linux-kernel - [PATCH v10 11/25] efi: Let architectures decide the flags that should be saved/restored

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Message-Id: <1548946743-38979-12-git-send-email-julien.thierry@arm.com>
Date:   Thu, 31 Jan 2019 14:58:49 +0000
From:   Julien Thierry <julien.thierry@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, daniel.thompson@...aro.org,
        joel@...lfernandes.org, marc.zyngier@....com,
        christoffer.dall@....com, james.morse@....com,
        catalin.marinas@....com, will.deacon@....com, mark.rutland@....com,
        Julien Thierry <julien.thierry@....com>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        linux-efi@...r.kernel.org
Subject: [PATCH v10 11/25] efi: Let architectures decide the flags that should be saved/restored

Currently, irqflags are saved before calling runtime services and
checked for mismatch on return.

Provide a pair of overridable macros to save and restore (if needed) the
state that need to be preserved on return from a runtime service.
This allows to check for flags that are not necesarly related to
irqflags.

Signed-off-by: Julien Thierry <julien.thierry@....com>
Acked-by: Catalin Marinas <catalin.marinas@....com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Acked-by: Marc Zyngier <marc.zyngier@....com>
Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc: linux-efi@...r.kernel.org
---
 drivers/firmware/efi/runtime-wrappers.c | 17 +++++++++++++++--
 include/linux/efi.h                     |  5 +++--
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c
index 8903b9c..c70df5a 100644
--- a/drivers/firmware/efi/runtime-wrappers.c
+++ b/drivers/firmware/efi/runtime-wrappers.c
@@ -89,11 +89,24 @@
 	efi_rts_work.status;						\
 })
 
+#ifndef arch_efi_save_flags
+#define arch_efi_save_flags(state_flags)	local_save_flags(state_flags)
+#define arch_efi_restore_flags(state_flags)	local_irq_restore(state_flags)
+#endif
+
+unsigned long efi_call_virt_save_flags(void)
+{
+	unsigned long flags;
+
+	arch_efi_save_flags(flags);
+	return flags;
+}
+
 void efi_call_virt_check_flags(unsigned long flags, const char *call)
 {
 	unsigned long cur_flags, mismatch;
 
-	local_save_flags(cur_flags);
+	cur_flags = efi_call_virt_save_flags();
 
 	mismatch = flags ^ cur_flags;
 	if (!WARN_ON_ONCE(mismatch & ARCH_EFI_IRQ_FLAGS_MASK))
@@ -102,7 +115,7 @@ void efi_call_virt_check_flags(unsigned long flags, const char *call)
 	add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE);
 	pr_err_ratelimited(FW_BUG "IRQ flags corrupted (0x%08lx=>0x%08lx) by EFI %s\n",
 			   flags, cur_flags, call);
-	local_irq_restore(flags);
+	arch_efi_restore_flags(flags);
 }
 
 /*
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 45ff763..bd80b7e 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1607,6 +1607,7 @@ efi_status_t efi_setup_gop(efi_system_table_t *sys_table_arg,
 
 bool efi_runtime_disabled(void);
 extern void efi_call_virt_check_flags(unsigned long flags, const char *call);
+extern unsigned long efi_call_virt_save_flags(void);
 
 enum efi_secureboot_mode {
 	efi_secureboot_mode_unset,
@@ -1652,7 +1653,7 @@ enum efi_secureboot_mode {
 									\
 	arch_efi_call_virt_setup();					\
 									\
-	local_save_flags(__flags);					\
+	__flags = efi_call_virt_save_flags();				\
 	__s = arch_efi_call_virt(p, f, args);				\
 	efi_call_virt_check_flags(__flags, __stringify(f));		\
 									\
@@ -1667,7 +1668,7 @@ enum efi_secureboot_mode {
 									\
 	arch_efi_call_virt_setup();					\
 									\
-	local_save_flags(__flags);					\
+	__flags = efi_call_virt_save_flags();				\
 	arch_efi_call_virt(p, f, args);					\
 	efi_call_virt_check_flags(__flags, __stringify(f));		\
 									\
-- 
1.9.1