diff options
| author | Michael Ellerman <michael@ellerman.id.au> | 2008-07-16 14:21:34 +1000 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2008-08-20 16:34:57 +1000 |
| commit | 01f3880dd8a7fa78c419da2db740cba511ca7798 (patch) | |
| tree | 6a1e6ab37fa42ae1847f2ff44f26270dc6848c7c /arch/powerpc/kernel/entry_64.S | |
| parent | cd5aeb9f6cf7ada6baa218e01b4299e201497cde (diff) | |
| download | linux-01f3880dd8a7fa78c419da2db740cba511ca7798.tar.bz2 | |
powerpc: Streamline ret_from_except_lite for non-iSeries platforms
There is a small passage of code in ret_from_except_lite which is
only required on iSeries. For a multi-platform kernel on non-iSeries
machines this means we end up executing ~15 nops in ret_from_except_lite.
It would be nicer if non-iSeries could skip the code entirely, and on
iSeries we can jump out of line to execute the code.
I have no performance numbers to justify this, other than the assertion
that executing 15 nops takes longer than executing 0.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel/entry_64.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_64.S | 53 |
1 files changed, 29 insertions, 24 deletions
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 2d802e97097c..55445f1dba8a 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -512,31 +512,12 @@ _GLOBAL(ret_from_except_lite) #endif restore: - ld r5,SOFTE(r1) -#ifdef CONFIG_PPC_ISERIES BEGIN_FW_FTR_SECTION - cmpdi 0,r5,0 - beq 4f - /* Check for pending interrupts (iSeries) */ - ld r3,PACALPPACAPTR(r13) - ld r3,LPPACAANYINT(r3) - cmpdi r3,0 - beq+ 4f /* skip do_IRQ if no interrupts */ - - li r3,0 - stb r3,PACASOFTIRQEN(r13) /* ensure we are soft-disabled */ -#ifdef CONFIG_TRACE_IRQFLAGS - bl .trace_hardirqs_off - mfmsr r10 -#endif - ori r10,r10,MSR_EE - mtmsrd r10 /* hard-enable again */ - addi r3,r1,STACK_FRAME_OVERHEAD - bl .do_IRQ - b .ret_from_except_lite /* loop back and handle more */ -4: -END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES) -#endif + ld r5,SOFTE(r1) +FW_FTR_SECTION_ELSE + b iseries_check_pending_irqs +ALT_FW_FTR_SECTION_END_IFCLR(FW_FEATURE_ISERIES) +2: TRACE_AND_RESTORE_IRQ(r5); /* extract EE bit and use it to restore paca->hard_enabled */ @@ -592,6 +573,30 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES) rfid b . /* prevent speculative execution */ +iseries_check_pending_irqs: +#ifdef CONFIG_PPC_ISERIES + ld r5,SOFTE(r1) + cmpdi 0,r5,0 + beq 2b + /* Check for pending interrupts (iSeries) */ + ld r3,PACALPPACAPTR(r13) + ld r3,LPPACAANYINT(r3) + cmpdi r3,0 + beq+ 2b /* skip do_IRQ if no interrupts */ + + li r3,0 + stb r3,PACASOFTIRQEN(r13) /* ensure we are soft-disabled */ +#ifdef CONFIG_TRACE_IRQFLAGS + bl .trace_hardirqs_off + mfmsr r10 +#endif + ori r10,r10,MSR_EE + mtmsrd r10 /* hard-enable again */ + addi r3,r1,STACK_FRAME_OVERHEAD + bl .do_IRQ + b .ret_from_except_lite /* loop back and handle more */ +#endif + do_work: #ifdef CONFIG_PREEMPT andi. r0,r3,MSR_PR /* Returning to user mode? */ |