1/*
2 * Copyright 2011 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 * This routine is a helper for migrating the home of a set of pages to
15 * a new cpu.  See the documentation in homecache.c for more information.
16 */
17
18#include <linux/linkage.h>
19#include <linux/threads.h>
20#include <asm/page.h>
21#include <asm/thread_info.h>
22#include <asm/types.h>
23#include <asm/asm-offsets.h>
24#include <hv/hypervisor.h>
25
26	.text
27
28/*
29 * First, some definitions that apply to all the code in the file.
30 */
31
32/* Locals (caller-save) */
33#define r_tmp		r10
34#define r_save_sp	r11
35
36/* What we save where in the stack frame; must include all callee-saves. */
37#define FRAME_SP	8
38#define FRAME_R30	16
39#define FRAME_R31	24
40#define FRAME_R32	32
41#define FRAME_R33	40
42#define FRAME_SIZE	48
43
44
45
46
47/*
48 * On entry:
49 *
50 *   r0 the new context PA to install (moved to r_context)
51 *   r1 PTE to use for context access (moved to r_access)
52 *   r2 ASID to use for new context (moved to r_asid)
53 *   r3 pointer to cpumask with just this cpu set in it (r_my_cpumask)
54 */
55
56/* Arguments (caller-save) */
57#define r_context_in	r0
58#define r_access_in	r1
59#define r_asid_in	r2
60#define r_my_cpumask	r3
61
62/* Locals (callee-save); must not be more than FRAME_xxx above. */
63#define r_save_ics	r30
64#define r_context	r31
65#define r_access	r32
66#define r_asid		r33
67
68/*
69 * Caller-save locals and frame constants are the same as
70 * for homecache_migrate_stack_and_flush.
71 */
72
73STD_ENTRY(flush_and_install_context)
74	/*
75	 * Create a stack frame; we can't touch it once we flush the
76	 * cache until we install the new page table and flush the TLB.
77	 */
78	{
79	 move r_save_sp, sp
80	 st sp, lr
81	 addi sp, sp, -FRAME_SIZE
82	}
83	addi r_tmp, sp, FRAME_SP
84	{
85	 st r_tmp, r_save_sp
86	 addi r_tmp, sp, FRAME_R30
87	}
88	{
89	 st r_tmp, r30
90	 addi r_tmp, sp, FRAME_R31
91	}
92	{
93	 st r_tmp, r31
94	 addi r_tmp, sp, FRAME_R32
95	}
96	{
97	 st r_tmp, r32
98	 addi r_tmp, sp, FRAME_R33
99	}
100	st r_tmp, r33
101
102	/* Move some arguments to callee-save registers. */
103	{
104	 move r_context, r_context_in
105	 move r_access, r_access_in
106	}
107	move r_asid, r_asid_in
108
109	/* Disable interrupts, since we can't use our stack. */
110	{
111	 mfspr r_save_ics, INTERRUPT_CRITICAL_SECTION
112	 movei r_tmp, 1
113	}
114	mtspr INTERRUPT_CRITICAL_SECTION, r_tmp
115
116	/* First, flush our L2 cache. */
117	{
118	 move r0, zero  /* cache_pa */
119	 moveli r1, hw2_last(HV_FLUSH_EVICT_L2)  /* cache_control */
120	}
121	{
122	 shl16insli r1, r1, hw1(HV_FLUSH_EVICT_L2)
123	 move r2, r_my_cpumask  /* cache_cpumask */
124	}
125	{
126	 shl16insli r1, r1, hw0(HV_FLUSH_EVICT_L2)
127	 move r3, zero  /* tlb_va */
128	}
129	{
130	 move r4, zero  /* tlb_length */
131	 move r5, zero  /* tlb_pgsize */
132	}
133	{
134	 move r6, zero  /* tlb_cpumask */
135	 move r7, zero  /* asids */
136	}
137	{
138	 move r8, zero  /* asidcount */
139	 jal hv_flush_remote
140	}
141	bnez r0, 1f
142
143	/* Now install the new page table. */
144	{
145	 move r0, r_context
146	 move r1, r_access
147	}
148	{
149	 move r2, r_asid
150	 movei r3, HV_CTX_DIRECTIO
151	}
152	jal hv_install_context
153	bnez r0, 1f
154
155	/* Finally, flush the TLB. */
156	{
157	 movei r0, 0   /* preserve_global */
158	 jal hv_flush_all
159	}
160
1611:      /* Reset interrupts back how they were before. */
162	mtspr INTERRUPT_CRITICAL_SECTION, r_save_ics
163
164	/* Restore the callee-saved registers and return. */
165	addli lr, sp, FRAME_SIZE
166	{
167	 ld lr, lr
168	 addli r_tmp, sp, FRAME_R30
169	}
170	{
171	 ld r30, r_tmp
172	 addli r_tmp, sp, FRAME_R31
173	}
174	{
175	 ld r31, r_tmp
176	 addli r_tmp, sp, FRAME_R32
177	}
178	{
179	 ld r32, r_tmp
180	 addli r_tmp, sp, FRAME_R33
181	}
182	{
183	 ld r33, r_tmp
184	 addi sp, sp, FRAME_SIZE
185	}
186	jrp lr
187	STD_ENDPROC(flush_and_install_context)
188