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authorAndreas Schwab <schwab@suse.de>2016-08-08 09:29:18 +0200
committerAndreas Schwab <schwab@suse.de>2016-08-15 17:10:21 +0200
commit9e2ff6c9cc54c0b4402b8d49e4abe7000fde7617 (patch)
tree836351fddf2c2f3ab7a690e25df3b3d8e44943e3 /sysdeps/unix/sysv/linux/arm/setcontext.S
parent89b7dd27eab6c265e97f028fab6e3977c54a5fa6 (diff)
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arm: mark __startcontext as .cantunwind (bug 20435)
__startcontext marks the bottom of the call stack of the contexts created
by makecontext.
Diffstat (limited to 'sysdeps/unix/sysv/linux/arm/setcontext.S')
-rw-r--r--sysdeps/unix/sysv/linux/arm/setcontext.S7
1 files changed, 7 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/arm/setcontext.S b/sysdeps/unix/sysv/linux/arm/setcontext.S
index 603e508858..d1f168fece 100644
--- a/sysdeps/unix/sysv/linux/arm/setcontext.S
+++ b/sysdeps/unix/sysv/linux/arm/setcontext.S
@@ -86,12 +86,19 @@ weak_alias(__setcontext, setcontext)
 
 	/* Called when a makecontext() context returns.  Start the
 	   context in R4 or fall through to exit().  */
+	/* Unwind descriptors are looked up based on PC - 2, so we have to
+	   make sure to mark the instruction preceding the __startcontext
+	   label as .cantunwind.  */
+	.fnstart
+	.cantunwind
+	nop
 ENTRY(__startcontext)
 	movs    r0, r4
 	bne     PLTJMP(__setcontext)
 
 	@ New context was 0 - exit
 	b       PLTJMP(HIDDEN_JUMPTARGET(exit))
+	.fnend
 END(__startcontext)
 
 #ifdef PIC