[PATCH] ARM: Move signal return code into vector page
Move the signal return code into the vector page instead of placing
it on the user mode stack, which will allow us to avoid flushing
the instruction cache on signals, as well as eventually allowing
non-exec stack.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 45d2a03..2fb0a4c 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -30,6 +30,7 @@
#include <asm/traps.h>
#include "ptrace.h"
+#include "signal.h"
const char *processor_modes[]=
{ "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
@@ -683,6 +684,14 @@
memcpy((void *)0xffff0000, __vectors_start, __vectors_end - __vectors_start);
memcpy((void *)0xffff0200, __stubs_start, __stubs_end - __stubs_start);
memcpy((void *)0xffff1000 - kuser_sz, __kuser_helper_start, kuser_sz);
+
+ /*
+ * Copy signal return handlers into the vector page, and
+ * set sigreturn to be a pointer to these.
+ */
+ memcpy((void *)KERN_SIGRETURN_CODE, sigreturn_codes,
+ sizeof(sigreturn_codes));
+
flush_icache_range(0xffff0000, 0xffff0000 + PAGE_SIZE);
modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
}