From e8f263dfd32a784a816fe68956e564f8ede4a9fc Mon Sep 17 00:00:00 2001 From: Mike Frysinger Date: Tue, 26 Jan 2010 07:33:53 +0000 Subject: [PATCH] Blackfin: initial tracehook support Signed-off-by: Mike Frysinger --- arch/blackfin/Kconfig | 1 + arch/blackfin/include/asm/ptrace.h | 23 +++++++ arch/blackfin/include/asm/syscall.h | 96 +++++++++++++++++++++++++++++ arch/blackfin/kernel/ptrace.c | 66 +++++--------------- arch/blackfin/kernel/signal.c | 14 +---- arch/blackfin/mach-common/entry.S | 6 +- 6 files changed, 144 insertions(+), 62 deletions(-) create mode 100644 arch/blackfin/include/asm/syscall.h diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig index 970df5b5c525..c078849df7f9 100644 --- a/arch/blackfin/Kconfig +++ b/arch/blackfin/Kconfig @@ -24,6 +24,7 @@ config RWSEM_XCHGADD_ALGORITHM config BLACKFIN def_bool y select HAVE_ARCH_KGDB + select HAVE_ARCH_TRACEHOOK select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER select HAVE_FUNCTION_TRACE_MCOUNT_TEST diff --git a/arch/blackfin/include/asm/ptrace.h b/arch/blackfin/include/asm/ptrace.h index c1aebdb981c7..aaa1c6c2bc19 100644 --- a/arch/blackfin/include/asm/ptrace.h +++ b/arch/blackfin/include/asm/ptrace.h @@ -24,6 +24,8 @@ #ifndef __ASSEMBLY__ +struct task_struct; + /* this struct defines the way the registers are stored on the stack during a system call. */ @@ -101,9 +103,30 @@ struct pt_regs { master interrupt enable. */ #define user_mode(regs) (!(((regs)->ipend & ~0x10) & (((regs)->ipend & ~0x10) - 1))) #define instruction_pointer(regs) ((regs)->pc) +#define user_stack_pointer(regs) ((regs)->usp) #define profile_pc(regs) instruction_pointer(regs) extern void show_regs(struct pt_regs *); +#define arch_has_single_step() (1) +extern void user_enable_single_step(struct task_struct *child); +extern void user_disable_single_step(struct task_struct *child); +/* common code demands this function */ +#define ptrace_disable(child) user_disable_single_step(child) + +/* + * Get the address of the live pt_regs for the specified task. + * These are saved onto the top kernel stack when the process + * is not running. + * + * Note: if a user thread is execve'd from kernel space, the + * kernel stack will not be empty on entry to the kernel, so + * ptracing these tasks will fail. + */ +#define task_pt_regs(task) \ + (struct pt_regs *) \ + ((unsigned long)task_stack_page(task) + \ + (THREAD_SIZE - sizeof(struct pt_regs))) + #endif /* __KERNEL__ */ #endif /* __ASSEMBLY__ */ diff --git a/arch/blackfin/include/asm/syscall.h b/arch/blackfin/include/asm/syscall.h new file mode 100644 index 000000000000..4921a4815cce --- /dev/null +++ b/arch/blackfin/include/asm/syscall.h @@ -0,0 +1,96 @@ +/* + * Magic syscall break down functions + * + * Copyright 2010 Analog Devices Inc. + * + * Licensed under the GPL-2 or later. + */ + +#ifndef __ASM_BLACKFIN_SYSCALL_H__ +#define __ASM_BLACKFIN_SYSCALL_H__ + +/* + * Blackfin syscalls are simple: + * enter: + * p0: syscall number + * r{0,1,2,3,4,5}: syscall args 0,1,2,3,4,5 + * exit: + * r0: return/error value + */ + +#include +#include +#include + +static inline long +syscall_get_nr(struct task_struct *task, struct pt_regs *regs) +{ + return regs->p0; +} + +static inline void +syscall_rollback(struct task_struct *task, struct pt_regs *regs) +{ + regs->p0 = regs->orig_p0; +} + +static inline long +syscall_get_error(struct task_struct *task, struct pt_regs *regs) +{ + return IS_ERR_VALUE(regs->r0) ? regs->r0 : 0; +} + +static inline long +syscall_get_return_value(struct task_struct *task, struct pt_regs *regs) +{ + return regs->r0; +} + +static inline void +syscall_set_return_value(struct task_struct *task, struct pt_regs *regs, + int error, long val) +{ + regs->r0 = error ? -error : val; +} + +/** + * syscall_get_arguments() + * @task: unused + * @regs: the register layout to extract syscall arguments from + * @i: first syscall argument to extract + * @n: number of syscall arguments to extract + * @args: array to return the syscall arguments in + * + * args[0] gets i'th argument, args[n - 1] gets the i+n-1'th argument + */ +static inline void +syscall_get_arguments(struct task_struct *task, struct pt_regs *regs, + unsigned int i, unsigned int n, unsigned long *args) +{ + /* + * Assume the ptrace layout doesn't change -- r5 is first in memory, + * then r4, ..., then r0. So we simply reverse the ptrace register + * array in memory to store into the args array. + */ + long *aregs = ®s->r0 - i; + + BUG_ON(i > 5 || i + n > 6); + + while (n--) + *args++ = *aregs--; +} + +/* See syscall_get_arguments() comments */ +static inline void +syscall_set_arguments(struct task_struct *task, struct pt_regs *regs, + unsigned int i, unsigned int n, const unsigned long *args) +{ + long *aregs = ®s->r0 - i; + + BUG_ON(i > 5 || i + n > 6); + + while (n--) + *aregs-- = *args++; +} + +#endif diff --git a/arch/blackfin/kernel/ptrace.c b/arch/blackfin/kernel/ptrace.c index 92b4ca0b5af6..0618b8287e34 100644 --- a/arch/blackfin/kernel/ptrace.c +++ b/arch/blackfin/kernel/ptrace.c @@ -1,6 +1,6 @@ /* * linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds - * these modifications are Copyright 2004-2009 Analog Devices Inc. + * these modifications are Copyright 2004-2010 Analog Devices Inc. * * Licensed under the GPL-2 */ @@ -15,6 +15,7 @@ #include #include #include +#include #include #include @@ -32,25 +33,6 @@ * in exit.c or in signal.c. */ -/* Find the stack offset for a register, relative to thread.esp0. */ -#define PT_REG(reg) ((long)&((struct pt_regs *)0)->reg) - -/* - * Get the address of the live pt_regs for the specified task. - * These are saved onto the top kernel stack when the process - * is not running. - * - * Note: if a user thread is execve'd from kernel space, the - * kernel stack will not be empty on entry to the kernel, so - * ptracing these tasks will fail. - */ -static inline struct pt_regs *task_pt_regs(struct task_struct *task) -{ - return (struct pt_regs *) - ((unsigned long)task_stack_page(task) + - (THREAD_SIZE - sizeof(struct pt_regs))); -} - /* * Get contents of register REGNO in task TASK. */ @@ -234,18 +216,13 @@ const struct user_regset_view *task_user_regset_view(struct task_struct *task) return &user_bfin_native_view; } -void ptrace_enable(struct task_struct *child) +void user_enable_single_step(struct task_struct *child) { struct pt_regs *regs = task_pt_regs(child); regs->syscfg |= SYSCFG_SSSTEP; } -/* - * Called by kernel/ptrace.c when detaching.. - * - * Make sure the single step bit is not set. - */ -void ptrace_disable(struct task_struct *child) +void user_disable_single_step(struct task_struct *child) { struct pt_regs *regs = task_pt_regs(child); regs->syscfg &= ~SYSCFG_SSSTEP; @@ -412,27 +389,18 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data) return ret; } -asmlinkage void syscall_trace(void) +asmlinkage int syscall_trace_enter(struct pt_regs *regs) { - if (!test_thread_flag(TIF_SYSCALL_TRACE)) - return; - - if (!(current->ptrace & PT_PTRACED)) - return; - - /* the 0x80 provides a way for the tracing parent to distinguish - * between a syscall stop and SIGTRAP delivery - */ - 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; - } + int ret = 0; + + if (test_thread_flag(TIF_SYSCALL_TRACE)) + ret = tracehook_report_syscall_entry(regs); + + return ret; +} + +asmlinkage void syscall_trace_leave(struct pt_regs *regs) +{ + if (test_thread_flag(TIF_SYSCALL_TRACE)) + tracehook_report_syscall_exit(regs, 0); } diff --git a/arch/blackfin/kernel/signal.c b/arch/blackfin/kernel/signal.c index e0fd63e9e38a..e60990c0a1f0 100644 --- a/arch/blackfin/kernel/signal.c +++ b/arch/blackfin/kernel/signal.c @@ -1,5 +1,5 @@ /* - * Copyright 2004-2009 Analog Devices Inc. + * Copyright 2004-2010 Analog Devices Inc. * * Licensed under the GPL-2 or later */ @@ -206,16 +206,6 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t * info, regs->r1 = (unsigned long)(&frame->info); regs->r2 = (unsigned long)(&frame->uc); - /* - * Clear the trace flag when entering the signal handler, but - * notify any tracer that was single-stepping it. The tracer - * may want to single-step inside the handler too. - */ - if (regs->syscfg & TRACE_BITS) { - regs->syscfg &= ~TRACE_BITS; - ptrace_notify(SIGTRAP); - } - return 0; give_sigsegv: @@ -315,6 +305,8 @@ asmlinkage void do_signal(struct pt_regs *regs) * clear the TIF_RESTORE_SIGMASK flag */ if (test_thread_flag(TIF_RESTORE_SIGMASK)) clear_thread_flag(TIF_RESTORE_SIGMASK); + + tracehook_signal_handler(signr, &info, &ka, regs, 1); } return; diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S index 1fa414f7852f..0df5b834d34e 100644 --- a/arch/blackfin/mach-common/entry.S +++ b/arch/blackfin/mach-common/entry.S @@ -736,7 +736,8 @@ ENDPROC(_system_call) * this symbol need not be global anyways, so ... */ _sys_trace: - pseudo_long_call _syscall_trace, p5; + r0 = sp; + pseudo_long_call _syscall_trace_enter, p5; /* Execute the appropriate system call */ @@ -760,7 +761,8 @@ _sys_trace: SP += 24; [sp + PT_R0] = r0; - pseudo_long_call _syscall_trace, p5; + r0 = sp; + pseudo_long_call _syscall_trace_leave, p5; jump .Lresume_userspace; ENDPROC(_sys_trace) -- 2.39.2