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[PATCH 1/3] Split vDSO range lookup to a gdbarch hook
- From: Pedro Alves <palves at redhat dot com>
- To: gdb-patches at sourceware dot org
- Date: Fri, 26 Sep 2014 13:25:27 +0100
- Subject: [PATCH 1/3] Split vDSO range lookup to a gdbarch hook
- Authentication-results: sourceware.org; auth=none
- References: <1411734329-4707-1-git-send-email-palves at redhat dot com>
We have a case in solib-svr4.c where we could reuse symfile-mem.c's
vDSO range lookup. Since symfile-mem.c is not present in all
configurations solib-svr4.c is, move that lookup to a gdbarch hook.
This has the minor (good) side effect that we stop even trying the
target_auxv_search lookup against targets that don't have a concept of
a vDSO, in case symfile-mem.c happens to be linked in the build
(--enable-targets=all).
Tested on x86_64 Fedora 20.
gdb/
2014-09-26 Pedro Alves <palves@redhat.com>
* arch-utils.c (default_vsyscall_range): New function.
* arch-utils.h (default_vsyscall_range): New declaration.
* gdbarch.sh (vsyscall_range): New hook.
* gdbarch.h, gdbarch.c: Regenerate.
* linux-tdep.c (linux_vsyscall_range): New function.
(linux_init_abi): Install linux_vsyscall_range as
vsyscall_range gdbarch hook.
* memrange.c (address_in_mem_range): New function.
* memrange.h (address_in_mem_range): New declaration.
* symfile-mem.c (find_vdso_size): Delete function.
(add_vsyscall_page): Use gdbarch_vsyscall_range.
---
gdb/arch-utils.c | 8 ++++++++
gdb/arch-utils.h | 4 ++++
gdb/gdbarch.c | 23 +++++++++++++++++++++++
gdb/gdbarch.h | 10 ++++++++++
gdb/gdbarch.sh | 7 +++++++
gdb/linux-tdep.c | 35 +++++++++++++++++++++++++++++++++++
gdb/memrange.c | 9 +++++++++
gdb/memrange.h | 5 +++++
gdb/symfile-mem.c | 31 +++++--------------------------
9 files changed, 106 insertions(+), 26 deletions(-)
diff --git a/gdb/arch-utils.c b/gdb/arch-utils.c
index 5ae9fb3..41cf828 100644
--- a/gdb/arch-utils.c
+++ b/gdb/arch-utils.c
@@ -243,6 +243,14 @@ default_remote_register_number (struct gdbarch *gdbarch,
return regno;
}
+/* See arch-utils.h. */
+
+int
+default_vsyscall_range (struct gdbarch *gdbarch, struct mem_range *range)
+{
+ return 0;
+}
+
/* Functions to manipulate the endianness of the target. */
diff --git a/gdb/arch-utils.h b/gdb/arch-utils.h
index 46d1573..a609662 100644
--- a/gdb/arch-utils.h
+++ b/gdb/arch-utils.h
@@ -174,4 +174,8 @@ extern int default_return_in_first_hidden_param_p (struct gdbarch *,
extern int default_insn_is_call (struct gdbarch *, CORE_ADDR);
extern int default_insn_is_ret (struct gdbarch *, CORE_ADDR);
extern int default_insn_is_jump (struct gdbarch *, CORE_ADDR);
+
+/* Do-nothing version of vsyscall_range. Returns false. */
+
+extern int default_vsyscall_range (struct gdbarch *gdbarch, struct mem_range *range);
#endif
diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
index b0ee79d..b061f81 100644
--- a/gdb/gdbarch.c
+++ b/gdb/gdbarch.c
@@ -316,6 +316,7 @@ struct gdbarch
gdbarch_insn_is_ret_ftype *insn_is_ret;
gdbarch_insn_is_jump_ftype *insn_is_jump;
gdbarch_auxv_parse_ftype *auxv_parse;
+ gdbarch_vsyscall_range_ftype *vsyscall_range;
};
/* Create a new ``struct gdbarch'' based on information provided by
@@ -408,6 +409,7 @@ gdbarch_alloc (const struct gdbarch_info *info,
gdbarch->insn_is_call = default_insn_is_call;
gdbarch->insn_is_ret = default_insn_is_ret;
gdbarch->insn_is_jump = default_insn_is_jump;
+ gdbarch->vsyscall_range = default_vsyscall_range;
/* gdbarch_alloc() */
return gdbarch;
@@ -627,6 +629,7 @@ verify_gdbarch (struct gdbarch *gdbarch)
/* Skip verify of insn_is_ret, invalid_p == 0 */
/* Skip verify of insn_is_jump, invalid_p == 0 */
