[coreboot-gerrit] New patch to review for coreboot: commonlib/lz4: Avoid unaligned memory access on RISC-V

[Jonathan Neuschäfer]

Jonathan Neuschäfer ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/14983

-gerrit

commit a898edc645d73caffd2182b82b19c26ff71fad96
Author: Jonathan Neuschäfer 
Date:   Fri May 27 09:05:02 2016 +0200

commonlib/lz4: Avoid unaligned memory access on RISC-V

From the User-Level ISA Specification v2.0:

"We do not mandate atomicity for misaligned accesses so simple
        implementations can just use a machine trap and software handler to
        handle misaligned accesses." (— http://riscv.org/specifications/)

Spike traps on unaligned accesses.

Change-Id: Ia57786916f4076cc08513f4e331c2deec9cfa785
    Signed-off-by: Jonathan Neuschäfer 
---
 src/commonlib/lz4_wrapper.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/commonlib/lz4_wrapper.c b/src/commonlib/lz4_wrapper.c
index 772f791..ad014fa 100644
--- a/src/commonlib/lz4_wrapper.c
+++ b/src/commonlib/lz4_wrapper.c
@@ -63,6 +63,10 @@ static void LZ4_copy8(void *dst, const void *src)
    		: [src]"r"(src), [dst]"r"(dst)
    		: "memory" );
    #endif
+#elif __riscv__ /* RISC-V implementations may trap on any unaligned access. */
+	int i;
+	for (i = 0; i < 8; i++)
+		((uint8_t *)dst)[i] = ((uint8_t *)src)[i];
 #else
    *(uint64_t *)dst = *(const uint64_t *)src;
 #endif