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@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: linux-efi@vger.kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c
index 8903b9c..c70df5a 100644 (file)
--- a/drivers/firmware/efi/runtime-wrappers.c
+++ b/drivers/firmware/efi/runtime-wrappers.c
@@ -89,11 +89,24 @@ exit:                                                                       \
        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 (file)
--- 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 @@ void efi_retrieve_tpm2_eventlog(efi_system_table_t *sys_table);
                                                                        \
        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 @@ void efi_retrieve_tpm2_eventlog(efi_system_table_t *sys_table);
                                                                        \
        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));             \
                                                                        \