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| author | Nicholas Piggin <npiggin@gmail.com> | 2017-04-19 16:05:45 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-04-23 13:31:39 +0300 |
| commit | 544686cae8e4f5bbcd153998dcaf4a3d5b94e6be (patch) | |
| tree | 51eaa1f72ea0c6967e930ffcd3fe1d2562940bbe /arch/powerpc/kernel/idle_book3s.S | |
| parent | bf0153c143a694e7bb3b28d92eafd8b3ef6db870 (diff) | |
| download | linux-544686cae8e4f5bbcd153998dcaf4a3d5b94e6be.tar.xz | |
powerpc/64s: Stop using bit in HSPRG0 to test winkle
The POWER8 idle code has a neat trick of programming the power on engine
to restore a low bit into HSPRG0, so idle wakeup code can test and see
if it has been programmed this way and therefore lost all state. Restore
time can be reduced if winkle has not been reached.
However this messes with our r13 PACA pointer, and requires HSPRG0 to be
written to. It also optimizes the slowest and most uncommon case at the
expense of another SPR write in the common nap state wakeup.
Remove this complexity and assume winkle sleeps always require a state
restore. This speedup could be made entirely contained within the winkle
idle code by counting per-core winkles and setting a thread bitmap when
all have gone to winkle.
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/idle_book3s.S')
| -rw-r--r-- | arch/powerpc/kernel/idle_book3s.S | 27 |
1 files changed, 10 insertions, 17 deletions
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S index 99de9de7efe7..a80d76f9e961 100644 --- a/arch/powerpc/kernel/idle_book3s.S +++ b/arch/powerpc/kernel/idle_book3s.S @@ -415,11 +415,12 @@ power9_dd1_recover_paca: stb r0,PACA_NAPSTATELOST(r13) blr +/* + * Called from reset vector for powersave wakeups. + * cr3 - set to gt if waking up with partial/complete hypervisor state loss + */ .global pnv_powersave_wakeup pnv_powersave_wakeup: -BEGIN_FTR_SECTION - GET_PACA(r13) /* Restore HSPRG0 to get the winkle bit in r13 */ -END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300) bl pnv_restore_hyp_resource li r0,PNV_THREAD_RUNNING @@ -446,18 +447,18 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300) * Check whether we have woken up with hypervisor state loss. * If yes, restore hypervisor state and return back to link. * - * r13 - Contents of HSPRG0 * cr3 - set to gt if waking up with partial/complete hypervisor state loss */ pnv_restore_hyp_resource: BEGIN_FTR_SECTION -BEGIN_FTR_SECTION_NESTED(70) mflr r6 bl power9_dd1_recover_paca mtlr r6 -FTR_SECTION_ELSE_NESTED(70) +FTR_SECTION_ELSE ld r2, PACATOC(r13) -ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_POWER9_DD1, 70) +ALT_FTR_SECTION_END_IFSET(CPU_FTR_POWER9_DD1) + +BEGIN_FTR_SECTION /* * POWER ISA 3. Use PSSCR to determine if we * are waking up from deep idle state @@ -480,19 +481,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) /* * POWER ISA 2.07 or less. - * Check if last bit of HSPGR0 is set. This indicates whether we are - * waking up from winkle. + * Check if we slept with winkle. */ - clrldi r5,r13,63 - clrrdi r13,r13,1 - - /* Now that we are sure r13 is corrected, load TOC */ - ld r2,PACATOC(r13); - cmpwi cr4,r5,1 - mtspr SPRN_HSPRG0,r13 - lbz r0,PACA_THREAD_IDLE_STATE(r13) cmpwi cr2,r0,PNV_THREAD_NAP + cmpwi cr4,r0,PNV_THREAD_WINKLE bgt cr2,pnv_wakeup_tb_loss /* Either sleep or Winkle */ /* |