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132 vana 1
#
2071 jermar 2
# Copyright (c) 2001-2004 Jakub Jermar
132 vana 3
# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions
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# are met:
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#
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# - Redistributions of source code must retain the above copyright
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#   notice, this list of conditions and the following disclaimer.
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# - Redistributions in binary form must reproduce the above copyright
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#   notice, this list of conditions and the following disclaimer in the
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#   documentation and/or other materials provided with the distribution.
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# - The name of the author may not be used to endorse or promote products
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#   derived from this software without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#
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## very low and hardware-level functions
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2613 jermar 31
# Mask for interrupts 0 - 31 (bits 0 - 31) where 0 means that int has no error
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# word and 1 means interrupt with error word
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#define ERROR_WORD_INTERRUPT_LIST 0x00027d00
132 vana 34
 
35
.text
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37
.global paging_on
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.global enable_l_apic_in_msr
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.global interrupt_handlers
3043 jermar 40
.global memsetb
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.global memsetw
1288 jermar 42
.global memcpy
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.global memcpy_from_uspace
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.global memcpy_from_uspace_failover_address
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.global memcpy_to_uspace
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.global memcpy_to_uspace_failover_address
132 vana 47
 
1288 jermar 48
 
3043 jermar 49
# Wrapper for generic memsetb
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memsetb:
51
	jmp _memsetb
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53
# Wrapper for generic memsetw
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memsetw:
55
	jmp _memsetw
56
 
57
 
1288 jermar 58
#define MEMCPY_DST	4
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#define MEMCPY_SRC	8
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#define MEMCPY_SIZE	12
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62
/** Copy memory to/from userspace.
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 *
64
 * This is almost conventional memcpy().
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 * The difference is that there is a failover part
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 * to where control is returned from a page fault
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 * if the page fault occurs during copy_from_uspace()
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 * or copy_to_uspace().
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 *
70
 * @param MEMCPY_DST(%esp)	Destination address.
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 * @param MEMCPY_SRC(%esp)	Source address.
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 * @param MEMCPY_SIZE(%esp)	Size.
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 *
3274 jermar 74
 * @return MEMCPY_DST(%esp) on success and 0 on failure.
1288 jermar 75
 */
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memcpy:
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memcpy_from_uspace:
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memcpy_to_uspace:
2613 jermar 79
	movl %edi, %edx			/* save %edi */
80
	movl %esi, %eax			/* save %esi */
1288 jermar 81
 
82
	movl MEMCPY_SIZE(%esp), %ecx
2613 jermar 83
	shrl $2, %ecx			/* size / 4 */
1288 jermar 84
 
85
	movl MEMCPY_DST(%esp), %edi
86
	movl MEMCPY_SRC(%esp), %esi
87
 
2613 jermar 88
	rep movsl			/* copy whole words */
1288 jermar 89
 
90
	movl MEMCPY_SIZE(%esp), %ecx
2613 jermar 91
	andl $3, %ecx			/* size % 4 */
1288 jermar 92
	jz 0f
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2613 jermar 94
	rep movsb			/* copy the rest byte by byte */
1288 jermar 95
 
96
0:
97
	movl %edx, %edi
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	movl %eax, %esi
3274 jermar 99
	movl MEMCPY_DST(%esp), %eax	/* MEMCPY_DST(%esp), success */
1288 jermar 100
	ret
101
 
102
/*
103
 * We got here from as_page_fault() after the memory operations
104
 * above had caused a page fault.
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 */
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memcpy_from_uspace_failover_address:
107
memcpy_to_uspace_failover_address:
108
	movl %edx, %edi
109
	movl %eax, %esi
2613 jermar 110
	xorl %eax, %eax			/* return 0, failure */
1288 jermar 111
	ret
112
 
132 vana 113
## Turn paging on
114
#
115
# Enable paging and write-back caching in CR0.
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#
117
paging_on:
2613 jermar 118
	movl %cr0, %edx
119
	orl $(1 << 31), %edx		# paging on
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	# clear Cache Disable and not Write Though
121
	andl $~((1 << 30) | (1 << 29)), %edx
316 jermar 122
	movl %edx,%cr0
132 vana 123
	jmp 0f
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0:
125
	ret
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127
 
128
## Enable local APIC
129
#
130
# Enable local APIC in MSR.
131
#
132
enable_l_apic_in_msr:
133
	movl $0x1b, %ecx
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	rdmsr
2613 jermar 135
	orl $(1 << 11), %eax
136
	orl $(0xfee00000), %eax
132 vana 137
	wrmsr
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	ret
139
 
1100 palkovsky 140
# Clear nested flag
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# overwrites %ecx
142
.macro CLEAR_NT_FLAG
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	pushfl
144
	pop %ecx
2613 jermar 145
	and $0xffffbfff, %ecx
1100 palkovsky 146
	push %ecx
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	popfl
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.endm	
132 vana 149
 
4153 mejdrech 150
/*
151
 * The SYSENTER syscall mechanism can be used for syscalls with
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 * four or fewer arguments. To pass these four arguments, we
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 * use four registers: EDX, ECX, EBX, ESI. The syscall number
154
 * is passed in EAX. We use EDI to remember the return address
155
 * and EBP to remember the stack. The INT-based syscall mechanism
156
 * can actually handle six arguments plus the syscall number
157
 * entirely in registers.
158
 */
159
.global sysenter_handler
160
sysenter_handler:
161
	sti
162
	pushl %ebp	# remember user stack
163
	pushl %edi	# remember return user address
164
 
