evie/android_kernel_oneplus_msm8998
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Merge "arm64: SW PAN: Point saved ttbr0 at the zero page when switching to init_mm"

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Linux Build Service Account 2017-12-30 20:50:17 -08:00 • committed by Gerrit - the friendly Code Review server
commit a4f5f7d5ee
2 changed files with 14 additions and 12 deletions
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4
arch/arm64/include/asm/efi.h
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@ -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);
}
}
}

22
arch/arm64/include/asm/mmu_context.h
View file

@ -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)