arm64/cpufeature: Use helper macros to specify hwcaps
At present the hwcaps are hard to read and a bit error prone since the macros used to specify matches require us to write out the register name multiple times and explicitly specify the width of the field, hopefully using the correct constant. Now that all the ID registers are generated we can improve this somewhat by redoing the macros so that we specify the register, field and minimum value symbolically and use token pasting to initialise the capability struct with the appropriate values. We move from specifying like this: HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_EL1_BT_SHIFT, 4, FTR_UNSIGNED, ID_AA64PFR1_EL1_BT_IMP, CAP_HWCAP, KERNEL_HWCAP_BTI), to this: HWCAP_CAP(ID_AA64PFR1_EL1, BT, IMP, CAP_HWCAP, KERNEL_HWCAP_BTI), which is shorter due to having less duplicate information and makes it much harder to make an error like specifying the wrong field width or an invalid enumeration value since everything must be a constant defined for the sysreg and names are only typed once. There should be no functional effect from this change, a check of the generated .rodata showed no differences. Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20221207-arm64-sysreg-helpers-v4-5-25b6b3fb9d18@kernel.orgSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>
Showing
Please register or sign in to comment