[ Upstream commit b0672bbe133ebb6f7be21fce1d742d52f25bcdc7 ]
A number of Arm Ltd CPUs suffer from errata whereby an MSR to the SSBS
special-purpose register does not affect subsequent speculative
instructions, permitting speculative store bypassing for a window of
time.
We worked around this for a number of CPUs in commits:
* 7187bb7d0b5c7dfa ("arm64: errata: Add workaround for Arm errata 3194386 and 3312417")
* 75b3c43eab594bfb ("arm64: errata: Expand speculative SSBS workaround")
Since then, similar errata have been published for a number of other Arm
Ltd CPUs, for which the same mitigation is sufficient. This is described
in their respective Software Developer Errata Notice (SDEN) documents:
* Cortex-A76 (MP052) SDEN v31.0, erratum 3324349
https://developer.arm.com/documentation/SDEN-885749/3100/
* Cortex-A77 (MP074) SDEN v19.0, erratum 3324348
https://developer.arm.com/documentation/SDEN-1152370/1900/
* Cortex-A78 (MP102) SDEN v21.0, erratum 3324344
https://developer.arm.com/documentation/SDEN-1401784/2100/
* Cortex-A78C (MP138) SDEN v16.0, erratum 3324346
https://developer.arm.com/documentation/SDEN-1707916/1600/
* Cortex-A78C (MP154) SDEN v10.0, erratum 3324347
https://developer.arm.com/documentation/SDEN-2004089/1000/
* Cortex-A725 (MP190) SDEN v5.0, erratum 3456106
https://developer.arm.com/documentation/SDEN-2832921/0500/
* Cortex-X1 (MP077) SDEN v21.0, erratum 3324344
https://developer.arm.com/documentation/SDEN-1401782/2100/
* Cortex-X1C (MP136) SDEN v16.0, erratum 3324346
https://developer.arm.com/documentation/SDEN-1707914/1600/
* Neoverse-N1 (MP050) SDEN v32.0, erratum 3324349
https://developer.arm.com/documentation/SDEN-885747/3200/
* Neoverse-V1 (MP076) SDEN v19.0, erratum 3324341
https://developer.arm.com/documentation/SDEN-1401781/1900/
Note that due to the manner in which Arm develops IP and tracks errata,
some CPUs share a common erratum number and some CPUs have multiple
erratum numbers for the same HW issue.
On parts without SB, it is necessary to use ISB for the workaround. The
spec_bar() macro used in the mitigation will expand to a "DSB SY; ISB"
sequence in this case, which is sufficient on all affected parts.
Enable the existing mitigation by adding the relevant MIDRs to
erratum_spec_ssbs_list. The list is sorted alphanumerically (involving
moving Neoverse-V3 after Neoverse-V2) so that this is easy to audit and
potentially extend again in future. The Kconfig text is also updated to
clarify the set of affected parts and the mitigation.
Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Cc: James Morse <james.morse@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Reviewed-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Acked-by: Will Deacon <will@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240801101803.1982459-4-mark.rutland@xxxxxxx
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
[ Mark: trivial backport ]
Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
---
Documentation/arch/arm64/silicon-errata.rst | 18 +++++++++++++++++
arch/arm64/Kconfig | 22 +++++++++++++++------
arch/arm64/kernel/cpu_errata.c | 11 ++++++++++-
3 files changed, 44 insertions(+), 7 deletions(-)
diff --git a/Documentation/arch/arm64/silicon-errata.rst b/Documentation/arch/arm64/silicon-errata.rst
index bb83c5d8c6755..50327c05be8d1 100644
--- a/Documentation/arch/arm64/silicon-errata.rst
+++ b/Documentation/arch/arm64/silicon-errata.rst
@@ -122,10 +122,18 @@ stable kernels.
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-A76 | #1490853 | N/A |
+----------------+-----------------+-----------------+-----------------------------+
+| ARM | Cortex-A76 | #3324349 | ARM64_ERRATUM_3194386 |
++----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-A77 | #1491015 | N/A |
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-A77 | #1508412 | ARM64_ERRATUM_1508412 |
+----------------+-----------------+-----------------+-----------------------------+
+| ARM | Cortex-A77 | #3324348 | ARM64_ERRATUM_3194386 |
++----------------+-----------------+-----------------+-----------------------------+
+| ARM | Cortex-A78 | #3324344 | ARM64_ERRATUM_3194386 |
++----------------+-----------------+-----------------+-----------------------------+
+| ARM | Cortex-A78C | #3324346,3324347| ARM64_ERRATUM_3194386 |
++----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-A710 | #2119858 | ARM64_ERRATUM_2119858 |
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-A710 | #2054223 | ARM64_ERRATUM_2054223 |
@@ -138,8 +146,14 @@ stable kernels.
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-A720 | #3456091 | ARM64_ERRATUM_3194386 |
+----------------+-----------------+-----------------+-----------------------------+
+| ARM | Cortex-A725 | #3456106 | ARM64_ERRATUM_3194386 |
++----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-X1 | #1502854 | N/A |
+----------------+-----------------+-----------------+-----------------------------+
+| ARM | Cortex-X1 | #3324344 | ARM64_ERRATUM_3194386 |
++----------------+-----------------+-----------------+-----------------------------+
+| ARM | Cortex-X1C | #3324346 | ARM64_ERRATUM_3194386 |
++----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-X2 | #2119858 | ARM64_ERRATUM_2119858 |
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-X2 | #2224489 | ARM64_ERRATUM_2224489 |
@@ -160,6 +174,8 @@ stable kernels.
