From: Mark Rutland mark.rutland@arm.com
[ Upstream commit 6ebdf4db8fa564a150f46d32178af0873eb5abbb ]
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 Signed-off-by: Ard Biesheuvel ard.biesheuvel@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/include/asm/sysreg.h | 11 +++++++++++ 1 file changed, 11 insertions(+)
--- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -584,6 +584,17 @@ 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;