From cafa0319f8ff701b7edd56e3e244e79abcf84748 Mon Sep 17 00:00:00 2001 From: Andreas Schwab Date: Thu, 18 Aug 2016 11:38:28 +0200 Subject: arm: mark __startcontext as .cantunwind (bug 20435) __startcontext marks the bottom of the call stack of the contexts created by makecontext. (cherry picked from commit 9e2ff6c9cc54c0b4402b8d49e4abe7000fde7617) Also includes the NEWS update, cherry-picked from commits 056dd72af83f5459ce6d545a49dea6dba7d635dc and 4d047efdbc55b0d68947cde682e5363d16a66294. (cherry picked from commit 23446cad92195d8c50092410b4f72ca7f6d1d2f1) --- 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 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 -- cgit 1.4.1