sparc: Remove unwind information from signal return stubs [BZ #31244]

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>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
(cherry picked from commit 7bd06985c0a143cdcba2762bfe020e53514a53de)

diff --git a/sysdeps/sparc/sysdep.h b/sysdeps/sparc/sysdep.h
index 95068071ccb50168f4e1ce69af728b3ea99076b0..baab6817a6a7adef6b6d8012873ae163cae08e18 100644 (file)
--- 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 2829e881eb6f0e6d7120a8ddcbc6631d61dd7ffc..a1492ea59eddd1aeff0e50889adc2e7054304b5b 100644 (file)
--- 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)