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authorJean-Philippe Brucker <jean-philippe@linaro.org>2020-02-27 09:34:47 +0100
committerWill Deacon <will@kernel.org>2020-03-02 12:10:38 +0000
commit9abd515a6e4a5c58c6eb4d04110430325eb5f5ac (patch)
treea28cd22425a5ecb8c68df9aec0ff08c26c041c91 /arch
parent3ba52ad55b533760a1f65836aa0ec9d35e36bb4f (diff)
arm64: context: Fix ASID limit in boot messages
Since commit f88f42f853a8 ("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: f88f42f853a8 ("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>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/mm/context.c20
1 files changed, 15 insertions, 5 deletions
diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c
index 8ef73e89d514..d89bb22589f6 100644
--- a/arch/arm64/mm/context.c
+++ b/arch/arm64/mm/context.c
@@ -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);