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| author | Joey Gouly <joey.gouly@arm.com> | 2021-12-10 19:54:32 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-11 14:11:51 +0300 |
| commit | 97d8bdf33182494b7cb327ed555313d17d80c639 (patch) | |
| tree | b6af0f627d775cf588d93e173373331bd4d67e2f /Documentation/arm64/cpu-feature-registers.rst | |
| parent | 162aa002ec1a78e91cf2f0b8e7450e2770b2941f (diff) | |
| download | linux-97d8bdf33182494b7cb327ed555313d17d80c639.tar.xz | |
arm64: cpufeature: add HWCAP for FEAT_RPRES
commit 1175011a7d0030d49dc9c10bde36f08f26d0a8ee upstream.
Add a new HWCAP to detect the Increased precision of Reciprocal Estimate
and Reciprocal Square Root Estimate feature (FEAT_RPRES), introduced in Armv8.7.
Also expose this to userspace in the ID_AA64ISAR2_EL1 feature register.
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211210165432.8106-4-joey.gouly@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/arm64/cpu-feature-registers.rst')
| -rw-r--r-- | Documentation/arm64/cpu-feature-registers.rst | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/arm64/cpu-feature-registers.rst b/Documentation/arm64/cpu-feature-registers.rst index 1b19d20c2dbd..749ae970c319 100644 --- a/Documentation/arm64/cpu-feature-registers.rst +++ b/Documentation/arm64/cpu-feature-registers.rst @@ -283,6 +283,14 @@ infrastructure: | AFP | [47-44] | y | +------------------------------+---------+---------+ + 9) ID_AA64ISAR2_EL1 - Instruction set attribute register 2 + + +------------------------------+---------+---------+ + | Name | bits | visible | + +------------------------------+---------+---------+ + | RPRES | [7-4] | y | + +------------------------------+---------+---------+ + Appendix I: Example ------------------- |