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Commit d50efc6c authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86: fix UML and -regparm=3 



introduce the "asmregparm" calling convention: for functions
implemented in assembly with a fixed regparm input parameters
calling convention.

mark the semaphore and rwsem slowpath functions with that.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 3a556b26

include/asm-x86/linkage.h

+5 −0
Original line number Diff line number Diff line
@@ -9,6 +9,11 @@ 
#ifdef CONFIG_X86_32

#define asmlinkage CPP_ASMLINKAGE __attribute__((regparm(0)))

#define prevent_tail_call(ret) __asm__ ("" : "=r" (ret) : "0" (ret))

/*

 * For 32-bit UML - mark functions implemented in assembly that use

 * regparm input parameters:

 */

#define asmregparm __attribute__((regparm(3)))

#endif



#ifdef CONFIG_X86_ALIGNMENT_16

include/asm-x86/rwsem.h

+8 −4
Original line number Diff line number Diff line
@@ -44,10 +44,14 @@ 


struct rwsem_waiter;



extern struct rw_semaphore *FASTCALL(rwsem_down_read_failed(struct rw_semaphore *sem));

extern struct rw_semaphore *FASTCALL(rwsem_down_write_failed(struct rw_semaphore *sem));

extern struct rw_semaphore *FASTCALL(rwsem_wake(struct rw_semaphore *));

extern struct rw_semaphore *FASTCALL(rwsem_downgrade_wake(struct rw_semaphore *sem));

extern asmregparm struct rw_semaphore *

 rwsem_down_read_failed(struct rw_semaphore *sem);

extern asmregparm struct rw_semaphore *

 rwsem_down_write_failed(struct rw_semaphore *sem);

extern asmregparm struct rw_semaphore *

 rwsem_wake(struct rw_semaphore *);

extern asmregparm struct rw_semaphore *

 rwsem_downgrade_wake(struct rw_semaphore *sem);



/*

 * the semaphore definition

include/asm-x86/semaphore_32.h

+4 −4
Original line number Diff line number Diff line
@@ -83,10 +83,10 @@ static inline void init_MUTEX_LOCKED (struct semaphore *sem) 
	sema_init(sem, 0);

}



void __down_failed(void /* special register calling convention */);

int  __down_failed_interruptible(void  /* params in registers */);

int  __down_failed_trylock(void  /* params in registers */);

void __up_wakeup(void /* special register calling convention */);

extern asmregparm void __down_failed(atomic_t *count_ptr);

extern asmregparm int  __down_failed_interruptible(atomic_t *count_ptr);

extern asmregparm int  __down_failed_trylock(atomic_t *count_ptr);

extern asmregparm void __up_wakeup(atomic_t *count_ptr);



/*

 * This is ugly, but we want the default case to fall through.

include/linux/linkage.h

+4 −0
Original line number Diff line number Diff line
@@ -13,6 +13,10 @@ 
#define asmlinkage CPP_ASMLINKAGE

#endif



#ifndef asmregparm

# define asmregparm

#endif



#ifndef prevent_tail_call

# define prevent_tail_call(ret) do { } while (0)

#endif

lib/rwsem.c

+4 −4
Original line number Diff line number Diff line
@@ -187,7 +187,7 @@ rwsem_down_failed_common(struct rw_semaphore *sem, 
/*

 * wait for the read lock to be granted

 */

struct rw_semaphore fastcall __sched *

asmregparm struct rw_semaphore __sched *

rwsem_down_read_failed(struct rw_semaphore *sem)

{

	struct rwsem_waiter waiter;
@@ -201,7 +201,7 @@ rwsem_down_read_failed(struct rw_semaphore *sem) 
/*

 * wait for the write lock to be granted

 */

struct rw_semaphore fastcall __sched *

asmregparm struct rw_semaphore __sched *

rwsem_down_write_failed(struct rw_semaphore *sem)

{

	struct rwsem_waiter waiter;
@@ -216,7 +216,7 @@ rwsem_down_write_failed(struct rw_semaphore *sem) 
 * handle waking up a waiter on the semaphore

 * - up_read/up_write has decremented the active part of count if we come here

 */

struct rw_semaphore fastcall *rwsem_wake(struct rw_semaphore *sem)

asmregparm struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)

{

	unsigned long flags;
@@ -236,7 +236,7 @@ struct rw_semaphore fastcall *rwsem_wake(struct rw_semaphore *sem) 
 * - caller incremented waiting part of count and discovered it still negative

 * - just wake up any readers at the front of the queue

 */

struct rw_semaphore fastcall *rwsem_downgrade_wake(struct rw_semaphore *sem)

asmregparm struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem)

{

	unsigned long flags;