arm64: ptrace: fix empty registers set in prstatus of aarch32 process core
authorVictor Kamensky <victor.kamensky@linaro.org>
Tue, 3 Jun 2014 18:21:30 +0000 (19:21 +0100)
committerCatalin Marinas <catalin.marinas@arm.com>
Wed, 18 Jun 2014 11:41:14 +0000 (12:41 +0100)
Currently core file of aarch32 process prstatus note has empty
registers set. As result aarch32 core files create by V8 kernel are
not very useful.

It happens because compat_gpr_get and compat_gpr_set functions can
copy registers values to/from either kbuf or ubuf. ELF core file
collection function fill_thread_core_info calls compat_gpr_get
with kbuf set and ubuf set to 0. But current compat_gpr_get and
compat_gpr_set function handle copy to/from only ubuf case.

Fix is to handle kbuf and ubuf as two separate cases in similar
way as other functions like user_regset_copyout, user_regset_copyin do.

Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
arch/arm64/kernel/ptrace.c

index 993cdb7..9fde010 100644 (file)
@@ -655,11 +655,16 @@ static int compat_gpr_get(struct task_struct *target,
                        reg = task_pt_regs(target)->regs[idx];
                }
 
-               ret = copy_to_user(ubuf, &reg, sizeof(reg));
-               if (ret)
-                       break;
-
-               ubuf += sizeof(reg);
+               if (kbuf) {
+                       memcpy(kbuf, &reg, sizeof(reg));
+                       kbuf += sizeof(reg);
+               } else {
+                       ret = copy_to_user(ubuf, &reg, sizeof(reg));
+                       if (ret)
+                               break;
+
+                       ubuf += sizeof(reg);
+               }
        }
 
        return ret;
@@ -689,11 +694,16 @@ static int compat_gpr_set(struct task_struct *target,
                unsigned int idx = start + i;
                compat_ulong_t reg;
 
-               ret = copy_from_user(&reg, ubuf, sizeof(reg));
-               if (ret)
-                       return ret;
+               if (kbuf) {
+                       memcpy(&reg, kbuf, sizeof(reg));
+                       kbuf += sizeof(reg);
+               } else {
+                       ret = copy_from_user(&reg, ubuf, sizeof(reg));
+                       if (ret)
+                               return ret;
 
-               ubuf += sizeof(reg);
+                       ubuf += sizeof(reg);
+               }
 
                switch (idx) {
                case 15: