[PATCH 2/3] Use register cache for x86_64 ps_get_thread_area
Richard Henderson
rth@redhat.com
Tue Nov 3 13:43:00 GMT 2015
* amd64-linux-nat.c (ps_get_thread_area): Use regcache to
fetch FS_BASE contents.
---
gdb/amd64-linux-nat.c | 71 +++++++++++++++------------------------------------
1 file changed, 21 insertions(+), 50 deletions(-)
diff --git a/gdb/amd64-linux-nat.c b/gdb/amd64-linux-nat.c
index 0a2cf45..b7211d3e 100644
--- a/gdb/amd64-linux-nat.c
+++ b/gdb/amd64-linux-nat.c
@@ -283,10 +283,11 @@ ps_err_e
ps_get_thread_area (const struct ps_prochandle *ph,
lwpid_t lwpid, int idx, void **base)
{
+ ps_err_e result;
+
if (gdbarch_bfd_arch_info (target_gdbarch ())->bits_per_word == 32)
{
unsigned int base_addr;
- ps_err_e result;
result = x86_linux_get_thread_area (lwpid, (void *) (long) idx,
&base_addr);
@@ -296,63 +297,33 @@ ps_get_thread_area (const struct ps_prochandle *ph,
a "long" and a "void *" are the same. */
(*base) = (void *) (long) base_addr;
}
- return result;
}
else
{
- /* This definition comes from prctl.h, but some kernels may not
- have it. */
-#ifndef PTRACE_ARCH_PRCTL
-#define PTRACE_ARCH_PRCTL 30
-#endif
+ struct cleanup *old_chain;
+ struct regcache *regcache;
+ enum amd64_regnum gdb_regnum;
+
/* FIXME: ezannoni-2003-07-09 see comment above about include
file order. We could be getting bogus values for these two. */
gdb_assert (FS < ELF_NGREG);
gdb_assert (GS < ELF_NGREG);
- switch (idx)
- {
- case FS:
-#ifdef HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE
- {
- /* PTRACE_ARCH_PRCTL is obsolete since 2.6.25, where the
- fs_base and gs_base fields of user_regs_struct can be
- used directly. */
- unsigned long fs;
- errno = 0;
- fs = ptrace (PTRACE_PEEKUSER, lwpid,
- offsetof (struct user_regs_struct, fs_base), 0);
- if (errno == 0)
- {
- *base = (void *) fs;
- return PS_OK;
- }
- }
-#endif
- if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_FS) == 0)
- return PS_OK;
- break;
- case GS:
-#ifdef HAVE_STRUCT_USER_REGS_STRUCT_GS_BASE
- {
- unsigned long gs;
- errno = 0;
- gs = ptrace (PTRACE_PEEKUSER, lwpid,
- offsetof (struct user_regs_struct, gs_base), 0);
- if (errno == 0)
- {
- *base = (void *) gs;
- return PS_OK;
- }
- }
-#endif
- if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_GS) == 0)
- return PS_OK;
- break;
- default: /* Should not happen. */
- return PS_BADADDR;
- }
+ if (idx == FS)
+ gdb_regnum = AMD64_FSBASE_REGNUM;
+ else if (idx == GS)
+ gdb_regnum = AMD64_GSBASE_REGNUM;
+ else
+ return PS_BADADDR;
+
+ old_chain = save_inferior_ptid ();
+ inferior_ptid = ptid_build (ptid_get_pid (ph->ptid), lwpid, 0);
+ regcache = get_thread_arch_regcache (inferior_ptid, target_gdbarch ());
+ result = (regcache_raw_read (regcache, gdb_regnum, (gdb_byte *) base)
+ == REG_VALID ? PS_OK : PS_ERR);
+ do_cleanups (old_chain);
}
- return PS_ERR; /* ptrace failed. */
+
+ return result;
}
--
2.4.3
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