h"
#include "arch-utils.h"
#include "floatformat.h"
+#include "frame.h"
+#include "frame-unwind.h"
#include "osabi.h"
#include "regcache.h"
#include "regset.h"
+#include "symtab.h"
#include "trad-frame.h"
-#include "tramp-frame.h"
#include "gdb_assert.h"
#include "gdb_string.h"
/* Signal trampolines. */
-static void
-ppcobsd_sigtramp_cache_init (const struct tramp_frame *self,
- struct frame_info *next_frame,
- struct trad_frame_cache *this_cache,
- CORE_ADDR func)
+/* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
+ in virtual memory. The randomness makes it somewhat tricky to
+ detect it, but fortunately we can rely on the fact that the start
+ of the sigtramp routine is page-aligned. We recognize the
+ trampoline by looking for the code that invokes the sigreturn
+ system call. The offset where we can find that code varies from
+ release to release.
+
+ By the way, the mapping mentioned above is read-only, so you cannot
+ place a breakpoint in the signal trampoline. */
+
+/* Default page size. */
+static const int ppcobsd_page_size = 4096;
+
+/* Offset for sigreturn(2). */
+static const int ppcobsd_sigreturn_offset[] = {
+ 0x98, /* OpenBSD 3.8 */
+ 0x0c, /* OpenBSD 3.2 */
+ -1
+};
+
+static int
+ppcobsd_sigtramp_p (struct frame_info *next_frame)
+{
+ CORE_ADDR pc = frame_pc_unwind (next_frame);
+ CORE_ADDR start_pc = (pc & ~(ppcobsd_page_size - 1));
+ const int *offset;
+ char *name;
+
+ find_pc_partial_function (pc, &name, NULL, NULL);
+ if (name)
+ return 0;
+
+ for (offset = ppcobsd_sigreturn_offset; *offset != -1; offset++)
+ {
+ gdb_byte buf[2 * PPC_INSN_SIZE];
+ unsigned long insn;
+
+ if (!safe_frame_unwind_memory (next_frame, start_pc + *offset,
+ buf, sizeof buf))
+ continue;
+
+ /* Check for "li r0,SYS_sigreturn". */
+ insn = extract_unsigned_integer (buf, PPC_INSN_SIZE);
+ if (insn != 0x38000067)
+ continue;
+
+ /* Check for "sc". */
+ insn = extract_unsigned_integer (buf + PPC_INSN_SIZE, PPC_INSN_SIZE);
+ if (insn != 0x44000002)
+ continue;
+
+ return 1;
+ }
+
+ return 0;
+}
+
+static struct trad_frame_cache *
+ppcobsd_sigtramp_frame_cache (struct frame_info *next_frame, void **this_cache)
{
struct gdbarch *gdbarch = get_frame_arch (next_frame);
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
- CORE_ADDR addr, base;
+ struct trad_frame_cache *cache;
+ CORE_ADDR addr, base, func;
+ gdb_byte buf[PPC_INSN_SIZE];
+ unsigned long insn, sigcontext_offset;
int i;
+ if (*this_cache)
+ return *this_cache;
+
+ cache = trad_frame_cache_zalloc (next_frame);
+ *this_cache = cache;
+
+ func = frame_pc_unwind (next_frame);
+ func &= ~(ppcobsd_page_size - 1);
+ if (!safe_frame_unwind_memory (next_frame, func, buf, sizeof buf))
+ return cache;
+
+ /* Calculate the offset where we can find `struct sigcontext'. We
+ base our calculation on the amount of stack space reserved by the
+ first instruction of the signal trampoline. */
+ insn = extract_unsigned_integer (buf, PPC_INSN_SIZE);
+ sigcontext_offset = (0x10000 - (insn & 0x0000ffff)) + 8;
+
