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author | Mark Rutland <mark.rutland@arm.com> | 2018-06-15 18:47:23 +0300 |
---|---|---|
committer | Marc Zyngier <marc.zyngier@arm.com> | 2018-06-21 11:14:54 +0300 |
commit | 6ebdf4db8fa564a150f46d32178af0873eb5abbb (patch) | |
tree | 02be276f8b9df33f97f9ff14ef4c4126ad787ce1 /arch | |
parent | ba56bc3a0786992755e6804fbcbdc60ef6cfc24c (diff) | |
download | linux-6ebdf4db8fa564a150f46d32178af0873eb5abbb.tar.xz |
arm64: Introduce sysreg_clear_set()
Currently we have a couple of helpers to manipulate bits in particular
sysregs:
* config_sctlr_el1(u32 clear, u32 set)
* change_cpacr(u64 val, u64 mask)
The parameters of these differ in naming convention, order, and size,
which is unfortunate. They also differ slightly in behaviour, as
change_cpacr() skips the sysreg write if the bits are unchanged, which
is a useful optimization when sysreg writes are expensive.
Before we gain yet another sysreg manipulation function, let's
unify these with a common helper, providing a consistent order for
clear/set operands, and the write skipping behaviour from
change_cpacr(). Code will be migrated to the new helper in subsequent
patches.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/arm64/include/asm/sysreg.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index 6171178075dc..a8f84812c6e8 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -728,6 +728,17 @@ asm( asm volatile("msr_s " __stringify(r) ", %x0" : : "rZ" (__val)); \ } while (0) +/* + * Modify bits in a sysreg. Bits in the clear mask are zeroed, then bits in the + * set mask are set. Other bits are left as-is. + */ +#define sysreg_clear_set(sysreg, clear, set) do { \ + u64 __scs_val = read_sysreg(sysreg); \ + u64 __scs_new = (__scs_val & ~(u64)(clear)) | (set); \ + if (__scs_new != __scs_val) \ + write_sysreg(__scs_new, sysreg); \ +} while (0) + static inline void config_sctlr_el1(u32 clear, u32 set) { u32 val; |