diff options
| author | David Mosberger-Tang <davidm@hpl.hp.com> | 2005-04-28 06:17:03 +0200 |
|---|---|---|
| committer | Tony Luck <tony.luck@intel.com> | 2005-04-28 06:17:03 +0200 |
| commit | 060561ff79b01eea58e6d72abfb8e7580ff21f2a (patch) | |
| tree | 7c3f95456480d3c6b44842df5a7619be98f2e14d /arch/ia64/kernel/ivt.S | |
| parent | [IA64] On return from syscall, hint b7 with __kernel_syscall_via_epc(). (diff) | |
| download | linux-060561ff79b01eea58e6d72abfb8e7580ff21f2a.tar.xz linux-060561ff79b01eea58e6d72abfb8e7580ff21f2a.zip | |
[IA64] In syscall-entry, use st8 instead of stf8 to clear pt_regs.r8
Using stf8 seemed like a clever idea at the time, but stf8 forces
the cache-line to be invalidated in the L1D (if it happens to be
there already). This patch eliminates a guaranteed L1D cache-miss
and, by itself, is good for a 1-2 cycle improvement for heavy-weight
syscalls.
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/ivt.S')
| -rw-r--r-- | arch/ia64/kernel/ivt.S | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/ia64/kernel/ivt.S b/arch/ia64/kernel/ivt.S index d9c05d53435b..dc78c356ddd0 100644 --- a/arch/ia64/kernel/ivt.S +++ b/arch/ia64/kernel/ivt.S @@ -1,7 +1,7 @@ /* * arch/ia64/kernel/ivt.S * - * Copyright (C) 1998-2001, 2003 Hewlett-Packard Co + * Copyright (C) 1998-2001, 2003, 2005 Hewlett-Packard Co * Stephane Eranian <eranian@hpl.hp.com> * David Mosberger <davidm@hpl.hp.com> * Copyright (C) 2000, 2002-2003 Intel Co @@ -918,7 +918,7 @@ GLOBAL_ENTRY(ia64_syscall_setup) tnat.nz p14,p0=in6 cmp.lt p10,p9=r11,r8 // frame size can't be more than local+8 ;; - stf8 [r16]=f1 // ensure pt_regs.r8 != 0 (see handle_syscall_error) + mov r8=1 (p9) tnat.nz p10,p0=r15 adds r12=-16,r1 // switch to kernel memory stack (with 16 bytes of scratch) @@ -929,9 +929,9 @@ GLOBAL_ENTRY(ia64_syscall_setup) mov r13=r2 // establish `current' movl r1=__gp // establish kernel global pointer ;; + st8 [r16]=r8 // ensure pt_regs.r8 != 0 (see handle_syscall_error) (p14) mov in6=-1 (p8) mov in7=-1 - nop.i 0 cmp.eq pSys,pNonSys=r0,r0 // set pSys=1, pNonSys=0 movl r17=FPSR_DEFAULT |