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authorLinus Torvalds <torvalds@linux-foundation.org>2012-08-01 16:35:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-08-01 16:35:37 -0700
commit02a6ec6a24077ffda33b99cb193e8a536b90711d (patch)
tree567d2a81e4482085ef2b5e4c692483ca9108e0c0
parent9a2533c3eb91b3e769c2612c5d68e811bfc0ecf6 (diff)
parentc7aa00db074e4961b49277d7d0fc2f5367d914ca (diff)
downloadlinux-sh-02a6ec6a24077ffda33b99cb193e8a536b90711d.tar.gz
Merge branch 'audit' of git://git.linaro.org/people/rmk/linux-arm
Pull ARM audit/signal updates from Russell King: "ARM audit/signal handling updates from Al and Will. This improves on the work Viro did last merge window, and sorts out some of the issues found with that work." * 'audit' of git://git.linaro.org/people/rmk/linux-arm: ARM: 7475/1: sys_trace: allow all syscall arguments to be updated via ptrace ARM: 7474/1: get rid of TIF_SYSCALL_RESTARTSYS ARM: 7473/1: deal with handlerless restarts without leaving the kernel ARM: 7472/1: pull all work_pending logics into C function ARM: 7471/1: Revert "7442/1: Revert "remove unused restart trampoline"" ARM: 7470/1: Revert "7443/1: Revert "new way of handling ERESTART_RESTARTBLOCK""
-rw-r--r--arch/arm/kernel/entry-common.S24
-rw-r--r--arch/arm/kernel/ptrace.c1
-rw-r--r--arch/arm/kernel/signal.c114
-rw-r--r--arch/arm/kernel/signal.h2
-rw-r--r--arch/arm/kernel/traps.c2
5 files changed, 58 insertions, 85 deletions
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 49d9f9305247..978eac57e04a 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -51,23 +51,15 @@ ret_fast_syscall:
fast_work_pending:
str r0, [sp, #S_R0+S_OFF]! @ returned r0
work_pending:
- tst r1, #_TIF_NEED_RESCHED
- bne work_resched
- /*
- * TIF_SIGPENDING or TIF_NOTIFY_RESUME must've been set if we got here
- */
- ldr r2, [sp, #S_PSR]
mov r0, sp @ 'regs'
- tst r2, #15 @ are we returning to user mode?
- bne no_work_pending @ no? just leave, then...
mov r2, why @ 'syscall'
- tst r1, #_TIF_SIGPENDING @ delivering a signal?
- movne why, #0 @ prevent further restarts
- bl do_notify_resume
- b ret_slow_syscall @ Check work again
+ bl do_work_pending
+ cmp r0, #0
+ beq no_work_pending
+ movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
+ ldmia sp, {r0 - r6} @ have to reload r0 - r6
+ b local_restart @ ... and off we go
-work_resched:
- bl schedule
/*
* "slow" syscall return path. "why" tells us if this was a real syscall.
*/
@@ -409,6 +401,7 @@ ENTRY(vector_swi)
eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
#endif
+local_restart:
ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
stmdb sp!, {r4, r5} @ push fifth and sixth args
@@ -450,7 +443,8 @@ __sys_trace:
mov scno, r0 @ syscall number (possibly new)
add r1, sp, #S_R0 + S_OFF @ pointer to regs
cmp scno, #NR_syscalls @ check upper syscall limit
- ldmccia r1, {r0 - r3} @ have to reload r0 - r3
+ ldmccia r1, {r0 - r6} @ have to reload r0 - r6
+ stmccia sp, {r4, r5} @ and update the stack args
ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
b 2b
diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index dab711e6e1ca..3e0fc5f7ed4b 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -25,6 +25,7 @@
#include <linux/regset.h>
#include <linux/audit.h>
#include <linux/tracehook.h>
+#include <linux/unistd.h>
#include <asm/pgtable.h>
#include <asm/traps.h>
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 536c5d6b340b..f27789e4e38a 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -27,7 +27,6 @@
*/
#define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE))
#define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE))
-#define SWI_SYS_RESTART (0xef000000|__NR_restart_syscall|__NR_OABI_SYSCALL_BASE)
/*
* With EABI, the syscall number has to be loaded into r7.
@@ -48,18 +47,6 @@ const unsigned long sigreturn_codes[7] = {
};
/*
- * Either we support OABI only, or we have EABI with the OABI
- * compat layer enabled. In the later case we don't know if
- * user space is EABI or not, and if not we must not clobber r7.
- * Always using the OABI syscall solves that issue and works for
- * all those cases.
- */
-const unsigned long syscall_restart_code[2] = {
- SWI_SYS_RESTART, /* swi __NR_restart_syscall */
- 0xe49df004, /* ldr pc, [sp], #4 */
-};
-
-/*
* atomically swap in the new signal mask, and wait for a signal.
*/
asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask)
@@ -582,12 +569,13 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
* the kernel can handle, and then we build all the user-level signal handling
* stack-frames in one go after that.
*/
-static void do_signal(struct pt_regs *regs, int syscall)
+static int do_signal(struct pt_regs *regs, int syscall)
{
unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
struct k_sigaction ka;
siginfo_t info;
int signr;
+ int restart = 0;
/*
* If we were from a system call, check for system call restarting...
