Message ID | 20210118094533.2874082-14-maz@kernel.org (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | arm64: Early CPU feature override, and applications to VHE, BTI and PAuth | expand |
On Mon, Jan 18, 2021 at 09:45:25AM +0000, Marc Zyngier wrote: > diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h > index fe0130d6c0ff..80a5f423444e 100644 > --- a/arch/arm64/include/asm/cpufeature.h > +++ b/arch/arm64/include/asm/cpufeature.h > @@ -814,6 +814,9 @@ static inline unsigned int get_vmid_bits(u64 mmfr1) > return 8; > } > > +extern u64 id_aa64mmfr1_val; > +extern u64 id_aa64mmfr1_mask; > + > u32 get_kvm_ipa_limit(void); > void dump_cpu_features(void); > > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index 48a011935d8c..5b9343d2e9f0 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -555,6 +555,9 @@ static const struct arm64_ftr_bits ftr_raz[] = { > > #define ARM64_FTR_REG(id, table) ARM64_FTR_REG_OVERRIDE(id, table, NULL, NULL) > > +u64 id_aa64mmfr1_val; > +u64 id_aa64mmfr1_mask; > + > static const struct __ftr_reg_entry { > u32 sys_id; > struct arm64_ftr_reg *reg; > @@ -602,7 +605,8 @@ static const struct __ftr_reg_entry { > > /* Op1 = 0, CRn = 0, CRm = 7 */ > ARM64_FTR_REG(SYS_ID_AA64MMFR0_EL1, ftr_id_aa64mmfr0), > - ARM64_FTR_REG(SYS_ID_AA64MMFR1_EL1, ftr_id_aa64mmfr1), > + ARM64_FTR_REG_OVERRIDE(SYS_ID_AA64MMFR1_EL1, ftr_id_aa64mmfr1, > + &id_aa64mmfr1_val, &id_aa64mmfr1_mask), > ARM64_FTR_REG(SYS_ID_AA64MMFR2_EL1, ftr_id_aa64mmfr2), > > /* Op1 = 0, CRn = 1, CRm = 2 */ > diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c > index 392f93b67103..75d9845f489b 100644 > --- a/arch/arm64/kernel/idreg-override.c > +++ b/arch/arm64/kernel/idreg-override.c > @@ -10,6 +10,7 @@ > #include <linux/libfdt.h> > > #include <asm/cacheflush.h> > +#include <asm/cpufeature.h> > #include <asm/setup.h> > > struct reg_desc { > @@ -22,7 +23,18 @@ struct reg_desc { > } fields[]; > }; > > +static const struct reg_desc mmfr1 __initdata = { > + .name = "id_aa64mmfr1", > + .val = &id_aa64mmfr1_val, > + .mask = &id_aa64mmfr1_mask, > + .fields = { > + { "vh", ID_AA64MMFR1_VHE_SHIFT }, > + {} > + }, > +}; > + > static const struct reg_desc * const regs[] __initdata = { > + &mmfr1, > }; I'm ok in principle with how all these link together. I wonder however if we could skip the separate u64 variables and just have a struct reg_override with val and mask u64 rather than pointers. The ARM64_FTR_REG_OVERRIDE macro takes a pointer to this new struct reg_override and can access val/mask directly. Some 'const' may need to be dropped.
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index fe0130d6c0ff..80a5f423444e 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -814,6 +814,9 @@ static inline unsigned int get_vmid_bits(u64 mmfr1) return 8; } +extern u64 id_aa64mmfr1_val; +extern u64 id_aa64mmfr1_mask; + u32 get_kvm_ipa_limit(void); void dump_cpu_features(void); diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 48a011935d8c..5b9343d2e9f0 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -555,6 +555,9 @@ static const struct arm64_ftr_bits ftr_raz[] = { #define ARM64_FTR_REG(id, table) ARM64_FTR_REG_OVERRIDE(id, table, NULL, NULL) +u64 id_aa64mmfr1_val; +u64 id_aa64mmfr1_mask; + static const struct __ftr_reg_entry { u32 sys_id; struct arm64_ftr_reg *reg; @@ -602,7 +605,8 @@ static const struct __ftr_reg_entry { /* Op1 = 0, CRn = 0, CRm = 7 */ ARM64_FTR_REG(SYS_ID_AA64MMFR0_EL1, ftr_id_aa64mmfr0), - ARM64_FTR_REG(SYS_ID_AA64MMFR1_EL1, ftr_id_aa64mmfr1), + ARM64_FTR_REG_OVERRIDE(SYS_ID_AA64MMFR1_EL1, ftr_id_aa64mmfr1, + &id_aa64mmfr1_val, &id_aa64mmfr1_mask), ARM64_FTR_REG(SYS_ID_AA64MMFR2_EL1, ftr_id_aa64mmfr2), /* Op1 = 0, CRn = 1, CRm = 2 */ diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c index 392f93b67103..75d9845f489b 100644 --- a/arch/arm64/kernel/idreg-override.c +++ b/arch/arm64/kernel/idreg-override.c @@ -10,6 +10,7 @@ #include <linux/libfdt.h> #include <asm/cacheflush.h> +#include <asm/cpufeature.h> #include <asm/setup.h> struct reg_desc { @@ -22,7 +23,18 @@ struct reg_desc { } fields[]; }; +static const struct reg_desc mmfr1 __initdata = { + .name = "id_aa64mmfr1", + .val = &id_aa64mmfr1_val, + .mask = &id_aa64mmfr1_mask, + .fields = { + { "vh", ID_AA64MMFR1_VHE_SHIFT }, + {} + }, +}; + static const struct reg_desc * const regs[] __initdata = { + &mmfr1, }; static int __init find_field(const char *cmdline, const struct reg_desc *reg,
As we want to be able to disable VHE at runtime, let's match "id_aa64mmfr1.vh=" from the command line as an override. This doesn't have much effect yet as our boot code doesn't look at the cpufeature, but only at the HW registers. Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/include/asm/cpufeature.h | 3 +++ arch/arm64/kernel/cpufeature.c | 6 +++++- arch/arm64/kernel/idreg-override.c | 12 ++++++++++++ 3 files changed, 20 insertions(+), 1 deletion(-)