[PATCH v3 10/21] arm64: cpufeature: Use IDreg override in __read_sysreg_by_encoding()
From: Marc Zyngier <maz@kernel.org>
Date: 2021-01-11 13:40:00
Also in:
kvmarm, lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
__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> --- 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 465d2cb63bfc..fe0130d6c0ff 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h@@ -602,6 +602,7 @@ 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 492321054bd5..1cc93a2324dc 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c@@ -1131,14 +1131,17 @@ 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);
@@ -1181,6 +1184,14 @@ static u64 __read_sysreg_by_encoding(u32 sys_id) BUG(); return 0; } + + regp = get_arm64_ftr_reg(sys_id); + if (regp && regp->override_mask && regp->override_val) { + 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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