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| author |   Christopher Covington <cov@codeaurora.org> | 2017-02-08 15:08:37 -0500 |
|---|---|---|
| committer |   Will Deacon <will.deacon@arm.com> | 2017-02-10 11:22:12 +0000 |
| commit | 38fd94b0275c91071157a03cc27676909b23dcde (patch) | |
| tree | bd035ae9cfee02889ec65bcc1f94aef66a8c6a08 /arch/arm64/include/asm/cpucaps.h | |
| parent | arm64: head.S: Enable EL1 (host) access to SPE when entered at EL2 (diff) | |
| download | linux-dev-38fd94b0275c91071157a03cc27676909b23dcde.tar.xz linux-dev-38fd94b0275c91071157a03cc27676909b23dcde.zip | |
arm64: Work around Falkor erratum 1003
The Qualcomm Datacenter Technologies Falkor v1 CPU may allocate TLB entries
using an incorrect ASID when TTBRx_EL1 is being updated. When the erratum
is triggered, page table entries using the new translation table base
address (BADDR) will be allocated into the TLB using the old ASID. All
circumstances leading to the incorrect ASID being cached in the TLB arise
when software writes TTBRx_EL1[ASID] and TTBRx_EL1[BADDR], a memory
operation is in the process of performing a translation using the specific
TTBRx_EL1 being written, and the memory operation uses a translation table
descriptor designated as non-global. EL2 and EL3 code changing the EL1&0
ASID is not subject to this erratum because hardware is prohibited from
performing translations from an out-of-context translation regime.
Consider the following pseudo code.
write new BADDR and ASID values to TTBRx_EL1
Replacing the above sequence with the one below will ensure that no TLB
entries with an incorrect ASID are used by software.
write reserved value to TTBRx_EL1[ASID]
ISB
write new value to TTBRx_EL1[BADDR]
ISB
write new value to TTBRx_EL1[ASID]
ISB
When the above sequence is used, page table entries using the new BADDR
value may still be incorrectly allocated into the TLB using the reserved
ASID. Yet this will not reduce functionality, since TLB entries incorrectly
tagged with the reserved ASID will never be hit by a later instruction.
Based on work by Shanker Donthineni <shankerd@codeaurora.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Christopher Covington <cov@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/cpucaps.h')
| -rw-r--r-- | arch/arm64/include/asm/cpucaps.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index d1207ac696ac..fb78a5d3b60b 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -36,7 +36,8 @@ #define ARM64_MISMATCHED_CACHE_LINE_SIZE 15 #define ARM64_HAS_NO_FPSIMD 16 #define ARM64_WORKAROUND_REPEAT_TLBI 17 +#define ARM64_WORKAROUND_QCOM_FALKOR_E1003 18 -#define ARM64_NCAPS 18 +#define ARM64_NCAPS 19 #endif /* __ASM_CPUCAPS_H */ |