summaryrefslogtreecommitdiffstats
path: root/arch
diff options
context:
space:
mode:
authorMark Rutland <mark.rutland@arm.com>2018-06-15 16:47:23 +0100
committerMarc Zyngier <marc.zyngier@arm.com>2018-06-21 09:14:54 +0100
commit6ebdf4db8fa564a150f46d32178af0873eb5abbb (patch)
tree02be276f8b9df33f97f9ff14ef4c4126ad787ce1 /arch
parentba56bc3a0786992755e6804fbcbdc60ef6cfc24c (diff)
downloadlinux-6ebdf4db8fa564a150f46d32178af0873eb5abbb.tar.bz2
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.h11
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;