| Message ID | 3efc4cfd1d7c45a32752ced389d6666be15cde56.1641659630.git.luto@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm, sched: Rework lazy mm handling | expand |
On Sat, 8 Jan 2022 at 17:44, Andy Lutomirski <luto@kernel.org> wrote: > > This should be considerably more robust. It's also necessary for optimized > for_each_possible_lazymm_cpu() on x86 -- without this patch, EFI calls in > lazy context would remove the lazy mm from mm_cpumask(). > > Cc: Ard Biesheuvel <ardb@kernel.org> > Signed-off-by: Andy Lutomirski <luto@kernel.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> > --- > arch/x86/platform/efi/efi_64.c | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c > index 7515e78ef898..b9a571904363 100644 > --- a/arch/x86/platform/efi/efi_64.c > +++ b/arch/x86/platform/efi/efi_64.c > @@ -54,7 +54,7 @@ > * 0xffff_ffff_0000_0000 and limit EFI VA mapping space to 64G. > */ > static u64 efi_va = EFI_VA_START; > -static struct mm_struct *efi_prev_mm; > +static temp_mm_state_t efi_temp_mm_state; > > /* > * We need our own copy of the higher levels of the page tables > @@ -461,15 +461,12 @@ void __init efi_dump_pagetable(void) > */ > void efi_enter_mm(void) > { > - efi_prev_mm = current->active_mm; > - current->active_mm = &efi_mm; > - switch_mm(efi_prev_mm, &efi_mm, NULL); > + efi_temp_mm_state = use_temporary_mm(&efi_mm); > } > > void efi_leave_mm(void) > { > - current->active_mm = efi_prev_mm; > - switch_mm(&efi_mm, efi_prev_mm, NULL); > + unuse_temporary_mm(efi_temp_mm_state); > } > > static DEFINE_SPINLOCK(efi_runtime_lock); > -- > 2.33.1 >
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index 7515e78ef898..b9a571904363 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -54,7 +54,7 @@ * 0xffff_ffff_0000_0000 and limit EFI VA mapping space to 64G. */ static u64 efi_va = EFI_VA_START; -static struct mm_struct *efi_prev_mm; +static temp_mm_state_t efi_temp_mm_state; /* * We need our own copy of the higher levels of the page tables @@ -461,15 +461,12 @@ void __init efi_dump_pagetable(void) */ void efi_enter_mm(void) { - efi_prev_mm = current->active_mm; - current->active_mm = &efi_mm; - switch_mm(efi_prev_mm, &efi_mm, NULL); + efi_temp_mm_state = use_temporary_mm(&efi_mm); } void efi_leave_mm(void) { - current->active_mm = efi_prev_mm; - switch_mm(&efi_mm, efi_prev_mm, NULL); + unuse_temporary_mm(efi_temp_mm_state); } static DEFINE_SPINLOCK(efi_runtime_lock);
This should be considerably more robust. It's also necessary for optimized for_each_possible_lazymm_cpu() on x86 -- without this patch, EFI calls in lazy context would remove the lazy mm from mm_cpumask(). Cc: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Andy Lutomirski <luto@kernel.org> --- arch/x86/platform/efi/efi_64.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-)