[Qemu-devel] [PATCH v2 1/2] target-mips: Misaligned memory accesses for R6

[Yongbok Kim]

Release 6 requires misaligned memory access support for all ordinary memory
access instructions (for example, LW/SW, LWC1/SWC1).
However misaligned support is not provided for certain special memory accesses
such as atomics (for example, LL/SC).

Allows misaligned accesses from mips_cpu_do_unaligned_access() callback,
if it is a R6 core. As the helper functions of LL/SC is checking misalignment,
just allowing all for R6 is good enough.

Signed-off-by: Yongbok Kim <address@hidden>
---
 target-mips/op_helper.c      |    7 +++++++
 target-mips/translate_init.c |    2 +-
 2 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/target-mips/op_helper.c b/target-mips/op_helper.c
index 73a8e45..58f02cf 100644
--- a/target-mips/op_helper.c
+++ b/target-mips/op_helper.c
@@ -2215,6 +2215,13 @@ void mips_cpu_do_unaligned_access(CPUState *cs, vaddr 
addr,
     int error_code = 0;
     int excp;
 
+    if (env->insn_flags & ISA_MIPS32R6) {
+        /* Release 6 provides support for misaligned memory access for
+         * all ordinary memory reference instructions
+         * */
+        return;
+    }
+
     env->CP0_BadVAddr = addr;
 
     if (access_type == MMU_DATA_STORE) {
diff --git a/target-mips/translate_init.c b/target-mips/translate_init.c
index 85a65e7..ec54fef 100644
--- a/target-mips/translate_init.c
+++ b/target-mips/translate_init.c
@@ -607,7 +607,7 @@ static const mips_def_t mips_defs[] =
     },
     {
         /* A generic CPU supporting MIPS64 Release 6 ISA.
-           FIXME: Support IEEE 754-2008 FP and misaligned memory accesses.
+           FIXME: Support IEEE 754-2008 FP.
                   Eventually this should be replaced by a real CPU model. */
         .name = "MIPS64R6-generic",
         .CP0_PRid = 0x00010000,
-- 
1.7.5.4