linux-kernel - [PATCH v2 12/13] asm-generic: uaccess: 1-byte access is always aligned

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Date:   Fri, 14 May 2021 12:01:00 +0200
From:   Arnd Bergmann <arnd@...nel.org>
To:     linux-arch@...r.kernel.org
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Vineet Gupta <vgupta@...opsys.com>,
        Arnd Bergmann <arnd@...db.de>, linux-kernel@...r.kernel.org
Subject: [PATCH v2 12/13] asm-generic: uaccess: 1-byte access is always aligned

From: Arnd Bergmann <arnd@...db.de>

With the cleaned up version of asm-generic/unaligned.h,
there is a warning about the get_user/put_user helpers using
unaligned access for single-byte variables:

include/asm-generic/uaccess.h: In function ‘__get_user_fn’:
include/asm-generic/unaligned.h:13:15: warning: ‘packed’ attribute ignored for field of type ‘u8’ {aka ‘unsigned char’} [-Wattributes]
  const struct { type x __packed; } *__pptr = (typeof(__pptr))(ptr); \

Change these to use a direct pointer dereference to avoid the
warnings.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 include/asm-generic/uaccess.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h
index 4973328f3c6e..7e903e450659 100644
--- a/include/asm-generic/uaccess.h
+++ b/include/asm-generic/uaccess.h
@@ -19,7 +19,7 @@ __get_user_fn(size_t size, const void __user *from, void *to)
 
 	switch (size) {
 	case 1:
-		*(u8 *)to = get_unaligned((u8 __force *)from);
+		*(u8 *)to = *((u8 __force *)from);
 		return 0;
 	case 2:
 		*(u16 *)to = get_unaligned((u16 __force *)from);
@@ -45,7 +45,7 @@ __put_user_fn(size_t size, void __user *to, void *from)
 
 	switch (size) {
 	case 1:
-		put_unaligned(*(u8 *)from, (u8 __force *)to);
+		*(*(u8 *)from, (u8 __force *)to);
 		return 0;
 	case 2:
 		put_unaligned(*(u16 *)from, (u16 __force *)to);
-- 
2.29.2