From fb7fa8f1741c91f6c6e958762155abe9339476ca Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Wed, 30 Jan 2008 13:30:47 +0100 Subject: [PATCH] ptrace: arch_has_single_step This defines the new macro arch_has_single_step() in linux/ptrace.h, a default for when asm/ptrace.h does not define it. It declares the new user_enable_single_step and user_disable_single_step functions. This is not used yet, but paves the way to harmonize on this interface for the arch-specific calls on all machines. Signed-off-by: Roland McGrath Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- include/linux/ptrace.h | 46 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index 3ea5750a0f7e..8f06c6fb22a5 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -129,6 +129,52 @@ int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data); #define force_successful_syscall_return() do { } while (0) #endif +/* + * should define the following things inside #ifdef __KERNEL__. + * + * These do-nothing inlines are used when the arch does not + * implement single-step. The kerneldoc comments are here + * to document the interface for all arch definitions. + */ + +#ifndef arch_has_single_step +/** + * arch_has_single_step - does this CPU support user-mode single-step? + * + * If this is defined, then there must be function declarations or + * inlines for user_enable_single_step() and user_disable_single_step(). + * arch_has_single_step() should evaluate to nonzero iff the machine + * supports instruction single-step for user mode. + * It can be a constant or it can test a CPU feature bit. + */ +#define arch_has_single_step() (0) + +/** + * user_enable_single_step - single-step in user-mode task + * @task: either current or a task stopped in %TASK_TRACED + * + * This can only be called when arch_has_single_step() has returned nonzero. + * Set @task so that when it returns to user mode, it will trap after the + * next single instruction executes. + */ +static inline void user_enable_single_step(struct task_struct *task) +{ + BUG(); /* This can never be called. */ +} + +/** + * user_disable_single_step - cancel user-mode single-step + * @task: either current or a task stopped in %TASK_TRACED + * + * Clear @task of the effects of user_enable_single_step(). This can + * be called whether or not user_enable_single_step() was ever called + * on @task, and even if arch_has_single_step() returned zero. + */ +static inline void user_disable_single_step(struct task_struct *task) +{ +} +#endif /* arch_has_single_step */ + #endif #endif -- 2.20.1