This means: * add a per-thread flag to indicate whether a task is in the old or in the new universe, * reset it in _slow_ paths of syscall's entry/exit, * add helpers around the flag to sched.h, * export the status in /proc/<pid>/kgr_in_progress,
This was cherry-picked from the kGraft implementation and will serve as a base for kGraft-like patching in Live Patching. Miroslav helped to clean the assembly up and move to C. Signed-off-by: Jiri Slaby <[email protected]> Cc: Miroslav Benes <[email protected]> Cc: Martin Schwidefsky <[email protected]> Cc: Heiko Carstens <[email protected]> Cc: [email protected] Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: [email protected] --- arch/s390/include/asm/thread_info.h | 2 ++ arch/s390/kernel/Makefile | 1 + arch/s390/kernel/entry.S | 11 +++++++++++ arch/s390/kernel/livepatch.c | 14 ++++++++++++++ arch/x86/include/asm/thread_info.h | 11 +++++++---- arch/x86/kernel/ptrace.c | 7 +++++++ arch/x86/kernel/signal.c | 5 +++++ fs/proc/base.c | 14 ++++++++++++++ include/linux/sched.h | 23 +++++++++++++++++++++++ 9 files changed, 84 insertions(+), 4 deletions(-) create mode 100644 arch/s390/kernel/livepatch.c diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h index 4c27ec764c36..88a559531a7b 100644 --- a/arch/s390/include/asm/thread_info.h +++ b/arch/s390/include/asm/thread_info.h @@ -82,6 +82,7 @@ void arch_release_task_struct(struct task_struct *tsk); #define TIF_SINGLE_STEP 19 /* This task is single stepped */ #define TIF_BLOCK_STEP 20 /* This task is block stepped */ #define TIF_UPROBE_SINGLESTEP 21 /* This task is uprobe single stepped */ +#define TIF_KGR_IN_PROGRESS 22 /* This task has not finished patching */ #define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME) #define _TIF_SIGPENDING (1<<TIF_SIGPENDING) @@ -93,6 +94,7 @@ void arch_release_task_struct(struct task_struct *tsk); #define _TIF_UPROBE (1<<TIF_UPROBE) #define _TIF_31BIT (1<<TIF_31BIT) #define _TIF_SINGLE_STEP (1<<TIF_SINGLE_STEP) +#define _TIF_KGR_IN_PROGRESS (1<<TIF_KGR_IN_PROGRESS) #define is_32bit_task() (test_thread_flag(TIF_31BIT)) diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile index ffb87617a36c..ff3ecac94ebe 100644 --- a/arch/s390/kernel/Makefile +++ b/arch/s390/kernel/Makefile @@ -45,6 +45,7 @@ obj-$(CONFIG_AUDIT) += audit.o compat-obj-$(CONFIG_AUDIT) += compat_audit.o obj-$(CONFIG_COMPAT) += compat_linux.o compat_signal.o obj-$(CONFIG_COMPAT) += compat_wrapper.o $(compat-obj-y) +obj-$(CONFIG_LIVEPATCH) += livepatch.o obj-$(CONFIG_STACKTRACE) += stacktrace.o obj-$(CONFIG_KPROBES) += kprobes.o diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 99b44acbfcc7..f4be8e142a50 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -73,6 +73,15 @@ _PIF_WORK = (_PIF_PER_TRAP) #endif .endm + .macro HANDLE_KGRAFT TI_reg +#if IS_ENABLED(CONFIG_LIVEPATCH) + tm __TI_flags+5(\TI_reg),(_TIF_KGR_IN_PROGRESS >> 16) + jz 0f + brasl %r14,s390_handle_kgraft +0: +#endif + .endm + .macro LPP newpp #if IS_ENABLED(CONFIG_KVM) tm __LC_MACHINE_FLAGS+6,0x20 # MACHINE_FLAG_LPP @@ -217,6 +226,7 @@ ENTRY(system_call) mvc __PT_INT_CODE(4,%r11),__LC_SVC_ILC stg %r14,__PT_FLAGS(%r11) .Lsysc_do_svc: + HANDLE_KGRAFT %r12 lg %r10,__TI_sysc_table(%r12) # address of system call table llgh %r8,__PT_INT_CODE+2(%r11) slag %r8,%r8,2 # shift and test for svc 0 @@ -248,6 +258,7 @@ ENTRY(system_call) jnz .Lsysc_work # check for work tm __LC_CPU_FLAGS+7,_CIF_WORK jnz .Lsysc_work + HANDLE_KGRAFT %r12 .Lsysc_restore: lg %r14,__LC_VDSO_PER_CPU lmg %r0,%r10,__PT_R0(%r11) diff --git a/arch/s390/kernel/livepatch.c b/arch/s390/kernel/livepatch.c new file mode 100644 index 000000000000..99ace9df5576 --- /dev/null +++ b/arch/s390/kernel/livepatch.c @@ -0,0 +1,14 @@ +/* + * livepatch.c - s390-specific Kernel Live Patching Core + * + * Copyright (C) 2014-2015 SUSE + * + * This file is licensed under the GPLv2. + */ + +#include <linux/sched.h> + +asmlinkage void s390_handle_kgraft(void) +{ + klp_kgraft_mark_task_safe(current); +} diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index b4bdec3e9523..3dad428caa6b 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -106,6 +106,7 @@ struct thread_info { #define TIF_IO_BITMAP 22 /* uses I/O bitmap */ #define TIF_FORCED_TF 24 /* true if TF in eflags artificially */ #define TIF_BLOCKSTEP 25 /* set when we want DEBUGCTLMSR_BTF */ +#define TIF_KGR_IN_PROGRESS 26 /* kGraft patching running */ #define TIF_LAZY_MMU_UPDATES 27 /* task is updating the mmu lazily */ #define TIF_SYSCALL_TRACEPOINT 28 /* syscall tracepoint instrumentation */ #define TIF_ADDR32 29 /* 32-bit address space on 64 bits */ @@ -129,6 +130,7 @@ struct thread_info { #define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP) #define _TIF_FORCED_TF (1 << TIF_FORCED_TF) #define _TIF_BLOCKSTEP (1 << TIF_BLOCKSTEP) +#define _TIF_KGR_IN_PROGRESS (1 << TIF_KGR_IN_PROGRESS) #define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES) #define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT) #define _TIF_ADDR32 (1 << TIF_ADDR32) @@ -138,7 +140,7 @@ struct thread_info { #define _TIF_WORK_SYSCALL_ENTRY \ (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT | \ _TIF_SECCOMP | _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT | \ - _TIF_NOHZ) + _TIF_NOHZ | _TIF_KGR_IN_PROGRESS) /* work to do in syscall_trace_leave() */ #define _TIF_WORK_SYSCALL_EXIT \ @@ -149,17 +151,18 @@ struct thread_info { #define _TIF_WORK_MASK \ (0x0000FFFF & \ ~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT| \ - _TIF_SINGLESTEP|_TIF_SECCOMP|_TIF_SYSCALL_EMU)) + _TIF_SINGLESTEP|_TIF_SECCOMP|_TIF_SYSCALL_EMU) | \ + _TIF_KGR_IN_PROGRESS) /* work to do on any return to user space */ #define _TIF_ALLWORK_MASK \ ((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT | \ - _TIF_NOHZ) + _TIF_NOHZ | _TIF_KGR_IN_PROGRESS) /* Only used for 64 bit */ #define _TIF_DO_NOTIFY_MASK \ (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | \ - _TIF_USER_RETURN_NOTIFY | _TIF_UPROBE) + _TIF_USER_RETURN_NOTIFY | _TIF_UPROBE | _TIF_KGR_IN_PROGRESS) /* flags to check in __switch_to() */ #define _TIF_WORK_CTXSW \ diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index a7bc79480719..454f4734b840 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -1527,6 +1527,13 @@ unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch) } #endif +#if IS_ENABLED(CONFIG_LIVEPATCH) + if (work & _TIF_KGR_IN_PROGRESS) { + klp_kgraft_mark_task_safe(current); + work &= ~_TIF_KGR_IN_PROGRESS; + } +#endif + /* Do our best to finish without phase 2. */ if (work == 0) return ret; /* seccomp and/or nohz only (ret == 0 here) */ diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 1ea14fd53933..d5e38e2161ac 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -730,6 +730,11 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) if (thread_info_flags & _TIF_UPROBE) uprobe_notify_resume(regs); +#if IS_ENABLED(CONFIG_LIVEPATCH) + if (thread_info_flags & _TIF_KGR_IN_PROGRESS) + klp_kgraft_mark_task_safe(current); +#endif + /* deal with pending signal delivery */ if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs); diff --git a/fs/proc/base.c b/fs/proc/base.c index 093ca14f5701..4973ae795abd 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2052,6 +2052,17 @@ static const struct file_operations proc_timers_operations = { }; #endif /* CONFIG_CHECKPOINT_RESTORE */ +#if IS_ENABLED(CONFIG_LIVEPATCH) +static int proc_pid_kgr_in_progress(struct seq_file *m, + struct pid_namespace *ns, struct pid *pid, + struct task_struct *task) +{ + seq_printf(m, "%d\n", klp_kgraft_task_in_progress(task)); + + return 0; +} +#endif /* IS_ENABLED(CONFIG_LIVEPATCH) */ + static int proc_pident_instantiate(struct inode *dir, struct dentry *dentry, struct task_struct *task, const void *ptr) { @@ -2640,6 +2651,9 @@ static const struct pid_entry tgid_base_stuff[] = { #ifdef CONFIG_CHECKPOINT_RESTORE REG("timers", S_IRUGO, proc_timers_operations), #endif +#if IS_ENABLED(CONFIG_LIVEPATCH) + ONE("kgr_in_progress", S_IRUSR, proc_pid_kgr_in_progress), +#endif }; static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx) diff --git a/include/linux/sched.h b/include/linux/sched.h index 8222ae40ecb0..4c0555261cb1 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -3085,6 +3085,29 @@ static inline void mm_update_next_owner(struct mm_struct *mm) } #endif /* CONFIG_MEMCG */ +#if IS_ENABLED(CONFIG_LIVEPATCH) +static inline void klp_kgraft_mark_task_safe(struct task_struct *p) +{ + clear_tsk_thread_flag(p, TIF_KGR_IN_PROGRESS); +} +static inline void klp_kgraft_mark_task_in_progress(struct task_struct *p) +{ + set_tsk_thread_flag(p, TIF_KGR_IN_PROGRESS); +} + +static inline bool klp_kgraft_task_in_progress(struct task_struct *p) +{ + return test_tsk_thread_flag(p, TIF_KGR_IN_PROGRESS); +} +#else +static inline void klp_kgraft_mark_task_safe(struct task_struct *p) { } +static inline void klp_kgraft_mark_task_in_progress(struct task_struct *p) { } +static inline bool klp_kgraft_task_in_progress(struct task_struct *p) +{ + return false; +} +#endif /* IS_ENABLED(CONFIG_LIVEPATCH) */ + static inline unsigned long task_rlimit(const struct task_struct *tsk, unsigned int limit) { -- 2.3.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
