On Wed, Oct 21, 2020 at 11:46:11AM +0100, Qais Yousef wrote: > So that userspace can detect if the cpu has aarch32 support at EL0. > > CPUREGS_ATTR_RO() was renamed to CPUREGS_RAW_ATTR_RO() to better reflect > what it does. And fixed to accept both u64 and u32 without causing the > printf to print out a warning about mismatched type. This was caught > while testing to check the new CPUREGS_USER_ATTR_RO(). > > The new CPUREGS_USER_ATTR_RO() exports a Sanitised or RAW sys_reg based > on a @cond to user space. The exported fields match the definition in > arm64_ftr_reg so that the content of a register exported via MRS and > sysfs are kept cohesive. > > The @cond in our case is that the system is asymmetric aarch32 and the > controlling sysctl.enable_asym_32bit is enabled. > > Update Documentation/arm64/cpu-feature-registers.rst to reflect the > newly visible EL0 field in ID_AA64FPR0_EL1. > > Note that the MRS interface will still return the sanitized content > _only_. > > Signed-off-by: Qais Yousef <qais.yousef@xxxxxxx> > --- > > Example output. I was surprised that the 2nd field (bits[7:4]) is printed out > although it's set as FTR_HIDDEN. > > # cat /sys/devices/system/cpu/cpu*/regs/identification/id_aa64pfr0 > 0x0000000000000011 > 0x0000000000000011 > 0x0000000000000011 > 0x0000000000000011 > 0x0000000000000011 > 0x0000000000000011 > > # echo 1 > /proc/sys/kernel/enable_asym_32bit > > # cat /sys/devices/system/cpu/cpu*/regs/identification/id_aa64pfr0 > 0x0000000000000011 > 0x0000000000000011 > 0x0000000000000012 > 0x0000000000000012 > 0x0000000000000011 > 0x0000000000000011 > > Documentation/arm64/cpu-feature-registers.rst | 2 +- > arch/arm64/kernel/cpufeature.c | 2 +- > arch/arm64/kernel/cpuinfo.c | 58 +++++++++++++++++-- > 3 files changed, 54 insertions(+), 8 deletions(-) > > diff --git a/Documentation/arm64/cpu-feature-registers.rst b/Documentation/arm64/cpu-feature-registers.rst > index f28853f80089..bfcbda6d6f35 100644 > --- a/Documentation/arm64/cpu-feature-registers.rst > +++ b/Documentation/arm64/cpu-feature-registers.rst > @@ -166,7 +166,7 @@ infrastructure: > +------------------------------+---------+---------+ > | EL1 | [7-4] | n | > +------------------------------+---------+---------+ > - | EL0 | [3-0] | n | > + | EL0 | [3-0] | y | > +------------------------------+---------+---------+ > > > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index 6f795c8221f4..0f7307c8ad80 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -221,7 +221,7 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = { > ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL3_SHIFT, 4, 0), > ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL2_SHIFT, 4, 0), > ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_SHIFT, 4, ID_AA64PFR0_EL1_64BIT_ONLY), > - ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL0_SHIFT, 4, ID_AA64PFR0_EL0_64BIT_ONLY), > + ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL0_SHIFT, 4, ID_AA64PFR0_EL0_64BIT_ONLY), > ARM64_FTR_END, > }; > > diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c > index 93c55986ca7f..632b9d5b5230 100644 > --- a/arch/arm64/kernel/cpuinfo.c > +++ b/arch/arm64/kernel/cpuinfo.c > @@ -231,25 +231,71 @@ static struct kobj_type cpuregs_kobj_type = { > * future expansion without an ABI break. > */ > #define kobj_to_cpuinfo(kobj) container_of(kobj, struct cpuinfo_arm64, kobj) > -#define CPUREGS_ATTR_RO(_name, _field) \ > +#define CPUREGS_RAW_ATTR_RO(_name, _field) \ > static ssize_t _name##_show(struct kobject *kobj, \ > struct kobj_attribute *attr, char *buf) \ > { \ > struct cpuinfo_arm64 *info = kobj_to_cpuinfo(kobj); \ > \ > - if (info->reg_midr) \ > - return sprintf(buf, "0x%016x\n", info->reg_##_field); \ > - else \ > + if (info->reg_midr) { \ > + u64 val = info->reg_##_field; \ > + return sprintf(buf, "0x%016llx\n", val); \ Nit, for sysfs, use the new sysfs_emit() call instead of sprintf(). thanks, greg k-h