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-rw-r--r--arch/ia64/kernel/gate.S44
1 files changed, 22 insertions, 22 deletions
diff --git a/arch/ia64/kernel/gate.S b/arch/ia64/kernel/gate.S
index 3cd3f2e971f..272e64c0e21 100644
--- a/arch/ia64/kernel/gate.S
+++ b/arch/ia64/kernel/gate.S
@@ -72,41 +72,41 @@ GLOBAL_ENTRY(__kernel_syscall_via_epc)
* bundle get executed. The remaining code must be safe even if
* they do not get executed.
*/
- adds r17=-1024,r15
- mov r10=0 // default to successful syscall execution
- epc
+ adds r17=-1024,r15 // A
+ mov r10=0 // A default to successful syscall execution
+ epc // B causes split-issue
}
;;
- rsm psr.be // note: on McKinley "rsm psr.be/srlz.d" is slightly faster than "rum psr.be"
- LOAD_FSYSCALL_TABLE(r14)
+ rsm psr.be // M2 (5 cyc to srlz.d)
+ LOAD_FSYSCALL_TABLE(r14) // X
;;
- mov r16=IA64_KR(CURRENT) // 12 cycle read latency
- shladd r18=r17,3,r14
- mov r19=NR_syscalls-1
+ mov r16=IA64_KR(CURRENT) // M2 (12 cyc)
+ shladd r18=r17,3,r14 // A
+ mov r19=NR_syscalls-1 // A
;;
lfetch [r18] // M0|1
- mov r29=psr // read psr (12 cyc load latency)
- /* Note: if r17 is a NaT, p6 will be set to zero. */
- cmp.geu p6,p7=r19,r17 // (syscall > 0 && syscall < 1024+NR_syscalls)?
+ mov r29=psr // M2 (12 cyc)
+ // If r17 is a NaT, p6 will be zero
+ cmp.geu p6,p7=r19,r17 // A (sysnr > 0 && sysnr < 1024+NR_syscalls)?
;;
- mov r21=ar.fpsr
- tnat.nz p10,p9=r15
- mov r26=ar.pfs
+ mov r21=ar.fpsr // M2 (12 cyc)
+ tnat.nz p10,p9=r15 // I0
+ mov.i r26=ar.pfs // I0 (would stall anyhow due to srlz.d...)
;;
- srlz.d
-(p6) ld8 r18=[r18]
+ srlz.d // M0 (forces split-issue) ensure PSR.BE==0
+(p6) ld8 r18=[r18] // M0|1
nop.i 0
;;
nop.m 0
-(p6) mov b7=r18
-(p6) tbit.z.unc p8,p0=r18,0
+(p6) mov b7=r18 // I0
+(p6) tbit.z.unc p8,p0=r18,0 // I0 (dual-issues with "mov b7=r18"!)
nop.m 0
nop.i 0
-(p8) br.dptk.many b7
+(p8) br.dptk.many b7 // B
- mov r27=ar.rsc
-(p6) rsm psr.i
+ mov r27=ar.rsc // M2 (12 cyc)
+(p6) rsm psr.i // M2
/*
* brl.cond doesn't work as intended because the linker would convert this branch
* into a branch to a PLT. Perhaps there will be a way to avoid this with some
@@ -114,7 +114,7 @@ GLOBAL_ENTRY(__kernel_syscall_via_epc)
* instead.
*/
#ifdef CONFIG_ITANIUM
- add r14=-8,r14 // r14 <- addr of fsys_bubble_down entry
+(p6) add r14=-8,r14 // r14 <- addr of fsys_bubble_down entry
;;
(p6) ld8 r14=[r14] // r14 <- fsys_bubble_down
;;