Commit b3341ae0 authored by Marc Zyngier's avatar Marc Zyngier Committed by Will Deacon
Browse files

arm64: cpufeature: Use IDreg override in __read_sysreg_by_encoding() 



__read_sysreg_by_encoding() is used by a bunch of cpufeature helpers,
which should take the feature override into account. Let's do that.

For a good measure (and because we are likely to need to further
down the line), make this helper available to the rest of the
non-modular kernel.

Code that needs to know the *real* features of a CPU can still
use read_sysreg_s(), and find the bare, ugly truth.

Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Reviewed-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: default avatarDavid Brazdil <dbrazdil@google.com>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210208095732.3267263-12-maz@kernel.org


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 8f266a5d

arch/arm64/include/asm/cpufeature.h

+1 −0
Original line number Diff line number Diff line
@@ -606,6 +606,7 @@ void __init setup_cpu_features(void); 
void check_local_cpu_capabilities(void);



u64 read_sanitised_ftr_reg(u32 id);

u64 __read_sysreg_by_encoding(u32 sys_id);



static inline bool cpu_supports_mixed_endian_el0(void)

{

arch/arm64/kernel/cpufeature.c

+13 −2
Original line number Diff line number Diff line
@@ -1148,14 +1148,17 @@ u64 read_sanitised_ftr_reg(u32 id) 
EXPORT_SYMBOL_GPL(read_sanitised_ftr_reg);



#define read_sysreg_case(r)	\

	case r:		return read_sysreg_s(r)

	case r:		val = read_sysreg_s(r); break;



/*

 * __read_sysreg_by_encoding() - Used by a STARTING cpu before cpuinfo is populated.

 * Read the system register on the current CPU

 */

static u64 __read_sysreg_by_encoding(u32 sys_id)

u64 __read_sysreg_by_encoding(u32 sys_id)

{

	struct arm64_ftr_reg *regp;

	u64 val;



	switch (sys_id) {

	read_sysreg_case(SYS_ID_PFR0_EL1);

	read_sysreg_case(SYS_ID_PFR1_EL1);
@@ -1198,6 +1201,14 @@ static u64 __read_sysreg_by_encoding(u32 sys_id) 
		BUG();

		return 0;

	}



	regp  = get_arm64_ftr_reg(sys_id);

	if (regp) {

		val &= ~regp->override->mask;

		val |= (regp->override->val & regp->override->mask);

	}



	return val;

}



#include <linux/irqchip/arm-gic-v3.h>