[RFC PATCH 6/7] arm64/efi: Move uaccess en/disable out of efi_set_pgd()

[Ard Biesheuvel <ardb+git@google.com>]

From: Ard Biesheuvel <ardb@kernel.org>

efi_set_pgd() will no longer be called when invoking EFI runtime
services via the efi_rts_wq work queue, but the uaccess en/disable are
still needed when using PAN emulation using TTBR0 switching. So move
these into the callers.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/include/asm/efi.h | 3 ---
 arch/arm64/kernel/efi.c      | 3 +++
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
index decf87777f57..abe9176a3a23 100644
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -132,15 +132,12 @@ static inline void efi_set_pgd(struct mm_struct *mm)
 			 * exception when invoking the EFI run-time services.
 			 */
 			update_saved_ttbr0(current, mm);
-			uaccess_ttbr0_enable();
-			post_ttbr_update_workaround();
 		} else {
 			/*
 			 * 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
 			 */
-			uaccess_ttbr0_disable();
 			update_saved_ttbr0(current, current->active_mm);
 		}
 	}
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index d01ae156bb63..5d188c6c44d7 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -177,6 +177,8 @@ bool arch_efi_call_virt_setup(void)
 		return false;
 
 	efi_virtmap_load();
+	uaccess_ttbr0_enable();
+	post_ttbr_update_workaround();
 	__efi_fpsimd_begin();
 	return true;
 }
@@ -185,6 +187,7 @@ void arch_efi_call_virt_teardown(void)
 {
 	__efi_fpsimd_end();
 	efi_virtmap_unload();
+	uaccess_ttbr0_disable();
 	up(&efi_rt_lock);
 }
 
-- 
2.49.0.1101.gccaa498523-goog