From afb94c9e0b413bbdea779192eaca076c43ede031 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Mon, 13 Feb 2017 19:42:31 -0600 Subject: [PATCH] livepatch/x86: add TIF_PATCH_PENDING thread flag Add the TIF_PATCH_PENDING thread flag to enable the new livepatch per-task consistency model for x86_64. The bit getting set indicates the thread has a pending patch which needs to be applied when the thread exits the kernel. The bit is placed in the _TIF_ALLWORK_MASK macro, which results in exit_to_usermode_loop() calling klp_update_patch_state() when it's set. Signed-off-by: Josh Poimboeuf Acked-by: Andy Lutomirski Reviewed-by: Petr Mladek Reviewed-by: Miroslav Benes Reviewed-by: Kamalesh Babulal Acked-by: Ingo Molnar # for the x86 changes Signed-off-by: Jiri Kosina --- arch/x86/entry/common.c | 9 ++++++--- arch/x86/include/asm/thread_info.h | 4 +++- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index 370c42c7f046..cdefcfdd9e63 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include @@ -130,14 +131,13 @@ static long syscall_trace_enter(struct pt_regs *regs) #define EXIT_TO_USERMODE_LOOP_FLAGS \ (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE | \ - _TIF_NEED_RESCHED | _TIF_USER_RETURN_NOTIFY) + _TIF_NEED_RESCHED | _TIF_USER_RETURN_NOTIFY | _TIF_PATCH_PENDING) static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags) { /* * In order to return to user mode, we need to have IRQs off with - * none of _TIF_SIGPENDING, _TIF_NOTIFY_RESUME, _TIF_USER_RETURN_NOTIFY, - * _TIF_UPROBE, or _TIF_NEED_RESCHED set. Several of these flags + * none of EXIT_TO_USERMODE_LOOP_FLAGS set. Several of these flags * can be set at any time on preemptable kernels if we have IRQs on, * so we need to loop. Disabling preemption wouldn't help: doing the * work to clear some of the flags can sleep. @@ -164,6 +164,9 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags) if (cached_flags & _TIF_USER_RETURN_NOTIFY) fire_user_return_notifiers(); + if (cached_flags & _TIF_PATCH_PENDING) + klp_update_patch_state(current); + /* Disable IRQs and retry */ local_irq_disable(); diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 207d0d981287..83372dc43943 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -84,6 +84,7 @@ struct thread_info { #define TIF_SECCOMP 8 /* secure computing */ #define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */ #define TIF_UPROBE 12 /* breakpointed or singlestepping */ +#define TIF_PATCH_PENDING 13 /* pending live patching update */ #define TIF_NOTSC 16 /* TSC is not accessible in userland */ #define TIF_IA32 17 /* IA32 compatibility process */ #define TIF_NOHZ 19 /* in adaptive nohz mode */ @@ -107,6 +108,7 @@ struct thread_info { #define _TIF_SECCOMP (1 << TIF_SECCOMP) #define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY) #define _TIF_UPROBE (1 << TIF_UPROBE) +#define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING) #define _TIF_NOTSC (1 << TIF_NOTSC) #define _TIF_IA32 (1 << TIF_IA32) #define _TIF_NOHZ (1 << TIF_NOHZ) @@ -133,7 +135,7 @@ struct thread_info { (_TIF_SYSCALL_TRACE | _TIF_NOTIFY_RESUME | _TIF_SIGPENDING | \ _TIF_NEED_RESCHED | _TIF_SINGLESTEP | _TIF_SYSCALL_EMU | \ _TIF_SYSCALL_AUDIT | _TIF_USER_RETURN_NOTIFY | _TIF_UPROBE | \ - _TIF_NOHZ | _TIF_SYSCALL_TRACEPOINT) + _TIF_PATCH_PENDING | _TIF_NOHZ | _TIF_SYSCALL_TRACEPOINT) /* flags to check in __switch_to() */ #define _TIF_WORK_CTXSW \ -- 2.20.1