From 004ca29118a1993532360038bfa5abf2955f98fa Mon Sep 17 00:00:00 2001
From: John Mark Bell <jmb@netsurf-browser.org>
Date: Thu, 27 Oct 2011 00:21:24 +0000
Subject: Patch to fix bug in UnixLib stack extension causing the signal
 handler stack to be trampled.

svn path=/toolchains/; revision=13081
---
 .../recipes/patches/gcc4/unixlib-stack-incr.p      | 88 ++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 arm-unknown-riscos/recipes/patches/gcc4/unixlib-stack-incr.p

(limited to 'arm-unknown-riscos')

diff --git a/arm-unknown-riscos/recipes/patches/gcc4/unixlib-stack-incr.p b/arm-unknown-riscos/recipes/patches/gcc4/unixlib-stack-incr.p
new file mode 100644
index 0000000..8b8543a
--- /dev/null
+++ b/arm-unknown-riscos/recipes/patches/gcc4/unixlib-stack-incr.p
@@ -0,0 +1,88 @@
+Index: recipe/files/gcc/libunixlib/sys/stackalloc.c
+===================================================================
+--- recipe/files/gcc/libunixlib/sys/stackalloc.c	(revision 5392)
++++ recipe/files/gcc/libunixlib/sys/stackalloc.c	(working copy)
+@@ -326,9 +326,36 @@
+ void
+ __stackalloc_init (void)
+ {
+-  /* The initial stack chunk is set up in _syslib.s
+-     __ul_memory.stack points 8 bytes below the base of the initial chunk
+-     There are also 8 bytes spare above the initial chunk */
++  /* The stack is set up in _syslib.s as follows:
++   *
++   * appspace_himem   -------------
++   *                     8 bytes    - <-- dummytopblock
++   * Signalhandler SP ------------- -
++   *                                 \
++   *                                  \
++   *                   3584 bytes      \
++   *                                    \
++   *                                     } Signal handler chunk (4k)
++   * Signalhandler SL -------------     /
++   *                                   /
++   *                    512 bytes     /
++   *                                 /
++   *                  ------------- -
++   *                     8 bytes    - <-- signalhandlerblock (avoid!)
++   * Initial SP       ------------- -
++   *                                 \
++   *                                  \
++   *                   3560 bytes      \
++   *                                    \
++   *                                     } Initial chunk (4k)
++   * Initial SL       -------------     /
++   *                                   /
++   *                    536 bytes     /
++   *                                 /
++   *                  ------------- -
++   *                     8 bytes    - <-- initialblock
++   * __ulmemory.stack -------------
++   */
+ 
+ #ifdef DEBUG
+   debug_printf ("-- stackalloc_init: stack=%08x  appspace_himem=%08x  "
+@@ -350,9 +377,14 @@
+   dummybottomblock = initialblock - 1;
+   dummybottomblock->startofcon = NULL;
+ 
++  /* Initialise the signal handler block */
+   dummytopblock = initialblock + 1;
+   dummytopblock->size = 1;
++  dummytopblock->startofcon = NULL;
+ 
++  dummytopblock += 1;
++  dummytopblock->size = 1;
++
+   freelist = NULL;
+ }
+ 
+Index: recipe/files/gcc/libunixlib/sys/_syslib.s
+===================================================================
+--- recipe/files/gcc/libunixlib/sys/_syslib.s	(revision 5392)
++++ recipe/files/gcc/libunixlib/sys/_syslib.s	(working copy)
+@@ -142,10 +142,11 @@
+ 	@ in a dynamic area because GCC might generate trampolines.  In USR32
+ 	@ mode we could however.
+ 
+-	@ 8 bytes are needed above the initial chunk
++	@ Reserve the top 4K for the signal handler stack
++	@ 8 bytes are needed above the signal handler stack
+ 	@ for the stackalloc heap
+-	@ Reserve the top 4K for the signal handler stack
+ 	SUB	sp, sp, #8
++
+ 	STR	sp, [ip, #GBL_SIGNALHANDLER_SP]
+ 	@ The signal handler stack cannot be extended, so we don't need to
+ 	@ setup the chunk structure.
+@@ -153,6 +154,10 @@
+ 	ADD	sl, sp, #512
+ 	STR	sl, [ip, #GBL_SIGNALHANDLER_SL]
+ 
++	@ Reserve a further 8 bytes above the initial chunk
++	@ for the stackalloc heap
++	SUB	sp, sp, #8
++
+ 	SUB	a1, sp, #4096
+ 	ADD	sl, a1, #512 + CHUNK_OVERHEAD
+ 
-- 
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