From a31f6cf381a6f89c9f3ac4992376d2c92b07ce14 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 8 Feb 2021 09:57:20 +0000 Subject: [PATCH] FROMGIT: 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: Marc Zyngier Reviewed-by: Suzuki K Poulose Acked-by: David Brazdil Reviewed-by: Catalin Marinas Link: https://lore.kernel.org/r/20210208095732.3267263-12-maz@kernel.org Signed-off-by: Will Deacon (cherry picked from commit b3341ae0efa235726ad69e53ce83c6a3c445bda8 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/cpufeature) Signed-off-by: Will Deacon Bug: 175544340 Change-Id: Iac1fc235a5611efcd2c45dd6ec813e535e7deac9 --- 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 57f9c04770fb..42f652f88280 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 34c338518fb4..5113e9cdbb4c 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1194,14 +1194,17 @@ 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); @@ -1244,6 +1247,14 @@ 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