[v2] sparc: Remove unwind information from signal return stubs [BZ #31244]
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Commit Message
The functions were previously written in C, but were not compiled
with unwind information. The ENTRY/END macros includes .cfi_startproc
and .cfi_endproc which adds unwind information. This caused the
tests cleanup-8 and cleanup-10 in the GCC testsuite to fail.
This patch adds a version of the ENTRY/END macros without the
CFI instructions that can be used instead.
sigaction registers a restorer address that is located two instructions
before the stub function. This patch adds a two instruction padding to
avoid that the unwinder accesses the unwind information from the function
that the linker has placed right before it in memory. This fixes an issue
with pthread_cancel that caused tst-mutex8-static (and other tests) to fail.
Signed-off-by: Daniel Cederman <cederman@gaisler.com>
---
sysdeps/sparc/sysdep.h | 9 +++++++++
.../unix/sysv/linux/sparc/sparc32/sigreturn_stub.S | 11 +++++++----
2 files changed, 16 insertions(+), 4 deletions(-)
Comments
On 16/01/24 05:31, Daniel Cederman wrote:
> The functions were previously written in C, but were not compiled
> with unwind information. The ENTRY/END macros includes .cfi_startproc
> and .cfi_endproc which adds unwind information. This caused the
> tests cleanup-8 and cleanup-10 in the GCC testsuite to fail.
> This patch adds a version of the ENTRY/END macros without the
> CFI instructions that can be used instead.
>
> sigaction registers a restorer address that is located two instructions
> before the stub function. This patch adds a two instruction padding to
> avoid that the unwinder accesses the unwind information from the function
> that the linker has placed right before it in memory. This fixes an issue
> with pthread_cancel that caused tst-mutex8-static (and other tests) to fail.
>
> Signed-off-by: Daniel Cederman <cederman@gaisler.com>
LGTM, thanks.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
> ---
> sysdeps/sparc/sysdep.h | 9 +++++++++
> .../unix/sysv/linux/sparc/sparc32/sigreturn_stub.S | 11 +++++++----
> 2 files changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/sysdeps/sparc/sysdep.h b/sysdeps/sparc/sysdep.h
> index c00fe79fec..44a6952bff 100644
> --- a/sysdeps/sparc/sysdep.h
> +++ b/sysdeps/sparc/sysdep.h
> @@ -76,6 +76,15 @@ C_LABEL(name) \
> cfi_endproc; \
> .size name, . - name
>
> +#define ENTRY_NOCFI(name) \
> + .align 4; \
> + .global C_SYMBOL_NAME(name); \
> + .type name, @function; \
> +C_LABEL(name)
> +
> +#define END_NOCFI(name) \
> + .size name, . - name
> +
> #undef LOC
> #define LOC(name) .L##name
>
> diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/sigreturn_stub.S b/sysdeps/unix/sysv/linux/sparc/sparc32/sigreturn_stub.S
> index 832223f8ce..21d36c50df 100644
> --- a/sysdeps/unix/sysv/linux/sparc/sparc32/sigreturn_stub.S
> +++ b/sysdeps/unix/sysv/linux/sparc/sparc32/sigreturn_stub.S
> @@ -23,12 +23,15 @@
>
> [1] https://lkml.org/lkml/2016/5/27/465 */
>
> -ENTRY (__rt_sigreturn_stub)
> + nop
> + nop
> +
> +ENTRY_NOCFI (__rt_sigreturn_stub)
> mov __NR_rt_sigreturn, %g1
> ta 0x10
> -END (__rt_sigreturn_stub)
> +END_NOCFI (__rt_sigreturn_stub)
>
> -ENTRY (__sigreturn_stub)
> +ENTRY_NOCFI (__sigreturn_stub)
> mov __NR_sigreturn, %g1
> ta 0x10
> -END (__sigreturn_stub)
> +END_NOCFI (__sigreturn_stub)
@@ -76,6 +76,15 @@ C_LABEL(name) \
cfi_endproc; \
.size name, . - name
+#define ENTRY_NOCFI(name) \
+ .align 4; \
+ .global C_SYMBOL_NAME(name); \
+ .type name, @function; \
+C_LABEL(name)
+
+#define END_NOCFI(name) \
+ .size name, . - name
+
#undef LOC
#define LOC(name) .L##name
@@ -23,12 +23,15 @@
[1] https://lkml.org/lkml/2016/5/27/465 */
-ENTRY (__rt_sigreturn_stub)
+ nop
+ nop
+
+ENTRY_NOCFI (__rt_sigreturn_stub)
mov __NR_rt_sigreturn, %g1
ta 0x10
-END (__rt_sigreturn_stub)
+END_NOCFI (__rt_sigreturn_stub)
-ENTRY (__sigreturn_stub)
+ENTRY_NOCFI (__sigreturn_stub)
mov __NR_sigreturn, %g1
ta 0x10
-END (__sigreturn_stub)
+END_NOCFI (__sigreturn_stub)