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| author |   Dave Martin <Dave.Martin@arm.com> | 2017-10-31 15:51:19 +0000 |
|---|---|---|
| committer |   Will Deacon <will.deacon@arm.com> | 2017-11-03 15:24:21 +0000 |
| commit | 43994d824e8443263dc98b151e6326bf677be52e (patch) | |
| tree | ef769d01442f52999428d241b02b0c849489842b /arch/arm64/kernel/entry.S | |
| parent | arm64/sve: KVM: Hide SVE from CPU features exposed to guests (diff) | |
| download | linux-dev-43994d824e8443263dc98b151e6326bf677be52e.tar.xz linux-dev-43994d824e8443263dc98b151e6326bf677be52e.zip | |
arm64/sve: Detect SVE and activate runtime support
This patch enables detection of hardware SVE support via the
cpufeatures framework, and reports its presence to the kernel and
userspace via the new ARM64_SVE cpucap and HWCAP_SVE hwcap
respectively.
Userspace can also detect SVE using ID_AA64PFR0_EL1, using the
cpufeatures MRS emulation.
When running on hardware that supports SVE, this enables runtime
kernel support for SVE, and allows user tasks to execute SVE
instructions and make of the of the SVE-specific user/kernel
interface extensions implemented by this series.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/kernel/entry.S')
| -rw-r--r-- | arch/arm64/kernel/entry.S | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index a989e234dc32..6d14b8f29b5f 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -867,9 +867,10 @@ el0_svc: mov wscno, w8 // syscall number in w8 mov wsc_nr, #__NR_syscalls -#ifndef CONFIG_ARM64_SVE +#ifdef CONFIG_ARM64_SVE +alternative_if_not ARM64_SVE b el0_svc_naked -#else +alternative_else_nop_endif tbz x16, #TIF_SVE, el0_svc_naked // Skip unless TIF_SVE set: bic x16, x16, #_TIF_SVE // discard SVE state str x16, [tsk, #TSK_TI_FLAGS] @@ -884,7 +885,7 @@ el0_svc: mrs x9, cpacr_el1 bic x9, x9, #CPACR_EL1_ZEN_EL0EN // disable SVE for el0 msr cpacr_el1, x9 // synchronised by eret to el0 -#endif /* CONFIG_ARM64_SVE */ +#endif el0_svc_naked: // compat entry point stp x0, xscno, [sp, #S_ORIG_X0] // save the original x0 and syscall number |