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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>
16#include <linux/unistd.h>
17#include <asm/irqflags.h>
18#include <asm/processor.h>
19#include <arch/abi.h>
20#include <arch/spr_def.h>
21
22#ifdef __tilegx__
23#define bnzt bnezt
24#endif
25
26STD_ENTRY(current_text_addr)
27 { move r0, lr; jrp lr }
28 STD_ENDPROC(current_text_addr)
29
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 */
35STD_ENTRY(kernel_execve)
36 moveli TREG_SYSCALL_NR_NAME, __NR_execve
37 swint1
38 jrp lr
39 STD_ENDPROC(kernel_execve)
40
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
50ENTRY(__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
57STD_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
64STD_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)
70
71/*
72 * Reset our stack to r1/r2 (sp and ksp0+cpu respectively), then
73 * free the old stack (passed in r0) and re-invoke cpu_idle().
74 * We update sp and ksp0 simultaneously to avoid backtracer warnings.
75 */
76STD_ENTRY(cpu_idle_on_new_stack)
77 {
78 move sp, r1
79 mtspr SPR_SYSTEM_SAVE_K_0, r2
80 }
81 jal free_thread_info
82 j cpu_idle
83 STD_ENDPROC(cpu_idle_on_new_stack)
84
85/* Loop forever on a nap during SMP boot. */
86STD_ENTRY(smp_nap)
87 nap
88 j smp_nap /* we are not architecturally guaranteed not to exit nap */
89 jrp lr /* clue in the backtracer */
90 STD_ENDPROC(smp_nap)
91
92/*
93 * Enable interrupts racelessly and then nap until interrupted.
94 * Architecturally, we are guaranteed that enabling interrupts via
95 * mtspr to INTERRUPT_CRITICAL_SECTION only interrupts at the next PC.
96 * This function's _cpu_idle_nap address is special; see intvec.S.
97 * When interrupted at _cpu_idle_nap, we bump the PC forward 8, and
98 * as a result return to the function that called _cpu_idle().
99 */
100STD_ENTRY(_cpu_idle)
101 movei r1, 1
102 mtspr INTERRUPT_CRITICAL_SECTION, r1
103 IRQ_ENABLE(r2, r3) /* unmask, but still with ICS set */
104 mtspr INTERRUPT_CRITICAL_SECTION, zero
105 .global _cpu_idle_nap
106_cpu_idle_nap:
107 nap
108 jrp lr
109 STD_ENDPROC(_cpu_idle)
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>
16#include <linux/unistd.h>
17#include <asm/irqflags.h>
18#include <asm/processor.h>
19#include <arch/abi.h>
20#include <arch/spr_def.h>
21
22#ifdef __tilegx__
23#define bnzt bnezt
24#endif
25
26STD_ENTRY(current_text_addr)
27 { move r0, lr; jrp lr }
28 STD_ENDPROC(current_text_addr)
29
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 */
35STD_ENTRY(kernel_execve)
36 moveli TREG_SYSCALL_NR_NAME, __NR_execve
37 swint1
38 jrp lr
39 STD_ENDPROC(kernel_execve)
40
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
50ENTRY(__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
57STD_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
64STD_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)
70
71/* Loop forever on a nap during SMP boot. */
72STD_ENTRY(smp_nap)
73 nap
74 nop /* avoid provoking the icache prefetch with a jump */
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.
81 * Architecturally, we are guaranteed that enabling interrupts via
82 * mtspr to INTERRUPT_CRITICAL_SECTION only interrupts at the next PC.
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 */
87STD_ENTRY(_cpu_idle)
88 movei r1, 1
89 IRQ_ENABLE_LOAD(r2, r3)
90 mtspr INTERRUPT_CRITICAL_SECTION, r1
91 IRQ_ENABLE_APPLY(r2, r3) /* unmask, but still with ICS set */
92 mtspr INTERRUPT_CRITICAL_SECTION, zero
93 .global _cpu_idle_nap
94_cpu_idle_nap:
95 nap
96 nop /* avoid provoking the icache prefetch with a jump */
97 jrp lr
98 STD_ENDPROC(_cpu_idle)