The kernel may not support SVE if CONFIG_ARM64_SVE is not set and
will hide the feature from the from userspace.

Unfortunately, the fields of ID_AA64ZFR0_EL1 are still exposed and could
lead to undefined behavior in userspace.

The kernel should not used the register when CONFIG_SVE is disabled.
Therefore, we only need to hidden them from the userspace.

Signed-off-by: Julien Grall <julien.gr...@arm.com>
Fixes: 06a916feca2b ('arm64: Expose SVE2 features for userspace')
---
 arch/arm64/kernel/cpufeature.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index cabebf1a7976..80f459ad0190 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -176,11 +176,16 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = {
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = {
-       ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 
ID_AA64ZFR0_SM4_SHIFT, 4, 0),
-       ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 
ID_AA64ZFR0_SHA3_SHIFT, 4, 0),
-       ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 
ID_AA64ZFR0_BITPERM_SHIFT, 4, 0),
-       ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 
ID_AA64ZFR0_AES_SHIFT, 4, 0),
-       ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, 
ID_AA64ZFR0_SVEVER_SHIFT, 4, 0),
+       ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
+                      FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SM4_SHIFT, 4, 0),
+       ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
+                      FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SHA3_SHIFT, 4, 
0),
+       ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
+                      FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_BITPERM_SHIFT, 
4, 0),
+       ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
+                      FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_AES_SHIFT, 4, 0),
+       ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
+                      FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SVEVER_SHIFT, 4, 
0),
        ARM64_FTR_END,
 };
 
-- 
2.11.0

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