efi_mm is a kernel-owned address space used for EFI runtime
mappings, but it is currently treated like a user address space when
manipulating its page tables. There does not seem to be a good
reason for this, and it creates unnecessary complications when
creating its page tables.
Mark it with the new MMF_KERNEL flag so that the page table handling
treats it like init_mm. In particular, this means that:
* Split page table locks are no longer initialised or used for
efi_mm's page tables.
* pagetable_*_ctor() and pagetable_dtor() no longer need to be
called for efi_mm's page tables.
Assisted-by: Codex:GPT-5.5
Signed-off-by: Kevin Brodsky <redacted>
---
drivers/firmware/efi/efi.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 0327a39d31fa..e5ca45bdc890 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -69,6 +69,7 @@ struct mm_struct efi_mm = {
.mm_mt = MTREE_INIT_EXT(mm_mt, MM_MT_FLAGS, efi_mm.mmap_lock),
.mm_users = ATOMIC_INIT(2),
.mm_count = ATOMIC_INIT(1),
+ .flags = MM_FLAGS_INIT(MMF_KERNEL_MASK),
.write_protect_seq = SEQCNT_ZERO(efi_mm.write_protect_seq),
MMAP_LOCK_INITIALIZER(efi_mm)
.page_table_lock = __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
--
2.51.2