Merge "arm64: SW PAN: Update saved ttbr0 value on enter_lazy_tlb" (135ac26c) · Commits · e / devices / android_kernel_sony_msm8998

arch/arm64/include/asm/efi.h

+1 −3

Original line number	Diff line number	Diff line
		@@ -87,10 +87,8 @@ 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);
		}
		}

arch/arm64/include/asm/mmu_context.h

+23 −23

Original line number	Diff line number	Diff line
		@@ -165,29 +165,21 @@ void check_and_switch_context(struct mm_struct *mm, unsigned int cpu);

		#define init_new_context(tsk,mm) ({ atomic64_set(&(mm)->context.id, 0); 0; })

		/*
		* This is called when "tsk" is about to enter lazy TLB mode.
		*
		* mm: describes the currently active mm context
		* tsk: task which is entering lazy tlb
		* cpu: cpu number which is entering lazy tlb
		*
		* tsk->mm will be NULL
		*/
		static inline void
		enter_lazy_tlb(struct mm_struct mm, struct task_struct tsk)
		{
		}

		#ifdef CONFIG_ARM64_SW_TTBR0_PAN
		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,
		@@ -196,6 +188,16 @@ static inline void update_saved_ttbr0(struct task_struct *tsk,
		}
		#endif

		static inline void
		enter_lazy_tlb(struct mm_struct mm, struct task_struct tsk)
		{
		/*
		* We don't actually care about the ttbr0 mapping, so point it at the
		* zero page.
		*/
		update_saved_ttbr0(tsk, &init_mm);
		}

		static inline void __switch_mm(struct mm_struct *next)
		{
		unsigned int cpu = smp_processor_id();
		@@ -223,10 +225,8 @@ 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);
		}