Blackfin: simplify PTRACE_{PEEK,POKE}USR in preperation for regset support

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

2 files changed, 53 insertions, 67 deletions

diff --git a/arch/blackfin/include/asm/ptrace.h b/arch/blackfin/include/asm/ptrace.h
index b33a4488f498..c1aebdb981c7 100644
--- a/arch/blackfin/include/asm/ptrace.h
+++ b/arch/blackfin/include/asm/ptrace.h
@@ -173,4 +173,6 @@ extern void show_regs(struct pt_regs *);
 #define PT_FDPIC_EXEC 232
 #define PT_FDPIC_INTERP 236
 
+#define PT_LAST_PSEUDO PT_FDPIC_INTERP
+
 #endif                          /* _BFIN_PTRACE_H */
diff --git a/arch/blackfin/kernel/ptrace.c b/arch/blackfin/kernel/ptrace.c
index 14118e40f18f..9536c1e2d1c7 100644
--- a/arch/blackfin/kernel/ptrace.c
+++ b/arch/blackfin/kernel/ptrace.c
@@ -25,7 +25,6 @@
 #include <asm/cacheflush.h>
 #include <asm/mem_map.h>
 
-#define TEXT_OFFSET 0
 /*
  * does not yet catch signals sent when the child dies.
  * in exit.c or in signal.c.
@@ -43,7 +42,7 @@
  * kernel stack will not be empty on entry to the kernel, so
  * ptracing these tasks will fail.
  */
-static inline struct pt_regs *get_user_regs(struct task_struct *task)
+static inline struct pt_regs *task_pt_regs(struct task_struct *task)
 {
         return (struct pt_regs *)
             ((unsigned long)task_stack_page(task) +
@@ -56,7 +55,7 @@ static inline struct pt_regs *get_user_regs(struct task_struct *task)
 static inline int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
 {
         struct pt_regs regs;
-        memcpy(&regs, get_user_regs(tsk), sizeof(regs));
+        memcpy(&regs, task_pt_regs(tsk), sizeof(regs));
         regs.usp = tsk->thread.usp;
         return copy_to_user(uregs, &regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
 }
@@ -69,40 +68,49 @@ static inline int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
 /*
  * Get contents of register REGNO in task TASK.
  */
-static inline long get_reg(struct task_struct *task, int regno)
+static inline long
+get_reg(struct task_struct *task, long regno, unsigned long __user *datap)
 {
-        unsigned char *reg_ptr;
+        long tmp;
+        struct pt_regs *regs = task_pt_regs(task);
 
-        struct pt_regs *regs =
-            (struct pt_regs *)((unsigned long)task_stack_page(task) +
-                               (THREAD_SIZE - sizeof(struct pt_regs)));
-        reg_ptr = (char *)regs;
+        if (regno & 3 || regno > PT_LAST_PSEUDO || regno < 0)
+                return -EIO;
 
         switch (regno) {
+        case PT_TEXT_ADDR:
+                tmp = task->mm->start_code;
+                break;
+        case PT_TEXT_END_ADDR:
+                tmp = task->mm->end_code;
+                break;
+        case PT_DATA_ADDR:
+                tmp = task->mm->start_data;
+                break;
         case PT_USP:
-                return task->thread.usp;
+                tmp = task->thread.usp;
+                break;
         default:
-                if (regno <= 216)
-                        return *(long *)(reg_ptr + regno);
+                if (regno < sizeof(*regs)) {
+                        void *reg_ptr = regs;
+                        tmp = *(long *)(reg_ptr + regno);
+                } else
+                        return -EIO;
         }
-        /* slight mystery ... never seems to come here but kernel misbehaves without this code! */
 
-        printk(KERN_WARNING "Request to get for unknown register %d\n", regno);
-        return 0;
+        return put_user(tmp, datap);
 }
 
 /*
  * Write contents of register REGNO in task TASK.
  */
 static inline int
-put_reg(struct task_struct *task, int regno, unsigned long data)
+put_reg(struct task_struct *task, long regno, unsigned long data)
 {
-        char *reg_ptr;
+        struct pt_regs *regs = task_pt_regs(task);
 
