[deliverable/linux.git] / arch / tile / kernel / entry.S

/*
 * Copyright 2010 Tilera Corporation. All Rights Reserved.
 *
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation, version 2.
 *
 *   This program is distributed in the hope that it will be useful, but
 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 *   NON INFRINGEMENT.  See the GNU General Public License for
 *   more details.
 */

#include <linux/linkage.h>
#include <linux/unistd.h>
#include <asm/irqflags.h>
#include <asm/processor.h>
#include <arch/abi.h>
#include <arch/spr_def.h>

#ifdef __tilegx__
#define bnzt bnezt
#endif

STD_ENTRY(current_text_addr)
	{ move r0, lr; jrp lr }
	STD_ENDPROC(current_text_addr)

/*
 * Implement execve().  The i386 code has a note that forking from kernel
 * space results in no copy on write until the execve, so we should be
 * careful not to write to the stack here.
 */
STD_ENTRY(kernel_execve)
	moveli TREG_SYSCALL_NR_NAME, __NR_execve
	swint1
	jrp lr
	STD_ENDPROC(kernel_execve)

/*
 * We don't run this function directly, but instead copy it to a page
 * we map into every user process.  See vdso_setup().
 *
 * Note that libc has a copy of this function that it uses to compare
 * against the PC when a stack backtrace ends, so if this code is
 * changed, the libc implementation(s) should also be updated.
 */
	.pushsection .data
ENTRY(__rt_sigreturn)
	moveli TREG_SYSCALL_NR_NAME,__NR_rt_sigreturn
	swint1
	ENDPROC(__rt_sigreturn)
	ENTRY(__rt_sigreturn_end)
	.popsection

STD_ENTRY(dump_stack)
	{ move r2, lr; lnk r1 }
	{ move r4, r52; addli r1, r1, dump_stack - . }
	{ move r3, sp; j _dump_stack }
	jrp lr   /* keep backtracer happy */
	STD_ENDPROC(dump_stack)

STD_ENTRY(KBacktraceIterator_init_current)
	{ move r2, lr; lnk r1 }
	{ move r4, r52; addli r1, r1, KBacktraceIterator_init_current - . }
	{ move r3, sp; j _KBacktraceIterator_init_current }
	jrp lr   /* keep backtracer happy */
	STD_ENDPROC(KBacktraceIterator_init_current)

/* Loop forever on a nap during SMP boot. */
STD_ENTRY(smp_nap)
	nap
	nop       /* avoid provoking the icache prefetch with a jump */
	j smp_nap /* we are not architecturally guaranteed not to exit nap */
	jrp lr    /* clue in the backtracer */
	STD_ENDPROC(smp_nap)

