* [PATCH 1/2] arm64: Simplify early check for broken TX1 when KASLR is enabled
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
2020-01-15 14:29 ` [PATCH 2/2] arm64: Use register field helper in kaslr_requires_kpti() Will Deacon
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Will Deacon @ 2020-01-15 14:28 UTC (permalink / raw)
To: broonie
Cc: kernel-team, Suzuki K Poulose, Marc Zyngier, Catalin Marinas,
Will Deacon, linux-arm-kernel
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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^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 2/2] arm64: Use register field helper in kaslr_requires_kpti()
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 ` [PATCH 1/2] arm64: Simplify early check for broken TX1 when KASLR is enabled Will Deacon
@ 2020-01-15 14:29 ` 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
3 siblings, 1 reply; 6+ messages in thread
From: Will Deacon @ 2020-01-15 14:29 UTC (permalink / raw)
To: broonie
Cc: kernel-team, Suzuki K Poulose, Marc Zyngier, Catalin Marinas,
Will Deacon, linux-arm-kernel
Rather than open-code the extraction of the E0PD field from the MMFR2
register, we can use the cpuid_feature_extract_unsigned_field() helper
instead.
Signed-off-by: Will Deacon <will@kernel.org>
---
arch/arm64/kernel/cpufeature.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index d5242b44dc5a..1ebeb5bc17d2 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -980,7 +980,6 @@ has_useable_cnp(const struct arm64_cpu_capabilities *entry, int scope)
*/
bool kaslr_requires_kpti(void)
{
- u64 ftr;
if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE))
return false;
@@ -989,8 +988,9 @@ bool kaslr_requires_kpti(void)
* where available.
*/
if (IS_ENABLED(CONFIG_ARM64_E0PD)) {
- ftr = read_sysreg_s(SYS_ID_AA64MMFR2_EL1);
- if ((ftr >> ID_AA64MMFR2_E0PD_SHIFT) & 0xf)
+ u64 mmfr2 = read_sysreg_s(SYS_ID_AA64MMFR2_EL1);
+ if (cpuid_feature_extract_unsigned_field(mmfr2,
+ ID_AA64MMFR2_E0PD_SHIFT))
return false;
}
--
2.25.0.rc1.283.g88dfdc4193-goog
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^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH 2/2] arm64: Use register field helper in kaslr_requires_kpti()
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
0 siblings, 0 replies; 6+ messages in thread
From: Mark Brown @ 2020-01-15 17:06 UTC (permalink / raw)
To: Will Deacon
Cc: Marc Zyngier, Catalin Marinas, kernel-team, linux-arm-kernel,
Suzuki K Poulose
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On Wed, Jan 15, 2020 at 02:29:00PM +0000, Will Deacon wrote:
> Rather than open-code the extraction of the E0PD field from the MMFR2
> register, we can use the cpuid_feature_extract_unsigned_field() helper
> instead.
This was suggested by Suzuki at some point but I ended up not
doing it as the helper function name is so long I couldn't work
out how to lay the code out in a satisfactory way at the time.
Reviewed-by: Mark Brown <broonie@kernel.org>
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 0/2] A couple of cleanups on top of for-next/e0pd
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 ` [PATCH 1/2] arm64: Simplify early check for broken TX1 when KASLR is enabled Will Deacon
2020-01-15 14:29 ` [PATCH 2/2] arm64: Use register field helper in kaslr_requires_kpti() Will Deacon
@ 2020-01-15 15:11 ` Catalin Marinas
2020-01-15 16:47 ` Suzuki Kuruppassery Poulose
3 siblings, 0 replies; 6+ messages in thread
From: Catalin Marinas @ 2020-01-15 15:11 UTC (permalink / raw)
To: Will Deacon
Cc: Marc Zyngier, broonie, kernel-team, linux-arm-kernel,
Suzuki K Poulose
On Wed, Jan 15, 2020 at 02:28:58PM +0000, Will Deacon wrote:
> Will Deacon (2):
> arm64: Simplify early check for broken TX1 when KASLR is enabled
> arm64: Use register field helper in kaslr_requires_kpti()
The clean-ups look fine to me. With the latest patches we never call
kaslr_requires_kpti() after arm64_const_caps_ready has been set.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 0/2] A couple of cleanups on top of for-next/e0pd
2020-01-15 14:28 [PATCH 0/2] A couple of cleanups on top of for-next/e0pd Will Deacon
` (2 preceding siblings ...)
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
3 siblings, 0 replies; 6+ messages in thread
From: Suzuki Kuruppassery Poulose @ 2020-01-15 16:47 UTC (permalink / raw)
To: Will Deacon, broonie
Cc: Catalin Marinas, kernel-team, linux-arm-kernel, Marc Zyngier
On 15/01/2020 14:28, Will Deacon wrote:
> Hi Mark,
>
> I've queued the E0PD patches for 5.6 (thanks!), but in reading them a
> final time I noticed a couple of cleanups that I think we can make to
> kaslr_requires_kpti(). I don't have a TX1 to test them on, but I think
> the logic is sound.
>
> Please take a look, as I'd like to queue these on top.
>
> Thanks.
>
> Will
>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> Cc: Marc Zyngier <maz@kernel.org>
Looks good to me.
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
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^ permalink raw reply [flat|nested] 6+ messages in thread