arm64/traps: Avoid unnecessary kernel/user pointer conversion

Annotating a pointer from kernel to __user and then back again requires
an extra __force annotation to silent sparse warning. In call_undef_hook()
this unnecessary complexity can be avoided by modifying the intermediate
user pointer to unsigned long.

This way there is no inter-changeable use of user and kernel pointers
and the code is consistent.

Note: This patch adds no functional changes to code.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210917055811.22341-1-amit.kachhap@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index b03e383..0923675 100644 (file)
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -400,11 +400,11 @@ static int call_undef_hook(struct pt_regs *regs)
        unsigned long flags;
        u32 instr;
        int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
-       void __user *pc = (void __user *)instruction_pointer(regs);
+       unsigned long pc = instruction_pointer(regs);
 
        if (!user_mode(regs)) {
                __le32 instr_le;
-               if (get_kernel_nofault(instr_le, (__force __le32 *)pc))
+               if (get_kernel_nofault(instr_le, (__le32 *)pc))
                        goto exit;
                instr = le32_to_cpu(instr_le);
        } else if (compat_thumb_mode(regs)) {