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Commit 9dbbedaa authored by Sai Praneeth's avatar Sai Praneeth Committed by Ard Biesheuvel
Browse files

efi: Make efi_rts_work accessible to efi page fault handler 



After the kernel has booted, if any accesses by firmware causes a page
fault, the efi page fault handler would freeze efi_rts_wq and schedules
a new process. To do this, the efi page fault handler needs
efi_rts_work. Hence, make it accessible.

There will be no race conditions in accessing this structure, because
all the calls to efi runtime services are already serialized.

Tested-by: default avatarBhupesh Sharma <bhsharma@redhat.com>
Suggested-by: default avatarMatt Fleming <matt@codeblueprint.co.uk>
Based-on-code-from: Ricardo Neri <ricardo.neri@intel.com>
Signed-off-by: default avatarSai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
parent bcb31c62

drivers/firmware/efi/runtime-wrappers.c

+9 −44
Original line number Diff line number Diff line
@@ -45,39 +45,7 @@ 
#define __efi_call_virt(f, args...) \

	__efi_call_virt_pointer(efi.systab->runtime, f, args)



/* efi_runtime_service() function identifiers */

enum efi_rts_ids {

	GET_TIME,

	SET_TIME,

	GET_WAKEUP_TIME,

	SET_WAKEUP_TIME,

	GET_VARIABLE,

	GET_NEXT_VARIABLE,

	SET_VARIABLE,

	QUERY_VARIABLE_INFO,

	GET_NEXT_HIGH_MONO_COUNT,

	UPDATE_CAPSULE,

	QUERY_CAPSULE_CAPS,

};



/*

 * efi_runtime_work:	Details of EFI Runtime Service work

 * @arg<1-5>:		EFI Runtime Service function arguments

 * @status:		Status of executing EFI Runtime Service

 * @efi_rts_id:		EFI Runtime Service function identifier

 * @efi_rts_comp:	Struct used for handling completions

 */

struct efi_runtime_work {

	void *arg1;

	void *arg2;

	void *arg3;

	void *arg4;

	void *arg5;

	efi_status_t status;

	struct work_struct work;

	enum efi_rts_ids efi_rts_id;

	struct completion efi_rts_comp;

};

struct efi_runtime_work efi_rts_work;



/*

 * efi_queue_work:	Queue efi_runtime_service() and wait until it's done
@@ -91,7 +59,6 @@ struct efi_runtime_work { 
 */

#define efi_queue_work(_rts, _arg1, _arg2, _arg3, _arg4, _arg5)		\

({									\

	struct efi_runtime_work efi_rts_work;				\

	efi_rts_work.status = EFI_ABORTED;				\

									\

	init_completion(&efi_rts_work.efi_rts_comp);			\
@@ -184,18 +151,16 @@ static DEFINE_SEMAPHORE(efi_runtime_lock); 
 */

static void efi_call_rts(struct work_struct *work)

{

	struct efi_runtime_work *efi_rts_work;

	void *arg1, *arg2, *arg3, *arg4, *arg5;

	efi_status_t status = EFI_NOT_FOUND;



	efi_rts_work = container_of(work, struct efi_runtime_work, work);

	arg1 = efi_rts_work->arg1;

	arg2 = efi_rts_work->arg2;

	arg3 = efi_rts_work->arg3;

	arg4 = efi_rts_work->arg4;

	arg5 = efi_rts_work->arg5;

	arg1 = efi_rts_work.arg1;

	arg2 = efi_rts_work.arg2;

	arg3 = efi_rts_work.arg3;

	arg4 = efi_rts_work.arg4;

	arg5 = efi_rts_work.arg5;



	switch (efi_rts_work->efi_rts_id) {

	switch (efi_rts_work.efi_rts_id) {

	case GET_TIME:

		status = efi_call_virt(get_time, (efi_time_t *)arg1,

				       (efi_time_cap_t *)arg2);
@@ -253,8 +218,8 @@ static void efi_call_rts(struct work_struct *work) 
		 */

		pr_err("Requested executing invalid EFI Runtime Service.\n");

	}

	efi_rts_work->status = status;

	complete(&efi_rts_work->efi_rts_comp);

	efi_rts_work.status = status;

	complete(&efi_rts_work.efi_rts_comp);

}



static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)

include/linux/efi.h

+36 −0
Original line number Diff line number Diff line
@@ -1662,6 +1662,42 @@ struct linux_efi_tpm_eventlog { 


extern int efi_tpm_eventlog_init(void);



/* efi_runtime_service() function identifiers */

enum efi_rts_ids {

	GET_TIME,

	SET_TIME,

	GET_WAKEUP_TIME,

	SET_WAKEUP_TIME,

	GET_VARIABLE,

	GET_NEXT_VARIABLE,

	SET_VARIABLE,

	QUERY_VARIABLE_INFO,

	GET_NEXT_HIGH_MONO_COUNT,

	UPDATE_CAPSULE,

	QUERY_CAPSULE_CAPS,

};



/*

 * efi_runtime_work:	Details of EFI Runtime Service work

 * @arg<1-5>:		EFI Runtime Service function arguments

 * @status:		Status of executing EFI Runtime Service

 * @efi_rts_id:		EFI Runtime Service function identifier

 * @efi_rts_comp:	Struct used for handling completions

 */

struct efi_runtime_work {

	void *arg1;

	void *arg2;

	void *arg3;

	void *arg4;

	void *arg5;

	efi_status_t status;

	struct work_struct work;

	enum efi_rts_ids efi_rts_id;

	struct completion efi_rts_comp;

};



extern struct efi_runtime_work efi_rts_work;



/* Workqueue to queue EFI Runtime Services */

extern struct workqueue_struct *efi_rts_wq;