arm64: context: Fix ASID limit in boot messages (9abd515a) · Commits · 戴 / test

Since commit ("arm64: context: Free up kernel ASIDs if KPTI is not in use"), the NUM_USER_ASIDS macro doesn't correspond to the effective number of ASIDs when KPTI is enabled. Get an accurate number of available ASIDs in an arch_initcall, once we've discovered all CPUs' capabilities and know if we still need to halve the ASID space for KPTI. Fixes: ("arm64: context: Free up kernel ASIDs if KPTI is not in use") Reviewed-by:

Vladimir Murzin <vladimir.murzin@arm.com> Signed-off-by:

Jean-Philippe Brucker <jean-philippe@linaro.org> Signed-off-by:

Will Deacon <will@kernel.org>

arch/arm64/mm/context.c

+15 −5

Original line number	Diff line number	Diff line
		@@ -260,14 +260,26 @@ asmlinkage void post_ttbr_update_workaround(void)
		CONFIG_CAVIUM_ERRATUM_27456));
		}

		static int asids_init(void)
		static int asids_update_limit(void)
		{
		asid_bits = get_cpu_asid_bits();
		unsigned long num_available_asids = NUM_USER_ASIDS;

		if (arm64_kernel_unmapped_at_el0())
		num_available_asids /= 2;
		/*
		* Expect allocation after rollover to fail if we don't have at least
		* one more ASID than CPUs. ASID #0 is reserved for init_mm.
		*/
		WARN_ON(NUM_USER_ASIDS - 1 <= num_possible_cpus());
		WARN_ON(num_available_asids - 1 <= num_possible_cpus());
		pr_info("ASID allocator initialised with %lu entries\n",
		num_available_asids);
		return 0;
		}
		arch_initcall(asids_update_limit);

		static int asids_init(void)
		{
		asid_bits = get_cpu_asid_bits();
		atomic64_set(&asid_generation, ASID_FIRST_VERSION);
		asid_map = kcalloc(BITS_TO_LONGS(NUM_USER_ASIDS), sizeof(*asid_map),
		GFP_KERNEL);
		@@ -282,8 +294,6 @@ static int asids_init(void)
		*/
		if (IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0))
		set_kpti_asid_bits();

		pr_info("ASID allocator initialised with %lu entries\n", NUM_USER_ASIDS);
		return 0;
		}
		early_initcall(asids_init);

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