[PATCH v4] ACPI, APEI: Cleanup alignment related codes for APEI

["Chen, Gong" <gong.chen@xxxxxxxxxxxxxxx>]

We ever used *memcpy* to avoid access alignment issue between
firmware and OS. Now we can use a better and standard way
to avoid this issue.

Because ERST record id cache is implemented in the memory to
increase the access speed via caching ERST content, so it
doesn't matter with firmware access. BTW, simplify some
variable names to avoid the limit of 80 characters per line.

v4->v3: Add more detail description.
v3->v2: Fix an evaluation error.
v2->v1: Make description information clearer.

Signed-off-by: Chen, Gong <gong.chen@xxxxxxxxxxxxxxx>
Acked-by: Borislav Petkov <bp@xxxxxxx>
---
 drivers/acpi/apei/apei-base.c |  4 ++--
 drivers/acpi/apei/einj.c      | 19 +++++++++----------
 drivers/acpi/apei/erst.c      |  2 +-
 3 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/drivers/acpi/apei/apei-base.c b/drivers/acpi/apei/apei-base.c
index 6d2c49b..e55584a 100644
--- a/drivers/acpi/apei/apei-base.c
+++ b/drivers/acpi/apei/apei-base.c
@@ -41,6 +41,7 @@
 #include <linux/rculist.h>
 #include <linux/interrupt.h>
 #include <linux/debugfs.h>
+#include <asm/unaligned.h>
 
 #include "apei-internal.h"
 
@@ -567,8 +568,7 @@ static int apei_check_gar(struct acpi_generic_address *reg, u64 *paddr,
 	bit_offset = reg->bit_offset;
 	access_size_code = reg->access_width;
 	space_id = reg->space_id;
-	/* Handle possible alignment issues */
-	memcpy(paddr, &reg->address, sizeof(*paddr));
+	*paddr = get_unaligned(&reg->address);
 	if (!*paddr) {
 		pr_warning(FW_BUG APEI_PFX
 			   "Invalid physical address in GAR [0x%llx/%u/%u/%u/%u]\n",
diff --git a/drivers/acpi/apei/einj.c b/drivers/acpi/apei/einj.c
index fb57d03..361177a 100644
--- a/drivers/acpi/apei/einj.c
+++ b/drivers/acpi/apei/einj.c
@@ -34,6 +34,7 @@
 #include <linux/delay.h>
 #include <linux/mm.h>
 #include <acpi/acpi.h>
+#include <asm/unaligned.h>
 
 #include "apei-internal.h"
 
@@ -216,7 +217,7 @@ static void check_vendor_extension(u64 paddr,
 static void *einj_get_parameter_address(void)
 {
 	int i;
-	u64 paddrv4 = 0, paddrv5 = 0;
+	u64 pa_v4 = 0, pa_v5 = 0;
 	struct acpi_whea_header *entry;
 
 	entry = EINJ_TAB_ENTRY(einj_tab);
@@ -225,30 +226,28 @@ static void *einj_get_parameter_address(void)
 		    entry->instruction == ACPI_EINJ_WRITE_REGISTER &&
 		    entry->register_region.space_id ==
 		    ACPI_ADR_SPACE_SYSTEM_MEMORY)
-			memcpy(&paddrv4, &entry->register_region.address,
-			       sizeof(paddrv4));
+			pa_v4 = get_unaligned(&entry->register_region.address);
 		if (entry->action == ACPI_EINJ_SET_ERROR_TYPE_WITH_ADDRESS &&
 		    entry->instruction == ACPI_EINJ_WRITE_REGISTER &&
 		    entry->register_region.space_id ==
 		    ACPI_ADR_SPACE_SYSTEM_MEMORY)
-			memcpy(&paddrv5, &entry->register_region.address,
-			       sizeof(paddrv5));
+			pa_v5 = get_unaligned(&entry->register_region.address);
 		entry++;
 	}
-	if (paddrv5) {
+	if (pa_v5) {
 		struct set_error_type_with_address *v5param;
 
-		v5param = acpi_os_map_memory(paddrv5, sizeof(*v5param));
+		v5param = acpi_os_map_memory(pa_v5, sizeof(*v5param));
 		if (v5param) {
 			acpi5 = 1;
-			check_vendor_extension(paddrv5, v5param);
+			check_vendor_extension(pa_v5, v5param);
 			return v5param;
 		}
 	}
-	if (param_extension && paddrv4) {
+	if (param_extension && pa_v4) {
 		struct einj_parameter *v4param;
 
-		v4param = acpi_os_map_memory(paddrv4, sizeof(*v4param));
+		v4param = acpi_os_map_memory(pa_v4, sizeof(*v4param));
 		if (!v4param)
 			return NULL;
 		if (v4param->reserved1 || v4param->reserved2) {
diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c
index 26311f2..bf30a12 100644
--- a/drivers/acpi/apei/erst.c
+++ b/drivers/acpi/apei/erst.c
@@ -611,7 +611,7 @@ static void __erst_record_id_cache_compact(void)
 		if (entries[i] == APEI_ERST_INVALID_RECORD_ID)
 			continue;
 		if (wpos != i)
-			memcpy(&entries[wpos], &entries[i], sizeof(entries[i]));
+			entries[wpos] = entries[i];
 		wpos++;
 	}
 	erst_record_id_cache.len = wpos;
-- 
1.8.4.3

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