From: Will Deacon <will@kernel.org>
To: broonie@kernel.org
Cc: kernel-team@android.com,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Marc Zyngier <maz@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/2] arm64: Simplify early check for broken TX1 when KASLR is enabled
Date: Wed, 15 Jan 2020 14:28:59 +0000 [thread overview]
Message-ID: <20200115142900.28976-2-will@kernel.org> (raw)
In-Reply-To: <20200115142900.28976-1-will@kernel.org>
Now that the decision to use non-global mappings is stored in a variable,
the check to avoid enabling them for the terminally broken ThunderX1
platform can be simplified so that it is only keyed off the MIDR value.
Signed-off-by: Will Deacon <will@kernel.org>
---
arch/arm64/kernel/cpufeature.c | 15 ++++-----------
1 file changed, 4 insertions(+), 11 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 4a031111ceb5..d5242b44dc5a 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -980,9 +980,7 @@ has_useable_cnp(const struct arm64_cpu_capabilities *entry, int scope)
*/
bool kaslr_requires_kpti(void)
{
- bool tx1_bug;
u64 ftr;
-
if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE))
return false;
@@ -1000,18 +998,13 @@ bool kaslr_requires_kpti(void)
* Systems affected by Cavium erratum 24756 are incompatible
* with KPTI.
*/
- if (!IS_ENABLED(CONFIG_CAVIUM_ERRATUM_27456)) {
- tx1_bug = false;
- } else if (!static_branch_likely(&arm64_const_caps_ready)) {
+ if (IS_ENABLED(CONFIG_CAVIUM_ERRATUM_27456)) {
extern const struct midr_range cavium_erratum_27456_cpus[];
- tx1_bug = is_midr_in_range_list(read_cpuid_id(),
- cavium_erratum_27456_cpus);
- } else {
- tx1_bug = __cpus_have_const_cap(ARM64_WORKAROUND_CAVIUM_27456);
+ if (is_midr_in_range_list(read_cpuid_id(),
+ cavium_erratum_27456_cpus))
+ return false;
}
- if (tx1_bug)
- return false;
return kaslr_offset() > 0;
}
--
2.25.0.rc1.283.g88dfdc4193-goog
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next prev parent reply other threads:[~2020-01-15 14:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-15 14:28 [PATCH 0/2] A couple of cleanups on top of for-next/e0pd Will Deacon
2020-01-15 14:28 ` Will Deacon [this message]
2020-01-15 14:29 ` [PATCH 2/2] arm64: Use register field helper in kaslr_requires_kpti() Will Deacon
2020-01-15 17:06 ` Mark Brown
2020-01-15 15:11 ` [PATCH 0/2] A couple of cleanups on top of for-next/e0pd Catalin Marinas
2020-01-15 16:47 ` Suzuki Kuruppassery Poulose
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