base = frame_unwind_register_unsigned (next_frame, SP_REGNUM);
- addr = base + 0x18 + 2 * tdep->wordsize;
+ addr = base + sigcontext_offset + 2 * tdep->wordsize;
for (i = 0; i < ppc_num_gprs; i++, addr += tdep->wordsize)
{
int regnum = i + tdep->ppc_gp0_regnum;
- trad_frame_set_reg_addr (this_cache, regnum, addr);
+ trad_frame_set_reg_addr (cache, regnum, addr);
}
- trad_frame_set_reg_addr (this_cache, tdep->ppc_lr_regnum, addr);
+ trad_frame_set_reg_addr (cache, tdep->ppc_lr_regnum, addr);
addr += tdep->wordsize;
- trad_frame_set_reg_addr (this_cache, tdep->ppc_cr_regnum, addr);
+ trad_frame_set_reg_addr (cache, tdep->ppc_cr_regnum, addr);
addr += tdep->wordsize;
- trad_frame_set_reg_addr (this_cache, tdep->ppc_xer_regnum, addr);
+ trad_frame_set_reg_addr (cache, tdep->ppc_xer_regnum, addr);
addr += tdep->wordsize;
- trad_frame_set_reg_addr (this_cache, tdep->ppc_ctr_regnum, addr);
+ trad_frame_set_reg_addr (cache, tdep->ppc_ctr_regnum, addr);
addr += tdep->wordsize;
- trad_frame_set_reg_addr (this_cache, PC_REGNUM, addr); /* SRR0? */
+ trad_frame_set_reg_addr (cache, PC_REGNUM, addr); /* SRR0? */
addr += tdep->wordsize;
/* Construct the frame ID using the function start. */
- trad_frame_set_id (this_cache, frame_id_build (base, func));
+ trad_frame_set_id (cache, frame_id_build (base, func));
+
+ return cache;
}
-static const struct tramp_frame ppcobsd_sigtramp =
+static void
+ppcobsd_sigtramp_frame_this_id (struct frame_info *next_frame,
+ void **this_cache, struct frame_id *this_id)
+{
+ struct trad_frame_cache *cache =
+ ppcobsd_sigtramp_frame_cache (next_frame, this_cache);
+
+ trad_frame_get_id (cache, this_id);
+}
+
+static void
+ppcobsd_sigtramp_frame_prev_register (struct frame_info *next_frame,
+ void **this_cache, int regnum,
+ int *optimizedp, enum lval_type *lvalp,
+ CORE_ADDR *addrp, int *realnump,
+ gdb_byte *valuep)
{
+ struct trad_frame_cache *cache =
+ ppcobsd_sigtramp_frame_cache (next_frame, this_cache);
+
+ trad_frame_get_register (cache, next_frame, regnum,
+ optimizedp, lvalp, addrp, realnump, valuep);
+}
+
+static const struct frame_unwind ppcobsd_sigtramp_frame_unwind = {
SIGTRAMP_FRAME,
- 4,
- {
- { 0x3821fff0, -1 }, /* add r1,r1,-16 */
- { 0x4e800021, -1 }, /* blrl */
- { 0x38610018, -1 }, /* addi r3,r1,24 */
- { 0x38000067, -1 }, /* li r0,103 */
- { 0x44000002, -1 }, /* sc */
- { 0x38000001, -1 }, /* li r0,1 */
- { 0x44000002, -1 }, /* sc */
- { TRAMP_SENTINEL_INSN, -1 }
- },
- ppcobsd_sigtramp_cache_init
+ ppcobsd_sigtramp_frame_this_id,
+ ppcobsd_sigtramp_frame_prev_register
};
+
+static const struct frame_unwind *
+ppcobsd_sigtramp_frame_sniffer (struct frame_info *next_frame)
+{
+ if (ppcobsd_sigtramp_p (next_frame))
+ return &ppcobsd_sigtramp_frame_unwind;
+
+ return NULL;
+}
\f
static void
set_gdbarch_regset_from_core_section
(gdbarch, ppcobsd_regset_from_core_section);
- tramp_frame_prepend_unwinder (gdbarch, &ppcobsd_sigtramp);
+ frame_unwind_append_sniffer (gdbarch, ppcobsd_sigtramp_frame_sniffer);
}
\f
projects / binutils-gdb.git / commitdiff