Julius Werner (jwerner@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@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@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)