From dc802c2d2e66e2d1544e023bfd4be6cdee48d57b Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Wed, 30 Jan 2008 13:30:53 +0100 Subject: [PATCH] ptrace: arch_has_block_step This defines the new macro arch_has_block_step() in linux/ptrace.h, a default for when asm/ptrace.h does not define it. This is the analog of arch_has_single_step() for step-until-branch on machines that have it. It declares the new user_enable_block_step function, which goes with the existing user_enable_single_step and user_disable_single_step. 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 | 37 +++++++++++++++++++++++++++++++++---- 1 file changed, 33 insertions(+), 4 deletions(-) diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index 8f06c6fb22..1febc541dd 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -155,7 +155,8 @@ int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data); * * 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. + * next single instruction executes. If arch_has_block_step() is defined, + * this must clear the effects of user_enable_block_step() too. */ static inline void user_enable_single_step(struct task_struct *task) { @@ -166,15 +167,43 @@ static inline void user_enable_single_step(struct task_struct *task) * 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. + * Clear @task of the effects of user_enable_single_step() and + * user_enable_block_step(). This can be called whether or not either + * of those 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 */ +#ifndef arch_has_block_step +/** + * arch_has_block_step - does this CPU support user-mode block-step? + * + * If this is defined, then there must be a function declaration or inline + * for user_enable_block_step(), and arch_has_single_step() must be defined + * too. arch_has_block_step() should evaluate to nonzero iff the machine + * supports step-until-branch for user mode. It can be a constant or it + * can test a CPU feature bit. + */ +#define arch_has_single_step() (0) + +/** + * user_enable_block_step - step until branch in user-mode task + * @task: either current or a task stopped in %TASK_TRACED + * + * This can only be called when arch_has_block_step() has returned nonzero, + * and will never be called when single-instruction stepping is being used. + * Set @task so that when it returns to user mode, it will trap after the + * next branch or trap taken. + */ +static inline void user_enable_block_step(struct task_struct *task) +{ + BUG(); /* This can never be called. */ +} +#endif /* arch_has_block_step */ + #endif #endif -- 2.39.5