[coreboot-gerrit] New patch to review for coreboot: cbmem: Add custom aligned memcpy() implementation
Julius Werner (jwerner@chromium.org)
gerrit at coreboot.org
Tue Feb 7 00:31:19 CET 2017
Julius Werner (jwerner at chromium.org) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/18300
-gerrit
commit 6f195e2b8c324134b64163c92745b826e36315c6
Author: Julius Werner <jwerner at chromium.org>
Date: Fri Feb 3 12:50:03 2017 -0800
cbmem: Add custom aligned memcpy() implementation
On some architectures (like AArch64), /dev/mem mappings outside of the
area marked as normal RAM use a memory type that does not support
unaligned accesses. The libc memcpy() implementation on these
architectures may not know or expect that and make an unaligned access
for certain source/dest/length alignments. Add a custom memcpy()
implementation that takes these restrictions into account and use it
anywhere we copy straight out of /dev/mem memory.
Change-Id: I03eece380a14a69d4be3805ed72fba640f6f7d9c
Signed-off-by: Julius Werner <jwerner at chromium.org>
---
util/cbmem/cbmem.c | 32 +++++++++++++++++++++++++++++++-
1 file changed, 31 insertions(+), 1 deletion(-)
diff --git a/util/cbmem/cbmem.c b/util/cbmem/cbmem.c
index 7b434d87..99f25f8 100644
--- a/util/cbmem/cbmem.c
+++ b/util/cbmem/cbmem.c
@@ -61,6 +61,36 @@ static uint64_t lbtable_address;
static size_t lbtable_size;
/*
+ * Some architectures map /dev/mem memory in a way that doesn't support
+ * unaligned accesses. Most normal libc memcpy()s aren't safe to use in this
+ * case, so build our own which makes sure to never do unaligned accesses on
+ * *src (*dest is fine since we never map /dev/mem for writing).
+ */
+static void *aligned_memcpy(void *dest, const void *src, size_t n)
+{
+ u8 *d = dest;
+ const u8 *s = src;
+
+ while ((uintptr_t)s & (sizeof(size_t) - 1)) {
+ if (n-- == 0)
+ return dest;
+ *d++ = *s++;
+ }
+
+ while (n >= sizeof(size_t)) {
+ *(size_t *)d = *(size_t *)s;
+ d += sizeof(size_t);
+ s += sizeof(size_t);
+ n -= sizeof(size_t);
+ }
+
+ while (n-- > 0)
+ *d++ = *s++;
+
+ return dest;
+}
+
+/*
* calculate ip checksum (16 bit quantities) on a passed in buffer. In case
* the buffer length is odd last byte is excluded from the calculation
*/
@@ -608,7 +638,7 @@ static void dump_console(void)
console_p = map_memory_size((unsigned long)console.cbmem_addr,
size + sizeof(size) + sizeof(cursor), 1);
- memcpy(console_c, console_p + 8, size);
+ aligned_memcpy(console_c, console_p + 8, size);
printf("%s\n", console_c);
if (size < cursor)
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