/* Skip verify of auxv_parse, has predicate. */
+ /* Skip verify of vsyscall_range, invalid_p == 0 */
buf = ui_file_xstrdup (log, &length);
make_cleanup (xfree, buf);
if (length > 0)
@@ -1296,6 +1299,9 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
"gdbarch_dump: virtual_frame_pointer = <%s>\n",
host_address_to_string (gdbarch->virtual_frame_pointer));
fprintf_unfiltered (file,
+ "gdbarch_dump: vsyscall_range = <%s>\n",
+ host_address_to_string (gdbarch->vsyscall_range));
+ fprintf_unfiltered (file,
"gdbarch_dump: vtable_function_descriptors = %s\n",
plongest (gdbarch->vtable_function_descriptors));
fprintf_unfiltered (file,
@@ -4403,6 +4409,23 @@ set_gdbarch_auxv_parse (struct gdbarch *gdbarch,
gdbarch->auxv_parse = auxv_parse;
}
+int
+gdbarch_vsyscall_range (struct gdbarch *gdbarch, struct mem_range *range)
+{
+ gdb_assert (gdbarch != NULL);
+ gdb_assert (gdbarch->vsyscall_range != NULL);
+ if (gdbarch_debug >= 2)
+ fprintf_unfiltered (gdb_stdlog, "gdbarch_vsyscall_range called\n");
+ return gdbarch->vsyscall_range (gdbarch, range);
+}
+
+void
+set_gdbarch_vsyscall_range (struct gdbarch *gdbarch,
+ gdbarch_vsyscall_range_ftype vsyscall_range)
+{
+ gdbarch->vsyscall_range = vsyscall_range;
+}
+
/* Keep a registry of per-architecture data-pointers required by GDB
modules. */
diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
index 0303b2e..1215154 100644
--- a/gdb/gdbarch.h
+++ b/gdb/gdbarch.h
@@ -59,6 +59,7 @@ struct axs_value;
struct stap_parse_info;
struct ravenscar_arch_ops;
struct elf_internal_linux_prpsinfo;
+struct mem_range;
/* The architecture associated with the inferior through the
connection to the target.
@@ -1317,6 +1318,15 @@ typedef int (gdbarch_auxv_parse_ftype) (struct gdbarch *gdbarch, gdb_byte **read
extern int gdbarch_auxv_parse (struct gdbarch *gdbarch, gdb_byte **readptr, gdb_byte *endptr, CORE_ADDR *typep, CORE_ADDR *valp);
extern void set_gdbarch_auxv_parse (struct gdbarch *gdbarch, gdbarch_auxv_parse_ftype *auxv_parse);
+/* Find the address range of the current inferior's vsyscall/vDSO, and
+ write it to *RANGE. If the vsyscall's length can't be determined, a
+ range with zero length is returned. Returns true if the vsyscall is
+ found, false otherwise. */
+
+typedef int (gdbarch_vsyscall_range_ftype) (struct gdbarch *gdbarch, struct mem_range *range);
+extern int gdbarch_vsyscall_range (struct gdbarch *gdbarch, struct mem_range *range);
+extern void set_gdbarch_vsyscall_range (struct gdbarch *gdbarch, gdbarch_vsyscall_range_ftype *vsyscall_range);
+
/* Definition for an unknown syscall, used basically in error-cases. */
#define UNKNOWN_SYSCALL (-1)
diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
index 2a8bca8..be5f2de 100755
--- a/gdb/gdbarch.sh
+++ b/gdb/gdbarch.sh
@@ -1029,6 +1029,12 @@ m:int:insn_is_jump:CORE_ADDR addr:addr::default_insn_is_jump::0
# Return -1 if there is insufficient buffer for a whole entry.
# Return 1 if an entry was read into *TYPEP and *VALP.
M:int:auxv_parse:gdb_byte **readptr, gdb_byte *endptr, CORE_ADDR *typep, CORE_ADDR *valp:readptr, endptr, typep, valp
+
+# Find the address range of the current inferior's vsyscall/vDSO, and
+# write it to *RANGE. If the vsyscall's length can't be determined, a
+# range with zero length is returned. Returns true if the vsyscall is
+# found, false otherwise.
+m:int:vsyscall_range:struct mem_range *range:range::default_vsyscall_range::0
EOF
}
@@ -1148,6 +1154,7 @@ struct axs_value;
struct stap_parse_info;
struct ravenscar_arch_ops;
struct elf_internal_linux_prpsinfo;
+struct mem_range;
/* The architecture associated with the inferior through the
connection to the target.
diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
index dae59c5..2a5e57d 100644
--- a/gdb/linux-tdep.c
+++ b/gdb/linux-tdep.c
@@ -1782,6 +1782,40 @@ linux_gdb_signal_to_target (struct gdbarch *gdbarch,
return -1;
}
+/* Rummage through mappings to find a mapping's size. */
+
+static int
+find_mapping_size (CORE_ADDR vaddr, unsigned long size,
+ int read, int write, int exec, int modified,
+ void *data)
+{
+ struct mem_range *range = data;
+
+ if (vaddr == range->start)
+ {
+ range->length = size;
+ return 1;
+ }
+ return 0;
+}
+
+/* Implementation of the "vsyscall_range" gdbarch hook. */
+
+static int
+linux_vsyscall_range (struct gdbarch *gdbarch, struct mem_range *range)
+{
+ if (target_auxv_search (¤t_target, AT_SYSINFO_EHDR, &range->start) <= 0)
+ return 0;
+
+ /* This is installed by linux_init_abi below, so should always be
+ available. */
+ gdb_assert (gdbarch_find_memory_regions_p (target_gdbarch ()));
+
+ range->length = 0;
+ gdbarch_find_memory_regions (gdbarch, find_mapping_size, range);
+ return 1;
+}
+
/* To be called from the various GDB_OSABI_LINUX handlers for the
various GNU/Linux architectures and machine types. */
@@ -1799,6 +1833,7 @@ linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
linux_gdb_signal_from_target);
set_gdbarch_gdb_signal_to_target (gdbarch,
linux_gdb_signal_to_target);
+ set_gdbarch_vsyscall_range (gdbarch, linux_vsyscall_range);
}
/* Provide a prototype to silence -Wmissing-prototypes. */
diff --git a/gdb/memrange.c b/gdb/memrange.c
index 2895ff2..485550b 100644
--- a/gdb/memrange.c
+++ b/gdb/memrange.c
@@ -31,6 +31,15 @@ mem_ranges_overlap (CORE_ADDR start1, int len1,
return (l < h);
}
+/* See memrange.h. */
+
+int
+address_in_mem_range (CORE_ADDR address, const struct mem_range *r)
+{
+ return (r->start <= address
+ && (address - r->start) < r->length);
+}
+
/* qsort comparison function, that compares mem_ranges. Ranges are
sorted in ascending START order. */
diff --git a/gdb/memrange.h b/gdb/memrange.h
index 8c25d0a..2591789 100644
--- a/gdb/memrange.h
+++ b/gdb/memrange.h
@@ -43,6 +43,11 @@ DEF_VEC_O(mem_range_s);
extern int mem_ranges_overlap (CORE_ADDR start1, int len1,
CORE_ADDR start2, int len2);
+/* Returns true if ADDR is in RANGE. */
+
+extern int address_in_mem_range (CORE_ADDR addr,
+ const struct mem_range *range);
+
/* Sort ranges by start address, then coalesce contiguous or
overlapping ranges. */
diff --git a/gdb/symfile-mem.c b/gdb/symfile-mem.c
index ef48f7d..2872e15 100644
--- a/gdb/symfile-mem.c
+++ b/gdb/symfile-mem.c
@@ -188,33 +188,15 @@ symbol_file_add_from_memory_wrapper (struct ui_out *uiout, void *data)
return 0;
}
-/* Rummage through mappings to find the vsyscall page size. */
-
-static int
-find_vdso_size (CORE_ADDR vaddr, unsigned long size,
- int read, int write, int exec, int modified,
- void *data)
-{
- struct symbol_file_add_from_memory_args *args = data;
-
- if (vaddr == args->sysinfo_ehdr)
- {
- args->size = size;
- return 1;
- }
- return 0;
-}
-
/* Try to add the symbols for the vsyscall page, if there is one.
This function is called via the inferior_created observer. */
static void
add_vsyscall_page (struct target_ops *target, int from_tty)
{
- CORE_ADDR sysinfo_ehdr;
+ struct mem_range vsyscall_range;
- if (target_auxv_search (target, AT_SYSINFO_EHDR, &sysinfo_ehdr) > 0
- && sysinfo_ehdr != (CORE_ADDR) 0)
+ if (gdbarch_vsyscall_range (target_gdbarch (), &vsyscall_range))
{
struct bfd *bfd;
struct symbol_file_add_from_memory_args args;
@@ -237,14 +219,11 @@ add_vsyscall_page (struct target_ops *target, int from_tty)
return;
}
args.bfd = bfd;
- args.sysinfo_ehdr = sysinfo_ehdr;
- args.size = 0;
- if (gdbarch_find_memory_regions_p (target_gdbarch ()))
- (void) gdbarch_find_memory_regions (target_gdbarch (),
- find_vdso_size, &args);
+ args.sysinfo_ehdr = vsyscall_range.start;
+ args.size = vsyscall_range.length;
args.name = xstrprintf ("system-supplied DSO at %s",
- paddress (target_gdbarch (), sysinfo_ehdr));
+ paddress (target_gdbarch (), vsyscall_range.start));
/* Pass zero for FROM_TTY, because the action of loading the
vsyscall DSO was not triggered by the user, even if the user
typed "run" at the TTY. */
--
1.9.3