ia64/kernel/fsys.S

1 /* SPDX-License-Identifier: GPL-2.0 */
3  * This file contains the light-weight system call handlers (fsyscall-handlers).
5  * Copyright (C) 2003 Hewlett-Packard Co
6  * 	David Mosberger-Tang <davidm@hpl.hp.com>
8  * 25-Sep-03 davidm	Implement fsys_rt_sigprocmask().
9  * 18-Feb-03 louisk	Implement fsys_gettimeofday().
10  * 28-Feb-03 davidm	Fixed several bugs in fsys_gettimeofday().  Tuned it some more,
11  *			probably broke it along the way... ;-)
12  * 13-Jul-04 clameter   Implement fsys_clock_gettime and revise fsys_gettimeofday to make
14  * 08-Feb-07 Fenghua Yu Implement fsys_getcpu.
20 #include <asm/asm-offsets.h>
34  *   r10	= 0 (i.e., defaults to "successful syscall return")
35  *   r11	= saved ar.pfs (a user-level value)
37  *   r16	= "current" task pointer (in normal kernel-mode, this is in r13)
38  *   r32-r39	= system call arguments
39  *   b6		= return address (a user-level value)
40  *   ar.pfs	= previous frame-state (a user-level value)
41  *   PSR.be	= cleared to zero (i.e., little-endian byte order is in effect)
42  *   all other registers may contain values passed in from user-mode
47  *   r32-r39	= system call arguments (as passed into the fsyscall handler)
49  *   ar.pfs	= previous frame-state (as passed into the fsyscall handler)
57 	mov r10=-1
67 	ld8 r17=[r17]				// r17 = current->signal
74 	ld8 r17=[r17]				// r17 = current->signal->pids[PIDTYPE_TGID]
78 	ld4 r8=[r8]				// r8 = pid->level
79 	add r17=IA64_PID_UPID_OFFSET,r17	// r17 = &pid->numbers[0]
83 	add r17=r17,r8				// r17 = &pid->numbers[pid->level]
85 	ld4 r8=[r17]				// r8 = pid->numbers[pid->level].nr
103 	ld8 r17=[r17]				// r17 = current->thread_pid
109 	ld4 r8=[r8]				// r8 = pid->level
110 	add r17=IA64_PID_UPID_OFFSET,r17	// r17 = &pid->numbers[0]
114 	add r17=r17,r8				// r17 = &pid->numbers[pid->level]
116 	ld4 r8=[r17]				// r8 = pid->numbers[pid->level].nr
119 	mov r17=-1
125 	mov r17=0			// i must not leak kernel bits...
126 	mov r18=0			// i must not leak kernel bits...
154 	// r2,r3 = temp r4-r7 preserved
163 	// r16 = preserved: current task pointer
183 	// p10 = timesource mmio32 - not used
185 	// p12 = memory time source ( = p9 | p10) - not used
219 	ld8 r30 = [r21]		// clocksource->mmio_ptr
241 	ld8 r8 = [r22],-IA64_TIME_SN_SPEC_SNSEC_OFFSET	// snsec
245 	sub r10 = r2,r24	// current_cycle - last_cycle
259 	nop.i 123
263 	xmpy.l f8 = f8,f7	// nsec_per_cyc*(counter-last_counter)
275 	// Now r8=tv->tv_nsec and r9=tv->tv_sec
308 	mov r10 = -1
312 	mov r10 = -1
330  * current_thread_info()->cpu and corresponding node in cpu_to_node_map.
341 	ld4 r3=[r3]				// M r3 = thread_info->cpu
342 	ld4 r2=[r2]				// M r2 = thread_info->flags
345 	tnat.nz p7,p0 = r33			// I guard against NaT argument
390 	 * We only get here from light-weight syscall handlers.  Thus, we already
391 	 * know that r15 contains a valid syscall number.  No need to re-check.
393 	adds r17=-1024,r15
399 	ld8 r18=[r18]				// load normal (heavy-weight) syscall entry-point
415 	 * interruption had occurred.  To make syscall-restarts work,
426 	 *	- normal fsyscall handler register usage, except
428 	 *	- r18: address of syscall entry point
429 	 *	- r21: ar.fpsr
430 	 *	- r26: ar.pfs
431 	 *	- r27: ar.rsc
432 	 *	- r29: psr
439 	 * ended up clearing PSR.{BE,AC,I,DFL,DFH,DI,DB,SI,TB}.
444 	 * PSR.I  : already turned off by the time fsys_bubble_down gets
447 	 * PSR.DFH: don't care --- kernel never touches f32-f127 on its own
451 	 * PSR.DB : don't care --- kernel never enables kernel-level
455 	 *          will trigger a taken branch; the taken-trap-handler then
456 	 *          converts the syscall into a break-based system-call.
459 	 * Reading psr.l gives us only bits 0-31, psr.it, and psr.mc.
473 	mov r2=r16				// A    get task addr to addl-addressable register
477 	st1 [r16]=r0				// M2|3 clear current->thread.on_ustack flag
481 	ld4 r3=[r3]				// M0|1 r3 = current_thread_info()->flags
482 	lfetch.fault.excl.nt1 [r22]		// M0|1 prefetch register backing-store
483 	nop.i 0
491 	nop.i 0
494 	mov.m r24=ar.rnat			// M2 (5 cyc) read ar.rnat (dual-issues!)
495 	nop.i 0
505 	mov b6=r18				// I0   copy syscall entry-point to b6 (7 cyc)
506 	addl r1=IA64_STK_OFFSET-IA64_PT_REGS_SIZE,r2 // A compute base of memory stack
509 	cmp.ne pKStk,pUStk=r0,r0		// A    set pKStk <- 0, pUStk <- 1
517 	ld8 r18=[r16],TI_AC_STIME-TI_AC_STAMP	// time at last check in kernel
518 	ld8 r19=[r17],TI_AC_UTIME-TI_AC_LEAVE	// time at leave kernel
520 	ld8 r20=[r16],TI_AC_STAMP-TI_AC_STIME	// cumulated stime
524 	st8 [r16]=r30,TI_AC_STIME-TI_AC_STAMP	// update stamp
540 (p10)	br.cond.spnt.many ia64_ret_from_syscall	// B    return if bad call-frame or r15 is a NaT
837 	.space fsyscall_table + 8*NR_syscalls - .zero, 0