diff options
| author | Kevin Hao <haokexin@gmail.com> | 2015-10-22 20:23:48 +0800 |
|---|---|---|
| committer | Scott Wood <scottwood@freescale.com> | 2015-10-27 18:14:40 -0500 |
| commit | e1f580e8ced56d7c0a2b096e00e8b8e861d13671 (patch) | |
| tree | 5f3195381d584c766113abf63eac85e74508dc9d /arch/powerpc/mm/tlb_low_64e.S | |
| parent | da414bb923d95f1f59fbf534a0e2ef9f52ffc667 (diff) | |
| download | talos-obmc-linux-e1f580e8ced56d7c0a2b096e00e8b8e861d13671.tar.gz talos-obmc-linux-e1f580e8ced56d7c0a2b096e00e8b8e861d13671.zip | |
powerpc/e6500: hw tablewalk: make sure we invalidate and write to the same tlb entry
In order to workaround Erratum A-008139, we have to invalidate the
tlb entry with tlbilx before overwriting. Due to the performance
consideration, we don't add any memory barrier when acquire/release
the tcd lock. This means the two load instructions for esel_next do
have the possibility to return different value. This is definitely
not acceptable due to the Erratum A-008139. We have two options to
fix this issue:
a) Add memory barrier when acquire/release tcd lock to order the
load/store to esel_next.
b) Just make sure to invalidate and write to the same tlb entry and
tolerate the race that we may get the wrong value and overwrite
the tlb entry just updated by the other thread.
We observe better performance using option b. So reserve an additional
register to save the value of the esel_next.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
Diffstat (limited to 'arch/powerpc/mm/tlb_low_64e.S')
| -rw-r--r-- | arch/powerpc/mm/tlb_low_64e.S | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/arch/powerpc/mm/tlb_low_64e.S b/arch/powerpc/mm/tlb_low_64e.S index e4185581c5a7..29d6987c37ba 100644 --- a/arch/powerpc/mm/tlb_low_64e.S +++ b/arch/powerpc/mm/tlb_low_64e.S @@ -68,11 +68,17 @@ END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV) ld r14,PACAPGD(r13) std r15,EX_TLB_R15(r12) std r10,EX_TLB_CR(r12) +#ifdef CONFIG_PPC_FSL_BOOK3E + std r7,EX_TLB_R7(r12) +#endif TLB_MISS_PROLOG_STATS .endm .macro tlb_epilog_bolted ld r14,EX_TLB_CR(r12) +#ifdef CONFIG_PPC_FSL_BOOK3E + ld r7,EX_TLB_R7(r12) +#endif ld r10,EX_TLB_R10(r12) ld r11,EX_TLB_R11(r12) ld r13,EX_TLB_R13(r12) @@ -297,6 +303,7 @@ itlb_miss_fault_bolted: * r13 = PACA * r11 = tlb_per_core ptr * r10 = crap (free to use) + * r7 = esel_next */ tlb_miss_common_e6500: crmove cr2*4+2,cr0*4+2 /* cr2.eq != 0 if kernel address */ @@ -325,7 +332,11 @@ BEGIN_FTR_SECTION /* CPU_FTR_SMT */ bne 10b b 1b .previous +END_FTR_SECTION_IFSET(CPU_FTR_SMT) + + lbz r7,TCD_ESEL_NEXT(r11) +BEGIN_FTR_SECTION /* CPU_FTR_SMT */ /* * Erratum A-008139 says that we can't use tlbwe to change * an indirect entry in any way (including replacing or @@ -334,8 +345,7 @@ BEGIN_FTR_SECTION /* CPU_FTR_SMT */ * with tlbilx before overwriting. */ - lbz r15,TCD_ESEL_NEXT(r11) - rlwinm r10,r15,16,0xff0000 + rlwinm r10,r7,16,0xff0000 oris r10,r10,MAS0_TLBSEL(1)@h mtspr SPRN_MAS0,r10 isync @@ -429,15 +439,14 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_SMT) mtspr SPRN_MAS2,r15 tlb_miss_huge_done_e6500: - lbz r15,TCD_ESEL_NEXT(r11) lbz r16,TCD_ESEL_MAX(r11) lbz r14,TCD_ESEL_FIRST(r11) - rlwimi r10,r15,16,0x00ff0000 /* insert esel_next into MAS0 */ - addi r15,r15,1 /* increment esel_next */ + rlwimi r10,r7,16,0x00ff0000 /* insert esel_next into MAS0 */ + addi r7,r7,1 /* increment esel_next */ mtspr SPRN_MAS0,r10 - cmpw r15,r16 - iseleq r15,r14,r15 /* if next == last use first */ - stb r15,TCD_ESEL_NEXT(r11) + cmpw r7,r16 + iseleq r7,r14,r7 /* if next == last use first */ + stb r7,TCD_ESEL_NEXT(r11) tlbwe |