165
	pushl %gs	# remember TLS
166
 
167
	pushl %eax	# syscall number
168
	subl $8, %esp	# unused sixth and fifth argument
169
	pushl %esi	# fourth argument
170
	pushl %ebx	# third argument
171
	pushl %ecx	# second argument
172
	pushl %edx	# first argument
173
 
174
	movw $16, %ax
175
	movw %ax, %ds
176
	movw %ax, %es
177
 
178
	cld
179
	call syscall_handler
180
	addl $28, %esp	# remove arguments from stack
181
 
182
	pop %gs		# restore TLS
183
 
184
	pop %edx	# prepare return EIP for SYSEXIT
185
	pop %ecx	# prepare userspace ESP for SYSEXIT
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187
	sysexit		# return to userspace
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189
 
132 vana 190
## Declare interrupt handlers
191
#
192
# Declare interrupt handlers for n interrupt
193
# vectors starting at vector i.
194
#
195
# The handlers setup data segment registers
576 palkovsky 196
# and call exc_dispatch().
132 vana 197
#
1278 palkovsky 198
#define INTERRUPT_ALIGN 64
132 vana 199
.macro handler i n
958 jermar 200
 
2613 jermar 201
.ifeq \i - 0x30     # Syscall handler
202
	pushl %ds
203
	pushl %es
204
	pushl %fs
205
	pushl %gs
1100 palkovsky 206
 
2613 jermar 207
	#
208
	# Push syscall arguments onto the stack
209
	#
210
	# NOTE: The idea behind the order of arguments passed in registers is to
211
	#	use all scratch registers first and preserved registers next.
212
	#	An optimized libc syscall wrapper can make use of this setup.
213
	#
214
	pushl %eax
215
	pushl %ebp
216
	pushl %edi
217
	pushl %esi
218
	pushl %ebx
219
	pushl %ecx
220
	pushl %edx
1100 palkovsky 221
 
222
	# we must fill the data segment registers
2613 jermar 223
	movw $16, %ax
224
	movw %ax, %ds
225
	movw %ax, %es
1100 palkovsky 226
 
2784 jermar 227
	cld
1100 palkovsky 228
	sti
2613 jermar 229
	# syscall_handler(edx, ecx, ebx, esi, edi, ebp, eax)
230
	call syscall_handler   
1100 palkovsky 231
	cli
2613 jermar 232
	addl $28, %esp         # clean-up of parameters
1100 palkovsky 233
 
2613 jermar 234
	popl %gs
235
	popl %fs
236
	popl %es
237
	popl %ds
1100 palkovsky 238
 
239
	CLEAR_NT_FLAG
240
	iret
241
.else	
1008 jermar 242
	/*
1021 jermar 243
	 * This macro distinguishes between two versions of ia32 exceptions.
244
	 * One version has error word and the other does not have it.
245
	 * The latter version fakes the error word on the stack so that the
246
	 * handlers and istate_t can be the same for both types.
1008 jermar 247
	 */
2613 jermar 248
	.iflt \i - 32
1021 jermar 249
		.if (1 << \i) & ERROR_WORD_INTERRUPT_LIST
1100 palkovsky 250
			/* 
251
			 * With error word, do nothing
1021 jermar 252
			 */
253
                .else
254
                        /*
255
                         * Version without error word,
256
                         */
257
			subl $4, %esp
258
                .endif
259
        .else
260
                /*
261
                 * Version without error word,
262
                 */
263
		subl $4, %esp
1100 palkovsky 264
	.endif
265
 
2613 jermar 266
	pushl %ds
267
	pushl %es
268
	pushl %fs
269
	pushl %gs
132 vana 270
 
2613 jermar 271
	pushl %edx
272
	pushl %ecx
273
	pushl %eax
1100 palkovsky 274
 
132 vana 275
	# we must fill the data segment registers
2613 jermar 276
	movw $16, %ax
277
	movw %ax, %ds
278
	movw %ax, %es
132 vana 279
 
2784 jermar 280
	cld
281
 
1100 palkovsky 282
	pushl %esp          # *istate
283
	pushl $(\i)         # intnum
284
	call exc_dispatch   # excdispatch(intnum, *istate)
2613 jermar 285
	addl $8, %esp       # Clear arguments from stack
132 vana 286
 
1100 palkovsky 287
	CLEAR_NT_FLAG # Modifies %ecx
288
 
2613 jermar 289
	popl %eax
290
	popl %ecx
291
	popl %edx
1100 palkovsky 292
 
2613 jermar 293
	popl %gs
294
	popl %fs
295
	popl %es
296
	popl %ds
132 vana 297
 
2613 jermar 298
	addl $4, %esp	# Skip error word, no matter whether real or fake.
316 jermar 299
	iret
1100 palkovsky 300
.endif
132 vana 301
 
1100 palkovsky 302
	.align INTERRUPT_ALIGN
2613 jermar 303
	.if (\n- \i) - 1
304
	handler "(\i + 1)", \n
132 vana 305
	.endif
306
.endm
307
 
308
# keep in sync with pm.h !!!
2613 jermar 309
IDT_ITEMS = 64
1100 palkovsky 310
.align INTERRUPT_ALIGN
132 vana 311
interrupt_handlers:
312
h_start:
1100 palkovsky 313
	handler 0 IDT_ITEMS
132 vana 314
h_end:
315
 
316
.data
317
.global interrupt_handler_size
318
 
2613 jermar 319
interrupt_handler_size: .long (h_end - h_start) / IDT_ITEMS