| From 3f4aa45ceea5789a4aade536acc27f2e0d3da5e1 Mon Sep 17 00:00:00 2001 |
| From: Vladimir Murzin <vladimir.murzin@arm.com> |
| Date: Thu, 27 Nov 2014 11:39:04 +0100 |
| Subject: ARM: 8226/1: cacheflush: get rid of restarting block |
| |
| From: Vladimir Murzin <vladimir.murzin@arm.com> |
| |
| commit 3f4aa45ceea5789a4aade536acc27f2e0d3da5e1 upstream. |
| |
| We cannot restart cacheflush safely if a process provides user-defined |
| signal handler and signal is pending. In this case -EINTR is returned |
| and it is expected that process re-invokes syscall. However, there are |
| a few problems with that: |
| * looks like nobody bothers checking return value from cacheflush |
| * but if it did, we don't provide the restart address for that, so the |
| process has to use the same range again |
| * ...and again, what might lead to looping forever |
| |
| So, remove cacheflush restarting code and terminate cache flushing |
| as early as fatal signal is pending. |
| |
| Reported-by: Chanho Min <chanho.min@lge.com> |
| Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> |
| Acked-by: Will Deacon <will.deacon@arm.com> |
| Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/arm/include/asm/thread_info.h | 11 ----------- |
| arch/arm/kernel/traps.c | 31 ++----------------------------- |
| 2 files changed, 2 insertions(+), 40 deletions(-) |
| |
| --- a/arch/arm/include/asm/thread_info.h |
| +++ b/arch/arm/include/asm/thread_info.h |
| @@ -43,16 +43,6 @@ struct cpu_context_save { |
| __u32 extra[2]; /* Xscale 'acc' register, etc */ |
| }; |
| |
| -struct arm_restart_block { |
| - union { |
| - /* For user cache flushing */ |
| - struct { |
| - unsigned long start; |
| - unsigned long end; |
| - } cache; |
| - }; |
| -}; |
| - |
| /* |
| * low level task data that entry.S needs immediate access to. |
| * __switch_to() assumes cpu_context follows immediately after cpu_domain. |
| @@ -78,7 +68,6 @@ struct thread_info { |
| unsigned long thumbee_state; /* ThumbEE Handler Base register */ |
| #endif |
| struct restart_block restart_block; |
| - struct arm_restart_block arm_restart_block; |
| }; |
| |
| #define INIT_THREAD_INFO(tsk) \ |
| --- a/arch/arm/kernel/traps.c |
| +++ b/arch/arm/kernel/traps.c |
| @@ -510,8 +510,6 @@ static int bad_syscall(int n, struct pt_ |
| return regs->ARM_r0; |
| } |
| |
| -static long do_cache_op_restart(struct restart_block *); |
| - |
| static inline int |
| __do_cache_op(unsigned long start, unsigned long end) |
| { |
| @@ -520,24 +518,8 @@ __do_cache_op(unsigned long start, unsig |
| do { |
| unsigned long chunk = min(PAGE_SIZE, end - start); |
| |
| - if (signal_pending(current)) { |
| - struct thread_info *ti = current_thread_info(); |
| - |
| - ti->restart_block = (struct restart_block) { |
| - .fn = do_cache_op_restart, |
| - }; |
| - |
| - ti->arm_restart_block = (struct arm_restart_block) { |
| - { |
| - .cache = { |
| - .start = start, |
| - .end = end, |
| - }, |
| - }, |
| - }; |
| - |
| - return -ERESTART_RESTARTBLOCK; |
| - } |
| + if (fatal_signal_pending(current)) |
| + return 0; |
| |
| ret = flush_cache_user_range(start, start + chunk); |
| if (ret) |
| @@ -550,15 +532,6 @@ __do_cache_op(unsigned long start, unsig |
| return 0; |
| } |
| |
| -static long do_cache_op_restart(struct restart_block *unused) |
| -{ |
| - struct arm_restart_block *restart_block; |
| - |
| - restart_block = ¤t_thread_info()->arm_restart_block; |
| - return __do_cache_op(restart_block->cache.start, |
| - restart_block->cache.end); |
| -} |
| - |
| static inline int |
| do_cache_op(unsigned long start, unsigned long end, int flags) |
| { |