From 36a033082b5243d45d508c5ccd47a754edbc6821 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Fri, 14 Mar 2008 17:46:38 -0700 Subject: [PATCH 1/7] x86: tracehook_signal_handler This makes the x86 signal handling code use tracehook_signal_handler() in place of calling into ptrace guts. The call is moved after the sa_mask processing, but there is no other change. This cleanup doesn't matter to existing debuggers, but is the sensible thing: have all facets of the handler setup complete before the debugger inspects the task again. Signed-off-by: Roland McGrath --- arch/x86/kernel/signal_32.c | 6 ++++-- arch/x86/kernel/signal_64.c | 6 ++++-- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/signal_32.c b/arch/x86/kernel/signal_32.c index 6fb5bcdd8933..22aae1683c14 100644 --- a/arch/x86/kernel/signal_32.c +++ b/arch/x86/kernel/signal_32.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include #include @@ -558,8 +559,6 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, * handler too. */ regs->flags &= ~X86_EFLAGS_TF; - if (test_thread_flag(TIF_SINGLESTEP)) - ptrace_notify(SIGTRAP); spin_lock_irq(¤t->sighand->siglock); sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask); @@ -568,6 +567,9 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); + tracehook_signal_handler(sig, info, ka, regs, + test_thread_flag(TIF_SINGLESTEP)); + return 0; } diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c index b45ef8ddd651..3beb2db88c5a 100644 --- a/arch/x86/kernel/signal_64.c +++ b/arch/x86/kernel/signal_64.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -444,8 +445,6 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, * handler too. */ regs->flags &= ~X86_EFLAGS_TF; - if (test_thread_flag(TIF_SINGLESTEP)) - ptrace_notify(SIGTRAP); spin_lock_irq(¤t->sighand->siglock); sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); @@ -453,6 +452,9 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, sigaddset(¤t->blocked,sig); recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); + + tracehook_signal_handler(sig, info, ka, regs, + test_thread_flag(TIF_SINGLESTEP)); } return ret; From eeea3c3ff8af7f6960a0515d46dff6479bdb91f9 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Sun, 16 Mar 2008 23:36:28 -0700 Subject: [PATCH 2/7] x86: tracehook syscall This changes x86 syscall tracing to use the new tracehook.h entry points. There is no change, only cleanup. Signed-off-by: Roland McGrath --- arch/x86/kernel/ptrace.c | 34 ++++++---------------------------- 1 file changed, 6 insertions(+), 28 deletions(-) diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index e37dccce85db..19a7d2c40560 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -1375,30 +1376,6 @@ void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code) force_sig_info(SIGTRAP, &info, tsk); } -static void syscall_trace(struct pt_regs *regs) -{ - if (!(current->ptrace & PT_PTRACED)) - return; - -#if 0 - printk("trace %s ip %lx sp %lx ax %d origrax %d caller %lx tiflags %x ptrace %x\n", - current->comm, - regs->ip, regs->sp, regs->ax, regs->orig_ax, __builtin_return_address(0), - current_thread_info()->flags, current->ptrace); -#endif - - ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) - ? 0x80 : 0)); - /* - * this isn't the same as continuing with a signal, but it will do - * for normal use. strace only continues with a signal if the - * stopping signal is not SIGTRAP. -brl - */ - if (current->exit_code) { - send_sig(current->exit_code, current, 1); - current->exit_code = 0; - } -} #ifdef CONFIG_X86_32 # define IS_IA32 1 @@ -1432,8 +1409,9 @@ asmregparm long syscall_trace_enter(struct pt_regs *regs) if (unlikely(test_thread_flag(TIF_SYSCALL_EMU))) ret = -1L; - if (ret || test_thread_flag(TIF_SYSCALL_TRACE)) - syscall_trace(regs); + if ((ret || test_thread_flag(TIF_SYSCALL_TRACE)) && + tracehook_report_syscall_entry(regs)) + ret = -1L; if (unlikely(current->audit_context)) { if (IS_IA32) @@ -1459,7 +1437,7 @@ asmregparm void syscall_trace_leave(struct pt_regs *regs) audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax); if (test_thread_flag(TIF_SYSCALL_TRACE)) - syscall_trace(regs); + tracehook_report_syscall_exit(regs, 