On 12/19/2014 02:01 AM, Markos Chandras wrote:
On 12/18/2014 06:50 PM, David Daney wrote:
On 12/18/2014 07:09 AM, Markos Chandras wrote:
MIPS R6 changed the opcodes for LL/SC instructions and reduced the
offset field to 9-bits. This has some undesired effects with the "m"
constrain since it implies a 16-bit immediate. As a result of which,
add a register ("r") constrain as well to make sure the entire address
is loaded to a register before the LL/SC operations. Also use macro
to set the appropriate ISA for the asm blocks
Has support for MIPS R6 been added to GCC?
If so, that should include a proper constraint to be used with the new
offset restrictions. We should probably use that, instead of forcing to
a "r" constraint.
Cc: Matthew Fortune <Matthew.Fortune@xxxxxxxxxx>
Signed-off-by: Markos Chandras <markos.chandras@xxxxxxxxxx>
---
arch/mips/include/asm/atomic.h | 50
+++++++++++++++++++++---------------------
1 file changed, 25 insertions(+), 25 deletions(-)
diff --git a/arch/mips/include/asm/atomic.h
b/arch/mips/include/asm/atomic.h
index 6dd6bfc607e9..8669e0ec97e3 100644
--- a/arch/mips/include/asm/atomic.h
+++ b/arch/mips/include/asm/atomic.h
@@ -60,13 +60,13 @@ static __inline__ void atomic_##op(int i, atomic_t
* v) \
\
do { \
__asm__ __volatile__( \
- " .set arch=r4000 \n" \
- " ll %0, %1 # atomic_" #op "\n" \
+ " .set "MIPS_ISA_ARCH_LEVEL" \n" \
+ " ll %0, 0(%3) # atomic_" #op "\n" \
" " #asm_op " %0, %2 \n" \
- " sc %0, %1 \n" \
+ " sc %0, 0(%3) \n" \
" .set mips0 \n" \
: "=&r" (temp), "+m" (v->counter) \
- : "Ir" (i)); \
+ : "Ir" (i), "r" (&v->counter)); \
You lost the "m" constraint, but are still modifying memory. There is
no "memory" clobber here, so we are no longer correctly describing what
is happening.
Sorry I don't understand what you mean by "you lost the "m"
constraint". +m (v->counter) is still there to denote that v->counter
memory is being modified no?
It looks like I misread the patch. On closer inspection, it seems that
the "m" constraint remains, so let's disregard my comment.
David Daney
