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arm64: context: Fix ASID limit in boot messages 

Since commit f88f42f853 ("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: f88f42f853 ("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>
This commit is contained in:
Jean-Philippe Brucker 2020-02-27 09:34:47 +01:00 committed by Will Deacon
parent 3ba52ad55b
commit 9abd515a6e
1 changed files with 15 additions and 5 deletions
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20
arch/arm64/mm/context.c
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@ -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);