0); /* * If TIF_SYSCALL_EMU is set, we only get here because of @@ -1475,6 +1453,6 @@ asmregparm void syscall_trace_leave(struct pt_regs *regs) * system call instruction. */ if (test_thread_flag(TIF_SINGLESTEP) && - (current->ptrace & PT_PTRACED)) + tracehook_consider_fatal_signal(current, SIGTRAP, SIG_DFL)) send_sigtrap(current, regs, 0); } From 68bd0f4ef7750fc277e1268bf40f443898382409 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Fri, 18 Apr 2008 17:08:44 -0700 Subject: [PATCH 3/7] x86: tracehook: asm/syscall.h Add asm/syscall.h for x86 with all the required entry points. This will allow arch-independent tracing code for system calls. Signed-off-by: Roland McGrath --- include/asm-x86/ptrace.h | 5 + include/asm-x86/syscall.h | 210 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 215 insertions(+) create mode 100644 include/asm-x86/syscall.h diff --git a/include/asm-x86/ptrace.h b/include/asm-x86/ptrace.h index 8a71db803da6..91a77f5c4678 100644 --- a/include/asm-x86/ptrace.h +++ b/include/asm-x86/ptrace.h @@ -213,6 +213,11 @@ static inline unsigned long frame_pointer(struct pt_regs *regs) return regs->bp; } +static inline unsigned long user_stack_pointer(struct pt_regs *regs) +{ + return regs->sp; +} + /* * These are defined as per linux/ptrace.h, which see. */ diff --git a/include/asm-x86/syscall.h b/include/asm-x86/syscall.h new file mode 100644 index 000000000000..6f293892895a --- /dev/null +++ b/include/asm-x86/syscall.h @@ -0,0 +1,210 @@ +/* + * Access to user system call parameters and results + * + * Copyright (C) 2008 Red Hat, Inc. All rights reserved. + * + * This copyrighted material is made available to anyone wishing to use, + * modify, copy, or redistribute it subject to the terms and conditions + * of the GNU General Public License v.2. + * + * See asm-generic/syscall.h for descriptions of what we must do here. + */ + +#ifndef _ASM_SYSCALL_H +#define _ASM_SYSCALL_H 1 + +#include + +static inline long syscall_get_nr(struct task_struct *task, + struct pt_regs *regs) +{ + /* + * We always sign-extend a -1 value being set here, + * so this is always either -1L or a syscall number. + */ + return regs->orig_ax; +} + +static inline void syscall_rollback(struct task_struct *task, + struct pt_regs *regs) +{ + regs->ax = regs->orig_ax; +} + +static inline long syscall_get_error(struct task_struct *task, + struct pt_regs *regs) +{ + unsigned long error = regs->ax; +#ifdef CONFIG_IA32_EMULATION + /* + * TS_COMPAT is set for 32-bit syscall entries and then + * remains set until we return to user mode. + */ + if (task_thread_info(task)->status & TS_COMPAT) + /* + * Sign-extend the value so (int)-EFOO becomes (long)-EFOO + * and will match correctly in comparisons. + */ + error = (long) (int) error; +#endif + return error >= -4095L ? error : 0; +} + +static inline long syscall_get_return_value(struct task_struct *task, + struct pt_regs *regs) +{ + return regs->ax; +} + +static inline void syscall_set_return_value(struct task_struct *task, + struct pt_regs *regs, + int error, long val) +{ + regs->ax = (long) error ?: val; +} + +#ifdef CONFIG_X86_32 + +static inline void syscall_get_arguments(struct task_struct *task, + struct pt_regs *regs, + unsigned int i, unsigned int n, + unsigned long *args) +{ + BUG_ON(i + n > 6); + memcpy(args, ®s->bx + i, n * sizeof(args[0])); +} + +static inline void syscall_set_arguments(struct task_struct *task, + struct pt_regs *regs, + unsigned int i, unsigned int n, + const unsigned long *args) +{ + BUG_ON(i + n > 6); + memcpy(®s->bx + i, args, n * sizeof(args[0])); +} + +#else /* CONFIG_X86_64 */ + +static inline void syscall_get_arguments(struct task_struct *task, + struct pt_regs *regs, + unsigned int i, unsigned int n, + unsigned long *args) +{ +# ifdef CONFIG_IA32_EMULATION + if (task_thread_info(task)->status & TS_COMPAT) + switch (i + n) { + case 6: + if (!n--) break; + *args++ = regs->bp; + case 5: + if (!n--) break; + *args++ = regs->di; + case 4: + if (!n--) break; + *args++ = regs->si; + case 3: + if (!n--) break; + *args++ = regs->dx; + case 2: + if (!n--) break; + *args++ = regs->cx; + case 1: + if (!n--) break; + *args++ = regs->bx; + case 0: + if (!n--) break; + default: + BUG(); + break; + } + else +# endif + switch (i + n) { + case 6: + if (!n--) break; + *args++ = regs->r9; + case 5: + if (!n--) break; + *args++ = regs->r8; + case 4: + if (!n--) break; + *args++ = regs->r10; + case 3: + if (!n--) break; + *args++ = regs->dx; + case 2: + if (!n--) break; + *args++ = regs->si; + case 1: + if (!n--) break; + *args++ = regs->di; + case 0: + if (!n--) break; + default: + BUG(); + break; + } +} + +static inline void syscall_set_arguments(struct task_struct *task, + struct pt_regs *regs, + unsigned int i, unsigned int n, + const unsigned long *args) +{ +# ifdef CONFIG_IA32_EMULATION + if (task_thread_info(task)->status & TS_COMPAT) + switch (i + n) { + case 6: + if (!n--) break; + regs->bp = *args++; + case 5: + if (!n--) break; + regs->di = *args++; + case 4: + if (!n--) break; + regs->si = *args++; + case 3: + if (!n--) break; + regs->dx = *args++; + case 2: + if (!n--) break; + regs->cx = *args++; + case 1: + if (!n--) break; + regs->bx = *args++; + case 0: + if (!n--) break; + default: + BUG(); + } + else +# endif + switch (i + n) { + case 6: + if (!n--) break; + regs->r9 = *args++; + case 5: + if (!n--) break; + regs->r8 = *args++; + case 4: + if (!n--) break; + regs->r10 = *args++; + case 3: + if (!n--) break; + regs->dx = *args++; + case 2: + if (!n--) break; + regs->si = *args++; + case 1: + if (!n--) break; + regs->di = *args++; + case 0: + if (!n--) break; + default: + BUG(); + } +} + +#endif /* CONFIG_X86_32 */ + +#endif /* _ASM_SYSCALL_H */ From 4dfcbb997aa9f3a6a3ed8c192f0dac28b027e08f Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Sat, 19 Apr 2008 15:37:09 -0700 Subject: [PATCH 4/7] x86 signals: use asm/syscall.h Replace local inlines with the asm/syscall.h interfaces that do the same things. Signed-off-by: Roland McGrath --- arch/x86/kernel/signal_64.c | 38 +++++-------------------------------- 1 file changed, 5 insertions(+), 33 deletions(-) diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c index 3beb2db88c5a..cb7cf0216ab7 100644 --- a/arch/x86/kernel/signal_64.c +++ b/arch/x86/kernel/signal_64.c @@ -27,6 +27,7 @@ #include #include #include +#include #include "sigframe.h" #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) @@ -346,35 +347,6 @@ give_sigsegv: return -EFAULT; } -/* - * Return -1L or the syscall number that @regs is executing. - */ -static long current_syscall(struct pt_regs *regs) -{ - /* - * We always sign-extend a -1 value being set here, - * so this is always either -1L or a syscall number. - */ - return regs->orig_ax; -} - -/* - * Return a value that is -EFOO if the system call in @regs->orig_ax - * returned an error. This only works for @regs from @current. - */ -static long current_syscall_ret(struct pt_regs *regs) -{ -#ifdef CONFIG_IA32_EMULATION - if (test_thread_flag(TIF_IA32)) - /* - * Sign-extend the value so (int)-EFOO becomes (long)-EFOO - * and will match correctly in comparisons. - */ - return (int) regs->ax; -#endif - return regs->ax; -} - /* * OK, we're invoking a handler */ @@ -386,9 +358,9 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, int ret; /* Are we from a system call? */ - if (current_syscall(regs) >= 0) { + if (syscall_get_nr(current, regs) >= 0) { /* If so, check system call restarting.. */ - switch (current_syscall_ret(regs)) { + switch (syscall_get_error(current, regs)) { case -ERESTART_RESTARTBLOCK: case -ERESTARTNOHAND: regs->ax = -EINTR; @@ -511,9 +483,9 @@ static void do_signal(struct pt_regs *regs) } /* Did we come from a system call? */ - if (current_syscall(regs) >= 0) { + if (syscall_get_nr(current, regs) >= 0) { /* Restart the system call - no handlers present */ - switch (current_syscall_ret(regs)) { + switch (syscall_get_error(current, regs)) { case -ERESTARTNOHAND: case -ERESTARTSYS: case -ERESTARTNOINTR: From 59e52130f04537d2c80ea44bb007cadd1ad29543 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Sat, 19 Apr 2008 19:10:57 -0700 Subject: [PATCH 5/7] x86: tracehook: TIF_NOTIFY_RESUME This adds TIF_NOTIFY_RESUME support for x86, both 64-bit and 32-bit. When set, we call tracehook_notify_resume() on the way to user