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arm64: Work around Falkor erratum 1009

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During a TLB invalidate sequence targeting the inner shareable domain,
Falkor may prematurely complete the DSB before all loads and stores using
the old translation are observed. Instruction fetches are not subject to
the conditions of this erratum. If the original code sequence includes
multiple TLB invalidate instructions followed by a single DSB, onle one of
the TLB instructions needs to be repeated to work around this erratum.
While the erratum only applies to cases in which the TLBI specifies the
inner-shareable domain (*IS form of TLBI) and the DSB is ISH form or
stronger (OSH, SYS), this changes applies the workaround overabundantly--
to local TLBI, DSB NSH sequences as well--for simplicity.

Based on work by Shanker Donthineni <shankerd@codeaurora.org>

Signed-off-by: Christopher Covington <cov@codeaurora.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Christopher Covington 2017-01-31 12:50:19 -05:00 committed by Will Deacon
parent ec663d967b
commit d9ff80f83e
5 changed files with 37 additions and 4 deletions
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1
Documentation/arm64/silicon-errata.txt
View file

@ -63,3 +63,4 @@ stable kernels.
| Cavium | ThunderX SMMUv2 | #27704 | N/A |
| | | | |
| Freescale/NXP | LS2080A/LS1043A | A-008585 | FSL_ERRATUM_A008585 |
| Qualcomm Tech. | Falkor v1 | E1009 | QCOM_FALKOR_ERRATUM_1009|

10
arch/arm64/Kconfig
View file

@ -480,6 +480,16 @@ config CAVIUM_ERRATUM_27456
If unsure, say Y.
config QCOM_FALKOR_ERRATUM_1009
bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
default y
help
On Falkor v1, the CPU may prematurely complete a DSB following a
TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
one more time to fix the issue.
If unsure, say Y.
endmenu

3
arch/arm64/include/asm/cpucaps.h
View file

@ -35,7 +35,8 @@
#define ARM64_HYP_OFFSET_LOW 14
#define ARM64_MISMATCHED_CACHE_LINE_SIZE 15
#define ARM64_HAS_NO_FPSIMD 16
#define ARM64_WORKAROUND_REPEAT_TLBI 17
#define ARM64_NCAPS 17
#define ARM64_NCAPS 18
#endif /* __ASM_CPUCAPS_H */

18
arch/arm64/include/asm/tlbflush.h
View file

@ -36,9 +36,21 @@
* not. The macros handles invoking the asm with or without the
* register argument as appropriate.
*/
#define __TLBI_0(op, arg) asm ("tlbi " #op)
#define __TLBI_1(op, arg) asm ("tlbi " #op ", %0" : : "r" (arg))
#define __TLBI_N(op, arg, n, ...) __TLBI_##n(op, arg)
#define __TLBI_0(op, arg) asm ("tlbi " #op "\n" \
ALTERNATIVE("nop\n nop", \
"dsb ish\n tlbi " #op, \
ARM64_WORKAROUND_REPEAT_TLBI, \
CONFIG_QCOM_FALKOR_ERRATUM_1009) \
: : )
#define __TLBI_1(op, arg) asm ("tlbi " #op ", %0\n" \
ALTERNATIVE("nop\n nop", \
"dsb ish\n tlbi " #op ", %0", \
ARM64_WORKAROUND_REPEAT_TLBI, \
CONFIG_QCOM_FALKOR_ERRATUM_1009) \
: : "r" (arg))
#define __TLBI_N(op, arg, n, ...) __TLBI_##n(op, arg)
#define __tlbi(op, ...) __TLBI_N(op, ##__VA_ARGS__, 1, 0)

9
arch/arm64/kernel/cpu_errata.c
View file

@ -133,6 +133,15 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
.def_scope = SCOPE_LOCAL_CPU,
.enable = cpu_enable_trap_ctr_access,
},
#ifdef CONFIG_QCOM_FALKOR_ERRATUM_1009
{
.desc = "Qualcomm Technologies Falkor erratum 1009",
.capability = ARM64_WORKAROUND_REPEAT_TLBI,
MIDR_RANGE(MIDR_QCOM_FALKOR_V1,
MIDR_CPU_VAR_REV(0, 0),
MIDR_CPU_VAR_REV(0, 0)),
},
#endif
{
}
};