@ -14,10 +14,79 @@
* This file is released under the GPLv2 .
*/
# include <linux/bug.h>
# include <linux/efi.h>
# include <linux/spinlock.h> /* spinlock_t */
# include <linux/mutex.h>
# include <linux/spinlock.h>
# include <asm/efi.h>
/*
* According to section 7.1 of the UEFI spec , Runtime Services are not fully
* reentrant , and there are particular combinations of calls that need to be
* serialized . ( source : UEFI Specification v2 .4 A )
*
* Table 31. Rules for Reentry Into Runtime Services
* + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
* | If previous call is busy in | Forbidden to call |
* + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
* | Any | SetVirtualAddressMap ( ) |
* + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
* | ConvertPointer ( ) | ConvertPointer ( ) |
* + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
* | SetVariable ( ) | ResetSystem ( ) |
* | UpdateCapsule ( ) | |
* | SetTime ( ) | |
* | SetWakeupTime ( ) | |
* | GetNextHighMonotonicCount ( ) | |
* + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
* | GetVariable ( ) | GetVariable ( ) |
* | GetNextVariableName ( ) | GetNextVariableName ( ) |
* | SetVariable ( ) | SetVariable ( ) |
* | QueryVariableInfo ( ) | QueryVariableInfo ( ) |
* | UpdateCapsule ( ) | UpdateCapsule ( ) |
* | QueryCapsuleCapabilities ( ) | QueryCapsuleCapabilities ( ) |
* | GetNextHighMonotonicCount ( ) | GetNextHighMonotonicCount ( ) |
* + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
* | GetTime ( ) | GetTime ( ) |
* | SetTime ( ) | SetTime ( ) |
* | GetWakeupTime ( ) | GetWakeupTime ( ) |
* | SetWakeupTime ( ) | SetWakeupTime ( ) |
* + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
*
* Due to the fact that the EFI pstore may write to the variable store in
* interrupt context , we need to use a spinlock for at least the groups that
* contain SetVariable ( ) and QueryVariableInfo ( ) . That leaves little else , as
* none of the remaining functions are actually ever called at runtime .
* So let ' s just use a single spinlock to serialize all Runtime Services calls .
*/
static DEFINE_SPINLOCK ( efi_runtime_lock ) ;
/*
* Some runtime services calls can be reentrant under NMI , even if the table
* above says they are not . ( source : UEFI Specification v2 .4 A )
*
* Table 32. Functions that may be called after Machine Check , INIT and NMI
* + - - - - - - - - - - - - - - - - - - - - - - - - - - - - + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
* | Function | Called after Machine Check , INIT and NMI |
* + - - - - - - - - - - - - - - - - - - - - - - - - - - - - + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
* | GetTime ( ) | Yes , even if previously busy . |
* | GetVariable ( ) | Yes , even if previously busy |
* | GetNextVariableName ( ) | Yes , even if previously busy |
* | QueryVariableInfo ( ) | Yes , even if previously busy |
* | SetVariable ( ) | Yes , even if previously busy |
* | UpdateCapsule ( ) | Yes , even if previously busy |
* | QueryCapsuleCapabilities ( ) | Yes , even if previously busy |
* | ResetSystem ( ) | Yes , even if previously busy |
* + - - - - - - - - - - - - - - - - - - - - - - - - - - - - + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
*
* In order to prevent deadlocks under NMI , the wrappers for these functions
* may only grab the efi_runtime_lock or rtc_lock spinlocks if ! efi_in_nmi ( ) .
* However , not all of the services listed are reachable through NMI code paths ,
* so the the special handling as suggested by the UEFI spec is only implemented
* for QueryVariableInfo ( ) and SetVariable ( ) , as these can be reached in NMI
* context through efi_pstore_write ( ) .
*/
/*
* As per commit ef68c8f87ed1 ( " x86: Serialize EFI time accesses on rtc_lock " ) ,
* the EFI specification requires that callers of the time related runtime
@ -32,7 +101,9 @@ static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)
efi_status_t status ;
spin_lock_irqsave ( & rtc_lock , flags ) ;
spin_lock ( & efi_runtime_lock ) ;
status = efi_call_virt ( get_time , tm , tc ) ;
spin_unlock ( & efi_runtime_lock ) ;
spin_unlock_irqrestore ( & rtc_lock , flags ) ;
return status ;
}
@ -43,7 +114,9 @@ static efi_status_t virt_efi_set_time(efi_time_t *tm)
efi_status_t status ;
spin_lock_irqsave ( & rtc_lock , flags ) ;
spin_lock ( & efi_runtime_lock ) ;
status = efi_call_virt ( set_time , tm ) ;
spin_unlock ( & efi_runtime_lock ) ;
spin_unlock_irqrestore ( & rtc_lock , flags ) ;
return status ;
}
@ -56,7 +129,9 @@ static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled,
efi_status_t status ;
spin_lock_irqsave ( & rtc_lock , flags ) ;
spin_lock ( & efi_runtime_lock ) ;
status = efi_call_virt ( get_wakeup_time , enabled , pending , tm ) ;
spin_unlock ( & efi_runtime_lock ) ;
spin_unlock_irqrestore ( & rtc_lock , flags ) ;
return status ;
}
@ -67,7 +142,9 @@ static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
efi_status_t status ;
spin_lock_irqsave ( & rtc_lock , flags ) ;
spin_lock ( & efi_runtime_lock ) ;
status = efi_call_virt ( set_wakeup_time , enabled , tm ) ;
spin_unlock ( & efi_runtime_lock ) ;
spin_unlock_irqrestore ( & rtc_lock , flags ) ;
return status ;
}
@ -78,14 +155,27 @@ static efi_status_t virt_efi_get_variable(efi_char16_t *name,
unsigned long * data_size ,
void * data )
{
return efi_call_virt ( get_variable , name , vendor , attr , data_size , data ) ;
unsigned long flags ;
efi_status_t status ;
spin_lock_irqsave ( & efi_runtime_lock , flags ) ;
status = efi_call_virt ( get_variable , name , vendor , attr , data_size ,
data ) ;
spin_unlock_irqrestore ( & efi_runtime_lock , flags ) ;
return status ;
}
static efi_status_t virt_efi_get_next_variable ( unsigned long * name_size ,
efi_char16_t * name ,
efi_guid_t * vendor )
{
return efi_call_virt ( get_next_variable , name_size , name , vendor ) ;
unsigned long flags ;
efi_status_t status ;
spin_lock_irqsave ( & efi_runtime_lock , flags ) ;
status = efi_call_virt ( get_next_variable , name_size , name , vendor ) ;
spin_unlock_irqrestore ( & efi_runtime_lock , flags ) ;
return status ;
}
static efi_status_t virt_efi_set_variable ( efi_char16_t * name ,
@ -94,24 +184,61 @@ static efi_status_t virt_efi_set_variable(efi_char16_t *name,
unsigned long data_size ,
void * data )
{
return efi_call_virt ( set_variable , name , vendor , attr , data_size , data ) ;
unsigned long flags ;
efi_status_t status ;
spin_lock_irqsave ( & efi_runtime_lock , flags ) ;
status = efi_call_virt ( set_variable , name , vendor , attr , data_size ,
data ) ;
spin_unlock_irqrestore ( & efi_runtime_lock , flags ) ;
return status ;
}
static efi_status_t
virt_efi_set_variable_nonblocking ( efi_char16_t * name , efi_guid_t * vendor ,
u32 attr , unsigned long data_size ,
void * data )
{
unsigned long flags ;
efi_status_t status ;
if ( ! spin_trylock_irqsave ( & efi_runtime_lock , flags ) )
return EFI_NOT_READY ;
status = efi_call_virt ( set_variable , name , vendor , attr , data_size ,
data ) ;
spin_unlock_irqrestore ( & efi_runtime_lock , flags ) ;
return status ;
}
static efi_status_t virt_efi_query_variable_info ( u32 attr ,
u64 * storage_space ,
u64 * remaining_space ,
u64 * max_variable_size )
{
unsigned long flags ;
efi_status_t status ;
if ( efi . runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION )
return EFI_UNSUPPORTED ;
return efi_call_virt ( query_variable_info , attr , storage_space ,
spin_lock_irqsave ( & efi_runtime_lock , flags ) ;
status = efi_call_virt ( query_variable_info , attr , storage_space ,
remaining_space , max_variable_size ) ;
spin_unlock_irqrestore ( & efi_runtime_lock , flags ) ;
return status ;
}
static efi_status_t virt_efi_get_next_high_mono_count ( u32 * count )
{
return efi_call_virt ( get_next_high_mono_count , count ) ;
unsigned long flags ;
efi_status_t status ;
spin_lock_irqsave ( & efi_runtime_lock , flags ) ;
status = efi_call_virt ( get_next_high_mono_count , count ) ;
spin_unlock_irqrestore ( & efi_runtime_lock , flags ) ;
return status ;
}
static void virt_efi_reset_system ( int reset_type ,
@ -119,17 +246,27 @@ static void virt_efi_reset_system(int reset_type,
unsigned long data_size ,
efi_char16_t * data )
{
unsigned long flags ;
spin_lock_irqsave ( & efi_runtime_lock , flags ) ;
__efi_call_virt ( reset_system , reset_type , status , data_size , data ) ;
spin_unlock_irqrestore ( & efi_runtime_lock , flags ) ;
}
static efi_status_t virt_efi_update_capsule ( efi_capsule_header_t * * capsules ,
unsigned long count ,
unsigned long sg_list )
{
unsigned long flags ;
efi_status_t status ;
if ( efi . runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION )
return EFI_UNSUPPORTED ;
return efi_call_virt ( update_capsule , capsules , count , sg_list ) ;
spin_lock_irqsave ( & efi_runtime_lock , flags ) ;
status = efi_call_virt ( update_capsule , capsules , count , sg_list ) ;
spin_unlock_irqrestore ( & efi_runtime_lock , flags ) ;
return status ;
}
static efi_status_t virt_efi_query_capsule_caps ( efi_capsule_header_t * * capsules ,
@ -137,11 +274,17 @@ static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules,
u64 * max_size ,
int * reset_type )
{
unsigned long flags ;
efi_status_t status ;
if ( efi . runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION )
return EFI_UNSUPPORTED ;
return efi_call_virt ( query_capsule_caps , capsules , count , max_size ,
spin_lock_irqsave ( & efi_runtime_lock , flags ) ;
status = efi_call_virt ( query_capsule_caps , capsules , count , max_size ,
reset_type ) ;
spin_unlock_irqrestore ( & efi_runtime_lock , flags ) ;
return status ;
}
void efi_native_runtime_setup ( void )
@ -153,6 +296,7 @@ void efi_native_runtime_setup(void)
efi . get_variable = virt_efi_get_variable ;
efi . get_next_variable = virt_efi_get_next_variable ;
efi . set_variable = virt_efi_set_variable ;
efi . set_variable_nonblocking = virt_efi_set_variable_nonblocking ;
efi . get_next_high_mono_count = virt_efi_get_next_high_mono_count ;
efi . reset_system = virt_efi_reset_system ;
efi . query_variable_info = virt_efi_query_variable_info ;
Linus Torvalds
10 years ago