mode. Signed-off-by: Roland McGrath --- arch/x86/kernel/signal_32.c | 5 +++++ arch/x86/kernel/signal_64.c | 5 +++++ include/asm-x86/thread_info.h | 4 +++- 3 files changed, 13 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/signal_32.c b/arch/x86/kernel/signal_32.c index 22aae1683c14..4445d26efd47 100644 --- a/arch/x86/kernel/signal_32.c +++ b/arch/x86/kernel/signal_32.c @@ -663,5 +663,10 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs); + if (thread_info_flags & _TIF_NOTIFY_RESUME) { + clear_thread_flag(TIF_NOTIFY_RESUME); + tracehook_notify_resume(regs); + } + clear_thread_flag(TIF_IRET); } diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c index cb7cf0216ab7..d01e3f6ef26d 100644 --- a/arch/x86/kernel/signal_64.c +++ b/arch/x86/kernel/signal_64.c @@ -523,6 +523,11 @@ void do_notify_resume(struct pt_regs *regs, void *unused, /* deal with pending signal delivery */ if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs); + + if (thread_info_flags & _TIF_NOTIFY_RESUME) { + clear_thread_flag(TIF_NOTIFY_RESUME); + tracehook_notify_resume(regs); + } } void signal_fault(struct pt_regs *regs, void __user *frame, char *where) diff --git a/include/asm-x86/thread_info.h b/include/asm-x86/thread_info.h index da0a675adf94..4cd5b7bdc8cc 100644 --- a/include/asm-x86/thread_info.h +++ b/include/asm-x86/thread_info.h @@ -71,6 +71,7 @@ struct thread_info { * Warning: layout of LSW is hardcoded in entry.S */ #define TIF_SYSCALL_TRACE 0 /* syscall trace active */ +#define TIF_NOTIFY_RESUME 1 /* callback before returning to user */ #define TIF_SIGPENDING 2 /* signal pending */ #define TIF_NEED_RESCHED 3 /* rescheduling necessary */ #define TIF_SINGLESTEP 4 /* reenable singlestep on user return*/ @@ -93,6 +94,7 @@ struct thread_info { #define TIF_BTS_TRACE_TS 27 /* record scheduling event timestamps */ #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) +#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) #define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP) #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) @@ -133,7 +135,7 @@ struct thread_info { /* Only used for 64 bit */ #define _TIF_DO_NOTIFY_MASK \ - (_TIF_SIGPENDING|_TIF_MCE_NOTIFY) + (_TIF_SIGPENDING|_TIF_MCE_NOTIFY|_TIF_NOTIFY_RESUME) /* flags to check in __switch_to() */ #define _TIF_WORK_CTXSW \ From 99bbc4b1e677ac695431e8d9c8e710ef391c567f Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Sun, 20 Apr 2008 14:35:12 -0700 Subject: [PATCH 6/7] x86: tracehook: CONFIG_HAVE_ARCH_TRACEHOOK The x86 arch code has all the prerequisites, so set HAVE_ARCH_TRACEHOOK. Signed-off-by: Roland McGrath --- arch/x86/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index b6fa2877b173..f463a8a3b21f 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -30,6 +30,7 @@ config X86 select HAVE_FTRACE select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64) select HAVE_ARCH_KGDB if !X86_VOYAGER + select HAVE_ARCH_TRACEHOOK select HAVE_EFFICIENT_UNALIGNED_ACCESS config ARCH_DEFCONFIG From 4ab4ba32aa16b012cb0faabf1a27952508fe67f2 Mon Sep 17 00:00:00 2001 From: Petr Tesarik Date: Wed, 3 Sep 2008 13:31:42 +0200 Subject: [PATCH 7/7] x86, tracehook: clean up implementation of syscall_get_error() The x86-tracehook code now contains this line in syscall_get_error(): return error >= -4095L ? error : 0; Hard-wiring a constant is not nice. Let's use the IS_ERR_VALUE macro from linux/err.h instead. Signed-off-by: Petr Tesarik Cc: utrace-devel@redhat.com Acked-by: Roland McGrath Signed-off-by: Ingo Molnar --- include/asm-x86/syscall.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/asm-x86/syscall.h b/include/asm-x86/syscall.h index 6f293892895a..04c47dc5597c 100644 --- a/include/asm-x86/syscall.h +++ b/include/asm-x86/syscall.h @@ -14,6 +14,7 @@ #define _ASM_SYSCALL_H 1 #include +#include static inline long syscall_get_nr(struct task_struct *task, struct pt_regs *regs) @@ -47,7 +48,7 @@ static inline long syscall_get_error(struct task_struct *task, */ error = (long) (int) error; #endif - return error >= -4095L ? error : 0; + return IS_ERR_VALUE(error) ? error : 0; } static inline long syscall_get_return_value(struct task_struct *task,