From 30d64f1904d44a7e52a93d711d57aabbac2efd72 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Mon, 13 Feb 2017 19:42:33 -0600 Subject: livepatch/s390: reorganize TIF thread flag bits Group the TIF thread flag bits by their inclusion in the _TIF_WORK and _TIF_TRACE macros. Signed-off-by: Jiri Slaby Signed-off-by: Josh Poimboeuf Reviewed-by: Miroslav Benes Acked-by: Heiko Carstens Signed-off-by: Jiri Kosina --- arch/s390/include/asm/thread_info.h | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) (limited to 'arch/s390') diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h index a5b54a445eb8..4977668788d7 100644 --- a/arch/s390/include/asm/thread_info.h +++ b/arch/s390/include/asm/thread_info.h @@ -51,14 +51,12 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); /* * thread information flags bit numbers */ +/* _TIF_WORK bits */ #define TIF_NOTIFY_RESUME 0 /* callback before returning to user */ #define TIF_SIGPENDING 1 /* signal pending */ #define TIF_NEED_RESCHED 2 /* rescheduling necessary */ -#define TIF_SYSCALL_TRACE 3 /* syscall trace active */ -#define TIF_SYSCALL_AUDIT 4 /* syscall auditing active */ -#define TIF_SECCOMP 5 /* secure computing */ -#define TIF_SYSCALL_TRACEPOINT 6 /* syscall tracepoint instrumentation */ -#define TIF_UPROBE 7 /* breakpointed or single-stepping */ +#define TIF_UPROBE 3 /* breakpointed or single-stepping */ + #define TIF_31BIT 16 /* 32bit process */ #define TIF_MEMDIE 17 /* is terminating due to OOM killer */ #define TIF_RESTORE_SIGMASK 18 /* restore signal mask in do_signal() */ @@ -66,15 +64,23 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); #define TIF_BLOCK_STEP 20 /* This task is block stepped */ #define TIF_UPROBE_SINGLESTEP 21 /* This task is uprobe single stepped */ +/* _TIF_TRACE bits */ +#define TIF_SYSCALL_TRACE 24 /* syscall trace active */ +#define TIF_SYSCALL_AUDIT 25 /* syscall auditing active */ +#define TIF_SECCOMP 26 /* secure computing */ +#define TIF_SYSCALL_TRACEPOINT 27 /* syscall tracepoint instrumentation */ + #define _TIF_NOTIFY_RESUME _BITUL(TIF_NOTIFY_RESUME) #define _TIF_SIGPENDING _BITUL(TIF_SIGPENDING) #define _TIF_NEED_RESCHED _BITUL(TIF_NEED_RESCHED) +#define _TIF_UPROBE _BITUL(TIF_UPROBE) + +#define _TIF_31BIT _BITUL(TIF_31BIT) +#define _TIF_SINGLE_STEP _BITUL(TIF_SINGLE_STEP) + #define _TIF_SYSCALL_TRACE _BITUL(TIF_SYSCALL_TRACE) #define _TIF_SYSCALL_AUDIT _BITUL(TIF_SYSCALL_AUDIT) #define _TIF_SECCOMP _BITUL(TIF_SECCOMP) #define _TIF_SYSCALL_TRACEPOINT _BITUL(TIF_SYSCALL_TRACEPOINT) -#define _TIF_UPROBE _BITUL(TIF_UPROBE) -#define _TIF_31BIT _BITUL(TIF_31BIT) -#define _TIF_SINGLE_STEP _BITUL(TIF_SINGLE_STEP) #endif /* _ASM_THREAD_INFO_H */ -- cgit v1.2.3 From 2f09ca60a56dd9c217d32d68340e1b08cbbe1ace Mon Sep 17 00:00:00 2001 From: Miroslav Benes Date: Mon, 13 Feb 2017 19:42:34 -0600 Subject: livepatch/s390: add TIF_PATCH_PENDING thread flag Update a task's patch state when returning from a system call or user space interrupt, or after handling a signal. This greatly increases the chances of a patch operation succeeding. If a task is I/O bound, it can be patched when returning from a system call. If a task is CPU bound, it can be patched when returning from an interrupt. If a task is sleeping on a to-be-patched function, the user can send SIGSTOP and SIGCONT to force it to switch. Since there are two ways the syscall can be restarted on return from a signal handling process, it is important to clear the flag before do_signal() is