Add a helper to check the MIDR of the running CPU against a given MODEL and a range of revision and variants (just like we do in is_affected_midr_range()). This will be useful for early checks for MIDR to detect CPU errata.
Cc: Mark Rutland <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Will Deacon <[email protected]> Cc: Marc Zyngier <[email protected]> Signed-off-by: Suzuki K Poulose <[email protected]> --- arch/arm64/include/asm/assembler.h | 40 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index 5dc4856f3bb9..596b693edb2c 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -25,6 +25,7 @@ #include <asm/asm-offsets.h> #include <asm/cpufeature.h> +#include <asm/cputype.h> #include <asm/debug-monitors.h> #include <asm/page.h> #include <asm/pgtable-hwdef.h> @@ -516,4 +517,43 @@ alternative_endif #endif .endm +/* + * Check the MIDR_EL1 of the current CPU for a given model and a range of + * variant/revision. See asm/cputype.h for the macros used below. + * + * model: MIDR_CPU_MODEL of CPU + * rv_min: Minimum of MIDR_CPU_VAR_REV() + * rv_max: Maximum of MIDR_CPU_VAR_REV() + * res: Result register. + * tmp1, tmp2, tmp3: Temporary registers + * + * Corrupts: res, tmp1, tmp2, tmp3 + * Returns: 0, if the CPU id doesn't match. Non-zero otherwise + */ + .macro cpu_midr_match model, rv_min, rv_max, res, tmp1, tmp2, tmp3 + mrs \res, midr_el1 + mov_q \tmp1, (MIDR_REVISION_MASK | MIDR_VARIANT_MASK) + mov_q \tmp2, MIDR_CPU_MODEL_MASK + and \tmp3, \res, \tmp2 // Extract model + and \tmp1, \res, \tmp1 // rev & variant + mov_q \tmp2, \model + cmp \tmp3, \tmp2 + cset \res, eq + cbz \res, .Ldone\@ // Model matches ? + + .if (\rv_min != 0) // Skip min check if rv_min == 0 + mov_q \tmp3, \rv_min + cmp \tmp1, \tmp3 + cset \res, ge + .endif // \rv_min != 0 + /* Skip rv_max check if rv_min == rv_max && rv_min != 0 */ + .if ((\rv_min != \rv_max) || \rv_min == 0) + mov_q \tmp2, \rv_max + cmp \tmp1, \tmp2 + cset \tmp2, le + and \res, \res, \tmp2 + .endif +.Ldone\@: + .endm + #endif /* __ASM_ASSEMBLER_H */ -- 2.13.6
