From: Will Deacon will.deacon@arm.com
commit 0c8ea531b774 upstream.
In preparation for separate kernel/user ASIDs, allocate them in pairs for each mm_struct. The bottom bit distinguishes the two: if it is set, then the ASID will map only userspace.
Reviewed-by: Mark Rutland mark.rutland@arm.com Tested-by: Laura Abbott labbott@redhat.com Tested-by: Shanker Donthineni shankerd@codeaurora.org Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Alex Shi alex.shi@linaro.org [v4.9 backport] Signed-off-by: Mark Rutland mark.rutland@arm.com [v4.9 backport] --- arch/arm64/include/asm/mmu.h | 2 ++ arch/arm64/mm/context.c | 25 +++++++++++++++++-------- 2 files changed, 19 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h index 8d9fce037b2f..49924e56048e 100644 --- a/arch/arm64/include/asm/mmu.h +++ b/arch/arm64/include/asm/mmu.h @@ -16,6 +16,8 @@ #ifndef __ASM_MMU_H #define __ASM_MMU_H
+#define USER_ASID_FLAG (UL(1) << 48) + typedef struct { atomic64_t id; void *vdso; diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c index efcf1f7ef1e4..f00f5eeb556f 100644 --- a/arch/arm64/mm/context.c +++ b/arch/arm64/mm/context.c @@ -39,7 +39,16 @@ static cpumask_t tlb_flush_pending;
#define ASID_MASK (~GENMASK(asid_bits - 1, 0)) #define ASID_FIRST_VERSION (1UL << asid_bits) -#define NUM_USER_ASIDS ASID_FIRST_VERSION + +#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 +#define NUM_USER_ASIDS (ASID_FIRST_VERSION >> 1) +#define asid2idx(asid) (((asid) & ~ASID_MASK) >> 1) +#define idx2asid(idx) (((idx) << 1) & ~ASID_MASK) +#else +#define NUM_USER_ASIDS (ASID_FIRST_VERSION) +#define asid2idx(asid) ((asid) & ~ASID_MASK) +#define idx2asid(idx) asid2idx(idx) +#endif
/* Get the ASIDBits supported by the current CPU */ static u32 get_cpu_asid_bits(void) @@ -104,7 +113,7 @@ static void flush_context(unsigned int cpu) */ if (asid == 0) asid = per_cpu(reserved_asids, i); - __set_bit(asid & ~ASID_MASK, asid_map); + __set_bit(asid2idx(asid), asid_map); per_cpu(reserved_asids, i) = asid; }
@@ -159,16 +168,16 @@ static u64 new_context(struct mm_struct *mm, unsigned int cpu) * We had a valid ASID in a previous life, so try to re-use * it if possible. */ - asid &= ~ASID_MASK; - if (!__test_and_set_bit(asid, asid_map)) + if (!__test_and_set_bit(asid2idx(asid), asid_map)) return newasid; }
/* * Allocate a free ASID. If we can't find one, take a note of the - * currently active ASIDs and mark the TLBs as requiring flushes. - * We always count from ASID #1, as we use ASID #0 when setting a - * reserved TTBR0 for the init_mm. + * currently active ASIDs and mark the TLBs as requiring flushes. We + * always count from ASID #2 (index 1), as we use ASID #0 when setting + * a reserved TTBR0 for the init_mm and we allocate ASIDs in even/odd + * pairs. */ asid = find_next_zero_bit(asid_map, NUM_USER_ASIDS, cur_idx); if (asid != NUM_USER_ASIDS) @@ -185,7 +194,7 @@ static u64 new_context(struct mm_struct *mm, unsigned int cpu) set_asid: __set_bit(asid, asid_map); cur_idx = asid; - return asid | generation; + return idx2asid(asid) | generation; }
void check_and_switch_context(struct mm_struct *mm, unsigned int cpu)