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-rw-r--r--arch/hexagon/kernel/vm_entry.S269
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diff --git a/arch/hexagon/kernel/vm_entry.S b/arch/hexagon/kernel/vm_entry.S
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1/*
2 * Event entry/exit for Hexagon
3 *
4 * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 and
8 * only version 2 as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
18 * 02110-1301, USA.
19 */
20
21#include <asm/asm-offsets.h> /* assembly-safer versions of C defines */
22#include <asm/mem-layout.h> /* sigh, except for page_offset */
23#include <asm/hexagon_vm.h>
24#include <asm/thread_info.h>
25
26/*
27 * Entry into guest-mode Linux under Hexagon Virtual Machine.
28 * Stack pointer points to event record - build pt_regs on top of it,
29 * set up a plausible C stack frame, and dispatch to the C handler.
30 * On return, do vmrte virtual instruction with SP where we started.
31 *
32 * VM Spec 0.5 uses a trap to fetch HVM record now.
33 */
34
35/*
36 * Save full register state, while setting up thread_info struct
37 * pointer derived from kernel stack pointer in THREADINFO_REG
38 * register, putting prior thread_info.regs pointer in a callee-save
39 * register (R24, which had better not ever be assigned to THREADINFO_REG),
40 * and updating thread_info.regs to point to current stack frame,
41 * so as to support nested events in kernel mode.
42 *
43 * As this is common code, we set the pt_regs system call number
44 * to -1 for all events. It will be replaced with the system call
45 * number in the case where we decode a system call (trap0(#1)).
46 */
47
48#define save_pt_regs()\
49 memd(R0 + #_PT_R3130) = R31:30; \
50 { memw(R0 + #_PT_R2928) = R28; \
51 R31 = memw(R0 + #_PT_ER_VMPSP); }\
52 { memw(R0 + #(_PT_R2928 + 4)) = R31; \
53 R31 = ugp; } \
54 { memd(R0 + #_PT_R2726) = R27:26; \
55 R30 = gp ; } \
56 memd(R0 + #_PT_R2524) = R25:24; \
57 memd(R0 + #_PT_R2322) = R23:22; \
58 memd(R0 + #_PT_R2120) = R21:20; \
59 memd(R0 + #_PT_R1918) = R19:18; \
60 memd(R0 + #_PT_R1716) = R17:16; \
61 memd(R0 + #_PT_R1514) = R15:14; \
62 memd(R0 + #_PT_R1312) = R13:12; \
63 { memd(R0 + #_PT_R1110) = R11:10; \
64 R15 = lc0; } \
65 { memd(R0 + #_PT_R0908) = R9:8; \
66 R14 = sa0; } \
67 { memd(R0 + #_PT_R0706) = R7:6; \
68 R13 = lc1; } \
69 { memd(R0 + #_PT_R0504) = R5:4; \
70 R12 = sa1; } \
71 { memd(R0 + #_PT_UGPGP) = R31:30; \
72 R11 = m1; \
73 R2.H = #HI(_THREAD_SIZE); } \
74 { memd(R0 + #_PT_LC0SA0) = R15:14; \
75 R10 = m0; \
76 R2.L = #LO(_THREAD_SIZE); } \
77 { memd(R0 + #_PT_LC1SA1) = R13:12; \
78 R15 = p3:0; \
79 R2 = neg(R2); } \
80 { memd(R0 + #_PT_M1M0) = R11:10; \
81 R14 = usr; \
82 R2 = and(R0,R2); } \
83 { memd(R0 + #_PT_PREDSUSR) = R15:14; \
84 THREADINFO_REG = R2; } \
85 { r24 = memw(THREADINFO_REG + #_THREAD_INFO_PT_REGS); \
86 memw(THREADINFO_REG + #_THREAD_INFO_PT_REGS) = R0; \
87 R2 = #-1; } \
88 { memw(R0 + #_PT_SYSCALL_NR) = R2; \
89 R30 = #0; }
90
91/*
92 * Restore registers and thread_info.regs state. THREADINFO_REG
93 * is assumed to still be sane, and R24 to have been correctly
94 * preserved. Don't restore R29 (SP) until later.
95 */
96
97#define restore_pt_regs() \
98 { memw(THREADINFO_REG + #_THREAD_INFO_PT_REGS) = R24; \
99 R15:14 = memd(R0 + #_PT_PREDSUSR); } \
100 { R11:10 = memd(R0 + #_PT_M1M0); \
101 p3:0 = R15; } \
102 { R13:12 = memd(R0 + #_PT_LC1SA1); \
103 usr = R14; } \
104 { R15:14 = memd(R0 + #_PT_LC0SA0); \
105 m1 = R11; } \
106 { R3:2 = memd(R0 + #_PT_R0302); \
107 m0 = R10; } \
108 { R5:4 = memd(R0 + #_PT_R0504); \
109 lc1 = R13; } \
110 { R7:6 = memd(R0 + #_PT_R0706); \
111 sa1 = R12; } \
112 { R9:8 = memd(R0 + #_PT_R0908); \
113 lc0 = R15; } \
114 { R11:10 = memd(R0 + #_PT_R1110); \
115 sa0 = R14; } \
116 { R13:12 = memd(R0 + #_PT_R1312); \
117 R15:14 = memd(R0 + #_PT_R1514); } \
118 { R17:16 = memd(R0 + #_PT_R1716); \
119 R19:18 = memd(R0 + #_PT_R1918); } \
120 { R21:20 = memd(R0 + #_PT_R2120); \
121 R23:22 = memd(R0 + #_PT_R2322); } \
122 { R25:24 = memd(R0 + #_PT_R2524); \
123 R27:26 = memd(R0 + #_PT_R2726); } \
124 R31:30 = memd(R0 + #_PT_UGPGP); \
125 { R28 = memw(R0 + #_PT_R2928); \
126 ugp = R31; } \
127 { R31:30 = memd(R0 + #_PT_R3130); \
128 gp = R30; }
129
130 /*
131 * Clears off enough space for the rest of pt_regs; evrec is a part
132 * of pt_regs in HVM mode. Save R0/R1, set handler's address in R1.
