diff options
| author | Will Deacon <will@kernel.org> | 2021-07-30 12:24:40 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-08-20 12:33:07 +0200 |
| commit | 7af33504d1c8077b40121294b5eb6e680a859468 (patch) | |
| tree | 0e752bf86c2ee085da287eab821325e9cd6faca0 /arch/arm64/kernel/cpufeature.c | |
| parent | df950811f4a884d08f05e22a8e0089d54bb4ba70 (diff) | |
arm64: Advertise CPUs capable of running 32-bit applications in sysfs
Since 32-bit applications will be killed if they are caught trying to
execute on a 64-bit-only CPU in a mismatched system, advertise the set
of 32-bit capable CPUs to userspace in sysfs.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210730112443.23245-14-will@kernel.org
Diffstat (limited to 'arch/arm64/kernel/cpufeature.c')
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 0af584549499..0a9bc7eff26e 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -67,6 +67,7 @@ #include <linux/crash_dump.h> #include <linux/sort.h> #include <linux/stop_machine.h> +#include <linux/sysfs.h> #include <linux/types.h> #include <linux/minmax.h> #include <linux/mm.h> @@ -1321,6 +1322,24 @@ const struct cpumask *system_32bit_el0_cpumask(void) return cpu_possible_mask; } +static ssize_t aarch32_el0_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + const struct cpumask *mask = system_32bit_el0_cpumask(); + + return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(mask)); +} +static const DEVICE_ATTR_RO(aarch32_el0); + +static int __init aarch32_el0_sysfs_init(void) +{ + if (!allow_mismatched_32bit_el0) + return 0; + + return device_create_file(cpu_subsys.dev_root, &dev_attr_aarch32_el0); +} +device_initcall(aarch32_el0_sysfs_init); + static bool has_32bit_el0(const struct arm64_cpu_capabilities *entry, int scope) { if (!has_cpuid_feature(entry, scope)) |