diff options
Diffstat (limited to 'arch/arm64/include/asm/mmu_context.h')
| -rw-r--r-- | arch/arm64/include/asm/mmu_context.h | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h index 600eacb..b1b2514 100644 --- a/arch/arm64/include/asm/mmu_context.h +++ b/arch/arm64/include/asm/mmu_context.h @@ -27,6 +27,7 @@ #include <asm-generic/mm_hooks.h> #include <asm/cputype.h> #include <asm/pgtable.h> +#include <asm/tlbflush.h> #ifdef CONFIG_PID_IN_CONTEXTIDR static inline void contextidr_thread_switch(struct task_struct *next) @@ -90,6 +91,30 @@ static inline void cpu_set_default_tcr_t0sz(void) } /* + * Remove the idmap from TTBR0_EL1 and install the pgd of the active mm. + * + * The idmap lives in the same VA range as userspace, but uses global entries + * and may use a different TCR_EL1.T0SZ. To avoid issues resulting from + * speculative TLB fetches, we must temporarily install the reserved page + * tables while we invalidate the TLBs and set up the correct TCR_EL1.T0SZ. + * + * If current is a not a user task, the mm covers the TTBR1_EL1 page tables, + * which should not be installed in TTBR0_EL1. In this case we can leave the + * reserved page tables in place. + */ +static inline void cpu_uninstall_idmap(void) +{ + struct mm_struct *mm = current->active_mm; + + cpu_set_reserved_ttbr0(); + local_flush_tlb_all(); + cpu_set_default_tcr_t0sz(); + + if (mm != &init_mm) + cpu_switch_mm(mm->pgd, mm); +} + +/* * It would be nice to return ASIDs back to the allocator, but unfortunately * that introduces a race with a generation rollover where we could erroneously * free an ASID allocated in a future generation. We could workaround this by |
