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| author | Marc Zyngier <marc.zyngier@arm.com> | 2016-06-30 19:40:42 +0200 |
|---|---|---|
| committer | Christoffer Dall <christoffer.dall@linaro.org> | 2016-07-03 23:41:27 +0200 |
| commit | d174591016ce9fcb61182e2a4d0aac951900fc32 (patch) | |
| tree | 20fb2ddc5379147ea866237838202cf00459a874 /arch | |
| parent | arm/arm64: KVM: Export __hyp_text_start/end symbols (diff) | |
| download | linux-d174591016ce9fcb61182e2a4d0aac951900fc32.tar.xz linux-d174591016ce9fcb61182e2a4d0aac951900fc32.zip | |
arm64: KVM: Runtime detection of lower HYP offset
Add the code that enables the switch to the lower HYP VA range.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'arch')
| -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 811773d1c1d0..ffb3e14dda60 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -726,6 +726,19 @@ static bool runs_at_el2(const struct arm64_cpu_capabilities *entry, int __unused return is_kernel_in_hyp_mode(); } +static bool hyp_offset_low(const struct arm64_cpu_capabilities *entry, + int __unused) +{ + phys_addr_t idmap_addr = virt_to_phys(__hyp_idmap_text_start); + + /* + * Activate the lower HYP offset only if: + * - the idmap doesn't clash with it, + * - the kernel is not running at EL2. + */ + return idmap_addr > GENMASK(VA_BITS - 2, 0) && !is_kernel_in_hyp_mode(); +} + static const struct arm64_cpu_capabilities arm64_features[] = { { .desc = "GIC system register CPU interface", @@ -803,6 +816,12 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .field_pos = ID_AA64PFR0_EL0_SHIFT, .min_field_value = ID_AA64PFR0_EL0_32BIT_64BIT, }, + { + .desc = "Reduced HYP mapping offset", + .capability = ARM64_HYP_OFFSET_LOW, + .def_scope = SCOPE_SYSTEM, + .matches = hyp_offset_low, + }, {}, }; |