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arm64: cpufeature: Use IDreg override in __read_sysreg_by_encoding()

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__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: Marc Zyngier <maz@kernel.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: David Brazdil <dbrazdil@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210208095732.3267263-12-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Marc Zyngier 2021-02-08 09:57:20 +00:00 committed by Will Deacon
parent 8f266a5d87
commit b3341ae0ef
2 changed files with 14 additions and 2 deletions
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1
arch/arm64/include/asm/cpufeature.h
View File

@ -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)
{

15
arch/arm64/kernel/cpufeature.c
View File

@ -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>