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authorRussell King <rmk@dyn-67.arm.linux.org.uk>2005-06-22 15:26:05 -0400
committerRussell King <rmk@dyn-67.arm.linux.org.uk>2005-06-22 15:26:05 -0400
commite00d349e7781a92cf35b242259c9e5341a9661bb (patch)
treecd7e9d10adb8bc3b18c20c3d925c64b4c6f3f3b0 /arch
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>
Diffstat (limited to 'arch')
-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 @@
19#include <asm/unistd.h> 19#include <asm/unistd.h>
20 20
21#include "ptrace.h" 21#include "ptrace.h"
22#include "signal.h"
22 23
23#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 24#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
24 25
@@ -35,7 +36,7 @@
35#define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE)) 36#define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
36#define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE)) 37#define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
37 38
38static const unsigned long retcodes[4] = { 39const unsigned long sigreturn_codes[4] = {
39 SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN, 40 SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN,
40 SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN 41 SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN
41}; 42};
@@ -500,17 +501,25 @@ setup_return(struct pt_regs *regs, struct k_sigaction *ka,
500 if (ka->sa.sa_flags & SA_SIGINFO) 501 if (ka->sa.sa_flags & SA_SIGINFO)
501 idx += 2; 502 idx += 2;
502 503
503 if (__put_user(retcodes[idx], rc)) 504 if (__put_user(sigreturn_codes[idx], rc))
504 return 1; 505 return 1;
505 506
506 /* 507 if (cpsr & MODE32_BIT) {
507 * Ensure that the instruction cache sees 508 /*
508 * the return code written onto the stack. 509 * 32-bit code can use the new high-page
509 */ 510 * signal return code support.
510 flush_icache_range((unsigned long)rc, 511 */
511 (unsigned long)(rc + 1)); 512 retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
512 513 } else {
513 retcode = ((unsigned long)rc) + thumb; 514 /*
515 * Ensure that the instruction cache sees
516 * the return code written onto the stack.
517 */
518 flush_icache_range((unsigned long)rc,
519 (unsigned long)(rc + 1));
520
521 retcode = ((unsigned long)rc) + thumb;
522 }
514 } 523 }
515 524
516 regs->ARM_r0 = usig; 525 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 @@
1/*
2 * linux/arch/arm/kernel/signal.h
3 *
4 * Copyright (C) 2005 Russell King.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10#define KERN_SIGRETURN_CODE 0xffff0500
11
12extern 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 @@
30#include <asm/traps.h> 30#include <asm/traps.h>
31 31
32#include "ptrace.h" 32#include "ptrace.h"
33#include "signal.h"
33 34
34const char *processor_modes[]= 35const char *processor_modes[]=
35{ "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" , 36{ "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)
683 memcpy((void *)0xffff0000, __vectors_start, __vectors_end - __vectors_start); 684 memcpy((void *)0xffff0000, __vectors_start, __vectors_end - __vectors_start);
684 memcpy((void *)0xffff0200, __stubs_start, __stubs_end - __stubs_start); 685 memcpy((void *)0xffff0200, __stubs_start, __stubs_end - __stubs_start);
685 memcpy((void *)0xffff1000 - kuser_sz, __kuser_helper_start, kuser_sz); 686 memcpy((void *)0xffff1000 - kuser_sz, __kuser_helper_start, kuser_sz);
687
688 /*
689 * Copy signal return handlers into the vector page, and
690 * set sigreturn to be a pointer to these.
691 */
692 memcpy((void *)KERN_SIGRETURN_CODE, sigreturn_codes,
693 sizeof(sigreturn_codes));
694
686 flush_icache_range(0xffff0000, 0xffff0000 + PAGE_SIZE); 695 flush_icache_range(0xffff0000, 0xffff0000 + PAGE_SIZE);
687 modify_domain(DOMAIN_USER, DOMAIN_CLIENT); 696 modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
688} 697}