diff options
| author | Andrew Murray <andrew.murray@arm.com> | 2019-04-09 10:52:40 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2019-04-16 16:27:12 +0100 |
| commit | aaba098fe6ce594ae6f963dc041be6307e499f19 (patch) | |
| tree | 619d471f27d373e460f251afacddc19889dafe5c /arch/arm64/include/uapi | |
| parent | a823c35ff2eda73046cc1847326071de350fceda (diff) | |
| download | linux-aaba098fe6ce594ae6f963dc041be6307e499f19.tar.bz2 | |
arm64: HWCAP: add support for AT_HWCAP2
As we will exhaust the first 32 bits of AT_HWCAP let's start
exposing AT_HWCAP2 to userspace to give us up to 64 caps.
Whilst it's possible to use the remaining 32 bits of AT_HWCAP, we
prefer to expand into AT_HWCAP2 in order to provide a consistent
view to userspace between ILP32 and LP64. However internal to the
kernel we prefer to continue to use the full space of elf_hwcap.
To reduce complexity and allow for future expansion, we now
represent hwcaps in the kernel as ordinals and use a
KERNEL_HWCAP_ prefix. This allows us to support automatic feature
based module loading for all our hwcaps.
We introduce cpu_set_feature to set hwcaps which complements the
existing cpu_have_feature helper. These helpers allow us to clean
up existing direct uses of elf_hwcap and reduce any future effort
required to move beyond 64 caps.
For convenience we also introduce cpu_{have,set}_named_feature which
makes use of the cpu_feature macro to allow providing a hwcap name
without a {KERNEL_}HWCAP_ prefix.
Signed-off-by: Andrew Murray <andrew.murray@arm.com>
[will: use const_ilog2() and tweak documentation]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/include/uapi')
| -rw-r--r-- | arch/arm64/include/uapi/asm/hwcap.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h index 5f0750c2199c..453b45af80b7 100644 --- a/arch/arm64/include/uapi/asm/hwcap.h +++ b/arch/arm64/include/uapi/asm/hwcap.h @@ -18,7 +18,7 @@ #define _UAPI__ASM_HWCAP_H /* - * HWCAP flags - for elf_hwcap (in kernel) and AT_HWCAP + * HWCAP flags - for AT_HWCAP */ #define HWCAP_FP (1 << 0) #define HWCAP_ASIMD (1 << 1) |