diff options
| -rw-r--r-- | arch/arm64/kernel/fpsimd.c | 62 |
1 files changed, 61 insertions, 1 deletions
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index fd3cfdd7f9be..88e5e6aef300 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -37,6 +37,7 @@ #include <linux/sched/task_stack.h> #include <linux/signal.h> #include <linux/slab.h> +#include <linux/sysctl.h> #include <asm/fpsimd.h> #include <asm/cputype.h> @@ -335,6 +336,65 @@ static unsigned int find_supported_vector_length(unsigned int vl) return sve_vl_from_vq(bit_to_vq(bit)); } +#ifdef CONFIG_SYSCTL + +static int sve_proc_do_default_vl(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos) +{ + int ret; + int vl = sve_default_vl; + struct ctl_table tmp_table = { + .data = &vl, + .maxlen = sizeof(vl), + }; + + ret = proc_dointvec(&tmp_table, write, buffer, lenp, ppos); + if (ret || !write) + return ret; + + /* Writing -1 has the special meaning "set to max": */ + if (vl == -1) { + /* Fail safe if sve_max_vl wasn't initialised */ + if (WARN_ON(!sve_vl_valid(sve_max_vl))) + vl = SVE_VL_MIN; + else + vl = sve_max_vl; + + goto chosen; + } + + if (!sve_vl_valid(vl)) + return -EINVAL; + + vl = find_supported_vector_length(vl); +chosen: + sve_default_vl = vl; + return 0; +} + +static struct ctl_table sve_default_vl_table[] = { + { + .procname = "sve_default_vector_length", + .mode = 0644, + .proc_handler = sve_proc_do_default_vl, + }, + { } +}; + +static int __init sve_sysctl_init(void) +{ + if (system_supports_sve()) + if (!register_sysctl("abi", sve_default_vl_table)) + return -EINVAL; + + return 0; +} + +#else /* ! CONFIG_SYSCTL */ +static int __init sve_sysctl_init(void) { return 0; } +#endif /* ! CONFIG_SYSCTL */ + #define ZREG(sve_state, vq, n) ((char *)(sve_state) + \ (SVE_SIG_ZREG_OFFSET(vq, n) - SVE_SIG_REGS_OFFSET)) @@ -1209,6 +1269,6 @@ static int __init fpsimd_init(void) if (!(elf_hwcap & HWCAP_ASIMD)) pr_notice("Advanced SIMD is not implemented\n"); - return 0; + return sve_sysctl_init(); } late_initcall(fpsimd_init); |