linux/arch/arm/common/sharpsl_param.c
Arnd Bergmann 34186b48d2
ARM: sharpsl_param: work around -Wstringop-overread warning
gcc warns that accessing a pointer based on a numeric constant may
be an offset into a NULL pointer, and would therefore has zero
accessible bytes:

arch/arm/common/sharpsl_param.c: In function ‘sharpsl_save_param’:
arch/arm/common/sharpsl_param.c:43:9: error: ‘memcpy’ reading 64 bytes from a region of size 0 [-Werror=stringop-overread]
   43 |         memcpy(&sharpsl_param, param_start(PARAM_BASE), sizeof(struct sharpsl_param_info));
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In this particular case, the warning is bogus since this is the actual
pointer, not an offset on a NULL pointer. Add a local variable to shut
up the warning and hope it doesn't come back.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Daniel Mack <daniel@zonque.org>
Cc: Daniel Mack <daniel@zonque.org>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Linus Walleij <linus.walleij@linaro.org>
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
Link: https://lore.kernel.org/r/20210927145332.2784005-1-arnd@kernel.org'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2021-10-05 15:44:56 +02:00

64 lines
1.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Hardware parameter area specific to Sharp SL series devices
*
* Copyright (c) 2005 Richard Purdie
*
* Based on Sharp's 2.4 kernel patches
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <asm/mach/sharpsl_param.h>
#include <asm/memory.h>
/*
* Certain hardware parameters determined at the time of device manufacture,
* typically including LCD parameters are loaded by the bootloader at the
* address PARAM_BASE. As the kernel will overwrite them, we need to store
* them early in the boot process, then pass them to the appropriate drivers.
* Not all devices use all parameters but the format is common to all.
*/
#ifdef CONFIG_ARCH_SA1100
#define PARAM_BASE 0xe8ffc000
#define param_start(x) (void *)(x)
#else
#define PARAM_BASE 0xa0000a00
#define param_start(x) __va(x)
#endif
#define MAGIC_CHG(a,b,c,d) ( ( d << 24 ) | ( c << 16 ) | ( b << 8 ) | a )
#define COMADJ_MAGIC MAGIC_CHG('C','M','A','D')
#define UUID_MAGIC MAGIC_CHG('U','U','I','D')
#define TOUCH_MAGIC MAGIC_CHG('T','U','C','H')
#define AD_MAGIC MAGIC_CHG('B','V','A','D')
#define PHAD_MAGIC MAGIC_CHG('P','H','A','D')
struct sharpsl_param_info sharpsl_param;
EXPORT_SYMBOL(sharpsl_param);
void sharpsl_save_param(void)
{
struct sharpsl_param_info *params = param_start(PARAM_BASE);
memcpy(&sharpsl_param, params, sizeof(*params));
if (sharpsl_param.comadj_keyword != COMADJ_MAGIC)
sharpsl_param.comadj=-1;
if (sharpsl_param.phad_keyword != PHAD_MAGIC)
sharpsl_param.phadadj=-1;
if (sharpsl_param.uuid_keyword != UUID_MAGIC)
sharpsl_param.uuid[0]=-1;
if (sharpsl_param.touch_keyword != TOUCH_MAGIC)
sharpsl_param.touch_xp=-1;
if (sharpsl_param.adadj_keyword != AD_MAGIC)
sharpsl_param.adadj=-1;
}