powerpc/uaccess: Use unsafe wrappers for ASM GOTO

ASM GOTO is miscompiled by GCC when it is used inside a auto cleanup scope:

bool foo(u32 __user *p, u32 val)
{
	scoped_guard(pagefault)
		unsafe_put_user(val, p, efault);
	return true;
efault:
	return false;
}

It ends up leaking the pagefault disable counter in the fault path. clang
at least fails the build.

Rename unsafe_*_user() to arch_unsafe_*_user() which makes the generic
uaccess header wrap it with a local label that makes both compilers emit
correct code. Same for the kernel_nofault() variants.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027083745.356628509@linutronix.de

diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index 4f5a46a77fa2b63dbeb726ece66e9ac0966a6c95..784a00e681fa37fc86f794cd068f8d8fd76fba26 100644 (file)
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -451,7 +451,7 @@ user_write_access_begin(const void __user *ptr, size_t len)
 #define user_write_access_begin        user_write_access_begin
 #define user_write_access_end          prevent_current_write_to_user
 
-#define unsafe_get_user(x, p, e) do {                                  \
+#define arch_unsafe_get_user(x, p, e) do {                     \
        __long_type(*(p)) __gu_val;                             \
        __typeof__(*(p)) __user *__gu_addr = (p);               \
                                                                \
@@ -459,7 +459,7 @@ user_write_access_begin(const void __user *ptr, size_t len)
        (x) = (__typeof__(*(p)))__gu_val;                       \
 } while (0)
 
-#define unsafe_put_user(x, p, e) \
+#define arch_unsafe_put_user(x, p, e)                          \
        __put_user_size_goto((__typeof__(*(p)))(x), (p), sizeof(*(p)), e)
 
 #define unsafe_copy_from_user(d, s, l, e) \
@@ -504,11 +504,11 @@ do {                                                                      \
                unsafe_put_user(*(u8*)(_src + _i), (u8 __user *)(_dst + _i), e); \
 } while (0)
 
-#define __get_kernel_nofault(dst, src, type, err_label)                        \
+#define arch_get_kernel_nofault(dst, src, type, err_label)             \
        __get_user_size_goto(*((type *)(dst)),                          \
                (__force type __user *)(src), sizeof(type), err_label)
 
-#define __put_kernel_nofault(dst, src, type, err_label)                        \
+#define arch_put_kernel_nofault(dst, src, type, err_label)             \
        __put_user_size_goto(*((type *)(src)),                          \
                (__force type __user *)(dst), sizeof(type), err_label)