133 * R0 is the address of pt_regs and is the parameter to save_pt_regs.
134 */
135
136/*
137 * Since the HVM isn't automagically pushing the EVREC onto the stack anymore,
138 * we'll subract the entire size out and then fill it in ourselves.
139 * Need to save off R0, R1, R2, R3 immediately.
140 */
141
142#define vm_event_entry(CHandler) \
143 { \
144 R29 = add(R29, #-(_PT_REGS_SIZE)); \
145 memd(R29 + #(_PT_R0100 + -_PT_REGS_SIZE)) = R1:0; \
146 } \
147 { \
148 memd(R29 +#_PT_R0302) = R3:2; \
149 } \
150 trap1(#HVM_TRAP1_VMGETREGS); \
151 { \
152 memd(R29 + #_PT_ER_VMEL) = R1:0; \
153 R0 = R29; \
154 R1.L = #LO(CHandler); \
155 } \
156 { \
157 memd(R29 + #_PT_ER_VMPSP) = R3:2; \
158 R1.H = #HI(CHandler); \
159 jump event_dispatch; \
160 }
161
162.text
163 /*
164 * Do bulk save/restore in one place.
165 * Adds a jump to dispatch latency, but
166 * saves hundreds of bytes.
167 */
168
169event_dispatch:
170 save_pt_regs()
171 callr r1
172
173 /*
174 * If we were in kernel mode, we don't need to check scheduler
175 * or signals if CONFIG_PREEMPT is not set. If set, then it has
176 * to jump to a need_resched kind of block.
177 * BTW, CONFIG_PREEMPT is not supported yet.
178 */
179
180#ifdef CONFIG_PREEMPT
181 R0 = #VM_INT_DISABLE
182 trap1(#HVM_TRAP1_VMSETIE)
183#endif
184
185 /* "Nested control path" -- if the previous mode was kernel */
186 R0 = memw(R29 + #_PT_ER_VMEST);
187 P0 = tstbit(R0, #HVM_VMEST_UM_SFT);
188 if !P0 jump restore_all;
189 /*
190 * Returning from system call, normally coming back from user mode
191 */
192return_from_syscall:
193 /* Disable interrupts while checking TIF */
194 R0 = #VM_INT_DISABLE
195 trap1(#HVM_TRAP1_VMSETIE)
196
197 /*
198 * Coming back from the C-world, our thread info pointer
199 * should be in the designated register (usually R19)
200 */
201 R1.L = #LO(_TIF_ALLWORK_MASK)
202 {
203 R1.H = #HI(_TIF_ALLWORK_MASK);
204 R0 = memw(THREADINFO_REG + #_THREAD_INFO_FLAGS);
205 }
206
207 /*
208 * Compare against the "return to userspace" _TIF_WORK_MASK
209 */
210 R1 = and(R1,R0);
211 { P0 = cmp.eq(R1,#0); if (!P0.new) jump:t work_pending;}
212 jump restore_all; /* we're outta here! */
213
214work_pending:
215 {
216 P0 = tstbit(R1, #TIF_NEED_RESCHED);
217 if (!P0.new) jump:nt work_notifysig;
218 }
219 call schedule
220 jump return_from_syscall; /* check for more work */
221
222work_notifysig:
223 /* this is the part that's kind of fuzzy. */
224 R1 = and(R0, #(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME));
225 P0 = cmp.eq(R1, #0);
226 if P0 jump restore_all
227 R1 = R0; /* unsigned long thread_info_flags */
228 R0 = R29; /* regs should still be at top of stack */
229 call do_notify_resume
230
231restore_all:
232 /* Disable interrupts, if they weren't already, before reg restore. */
233 R0 = #VM_INT_DISABLE
234 trap1(#HVM_TRAP1_VMSETIE)
235
236 /* do the setregs here for VM 0.5 */
237 /* R29 here should already be pointing at pt_regs */
238 R1:0 = memd(R29 + #_PT_ER_VMEL);
239 R3:2 = memd(R29 + #_PT_ER_VMPSP);
240 trap1(#HVM_TRAP1_VMSETREGS);
241
242 R0 = R29
243 restore_pt_regs()
244 R1:0 = memd(R29 + #_PT_R0100);
245 R29 = add(R29, #_PT_REGS_SIZE);
246 trap1(#HVM_TRAP1_VMRTE)
247 /* Notreached */
248
249 .globl _K_enter_genex
250_K_enter_genex:
251 vm_event_entry(do_genex)
252
253 .globl _K_enter_interrupt
254_K_enter_interrupt:
255 vm_event_entry(arch_do_IRQ)
256
257 .globl _K_enter_trap0
258_K_enter_trap0:
259 vm_event_entry(do_trap0)
260
261 .globl _K_enter_machcheck
262_K_enter_machcheck:
263 vm_event_entry(do_machcheck)
264
265
266 .globl ret_from_fork
267ret_from_fork:
268 call schedule_tail
269 jump return_from_syscall
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