x86-64 ptrace: use task_pt_regs

This cleans up the 64-bit ptrace code to use task_pt_regs instead of its
own redundant code that does the same thing a different way.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 12 insertions, 48 deletions

diff --git a/arch/x86/kernel/ptrace_64.c b/arch/x86/kernel/ptrace_64.c
index b129b1fbb5d9..d0a0aeaaa0c2 100644
--- a/arch/x86/kernel/ptrace_64.c
+++ b/arch/x86/kernel/ptrace_64.c
@@ -43,44 +43,6 @@
 #define FLAG_MASK 0x54dd5UL
 
 /*
- * eflags and offset of eflags on child stack..
- */
-#define EFLAGS offsetof(struct pt_regs, eflags)
-#define EFL_OFFSET ((int)(EFLAGS-sizeof(struct pt_regs)))
-
-/*
- * this routine will get a word off of the processes privileged stack. 
- * the offset is how far from the base addr as stored in the TSS.  
- * this routine assumes that all the privileged stacks are in our
- * data space.
- */   
-static inline unsigned long get_stack_long(struct task_struct *task, int offset)
-{
-        unsigned char *stack;
-
-        stack = (unsigned char *)task->thread.rsp0;
-        stack += offset;
-        return (*((unsigned long *)stack));
-}
-
-/*
- * this routine will put a word on the processes privileged stack. 
- * the offset is how far from the base addr as stored in the TSS.  
- * this routine assumes that all the privileged stacks are in our
- * data space.
- */
-static inline long put_stack_long(struct task_struct *task, int offset,
-        unsigned long data)
-{
-        unsigned char * stack;
-
-        stack = (unsigned char *) task->thread.rsp0;
-        stack += offset;
-        *(unsigned long *) stack = data;
-        return 0;
-}
-
-/*
  * Called by kernel/ptrace.c when detaching..
  *
  * Make sure the single step bit is not set.
@@ -90,11 +52,16 @@ void ptrace_disable(struct task_struct *child)
         user_disable_single_step(child);
 }
 
+static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long offset)
+{
+        BUILD_BUG_ON(offsetof(struct pt_regs, r15) != 0);
+        return &regs->r15 + (offset / sizeof(regs->r15));
+}
+
 static int putreg(struct task_struct *child,
         unsigned long regno, unsigned long value)
 {
-        unsigned long tmp; 
-        
+        struct pt_regs *regs = task_pt_regs(child);
         switch (regno) {
                 case offsetof(struct user_regs_struct,fs):
                         if (value && (value & 3) != 3)
@@ -152,9 +119,7 @@ static int putreg(struct task_struct *child,
                                 clear_tsk_thread_flag(child, TIF_FORCED_TF);
                         else if (test_tsk_thread_flag(child, TIF_FORCED_TF))
                                 value |= X86_EFLAGS_TF;
-                        tmp = get_stack_long(child, EFL_OFFSET); 
-                        tmp &= ~FLAG_MASK; 
-                        value |= tmp;
+                        value |= regs->eflags & ~FLAG_MASK;
                         break;
                 case offsetof(struct user_regs_struct,cs): 
                         if ((value & 3) != 3)
@@ -162,12 +127,13 @@ static int putreg(struct task_struct *child,
                         value &= 0xffff;
                         break;
         }
-        put_stack_long(child, regno - sizeof(struct pt_regs), value);
+        *pt_regs_access(regs, regno) = value;
         return 0;
 }
 
 static unsigned long getreg(struct task_struct *child, unsigned long regno)
 {
+        struct pt_regs *regs = task_pt_regs(child);
         unsigned long val;
         switch (regno) {
                 case offsetof(struct user_regs_struct, fs):
@@ -202,16 +168,14 @@ static unsigned long getreg(struct task_struct *child, unsigned long regno)
                         /*
                          * If the debugger set TF, hide it from the readout.
                          */
-                        regno = regno - sizeof(struct pt_regs);
-                        val = get_stack_long(child, regno);
+                        val = regs->eflags;
                         if (test_tsk_thread_flag(child, TIF_IA32))
                                 val &= 0xffffffff;
                         if (test_tsk_thread_flag(child, TIF_FORCED_TF))
                                 val &= ~X86_EFLAGS_TF;
                         return val;
                 default:
-                        regno = regno - sizeof(struct pt_regs);
-                        val = get_stack_long(child, regno);
+                        val = *pt_regs_access(regs, regno);
                         if (test_tsk_thread_flag(child, TIF_IA32))
                                 val &= 0xffffffff;
                         return val;