Messages in this thread Patch in this message | | | From | Marc Zyngier <> | Subject | [PATCH v6 10/21] arm64: cpufeature: Use IDreg override in __read_sysreg_by_encoding() | Date | Mon, 1 Feb 2021 11:56:26 +0000 |
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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> --- arch/arm64/include/asm/cpufeature.h | 1 + arch/arm64/kernel/cpufeature.c | 15 +++++++++++++-- 2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index b1f53147e2b2..b5bf7af68691 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -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) { diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index a4e5c619a516..97da9ed4b79d 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -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> -- 2.29.2
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