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Subject[PATCH 5.4 004/109] regmap: fix alignment issue
Date
From: Jens Thoms Toerring <jt@toerring.de>

[ Upstream commit 53d860952c8215cf9ae1ea33409c8cb71ad6ad3d ]

The assembly and disassembly of data to be sent to or received from
a device invoke functions regmap_format_XX() and regmap_parse_XX()
that extract or insert data items from or into a buffer, using
assignments. In some cases the functions are called with a buffer
pointer with an odd address. On architectures with strict alignment
requirements this can result in a kernel crash. The assignments
have been replaced by functions that take alignment into account.

Signed-off-by: Jens Thoms Toerring <jt@toerring.de>
Link: https://lore.kernel.org/r/20200531095300.GA27570@toerring.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/base/regmap/regmap.c | 100 ++++++++++++++++-------------------
1 file changed, 46 insertions(+), 54 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 508bbd6ea4396..320d23de02c29 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -17,6 +17,7 @@
#include <linux/delay.h>
#include <linux/log2.h>
#include <linux/hwspinlock.h>
+#include <asm/unaligned.h>

#define CREATE_TRACE_POINTS
#include "trace.h"
@@ -249,22 +250,20 @@ static void regmap_format_8(void *buf, unsigned int val, unsigned int shift)

static void regmap_format_16_be(void *buf, unsigned int val, unsigned int shift)
{
- __be16 *b = buf;
-
- b[0] = cpu_to_be16(val << shift);
+ put_unaligned_be16(val << shift, buf);
}

static void regmap_format_16_le(void *buf, unsigned int val, unsigned int shift)
{
- __le16 *b = buf;
-
- b[0] = cpu_to_le16(val << shift);
+ put_unaligned_le16(val << shift, buf);
}

static void regmap_format_16_native(void *buf, unsigned int val,
unsigned int shift)
{
- *(u16 *)buf = val << shift;
+ u16 v = val << shift;
+
+ memcpy(buf, &v, sizeof(v));
}

static void regmap_format_24(void *buf, unsigned int val, unsigned int shift)
@@ -280,43 +279,39 @@ static void regmap_format_24(void *buf, unsigned int val, unsigned int shift)

static void regmap_format_32_be(void *buf, unsigned int val, unsigned int shift)
{
- __be32 *b = buf;
-
- b[0] = cpu_to_be32(val << shift);
+ put_unaligned_be32(val << shift, buf);
}

static void regmap_format_32_le(void *buf, unsigned int val, unsigned int shift)
{
- __le32 *b = buf;
-
- b[0] = cpu_to_le32(val << shift);
+ put_unaligned_le32(val << shift, buf);
}

static void regmap_format_32_native(void *buf, unsigned int val,
unsigned int shift)
{
- *(u32 *)buf = val << shift;
+ u32 v = val << shift;
+
+ memcpy(buf, &v, sizeof(v));
}

#ifdef CONFIG_64BIT
static void regmap_format_64_be(void *buf, unsigned int val, unsigned int shift)
{
- __be64 *b = buf;
-
- b[0] = cpu_to_be64((u64)val << shift);
+ put_unaligned_be64((u64) val << shift, buf);
}

static void regmap_format_64_le(void *buf, unsigned int val, unsigned int shift)
{
- __le64 *b = buf;
-
- b[0] = cpu_to_le64((u64)val << shift);
+ put_unaligned_le64((u64) val << shift, buf);
}

static void regmap_format_64_native(void *buf, unsigned int val,
unsigned int shift)
{
- *(u64 *)buf = (u64)val << shift;
+ u64 v = (u64) val << shift;
+
+ memcpy(buf, &v, sizeof(v));
}
#endif

@@ -333,35 +328,34 @@ static unsigned int regmap_parse_8(const void *buf)

static unsigned int regmap_parse_16_be(const void *buf)
{
- const __be16 *b = buf;
-
- return be16_to_cpu(b[0]);
+ return get_unaligned_be16(buf);
}

static unsigned int regmap_parse_16_le(const void *buf)
{
- const __le16 *b = buf;
-
- return le16_to_cpu(b[0]);
+ return get_unaligned_le16(buf);
}

static void regmap_parse_16_be_inplace(void *buf)
{
- __be16 *b = buf;
+ u16 v = get_unaligned_be16(buf);

- b[0] = be16_to_cpu(b[0]);
+ memcpy(buf, &v, sizeof(v));
}

static void regmap_parse_16_le_inplace(void *buf)
{
- __le16 *b = buf;
+ u16 v = get_unaligned_le16(buf);

- b[0] = le16_to_cpu(b[0]);
+ memcpy(buf, &v, sizeof(v));
}

static unsigned int regmap_parse_16_native(const void *buf)
{
- return *(u16 *)buf;
+ u16 v;
+
+ memcpy(&v, buf, sizeof(v));
+ return v;
}

static unsigned int regmap_parse_24(const void *buf)
@@ -376,69 +370,67 @@ static unsigned int regmap_parse_24(const void *buf)

static unsigned int regmap_parse_32_be(const void *buf)
{
- const __be32 *b = buf;
-
- return be32_to_cpu(b[0]);
+ return get_unaligned_be32(buf);
}

static unsigned int regmap_parse_32_le(const void *buf)
{
- const __le32 *b = buf;
-
- return le32_to_cpu(b[0]);
+ return get_unaligned_le32(buf);
}

static void regmap_parse_32_be_inplace(void *buf)
{
- __be32 *b = buf;
+ u32 v = get_unaligned_be32(buf);

- b[0] = be32_to_cpu(b[0]);
+ memcpy(buf, &v, sizeof(v));
}

static void regmap_parse_32_le_inplace(void *buf)
{
- __le32 *b = buf;
+ u32 v = get_unaligned_le32(buf);

- b[0] = le32_to_cpu(b[0]);
+ memcpy(buf, &v, sizeof(v));
}

static unsigned int regmap_parse_32_native(const void *buf)
{
- return *(u32 *)buf;
+ u32 v;
+
+ memcpy(&v, buf, sizeof(v));
+ return v;
}

#ifdef CONFIG_64BIT
static unsigned int regmap_parse_64_be(const void *buf)
{
- const __be64 *b = buf;
-
- return be64_to_cpu(b[0]);
+ return get_unaligned_be64(buf);
}

static unsigned int regmap_parse_64_le(const void *buf)
{
- const __le64 *b = buf;
-
- return le64_to_cpu(b[0]);
+ return get_unaligned_le64(buf);
}

static void regmap_parse_64_be_inplace(void *buf)
{
- __be64 *b = buf;
+ u64 v = get_unaligned_be64(buf);

- b[0] = be64_to_cpu(b[0]);
+ memcpy(buf, &v, sizeof(v));
}

static void regmap_parse_64_le_inplace(void *buf)
{
- __le64 *b = buf;
+ u64 v = get_unaligned_le64(buf);

- b[0] = le64_to_cpu(b[0]);
+ memcpy(buf, &v, sizeof(v));
}

static unsigned int regmap_parse_64_native(const void *buf)
{
- return *(u64 *)buf;
+ u64 v;
+
+ memcpy(&v, buf, sizeof(v));
+ return v;
}
#endif

--
2.25.1


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