called. Otherwise we could miss the migration if we used SIGSTOP/SIGCONT procedure or fake signal to migrate patching blocking tasks. If we place our hook to sysc_work label in entry before TIF_SIGPENDING is evaluated we kill two birds with one stone. The task is correctly migrated in all return paths from a syscall. Signed-off-by: Miroslav Benes Signed-off-by: Josh Poimboeuf Acked-by: Heiko Carstens Signed-off-by: Jiri Kosina --- arch/s390/include/asm/thread_info.h | 2 ++ arch/s390/kernel/entry.S | 31 ++++++++++++++++++++++++++++++- 2 files changed, 32 insertions(+), 1 deletion(-) (limited to 'arch/s390') diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h index 4977668788d7..646845edf148 100644 --- a/arch/s390/include/asm/thread_info.h +++ b/arch/s390/include/asm/thread_info.h @@ -56,6 +56,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); #define TIF_SIGPENDING 1 /* signal pending */ #define TIF_NEED_RESCHED 2 /* rescheduling necessary */ #define TIF_UPROBE 3 /* breakpointed or single-stepping */ +#define TIF_PATCH_PENDING 4 /* pending live patching update */ #define TIF_31BIT 16 /* 32bit process */ #define TIF_MEMDIE 17 /* is terminating due to OOM killer */ @@ -74,6 +75,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); #define _TIF_SIGPENDING _BITUL(TIF_SIGPENDING) #define _TIF_NEED_RESCHED _BITUL(TIF_NEED_RESCHED) #define _TIF_UPROBE _BITUL(TIF_UPROBE) +#define _TIF_PATCH_PENDING _BITUL(TIF_PATCH_PENDING) #define _TIF_31BIT _BITUL(TIF_31BIT) #define _TIF_SINGLE_STEP _BITUL(TIF_SINGLE_STEP) diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index dff2152350a7..a08b5eea5567 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -47,7 +47,7 @@ STACK_SIZE = 1 << STACK_SHIFT STACK_INIT = STACK_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE _TIF_WORK = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \ - _TIF_UPROBE) + _TIF_UPROBE | _TIF_PATCH_PENDING) _TIF_TRACE = (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \ _TIF_SYSCALL_TRACEPOINT) _CIF_WORK = (_CIF_MCCK_PENDING | _CIF_ASCE_PRIMARY | \ @@ -334,6 +334,11 @@ ENTRY(system_call) #endif TSTMSK __PT_FLAGS(%r11),_PIF_PER_TRAP jo .Lsysc_singlestep +#ifdef CONFIG_LIVEPATCH + TSTMSK __TI_flags(%r12),_TIF_PATCH_PENDING + jo .Lsysc_patch_pending # handle live patching just before + # signals and possible syscall restart +#endif TSTMSK __TI_flags(%r12),_TIF_SIGPENDING jo .Lsysc_sigpending TSTMSK __TI_flags(%r12),_TIF_NOTIFY_RESUME @@ -408,6 +413,16 @@ ENTRY(system_call) jg uprobe_notify_resume #endif +# +# _TIF_PATCH_PENDING is set, call klp_update_patch_state +# +#ifdef CONFIG_LIVEPATCH +.Lsysc_patch_pending: + lg %r2,__LC_CURRENT # pass pointer to task struct + larl %r14,.Lsysc_return + jg klp_update_patch_state +#endif + # # _PIF_PER_TRAP is set, call do_per_trap # @@ -659,6 +674,10 @@ ENTRY(io_int_handler) jo .Lio_mcck_pending TSTMSK __TI_flags(%r12),_TIF_NEED_RESCHED jo .Lio_reschedule +#ifdef CONFIG_LIVEPATCH + TSTMSK __TI_flags(%r12),_TIF_PATCH_PENDING + jo .Lio_patch_pending +#endif TSTMSK __TI_flags(%r12),_TIF_SIGPENDING jo .Lio_sigpending TSTMSK __TI_flags(%r12),_TIF_NOTIFY_RESUME @@ -707,6 +726,16 @@ ENTRY(io_int_handler) TRACE_IRQS_OFF j .Lio_return +# +# _TIF_PATCH_PENDING is set, call klp_update_patch_state +# +#ifdef CONFIG_LIVEPATCH +.Lio_patch_pending: + lg %r2,__LC_CURRENT # pass pointer to task struct + larl %r14,.Lio_return + jg klp_update_patch_state +#endif + # # _TIF_SIGPENDING or is set, call do_signal # -- cgit v1.2.3