[binutils-gdb] bfd/riscv: prepare to handle bare metal core dump creation
Andrew Burgess
aburgess@sourceware.org
Fri Mar 5 17:23:11 GMT 2021
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=0897bb7d6dc4e803cd99d4656186c965f099d01c
commit 0897bb7d6dc4e803cd99d4656186c965f099d01c
Author: Andrew Burgess <andrew.burgess@embecosm.com>
Date: Mon Nov 30 12:14:38 2020 +0000
bfd/riscv: prepare to handle bare metal core dump creation
When creating a core file GDB will call the function
elfcore_write_prstatus to write out the general purpose registers
along with the pid/tid for the thread (into a prstatus structure) and
the executable name and arguments (into a prpsinfo_t structure).
However, for a bare metal RISC-V tool chain the prstatus_t and
prpsinfo_t types are not defined so the elfcore_write_prstatus
function will return NULL, preventing core file creation.
This commit provides the `elf_backend_write_core_note' hook and uses
the provided function to write out the required information.
In order to keep changes in the non bare metal tools to a minimum, the
provided backend function will itself return NULL when the prstatus_t
or pspsinfo_t types are available, the consequence of this is that the
generic code in elfcore_write_prstatus will be used just as before.
But, when prstatus_t or prpsinfo_t is not available, the new backend
function will write out the information using predefined offsets.
This new functionality will be used by a later GDB commit that will
add bare metal core dumps for RISC-V.
bfd/ChangeLog:
* elfnn-riscv.c (PRPSINFO_PR_FNAME_LENGTH): Define.
(PRPSINFO_PR_PSARGS_LENGTH): Define.
(riscv_write_core_note): New function.
(riscv_elf_grok_psinfo): Make use of two new length defines.
(elf_backend_write_core_note): Define.
Diff:
---
bfd/ChangeLog | 9 ++++++
bfd/elfnn-riscv.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 91 insertions(+), 2 deletions(-)
diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 31d0714da27..9e7f90e1625 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,12 @@
+2021-03-05 Craig Blackmore <craig.blackmore@embecosm.com>
+ Andrew Burgess <andrew.burgess@embecosm.com>
+
+ * elfnn-riscv.c (PRPSINFO_PR_FNAME_LENGTH): Define.
+ (PRPSINFO_PR_PSARGS_LENGTH): Define.
+ (riscv_write_core_note): New function.
+ (riscv_elf_grok_psinfo): Make use of two new length defines.
+ (elf_backend_write_core_note): Define.
+
2021-03-05 Craig Blackmore <craig.blackmore@embecosm.com>
Andrew Burgess <andrew.burgess@embecosm.com>
diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c
index ec8a3e73c8f..76d29b73332 100644
--- a/bfd/elfnn-riscv.c
+++ b/bfd/elfnn-riscv.c
@@ -4877,6 +4877,8 @@ _bfd_riscv_relax_section (bfd *abfd, asection *sec,
# define PRPSINFO_OFFSET_PR_PID 16
# define PRPSINFO_OFFSET_PR_FNAME 32
# define PRPSINFO_OFFSET_PR_PSARGS 48
+# define PRPSINFO_PR_FNAME_LENGTH 16
+# define PRPSINFO_PR_PSARGS_LENGTH 80
#else
# define PRSTATUS_SIZE 376
# define PRSTATUS_OFFSET_PR_CURSIG 12
@@ -4887,8 +4889,83 @@ _bfd_riscv_relax_section (bfd *abfd, asection *sec,
# define PRPSINFO_OFFSET_PR_PID 24
# define PRPSINFO_OFFSET_PR_FNAME 40
# define PRPSINFO_OFFSET_PR_PSARGS 56
+# define PRPSINFO_PR_FNAME_LENGTH 16
+# define PRPSINFO_PR_PSARGS_LENGTH 80
#endif
+/* Write PRSTATUS and PRPSINFO note into core file. This will be called
+ before the generic code in elf.c. By checking the compiler defines we
+ only perform any action here if the generic code would otherwise not be
+ able to help us. The intention is that bare metal core dumps (where the
+ prstatus_t and/or prpsinfo_t might not be available) will use this code,
+ while non bare metal tools will use the generic elf code. */
+
+static char *
+riscv_write_core_note (bfd *abfd ATTRIBUTE_UNUSED,
+ char *buf ATTRIBUTE_UNUSED,
+ int *bufsiz ATTRIBUTE_UNUSED,
+ int note_type ATTRIBUTE_UNUSED, ...)
