[RFC 3/9] arm64/cpufeature: add ARMv8.3 id_aa64isar1 bits

[Mark Rutland]

>From ARMv8.3 onwards, ID_AA64ISAR1 is no longer entirely RES0, and now
has four fields describing the presence of pointer authentication
functionality:

* APA - address authentication present, using an architected algorithm
* API - address authentication present, using an IMP DEF algorithm
* GPA - generic authentication present, using an architected algorithm
* GPI - generic authentication present, using an IMP DEF algoithm

This patch adds the requisite definitions so that we can identify the
presence of this functionality. For the timebeing, the features are
hidden from userspace.

Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
---
 arch/arm64/kernel/cpufeature.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 81a78d9..30255b2 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -101,7 +101,11 @@
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_LRCPC_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_FCMA_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_JSCVT_SHIFT, 4, 0),
-	ARM64_FTR_END,
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_GPI_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_GPA_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_API_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_APA_SHIFT, 4, 0),
+	ARM64_FTR_END
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
-- 
1.9.1