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| author | David Mosberger-Tang | 2005-05-04 22:25:00 +0200 |
|---|---|---|
| committer | Tony Luck | 2005-06-28 18:28:16 +0200 |
| commit | 458f935527372499b714bf4f8e646a68bb0f52e3 (patch) | |
| tree | bab3265d60b3c7c3f898eeefa6c9dac264d41195 /arch/ia64/kernel | |
| parent | [IA64] Recognize HP sx2000 chipset (diff) | |
| download | kernel-qcow2-linux-458f935527372499b714bf4f8e646a68bb0f52e3.tar.gz kernel-qcow2-linux-458f935527372499b714bf4f8e646a68bb0f52e3.tar.xz kernel-qcow2-linux-458f935527372499b714bf4f8e646a68bb0f52e3.zip | |
[IA64] Speed up lfetch.fault [NULL]
This patch greatly speeds up the handling of lfetch.fault instructions
which result in NaT consumption. Due to the NaT-page mapped at address
0, this is guaranteed to happen when lfetch.fault'ing a NULL pointer.
With this patch in place, we can even define prefetch()/prefetchw() as
lfetch.fault without significant performance degradation. More
importantly, it allows compilers to be more aggressive with using
lfetch.fault on pointers that might be NULL.
Signed-off-by: David Mosberger-Tang <davidm@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64/kernel')
| -rw-r--r-- | arch/ia64/kernel/ivt.S | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/ia64/kernel/ivt.S b/arch/ia64/kernel/ivt.S index b28d2212a779..3bb3a13c4047 100644 --- a/arch/ia64/kernel/ivt.S +++ b/arch/ia64/kernel/ivt.S @@ -1243,6 +1243,25 @@ END(disabled_fp_reg) // 0x5600 Entry 26 (size 16 bundles) Nat Consumption (11,23,37,50) ENTRY(nat_consumption) DBG_FAULT(26) + + mov r16=cr.ipsr + mov r17=cr.isr + mov r31=pr // save PR + ;; + and r18=0xf,r17 // r18 = cr.ipsr.code{3:0} + tbit.z p6,p0=r17,IA64_ISR_NA_BIT + ;; + cmp.ne.or p6,p0=IA64_ISR_CODE_LFETCH,r18 + dep r16=-1,r16,IA64_PSR_ED_BIT,1 +(p6) br.cond.spnt 1f // branch if (cr.ispr.na == 0 || cr.ipsr.code{3:0} != LFETCH) + ;; + mov cr.ipsr=r16 // set cr.ipsr.na + mov pr=r31,-1 + ;; + rfi + +1: mov pr=r31,-1 + ;; FAULT(26) END(nat_consumption) |