+{
+ switch (note_type)
+ {
+ default:
+ return NULL;
+
+#if !defined (HAVE_PRPSINFO_T)
+ case NT_PRPSINFO:
+ {
+ char data[PRPSINFO_SIZE] ATTRIBUTE_NONSTRING;
+ va_list ap;
+
+ va_start (ap, note_type);
+ memset (data, 0, sizeof (data));
+ strncpy (data + PRPSINFO_OFFSET_PR_FNAME, va_arg (ap, const char *),
+ PRPSINFO_PR_FNAME_LENGTH);
+#if GCC_VERSION == 8000 || GCC_VERSION == 8001
+ DIAGNOSTIC_PUSH;
+ /* GCC 8.0 and 8.1 warn about 80 equals destination size with
+ -Wstringop-truncation:
+ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85643
+ */
+ DIAGNOSTIC_IGNORE_STRINGOP_TRUNCATION;
+#endif
+ strncpy (data + PRPSINFO_OFFSET_PR_PSARGS, va_arg (ap, const char *),
+ PRPSINFO_PR_PSARGS_LENGTH);
+#if GCC_VERSION == 8000 || GCC_VERSION == 8001
+ DIAGNOSTIC_POP;
+#endif
+ va_end (ap);
+ return elfcore_write_note (abfd, buf, bufsiz,
+ "CORE", note_type, data, sizeof (data));
+ }
+#endif /* !HAVE_PRPSINFO_T */
+
+#if !defined (HAVE_PRSTATUS_T)
+ case NT_PRSTATUS:
+ {
+ char data[PRSTATUS_SIZE];
+ va_list ap;
+ long pid;
+ int cursig;
+ const void *greg;
+
+ va_start (ap, note_type);
+ memset (data, 0, sizeof(data));
+ pid = va_arg (ap, long);
+ bfd_put_32 (abfd, pid, data + PRSTATUS_OFFSET_PR_PID);
+ cursig = va_arg (ap, int);
+ bfd_put_16 (abfd, cursig, data + PRSTATUS_OFFSET_PR_CURSIG);
+ greg = va_arg (ap, const void *);
+ memcpy (data + PRSTATUS_OFFSET_PR_REG, greg,
+ PRSTATUS_SIZE - PRSTATUS_OFFSET_PR_REG - ARCH_SIZE / 8);
+ va_end (ap);
+ return elfcore_write_note (abfd, buf, bufsiz,
+ "CORE", note_type, data, sizeof (data));
+ }
+#endif /* !HAVE_PRSTATUS_T */
+ }
+}
+
/* Support for core dump NOTE sections. */
static bfd_boolean
@@ -4930,11 +5007,13 @@ riscv_elf_grok_psinfo (bfd *abfd, Elf_Internal_Note *note)
/* pr_fname */
elf_tdata (abfd)->core->program = _bfd_elfcore_strndup
- (abfd, note->descdata + PRPSINFO_OFFSET_PR_FNAME, 16);
+ (abfd, note->descdata + PRPSINFO_OFFSET_PR_FNAME,
+ PRPSINFO_PR_FNAME_LENGTH);
/* pr_psargs */
elf_tdata (abfd)->core->command = _bfd_elfcore_strndup
- (abfd, note->descdata + PRPSINFO_OFFSET_PR_PSARGS, 80);
+ (abfd, note->descdata + PRPSINFO_OFFSET_PR_PSARGS,
+ PRPSINFO_PR_PSARGS_LENGTH);
break;
}
@@ -5003,6 +5082,7 @@ riscv_elf_obj_attrs_arg_type (int tag)
#define elf_backend_grok_prstatus riscv_elf_grok_prstatus
#define elf_backend_grok_psinfo riscv_elf_grok_psinfo
#define elf_backend_object_p riscv_elf_object_p
+#define elf_backend_write_core_note riscv_write_core_note
#define elf_info_to_howto_rel NULL
#define elf_info_to_howto riscv_info_to_howto_rela
#define bfd_elfNN_bfd_relax_section _bfd_riscv_relax_section
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