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Commit 13b210dd authored by Julien Thierry's avatar Julien Thierry Committed by Catalin Marinas
Browse files

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: default avatarJulien Thierry <julien.thierry@arm.com>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Acked-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: linux-efi@vger.kernel.org
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 85738e05

drivers/firmware/efi/runtime-wrappers.c

+15 −2
Original line number Diff line number Diff line
@@ -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);

}



/*

include/linux/efi.h

+3 −2
Original line number Diff line number Diff line
@@ -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));		\

									\