arm64/efi: Move uaccess en/disable out of efi_set_pgd()

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.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 3 insertions, 10 deletions

diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
index bcd5622aa096..aa91165ca140 100644
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -126,21 +126,14 @@ static inline void efi_set_pgd(struct mm_struct *mm)
 		if (mm != current->active_mm) {
 			/*
 			 * Update the current thread's saved ttbr0 since it is
-			 * restored as part of a return from exception. Enable
-			 * access to the valid TTBR0_EL1 and invoke the errata
-			 * workaround directly since there is no return from
-			 * exception when invoking the EFI run-time services.
+			 * restored as part of a return from exception.
 			 */
 			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
+			 * Restore the current thread's saved ttbr0
+			 * corresponding to its active_mm
 			 */
-			uaccess_ttbr0_disable();
 			update_saved_ttbr0(current, current->active_mm);
 		}
 	}