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authorRussell King <rmk@dyn-67.arm.linux.org.uk>2005-06-22 20:26:05 +0100
committerRussell King <rmk@dyn-67.arm.linux.org.uk>2005-06-22 20:26:05 +0100
commite00d349e7781a92cf35b242259c9e5341a9661bb (patch)
treecd7e9d10adb8bc3b18c20c3d925c64b4c6f3f3b0
parent052162198b89e64d37c20238412674152d614997 (diff)
[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>
-rw-r--r--arch/arm/kernel/signal.c29
-rw-r--r--arch/arm/kernel/signal.h12
-rw-r--r--arch/arm/kernel/traps.c9
3 files changed, 40 insertions, 10 deletions
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 931919fd5121..07ddeed61766 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -19,6 +19,7 @@
#include <asm/unistd.h>
#include "ptrace.h"
+#include "signal.h"
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
@@ -35,7 +36,7 @@
#define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
#define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
-static const unsigned long retcodes[4] = {
+const unsigned long sigreturn_codes[4] = {
SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN,
SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN
};
@@ -500,17 +501,25 @@ setup_return(struct pt_regs *regs, struct k_sigaction *ka,
if (ka->sa.sa_flags & SA_SIGINFO)
idx += 2;
- if (__put_user(retcodes[idx], rc))
+ if (__put_user(sigreturn_codes[idx], rc))
return 1;
- /*
- * Ensure that the instruction cache sees
- * the return code written onto the stack.
- */
- flush_icache_range((unsigned long)rc,
- (unsigned long)(rc + 1));
-
- retcode = ((unsigned long)rc) + thumb;
+ if (cpsr & MODE32_BIT) {
+ /*
+ * 32-bit code can use the new high-page
+ * signal return code support.
+ */
+ retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
+ } else {
+ /*
+ * Ensure that the instruction cache sees
+ * the return code written onto the stack.
+ */
+ flush_icache_range((unsigned long)rc,
+ (unsigned long)(rc + 1));
+
+ retcode = ((unsigned long)rc) + thumb;
+ }
}
regs->ARM_r0 = usig;
diff --git a/arch/arm/kernel/signal.h b/arch/arm/kernel/signal.h
new file mode 100644
index 000000000000..91d26faca62b
--- /dev/null
+++ b/arch/arm/kernel/signal.h
@@ -0,0 +1,12 @@
+/*
+ * linux/arch/arm/kernel/signal.h
+ *
+ * Copyright (C) 2005 Russell King.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#define KERN_SIGRETURN_CODE 0xffff0500
+
+extern const unsigned long sigreturn_codes[4];
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 45d2a032d890..2fb0a4cfb37a 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 @@ void __init trap_init(void)
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);
}