arm64: ptrace: fix compat registes get/set to be endian clean

On a BE system the wrong half of the X registers is retrieved/written
when attempting to get/set the value of aarch32 registers through
ptrace.

Ensure that types are the correct width so that the relevant
casting occurs.

Signed-off-by: Matthew Leach <matthew.leach@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index fecdbf7..6777a21 100644 (file)
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -636,28 +636,27 @@ static int compat_gpr_get(struct task_struct *target,
 
        for (i = 0; i < num_regs; ++i) {
                unsigned int idx = start + i;
-               void *reg;
+               compat_ulong_t reg;
 
                switch (idx) {
                case 15:
-                       reg = (void *)&task_pt_regs(target)->pc;
+                       reg = task_pt_regs(target)->pc;
                        break;
                case 16:
-                       reg = (void *)&task_pt_regs(target)->pstate;
+                       reg = task_pt_regs(target)->pstate;
                        break;
                case 17:
-                       reg = (void *)&task_pt_regs(target)->orig_x0;
+                       reg = task_pt_regs(target)->orig_x0;
                        break;
                default:
-                       reg = (void *)&task_pt_regs(target)->regs[idx];
+                       reg = task_pt_regs(target)->regs[idx];
                }
 
-               ret = copy_to_user(ubuf, reg, sizeof(compat_ulong_t));
-
+               ret = copy_to_user(ubuf, &reg, sizeof(reg));
                if (ret)
                        break;
-               else
-                       ubuf += sizeof(compat_ulong_t);
+
+               ubuf += sizeof(reg);
        }
 
        return ret;
@@ -685,28 +684,28 @@ static int compat_gpr_set(struct task_struct *target,
 
        for (i = 0; i < num_regs; ++i) {
                unsigned int idx = start + i;
-               void *reg;
+               compat_ulong_t reg;
+
+               ret = copy_from_user(&reg, ubuf, sizeof(reg));
+               if (ret)
+                       return ret;
+
+               ubuf += sizeof(reg);
 
                switch (idx) {
                case 15:
-                       reg = (void *)&newregs.pc;
+                       newregs.pc = reg;
                        break;
                case 16:
-                       reg = (void *)&newregs.pstate;
+                       newregs.pstate = reg;
                        break;
                case 17:
-                       reg = (void *)&newregs.orig_x0;
+                       newregs.orig_x0 = reg;
                        break;
                default:
-                       reg = (void *)&newregs.regs[idx];
+                       newregs.regs[idx] = reg;
                }
 
-               ret = copy_from_user(reg, ubuf, sizeof(compat_ulong_t));
-
-               if (ret)
-                       goto out;
-               else
-                       ubuf += sizeof(compat_ulong_t);
        }
 
        if (valid_user_regs(&newregs.user_regs))
@@ -714,7 +713,6 @@ static int compat_gpr_set(struct task_struct *target,
        else
                ret = -EINVAL;
 
-out:
        return ret;
 }