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Subject[PATCH v9 11/26] efi: Let architectures decide the flags that should be saved/restored
Date
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@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: linux-efi@vger.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..2f4b68b 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
+
+inline 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
\
 
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