ARM: 7337/1: ptrace: fix ptrace_read_user for !CONFIG_MMU platforms

Commit 68b7f715 ("nommu: ptrace support") added definitions for
PT_TEXT_ADDR and friends, as well as adding ptrace support for reading
from these magic offsets.

Unfortunately, this has probably never worked, since ptrace_read_user
predicates reading on off < sizeof(struct user), returning -EIO
otherwise.

This patch moves the offset size check until after we have tried to
match it against either a magic value or an offset into pt_regs.

Cc: Paul Brook <paul@codesourcery.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index 45956c9..80abafb 100644 (file)
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -256,7 +256,7 @@ static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
 {
        unsigned long tmp;
 
-       if (off & 3 || off >= sizeof(struct user))
+       if (off & 3)
                return -EIO;
 
        tmp = 0;
@@ -268,6 +268,8 @@ static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
                tmp = tsk->mm->end_code;
        else if (off < sizeof(struct pt_regs))
                tmp = get_user_reg(tsk, off >> 2);
+       else if (off >= sizeof(struct user))
+               return -EIO;
 
        return put_user(tmp, ret);
 }