@@ -602,15 +590,15 @@ static void do_signal(struct pt_regs *regs, int syscall)
* debugger will see the already changed PSW.
*/
switch (retval) {
+ case -ERESTART_RESTARTBLOCK:
+ restart -= 2;
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
+ restart++;
regs->ARM_r0 = regs->ARM_ORIG_r0;
regs->ARM_pc = restart_addr;
break;
- case -ERESTART_RESTARTBLOCK:
- regs->ARM_r0 = -EINTR;
- break;
}
}
@@ -619,14 +607,17 @@ static void do_signal(struct pt_regs *regs, int syscall)
* point the debugger may change all our registers ...
*/
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
+ /*
+ * Depending on the signal settings we may need to revert the
+ * decision to restart the system call. But skip this if a
+ * debugger has chosen to restart at a different PC.
+ */
+ if (regs->ARM_pc != restart_addr)
+ restart = 0;
if (signr > 0) {
- /*
- * Depending on the signal settings we may need to revert the
- * decision to restart the system call. But skip this if a
- * debugger has chosen to restart at a different PC.
- */
- if (regs->ARM_pc == restart_addr) {
- if (retval == -ERESTARTNOHAND
+ if (unlikely(restart)) {
+ if (retval == -ERESTARTNOHAND ||
+ retval == -ERESTART_RESTARTBLOCK
|| (retval == -ERESTARTSYS
&& !(ka.sa.sa_flags & SA_RESTART))) {
regs->ARM_r0 = -EINTR;
@@ -635,52 +626,43 @@ static void do_signal(struct pt_regs *regs, int syscall)
}
handle_signal(signr, &ka, &info, regs);
- return;
- }
-
- if (syscall) {
- /*
- * Handle restarting a different system call. As above,
- * if a debugger has chosen to restart at a different PC,
- * ignore the restart.
- */
- if (retval == -ERESTART_RESTARTBLOCK
- && regs->ARM_pc == continue_addr) {
- if (thumb_mode(regs)) {
- regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
- regs->ARM_pc -= 2;
- } else {
-#if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
- regs->ARM_r7 = __NR_restart_syscall;
- regs->ARM_pc -= 4;
-#else
- u32 __user *usp;
-
- regs->ARM_sp -= 4;
- usp = (u32 __user *)regs->ARM_sp;
-
- if (put_user(regs->ARM_pc, usp) == 0) {
- regs->ARM_pc = KERN_RESTART_CODE;
- } else {
- regs->ARM_sp += 4;
- force_sigsegv(0, current);
- }
-#endif
- }
- }
+ return 0;
}
restore_saved_sigmask();
+ if (unlikely(restart))
+ regs->ARM_pc = continue_addr;
+ return restart;
}
-asmlinkage void
-do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
+asmlinkage int
+do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
{
- if (thread_flags & _TIF_SIGPENDING)
- do_signal(regs, syscall);
-
- if (thread_flags & _TIF_NOTIFY_RESUME) {
- clear_thread_flag(TIF_NOTIFY_RESUME);
- tracehook_notify_resume(regs);
- }
+ do {
+ if (likely(thread_flags & _TIF_NEED_RESCHED)) {
+ schedule();
+ } else {
+ if (unlikely(!user_mode(regs)))
+ return 0;
+ local_irq_enable();
+ if (thread_flags & _TIF_SIGPENDING) {
+ int restart = do_signal(regs, syscall);
+ if (unlikely(restart)) {
+ /*
+ * Restart without handlers.
+ * Deal with it without leaving
+ * the kernel space.
+ */
+ return restart;
+ }
+ syscall = 0;
+ } else {
+ clear_thread_flag(TIF_NOTIFY_RESUME);
+ tracehook_notify_resume(regs);
+ }
+ }
+ local_irq_disable();
+ thread_flags = current_thread_info()->flags;
+ } while (thread_flags & _TIF_WORK_MASK);
+ return 0;
}
diff --git a/arch/arm/kernel/signal.h b/arch/arm/kernel/signal.h
index 6fcfe8398aa4..5ff067b7c752 100644
--- a/arch/arm/kernel/signal.h
+++ b/arch/arm/kernel/signal.h
@@ -8,7 +8,5 @@
* published by the Free Software Foundation.
*/
#define KERN_SIGRETURN_CODE (CONFIG_VECTORS_BASE + 0x00000500)
-#define KERN_RESTART_CODE (KERN_SIGRETURN_CODE + sizeof(sigreturn_codes))
extern const unsigned long sigreturn_codes[7];
-extern const unsigned long syscall_restart_code[2];
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 7978d4f0f3ae..f7945218b8c6 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -844,8 +844,6 @@ void __init early_trap_init(void *vectors_base)
*/
memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE),
sigreturn_codes, sizeof(sigreturn_codes));
- memcpy((void *)(vectors + KERN_RESTART_CODE - CONFIG_VECTORS_BASE),
- syscall_restart_code, sizeof(syscall_restart_code));
flush_icache_range(vectors, vectors + PAGE_SIZE);
modify_domain(DOMAIN_USER, DOMAIN_CLIENT);