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Neoverse-N1 | #1542419 | ARM64_ERRATUM_1542419 |
+----------------+-----------------+-----------------+-----------------------------+
+| ARM | Neoverse-N1 | #3324349 | ARM64_ERRATUM_3194386 |
++----------------+-----------------+-----------------+-----------------------------+
| ARM | Neoverse-N2 | #2139208 | ARM64_ERRATUM_2139208 |
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Neoverse-N2 | #2067961 | ARM64_ERRATUM_2067961 |
@@ -170,6 +186,8 @@ stable kernels.
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Neoverse-V1 | #1619801 | N/A |
+----------------+-----------------+-----------------+-----------------------------+
+| ARM | Neoverse-V1 | #3324341 | ARM64_ERRATUM_3194386 |
++----------------+-----------------+-----------------+-----------------------------+
| ARM | Neoverse-V2 | #3324336 | ARM64_ERRATUM_3194386 |
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Neoverse-V3 | #3312417 | ARM64_ERRATUM_3194386 |
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index f580f5af4a51b..11bbdc15c6e5e 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1068,18 +1068,28 @@ config ARM64_ERRATUM_3117295
If unsure, say Y.
config ARM64_ERRATUM_3194386
- bool "Cortex-{A720,X4,X925}/Neoverse-V3: workaround for MSR SSBS not self-synchronizing"
+ bool "Cortex-*/Neoverse-*: workaround for MSR SSBS not self-synchronizing"
default y
help
This option adds the workaround for the following errata:
+ * ARM Cortex-A76 erratum 3324349
+ * ARM Cortex-A77 erratum 3324348
+ * ARM Cortex-A78 erratum 3324344
+ * ARM Cortex-A78C erratum 3324346
+ * ARM Cortex-A78C erratum 3324347
* ARM Cortex-A710 erratam 3324338
* ARM Cortex-A720 erratum 3456091
+ * ARM Cortex-A725 erratum 3456106
+ * ARM Cortex-X1 erratum 3324344
+ * ARM Cortex-X1C erratum 3324346
* ARM Cortex-X2 erratum 3324338
* ARM Cortex-X3 erratum 3324335
* ARM Cortex-X4 erratum 3194386
* ARM Cortex-X925 erratum 3324334
+ * ARM Neoverse-N1 erratum 3324349
* ARM Neoverse N2 erratum 3324339
+ * ARM Neoverse-V1 erratum 3324341
* ARM Neoverse V2 erratum 3324336
* ARM Neoverse-V3 erratum 3312417
@@ -1087,11 +1097,11 @@ config ARM64_ERRATUM_3194386
subsequent speculative instructions, which may permit unexepected
speculative store bypassing.
- Work around this problem by placing a speculation barrier after
- kernel changes to SSBS. The presence of the SSBS special-purpose
- register is hidden from hwcaps and EL0 reads of ID_AA64PFR1_EL1, such
- that userspace will use the PR_SPEC_STORE_BYPASS prctl to change
- SSBS.
+ Work around this problem by placing a Speculation Barrier (SB) or
+ Instruction Synchronization Barrier (ISB) after kernel changes to
+ SSBS. The presence of the SSBS special-purpose register is hidden
+ from hwcaps and EL0 reads of ID_AA64PFR1_EL1, such that userspace
+ will use the PR_SPEC_STORE_BYPASS prctl to change SSBS.
If unsure, say Y.
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 617424b73f8c3..f6b6b45073571 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -434,15 +434,24 @@ static const struct midr_range erratum_spec_unpriv_load_list[] = {
#ifdef CONFIG_ARM64_ERRATUM_3194386
static const struct midr_range erratum_spec_ssbs_list[] = {
+ MIDR_ALL_VERSIONS(MIDR_CORTEX_A76),
+ MIDR_ALL_VERSIONS(MIDR_CORTEX_A77),
+ MIDR_ALL_VERSIONS(MIDR_CORTEX_A78),
+ MIDR_ALL_VERSIONS(MIDR_CORTEX_A78C),
MIDR_ALL_VERSIONS(MIDR_CORTEX_A710),
MIDR_ALL_VERSIONS(MIDR_CORTEX_A720),
+ MIDR_ALL_VERSIONS(MIDR_CORTEX_A725),
+ MIDR_ALL_VERSIONS(MIDR_CORTEX_X1),
+ MIDR_ALL_VERSIONS(MIDR_CORTEX_X1C),
MIDR_ALL_VERSIONS(MIDR_CORTEX_X2),
MIDR_ALL_VERSIONS(MIDR_CORTEX_X3),
MIDR_ALL_VERSIONS(MIDR_CORTEX_X4),
MIDR_ALL_VERSIONS(MIDR_CORTEX_X925),
+ MIDR_ALL_VERSIONS(MIDR_NEOVERSE_N1),
MIDR_ALL_VERSIONS(MIDR_NEOVERSE_N2),
- MIDR_ALL_VERSIONS(MIDR_NEOVERSE_V3),
+ MIDR_ALL_VERSIONS(MIDR_NEOVERSE_V1),
MIDR_ALL_VERSIONS(MIDR_NEOVERSE_V2),
+ MIDR_ALL_VERSIONS(MIDR_NEOVERSE_V3),
{}
};
#endif
--
2.30.2
