diff options
| author |   Dave Anglin <dave.anglin@bell.net> | 2021-11-03 12:49:32 +0100 |
|---|---|---|
| committer |   Helge Deller <deller@gmx.de> | 2021-11-04 11:21:20 +0100 |
| commit | 7e992711dddbdb1c27d077432d8440fefd44819f (patch) | |
| tree | 01208b85e053dda7deeb9eac8e3924f62b9ba144 /arch/parisc/kernel/syscall.S | |
| parent | parisc: don't enable irqs unconditionally in handle_interruption() (diff) | |
| download | linux-dev-7e992711dddbdb1c27d077432d8440fefd44819f.tar.xz linux-dev-7e992711dddbdb1c27d077432d8440fefd44819f.zip | |
parisc: Don't disable interrupts in cmpxchg and futex operations
I no longer think interrupts can be disabled in the futex and cmpxchg
operations because of COW breaks. This not ideal but I suspect it's the
best we can do.
For the cmpxchg operations in syscall.S, we rely on the code to not
schedule off the gateway page. For the futex, I added code to disable
preemption.
So far, I haven't seen the warnings with the attached change but the
change is only lightly tested.
Signed-off-by: Dave Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to '')
| -rw-r--r-- | arch/parisc/kernel/syscall.S | 10 |
1 files changed, 0 insertions, 10 deletions
diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S index ec9675f58435..4fb3b6a993bf 100644 --- a/arch/parisc/kernel/syscall.S +++ b/arch/parisc/kernel/syscall.S @@ -597,13 +597,11 @@ cas_nocontend: # endif /* ENABLE_LWS_DEBUG */ - rsm PSW_SM_I, %r0 /* Disable interrupts */ /* COW breaks can cause contention on UP systems */ LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */ cmpb,<>,n %r0, %r28, cas_action /* Did we get it? */ cas_wouldblock: ldo 2(%r0), %r28 /* 2nd case */ - ssm PSW_SM_I, %r0 b lws_exit /* Contended... */ ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ @@ -639,8 +637,6 @@ cas_action: /* Clear thread register indicator */ stw %r0, 4(%sr2,%r20) #endif - /* Enable interrupts */ - ssm PSW_SM_I, %r0 /* Return to userspace, set no error */ b lws_exit copy %r0, %r21 @@ -652,7 +648,6 @@ cas_action: #if ENABLE_LWS_DEBUG stw %r0, 4(%sr2,%r20) #endif - ssm PSW_SM_I, %r0 b lws_exit ldo -EFAULT(%r0),%r21 /* set errno */ nop @@ -764,13 +759,11 @@ cas2_lock_start: shlw %r20, 4, %r20 add %r20, %r28, %r20 - rsm PSW_SM_I, %r0 /* Disable interrupts */ /* COW breaks can cause contention on UP systems */ LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */ cmpb,<>,n %r0, %r28, cas2_action /* Did we get it? */ cas2_wouldblock: ldo 2(%r0), %r28 /* 2nd case */ - ssm PSW_SM_I, %r0 b lws_exit /* Contended... */ ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ @@ -850,8 +843,6 @@ cas2_action: cas2_end: /* Free lock */ stw,ma %r20, 0(%sr2,%r20) - /* Enable interrupts */ - ssm PSW_SM_I, %r0 /* Return to userspace, set no error */ b lws_exit copy %r0, %r21 @@ -860,7 +851,6 @@ cas2_end: /* Error occurred on load or store */ /* Free lock */ stw,ma %r20, 0(%sr2,%r20) - ssm PSW_SM_I, %r0 ldo 1(%r0),%r28 b lws_exit ldo -EFAULT(%r0),%r21 /* set errno */ |