arm64: cpufeatures: Drop the ARM64_HYP_OFFSET_LOW feature flag

Now that we can dynamically compute the kernek/hyp VA mask, there
is no need for a feature flag to trigger the alternative patching.
Let's drop the flag and everything that depends on it.

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index bb26382..76a43a1 100644 (file)
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -32,7 +32,7 @@
 #define ARM64_HAS_VIRT_HOST_EXTN               11
 #define ARM64_WORKAROUND_CAVIUM_27456          12
 #define ARM64_HAS_32BIT_EL0                    13
-#define ARM64_HYP_OFFSET_LOW                   14
+/* #define ARM64_UNALLOCATED_ENTRY                     14 */
 #define ARM64_MISMATCHED_CACHE_LINE_SIZE       15
 #define ARM64_HAS_NO_FPSIMD                    16
 #define ARM64_WORKAROUND_REPEAT_TLBI           17

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 2985a06..5b25d56 100644 (file)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -831,19 +831,6 @@ 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 = __pa_symbol(__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 bool has_no_fpsimd(const struct arm64_cpu_capabilities *entry, int __unused)
 {
        u64 pfr0 = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);
@@ -1029,12 +1016,6 @@ 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,
-       },
 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
        {
                .desc = "Kernel page table isolation (KPTI)",