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| author | Linux Build Service Account <lnxbuild@quicinc.com> | 2017-12-30 20:50:17 -0800 |
|---|---|---|
| committer | Gerrit - the friendly Code Review server <code-review@localhost> | 2017-12-30 20:50:16 -0800 |
| commit | a4f5f7d5ee2c352486df5c01283de51837b074a0 (patch) | |
| tree | 3f8292b470921891b86ce93f21ad21ce34996164 /arch/arm64/include | |
| parent | 55ba1585b7024f2319c05c63e611916ab7d3f9a4 (diff) | |
| parent | 3ac2760ead2ccd7e0c2714aff6a12f81a16b2ce7 (diff) | |
Merge "arm64: SW PAN: Point saved ttbr0 at the zero page when switching to init_mm"
Diffstat (limited to 'arch/arm64/include')
| -rw-r--r-- | arch/arm64/include/asm/efi.h | 4 | ||||
| -rw-r--r-- | arch/arm64/include/asm/mmu_context.h | 22 |
2 files changed, 14 insertions, 12 deletions
diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h index 932f5a56d1a6..b7406e05056b 100644 --- a/arch/arm64/include/asm/efi.h +++ b/arch/arm64/include/asm/efi.h @@ -87,11 +87,9 @@ static inline void efi_set_pgd(struct mm_struct *mm) * Defer the switch to the current thread's TTBR0_EL1 * until uaccess_enable(). Restore the current * thread's saved ttbr0 corresponding to its active_mm - * (if different from init_mm). */ cpu_set_reserved_ttbr0(); - if (current->active_mm != &init_mm) - update_saved_ttbr0(current, current->active_mm); + update_saved_ttbr0(current, current->active_mm); } } } diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h index f926b95928ee..7e00215aa9f5 100644 --- a/arch/arm64/include/asm/mmu_context.h +++ b/arch/arm64/include/asm/mmu_context.h @@ -183,11 +183,17 @@ enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) static inline void update_saved_ttbr0(struct task_struct *tsk, struct mm_struct *mm) { - if (system_uses_ttbr0_pan()) { - BUG_ON(mm->pgd == swapper_pg_dir); - task_thread_info(tsk)->ttbr0 = - virt_to_phys(mm->pgd) | ASID(mm) << 48; - } + u64 ttbr; + + if (!system_uses_ttbr0_pan()) + return; + + if (mm == &init_mm) + ttbr = __pa_symbol(empty_zero_page); + else + ttbr = virt_to_phys(mm->pgd) | ASID(mm) << 48; + + task_thread_info(tsk)->ttbr0 = ttbr; } #else static inline void update_saved_ttbr0(struct task_struct *tsk, @@ -223,11 +229,9 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next, * Update the saved TTBR0_EL1 of the scheduled-in task as the previous * value may have not been initialised yet (activate_mm caller) or the * ASID has changed since the last run (following the context switch - * of another thread of the same process). Avoid setting the reserved - * TTBR0_EL1 to swapper_pg_dir (init_mm; e.g. via idle_task_exit). + * of another thread of the same process). */ - if (next != &init_mm) - update_saved_ttbr0(tsk, next); + update_saved_ttbr0(tsk, next); } #define deactivate_mm(tsk,mm) do { } while (0) |