openwrt-xburst/target/linux/pxa/patches-2.6.21/032-misalignment-handling.patch

Change the default alingment handling to not be silent failure
Index: linux-2.6.21.7/arch/arm/mm/alignment.c
===================================================================
--- linux-2.6.21.7.orig/arch/arm/mm/alignment.c
+++ linux-2.6.21.7/arch/arm/mm/alignment.c
@@ -797,6 +797,8 @@ static int __init alignment_init(void)
 	res->write_proc = proc_alignment_write;
 #endif
 
+	ai_usermode = CONFIG_ALIGNMENT_HANDLING;
+
 	hook_fault_code(1, do_alignment, SIGILL, "alignment exception");
 	hook_fault_code(3, do_alignment, SIGILL, "alignment exception");
 
Index: linux-2.6.21.7/arch/arm/Kconfig
===================================================================
--- linux-2.6.21.7.orig/arch/arm/Kconfig
+++ linux-2.6.21.7/arch/arm/Kconfig
@@ -709,6 +709,19 @@ config ALIGNMENT_TRAP
 	  correct operation of some network protocols. With an IP-only
 	  configuration it is safe to say N, otherwise say Y.
 
+config ALIGNMENT_HANDLING
+	hex "Userspace alignment trap handling"
+	default "0x3"
+	depends on ALIGNMENT_TRAP
+	help
+	  How should we handle alignment errors in userspace by default?  This is a bitfield where:
+	  0 - silently ignore alignment errors (will lead to unexpected results)
+	  1 - report alignment errors through printk (will lead to unexpected results, but you'll know about them)
+	  2 - fix the alignment and make things work properly (performance degradation for un-aligned code)
+	  4 - raise SIGBUS on alignment traps
+	  A good number to choose is probably either 3 (work slowly but log message) or 5 (log message and SIGBUS).
+	  You can change the behavior at runtime through /proc/cpu/alignment if you have PROC_FS enabled.
+
 endmenu
 
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