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efi: Make efi_rts_work accessible to efi page fault handler

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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: Bhupesh Sharma <bhsharma@redhat.com>
Suggested-by: Matt Fleming <matt@codeblueprint.co.uk>
Based-on-code-from: Ricardo Neri <ricardo.neri@intel.com>
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
This commit is contained in:
Sai Praneeth 2018-09-11 12:15:21 -07:00 committed by Ard Biesheuvel
parent bcb31c6225
commit 9dbbedaa61
2 changed files with 45 additions and 44 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
drivers/firmware/efi/runtime-wrappers.c
View File

@ -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)

36
include/linux/efi.h
View File

@ -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;