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s390: add stack switch helper 

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2017-09-07 17:03:19 +02:00
parent 53c99bd665
commit ff340d2472
2 changed files with 50 additions and 9 deletions
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49
arch/s390/include/asm/processor.h
View File

@ -250,6 +250,55 @@ static inline unsigned short stap(void)
return cpu_address;
}
#define CALL_ARGS_0() \
register unsigned long r2 asm("2")
#define CALL_ARGS_1(arg1) \
register unsigned long r2 asm("2") = (unsigned long)(arg1)
#define CALL_ARGS_2(arg1, arg2) \
CALL_ARGS_1(arg1); \
register unsigned long r3 asm("3") = (unsigned long)(arg2)
#define CALL_ARGS_3(arg1, arg2, arg3) \
CALL_ARGS_2(arg1, arg2); \
register unsigned long r4 asm("4") = (unsigned long)(arg3)
#define CALL_ARGS_4(arg1, arg2, arg3, arg4) \
CALL_ARGS_3(arg1, arg2, arg3); \
register unsigned long r4 asm("5") = (unsigned long)(arg4)
#define CALL_ARGS_5(arg1, arg2, arg3, arg4, arg5) \
CALL_ARGS_4(arg1, arg2, arg3, arg4); \
register unsigned long r4 asm("6") = (unsigned long)(arg5)
#define CALL_FMT_0
#define CALL_FMT_1 CALL_FMT_0, "0" (r2)
#define CALL_FMT_2 CALL_FMT_1, "d" (r3)
#define CALL_FMT_3 CALL_FMT_2, "d" (r4)
#define CALL_FMT_4 CALL_FMT_3, "d" (r5)
#define CALL_FMT_5 CALL_FMT_4, "d" (r6)
#define CALL_CLOBBER_5 "0", "1", "14", "cc", "memory"
#define CALL_CLOBBER_4 CALL_CLOBBER_5
#define CALL_CLOBBER_3 CALL_CLOBBER_4, "5"
#define CALL_CLOBBER_2 CALL_CLOBBER_3, "4"
#define CALL_CLOBBER_1 CALL_CLOBBER_2, "3"
#define CALL_CLOBBER_0 CALL_CLOBBER_1
#define CALL_ON_STACK(fn, stack, nr, args...) \
({ \
CALL_ARGS_##nr(args); \
unsigned long prev; \
\
asm volatile( \
" la %[_prev],0(15)\n" \
" la 15,0(%[_stack])\n" \
" stg %[_prev],%[_bc](15)\n" \
" brasl 14,%[_fn]\n" \
" la 15,0(%[_prev])\n" \
: "+&d" (r2), [_prev] "=&a" (prev) \
: [_stack] "a" (stack), \
[_bc] "i" (offsetof(struct stack_frame, back_chain)), \
[_fn] "X" (fn) CALL_FMT_##nr : CALL_CLOBBER_##nr); \
r2; \
})
/*
* Give up the time slice of the virtual PU.
*/

10
arch/s390/kernel/irq.c
View File

@ -172,15 +172,7 @@ void do_softirq_own_stack(void)
/* Check against async. stack address range. */
new = S390_lowcore.async_stack;
if (((new - old) >> (PAGE_SHIFT + THREAD_SIZE_ORDER)) != 0) {
/* Need to switch to the async. stack. */
new -= STACK_FRAME_OVERHEAD;
((struct stack_frame *) new)->back_chain = old;
asm volatile(" la 15,0(%0)\n"
" brasl 14,__do_softirq\n"
" la 15,0(%1)\n"
: : "a" (new), "a" (old)
: "0", "1", "2", "3", "4", "5", "14",
"cc", "memory" );
CALL_ON_STACK(__do_softirq, new, 0);
} else {
/* We are already on the async stack. */
__do_softirq();