[PATCH v14 10/39] arm64/sme: Implement sysctl to set the default vector length

Mark Brown
2022-04-19T11:24:14Z

As for SVE provide a sysctl which allows the default SME vector length to
be configured.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
---
arch/arm64/kernel/fpsimd.c | 29 ++++++++++++++++++++++++++++-
1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 5e5fbd9cba75..754a96563f6f 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -489,6 +489,30 @@ static int __init sve_sysctl_init(void)
static int __init sve_sysctl_init(void) { return 0; }
#endif /* ! (CONFIG_ARM64_SVE && CONFIG_SYSCTL) */

+#if defined(CONFIG_ARM64_SME) && defined(CONFIG_SYSCTL)
+static struct ctl_table sme_default_vl_table[] = {
+ {
+ .procname = "sme_default_vector_length",
+ .mode = 0644,
+ .proc_handler = vec_proc_do_default_vl,
+ .extra1 = &vl_info[ARM64_VEC_SME],
+ },
+ { }
+};
+
+static int __init sme_sysctl_init(void)
+{
+ if (system_supports_sme())
+ if (!register_sysctl("abi", sme_default_vl_table))
+ return -EINVAL;
+
+ return 0;
+}
+
+#else /* ! (CONFIG_ARM64_SME && CONFIG_SYSCTL) */
+static int __init sme_sysctl_init(void) { return 0; }
+#endif /* ! (CONFIG_ARM64_SME && CONFIG_SYSCTL) */
+
#define ZREG(sve_state, vq, n) ((char *)(sve_state) + \
(SVE_SIG_ZREG_OFFSET(vq, n) - SVE_SIG_REGS_OFFSET))

@@ -1687,6 +1711,9 @@ static int __init fpsimd_init(void)
if (cpu_have_named_feature(SME) && !cpu_have_named_feature(SVE))
pr_notice("SME is implemented but not SVE\n");

- return sve_sysctl_init();
+ sve_sysctl_init();
+ sme_sysctl_init();
+
+ return 0;
}
core_initcall(fpsimd_init);