From cdcb5ae8f013be7316832e6cfa07f98151696856 Mon Sep 17 00:00:00 2001
From: Will Deacon <will.deacon@arm.com>
Date: Tue, 14 Nov 2017 14:29:19 +0000
Subject: [PATCH 46/51] arm64: erratum: Work around Falkor erratum #E1003 in
trampoline code
Git-commit: d1777e686ad10ba7c594304429c6045fb79255a1
Patch-mainline: v4.16-rc1
References: bsc#1068032
We rely on an atomic swizzling of TTBR1 when transitioning from the entry
trampoline to the kernel proper on an exception. We can't rely on this
atomicity in the face of Falkor erratum #E1003, so on affected cores we
can issue a TLB invalidation to invalidate the walk cache prior to
jumping into the kernel. There is still the possibility of a TLB conflict
here due to conflicting walk cache entries prior to the invalidation, but
this doesn't appear to be the case on these CPUs in practice.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Tested-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
arch/arm64/Kconfig | 17 +++++------------
arch/arm64/kernel/entry.S | 12 ++++++++++++
2 files changed, 17 insertions(+), 12 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 0178b5324eff..0b2ecb24fa80 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -486,20 +486,13 @@ config CAVIUM_ERRATUM_27456
config QCOM_FALKOR_ERRATUM_1003
bool "Falkor E1003: Incorrect translation due to ASID change"
default y
- select ARM64_PAN if ARM64_SW_TTBR0_PAN
help
On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
- and BADDR are changed together in TTBRx_EL1. The workaround for this
- issue is to use a reserved ASID in cpu_do_switch_mm() before
- switching to the new ASID. Saying Y here selects ARM64_PAN if
- ARM64_SW_TTBR0_PAN is selected. This is done because implementing and
- maintaining the E1003 workaround in the software PAN emulation code
- would be an unnecessary complication. The affected Falkor v1 CPU
- implements ARMv8.1 hardware PAN support and using hardware PAN
- support versus software PAN emulation is mutually exclusive at
- runtime.
-
- If unsure, say Y.
+ and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
+ in TTBR1_EL1, this situation only occurs in the entry trampoline and
+ then only for entries in the walk cache, since the leaf translation
+ is unchanged. Work around the erratum by invalidating the walk cache
+ entries for the trampoline before entering the kernel proper.
config QCOM_FALKOR_ERRATUM_1009
bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index c17673415d00..4a6bb4e06cd5 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -964,6 +964,18 @@ __ni_sys_trace:
sub \tmp, \tmp, #(SWAPPER_DIR_SIZE + RESERVED_TTBR0_SIZE)
bic \tmp, \tmp, #USER_ASID_FLAG
msr ttbr1_el1, \tmp
+#ifdef CONFIG_QCOM_FALKOR_ERRATUM_1003
+alternative_if ARM64_WORKAROUND_QCOM_FALKOR_E1003
+ /* ASID already in \tmp[63:48] */
+ movk \tmp, #:abs_g2_nc:(TRAMP_VALIAS >> 12)
+ movk \tmp, #:abs_g1_nc:(TRAMP_VALIAS >> 12)
+ /* 2MB boundary containing the vectors, so we nobble the walk cache */
+ movk \tmp, #:abs_g0_nc:((TRAMP_VALIAS & ~(SZ_2M - 1)) >> 12)
+ isb
+ tlbi vae1, \tmp
+ dsb nsh
+alternative_else_nop_endif
+#endif /* CONFIG_QCOM_FALKOR_ERRATUM_1003 */
.endm
.macro tramp_unmap_kernel, tmp
--
2.11.0