[RFC PATCH 22/36] efi/runtime-wrappers: Permit architectures to override IRQ flags checks

[Vladimir Murzin]

Representation of IRQ flags on arm64 has recently changed. They now
track both DAIF and PMR state while remaining compatible with the
irqflags API by encoding the state in an unsigned long.

While the generic check can still detect corruption of the IRQ flags
caused by EFI runtime services, the resulting error message is cryptic
because it does not understand the arm64-specific representation.

Permit architectures to override the IRQ flags checks and associated
error messages, while keeping the existing implementation as the
default.

Signed-off-by: Vladimir Murzin <vladimir.murzin at arm.com>
---
 drivers/firmware/efi/runtime-wrappers.c | 32 +++++++++++++++----------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c
index da8d29621644..498fb3612643 100644
--- a/drivers/firmware/efi/runtime-wrappers.c
+++ b/drivers/firmware/efi/runtime-wrappers.c
@@ -137,6 +137,25 @@ struct efi_runtime_work efi_rts_work;
 #define arch_efi_restore_flags(state_flags)	local_irq_restore(state_flags)
 #endif
 
+#ifndef arch_efi_check_flags
+#define arch_efi_check_flags(state_flags, caller) 							\
+do {													\
+	unsigned long cur_flags, mismatch;								\
+													\
+	cur_flags = efi_call_virt_save_flags();								\
+													\
+	mismatch = state_flags ^ cur_flags;								\
+	if (!WARN_ON_ONCE(mismatch & ARCH_EFI_IRQ_FLAGS_MASK))						\
+		break;											\
+													\
+	add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE); 					\
+	pr_err_ratelimited(FW_BUG "IRQ flags corrupted (0x%08lx=>0x%08lx) by EFI call from %pS\n",	\
+			   state_flags, cur_flags,							\
+			   caller ?: __builtin_return_address(0));					\
+	arch_efi_restore_flags(state_flags);								\
+} while(0);
+#endif
+
 unsigned long efi_call_virt_save_flags(void)
 {
 	unsigned long flags;
@@ -147,18 +166,7 @@ unsigned long efi_call_virt_save_flags(void)
 
 void efi_call_virt_check_flags(unsigned long flags, const void *caller)
 {
-	unsigned long cur_flags, mismatch;
-
-	cur_flags = efi_call_virt_save_flags();
-
-	mismatch = flags ^ cur_flags;
-	if (!WARN_ON_ONCE(mismatch & ARCH_EFI_IRQ_FLAGS_MASK))
-		return;
-
-	add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE);
-	pr_err_ratelimited(FW_BUG "IRQ flags corrupted (0x%08lx=>0x%08lx) by EFI call from %pS\n",
-			   flags, cur_flags, caller ?: __builtin_return_address(0));
-	arch_efi_restore_flags(flags);
+	arch_efi_check_flags(flags, caller);
 }
 
 /*
-- 
2.34.1