x86/uaccess: Move variable into switch case statement

When building with automatic stack variable initialization, GCC 12
complains about variables defined outside of switch case statements.
Move the variable into the case that uses it, which silences the warning:

./arch/x86/include/asm/uaccess.h:317:23: warning: statement will never be executed [-Wswitch-unreachable]
  317 |         unsigned char x_u8__; \
      |                       ^~~~~~

Fixes: 865c50e1d279 ("x86/uaccess: utilize CONFIG_CC_HAS_ASM_GOTO_OUTPUT")
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211209043456.1377875-1-keescook@chromium.org

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 33a68407def3f535334e968779bbcef1b9bfb9bf..8ab9e79abb2b4c9707ec0945fdf088c870f343f8 100644 (file)
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -314,11 +314,12 @@ do {                                                                      \
 do {                                                                   \
        __chk_user_ptr(ptr);                                            \
        switch (size) {                                                 \
-       unsigned char x_u8__;                                           \
-       case 1:                                                         \
+       case 1: {                                                       \
+               unsigned char x_u8__;                                   \
                __get_user_asm(x_u8__, ptr, "b", "=q", label);          \
                (x) = x_u8__;                                           \
                break;                                                  \
+       }                                                               \
        case 2:                                                         \
                __get_user_asm(x, ptr, "w", "=r", label);               \
                break;                                                  \