/*
 * Enable interrupts racelessly and then nap until interrupted.
 * Architecturally, we are guaranteed that enabling interrupts via
 * mtspr to INTERRUPT_CRITICAL_SECTION only interrupts at the next PC.
 * This function's _cpu_idle_nap address is special; see intvec.S.
 * When interrupted at _cpu_idle_nap, we bump the PC forward 8, and
 * as a result return to the function that called _cpu_idle().
 */
STD_ENTRY(_cpu_idle)
	movei r1, 1
	IRQ_ENABLE_LOAD(r2, r3)
	mtspr INTERRUPT_CRITICAL_SECTION, r1
	IRQ_ENABLE_APPLY(r2, r3)       /* unmask, but still with ICS set */
	mtspr INTERRUPT_CRITICAL_SECTION, zero
	.global _cpu_idle_nap
_cpu_idle_nap:
	nap
	nop       /* avoid provoking the icache prefetch with a jump */
	jrp lr
	STD_ENDPROC(_cpu_idle)
Commit	Line	Data
867e359b CM	1	/*
	2	* Copyright 2010 Tilera Corporation. All Rights Reserved.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License
	6	* as published by the Free Software Foundation, version 2.
	7	*
	8	* This program is distributed in the hope that it will be useful, but
	9	* WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
	11	* NON INFRINGEMENT. See the GNU General Public License for
	12	* more details.
	13	*/
	14
	15	#include <linux/linkage.h>
0707ad30	16	#include <linux/unistd.h>
867e359b	17	#include <asm/irqflags.h>
a78c942d	18	#include <asm/processor.h>
0707ad30	19	#include <arch/abi.h>
a78c942d	20	#include <arch/spr_def.h>
867e359b CM	21
	22	#ifdef __tilegx__
	23	#define bnzt bnezt
	24	#endif
	25
	26	STD_ENTRY(current_text_addr)
	27	{ move r0, lr; jrp lr }
	28	STD_ENDPROC(current_text_addr)
	29
867e359b CM	30	/*
	31	* Implement execve(). The i386 code has a note that forking from kernel
	32	* space results in no copy on write until the execve, so we should be
	33	* careful not to write to the stack here.
	34	*/
	35	STD_ENTRY(kernel_execve)
	36	moveli TREG_SYSCALL_NR_NAME, __NR_execve
	37	swint1
	38	jrp lr
	39	STD_ENDPROC(kernel_execve)
	40
867e359b CM	41	/*
	42	* We don't run this function directly, but instead copy it to a page
	43	* we map into every user process. See vdso_setup().
	44	*
	45	* Note that libc has a copy of this function that it uses to compare
	46	* against the PC when a stack backtrace ends, so if this code is
	47	* changed, the libc implementation(s) should also be updated.
	48	*/
	49	.pushsection .data
	50	ENTRY(__rt_sigreturn)
	51	moveli TREG_SYSCALL_NR_NAME,__NR_rt_sigreturn
	52	swint1
	53	ENDPROC(__rt_sigreturn)
	54	ENTRY(__rt_sigreturn_end)
	55	.popsection
	56
	57	STD_ENTRY(dump_stack)
	58	{ move r2, lr; lnk r1 }
	59	{ move r4, r52; addli r1, r1, dump_stack - . }
	60	{ move r3, sp; j _dump_stack }
	61	jrp lr /* keep backtracer happy */
	62	STD_ENDPROC(dump_stack)
	63
	64	STD_ENTRY(KBacktraceIterator_init_current)
	65	{ move r2, lr; lnk r1 }
	66	{ move r4, r52; addli r1, r1, KBacktraceIterator_init_current - . }
	67	{ move r3, sp; j _KBacktraceIterator_init_current }
	68	jrp lr /* keep backtracer happy */
	69	STD_ENDPROC(KBacktraceIterator_init_current)
867e359b CM	70
	71	/* Loop forever on a nap during SMP boot. */
	72	STD_ENTRY(smp_nap)
	73	nap
8c92ba6c	74	nop /* avoid provoking the icache prefetch with a jump */
867e359b CM	75	j smp_nap /* we are not architecturally guaranteed not to exit nap */
	76	jrp lr /* clue in the backtracer */
	77	STD_ENDPROC(smp_nap)
	78
	79	/*
	80	* Enable interrupts racelessly and then nap until interrupted.
0b989cac CM	81	* Architecturally, we are guaranteed that enabling interrupts via
0b989cac CM	82	* mtspr to INTERRUPT_CRITICAL_SECTION only interrupts at the next PC.
867e359b CM	83	* This function's _cpu_idle_nap address is special; see intvec.S.
	84	* When interrupted at _cpu_idle_nap, we bump the PC forward 8, and
	85	* as a result return to the function that called _cpu_idle().
	86	*/
	87	STD_ENTRY(_cpu_idle)
0b989cac	88	movei r1, 1
51007004	89	IRQ_ENABLE_LOAD(r2, r3)
0b989cac	90	mtspr INTERRUPT_CRITICAL_SECTION, r1
51007004	91	IRQ_ENABLE_APPLY(r2, r3) /* unmask, but still with ICS set */
0b989cac	92	mtspr INTERRUPT_CRITICAL_SECTION, zero
867e359b CM	93	.global _cpu_idle_nap
	94	_cpu_idle_nap:
	95	nap
8c92ba6c	96	nop /* avoid provoking the icache prefetch with a jump */
867e359b CM	97	jrp lr
867e359b CM	98	STD_ENDPROC(_cpu_idle)