File startcontext-cantunwind.patch of Package glibc

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File startcontext-cantunwind.patch of Package glibc (Revision cafb1955909d31a3e5d33b68744cb460)

Currently displaying revision cafb1955909d31a3e5d33b68744cb460 , Show latest

From 1061d6fe364ddac7458a872839ea9efe8f7600f0 Mon Sep 17 00:00:00 2001
From: Andreas Schwab <schwab@suse.de>
Date: Mon, 8 Aug 2016 09:29:18 +0200
Subject: [PATCH] arm: mark __startcontext as .cantunwind

__startcontext marks the bottom of the call stack of the contexts created
by makecontext.

[BZ #20435]
	* sysdeps/unix/sysv/linux/arm/setcontext.S (__startcontext): Mark
	as .cantunwind.
---
 sysdeps/unix/sysv/linux/arm/setcontext.S | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/sysdeps/unix/sysv/linux/arm/setcontext.S b/sysdeps/unix/sysv/linux/arm/setcontext.S
index 603e508..d1f168f 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
-- 
2.9.2

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File startcontext-cantunwind.patch of Package glibc (Revision cafb1955909d31a3e5d33b68744cb460)

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