-        struct pt_regs *regs =
-            (struct pt_regs *)((unsigned long)task_stack_page(task) +
-                               (THREAD_SIZE - sizeof(struct pt_regs)));
-        reg_ptr = (char *)regs;
+        if (regno & 3 || regno > PT_LAST_PSEUDO || regno < 0)
+                return -EIO;
 
         switch (regno) {
         case PT_PC:
@@ -119,10 +127,18 @@ put_reg(struct task_struct *task, int regno, unsigned long data)
                 regs->usp = data;
                 task->thread.usp = data;
                 break;
+        case PT_SYSCFG: /* don't let userspace screw with this */
+                if ((data & ~1) != 0x6)
+                        pr_warning("ptrace: ignore syscfg write of %#lx\n", data);
+                break;          /* regs->syscfg = data; break; */
         default:
-                if (regno <= 216)
-                        *(long *)(reg_ptr + regno) = data;
+                if (regno < sizeof(*regs)) {
+                        void *reg_offset = regs;
+                        *(long *)(reg_offset + regno) = data;
+                }
+                /* Ignore writes to pseudo registers */
         }
+
         return 0;
 }
 
@@ -231,40 +247,6 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                         break;
                 }
 
-                /* read the word at location addr in the USER area. */
-        case PTRACE_PEEKUSR:
-                {
-                        unsigned long tmp;
-                        ret = -EIO;
-                        tmp = 0;
-                        if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
-                                printk(KERN_WARNING "ptrace error : PEEKUSR : temporarily returning "
-                                                    "0 - %x sizeof(pt_regs) is %lx\n",
-                                     (int)addr, sizeof(struct pt_regs));
-                                break;
-                        }
-                        if (addr == sizeof(struct pt_regs)) {
-                                /* PT_TEXT_ADDR */
-                                tmp = child->mm->start_code + TEXT_OFFSET;
-                        } else if (addr == (sizeof(struct pt_regs) + 4)) {
-                                /* PT_TEXT_END_ADDR */
-                                tmp = child->mm->end_code;
-                        } else if (addr == (sizeof(struct pt_regs) + 8)) {
-                                /* PT_DATA_ADDR */
-                                tmp = child->mm->start_data;
-#ifdef CONFIG_BINFMT_ELF_FDPIC
-                        } else if (addr == (sizeof(struct pt_regs) + 12)) {
-                                goto case_PTRACE_GETFDPIC_EXEC;
-                        } else if (addr == (sizeof(struct pt_regs) + 16)) {
-                                goto case_PTRACE_GETFDPIC_INTERP;
-#endif
-                        } else {
-                                tmp = get_reg(child, addr);
-                        }
-                        ret = put_user(tmp, datap);
-                        break;
-                }
-
 #ifdef CONFIG_BINFMT_ELF_FDPIC
         case PTRACE_GETFDPIC: {
                 unsigned long tmp = 0;
@@ -327,19 +309,21 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                         break;
                 }
 
-        case PTRACE_POKEUSR:    /* write the word at location addr in the USER area */
-                ret = -EIO;
-                if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
-                        printk(KERN_WARNING "ptrace error : POKEUSR: temporarily returning 0\n");
-                        break;
+        case PTRACE_PEEKUSR:
+                switch (addr) {
+#ifdef CONFIG_BINFMT_ELF_FDPIC  /* backwards compat */
+                case PT_FDPIC_EXEC:   goto case_PTRACE_GETFDPIC_EXEC;
+                case PT_FDPIC_INTERP: goto case_PTRACE_GETFDPIC_INTERP;
+#endif
+                default:
+                        ret = get_reg(child, addr, datap);
                 }
+                pr_debug("ptrace: PEEKUSR reg %li with %#lx = %i\n", addr, data, ret);
+                break;
 
-                /* Ignore writes to SYSCFG and other pseudo regs */
-                if (addr >= PT_SYSCFG) {
-                        ret = 0;
-                        break;
-                }
+        case PTRACE_POKEUSR:
                 ret = put_reg(child, addr, data);
+                pr_debug("ptrace: POKEUSR reg %li with %li = %i\n", addr, data, ret);
                 break;
 
         case PTRACE_GETREGS: