[PATCH] gdb: support rseq auxvs

[PATCH] gdb: support rseq auxvs

[Ilya Leoshkevich]

Linux kernel commit commit 317c8194e6ae ("rseq: Introduce feature size
and alignment ELF auxiliary vector entries") introduced two new auxvs:
AT_RSEQ_FEATURE_SIZE and AT_RSEQ_ALIGN.  Support them in GDB.  This
fixes auxv.exp on kernels >= v6.3.
---
 gdb/auxv.c           | 4 ++++
 include/elf/common.h | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/gdb/auxv.c b/gdb/auxv.c
index 812b2807554..3ce5ccd3342 100644
--- a/gdb/auxv.c
+++ b/gdb/auxv.c
@@ -493,6 +493,10 @@ default_print_auxv_entry (struct gdbarch *gdbarch, struct ui_file *file,
 	   AUXV_FORMAT_STR);
       TAG (AT_RANDOM, _("Address of 16 random bytes"), AUXV_FORMAT_HEX);
       TAG (AT_HWCAP2, _("Extension of AT_HWCAP"), AUXV_FORMAT_HEX);
+      TAG (AT_RSEQ_FEATURE_SIZE, _("rseq supported feature size"),
+	   AUXV_FORMAT_HEX);
+      TAG (AT_RSEQ_ALIGN, _("rseq allocation alignment"),
+	   AUXV_FORMAT_HEX);
       TAG (AT_EXECFN, _("File name of executable"), AUXV_FORMAT_STR);
       TAG (AT_SECURE, _("Boolean, was exec setuid-like?"), AUXV_FORMAT_DEC);
       TAG (AT_SYSINFO, _("Special system info/entry points"), AUXV_FORMAT_HEX);
diff --git a/include/elf/common.h b/include/elf/common.h
index ffa6b60bd2b..3ebaebfb34b 100644
--- a/include/elf/common.h
+++ b/include/elf/common.h
@@ -1374,6 +1374,8 @@
 					   may differ from AT_PLATFORM.  */
 #define AT_RANDOM	25		/* Address of 16 random bytes.  */
 #define AT_HWCAP2	26		/* Extension of AT_HWCAP.  */
+#define AT_RSEQ_FEATURE_SIZE	27	/* rseq supported feature size */
+#define AT_RSEQ_ALIGN	28		/* rseq allocation alignment */
 #define AT_EXECFN	31		/* Filename of executable.  */
 /* Pointer to the global system page used for system calls and other
    nice things.  */
-- 
2.40.1

Re: [PATCH] gdb: support rseq auxvs

[Tom Tromey]

>>>>> "Ilya" == Ilya Leoshkevich via Gdb-patches <gdb-patches@sourceware.org> writes:

Ilya> Linux kernel commit commit 317c8194e6ae ("rseq: Introduce feature size
Ilya> and alignment ELF auxiliary vector entries") introduced two new auxvs:
Ilya> AT_RSEQ_FEATURE_SIZE and AT_RSEQ_ALIGN.  Support them in GDB.  This
Ilya> fixes auxv.exp on kernels >= v6.3.

Thank you for the patch.  I didn't see a review of this.  The patch
looks good to me.

Can you add this trailer the commit?

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30540

Thanks.

Approved-By: Tom Tromey <tom@tromey.com>

Tom

Re: [PATCH] gdb: support rseq auxvs

[Simon Marchi]

On 10/3/23 15:05, Tom Tromey wrote:
>>>>>> "Ilya" == Ilya Leoshkevich via Gdb-patches <gdb-patches@sourceware.org> writes:
> 
> Ilya> Linux kernel commit commit 317c8194e6ae ("rseq: Introduce feature size
> Ilya> and alignment ELF auxiliary vector entries") introduced two new auxvs:
> Ilya> AT_RSEQ_FEATURE_SIZE and AT_RSEQ_ALIGN.  Support them in GDB.  This
> Ilya> fixes auxv.exp on kernels >= v6.3.
> 
> Thank you for the patch.  I didn't see a review of this.  The patch
> looks good to me.
> 
> Can you add this trailer the commit?
> 
> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30540
> 
> Thanks.
> 
> Approved-By: Tom Tromey <tom@tromey.com>
> 
> Tom

I stumbled on this problem, so I went ahead and pushed the patch.  I
made a little change, I used AUXV_FORMAT_DEC for both values, I think
it's more natural.

Simon