WebSVN – HelenOS – Diff – /kernel/trunk/arch/ia32/src/asm.S

+#
 # Copyright (C) 2001-2004 Jakub Jermar
 # All rights reserved.
+#
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
 # are met:
+#
 # - Redistributions of source code must retain the above copyright
 #   notice, this list of conditions and the following disclaimer.
 # - Redistributions in binary form must reproduce the above copyright
 #   notice, this list of conditions and the following disclaimer in the
 #   documentation and/or other materials provided with the distribution.
 # - The name of the author may not be used to endorse or promote products
 #   derived from this software without specific prior written permission.
+#
 # THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 # IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 # OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 # IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 # NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 # THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
 ## very low and hardware-level functions
 # Mask for interrupts 0 - 31 (bits 0 - 31) where 0 means that int has no error word
 # and 1 means interrupt with error word
 #define ERROR_WORD_INTERRUPT_LIST 0x00027D00
 .text
 .global paging_on
 .global enable_l_apic_in_msr
 .global interrupt_handlers
+.global memcpy
+.global memcpy_from_uspace
+.global memcpy_from_uspace_failover_address
+.global memcpy_to_uspace
+.global memcpy_to_uspace_failover_address
+#define MEMCPY_DST	4
+#define MEMCPY_SRC	8
+#define MEMCPY_SIZE	12
+/** Copy memory to/from userspace.
+ *
+ * This is almost conventional memcpy().
+ * The difference is that there is a failover part
+ * to where control is returned from a page fault
+ * if the page fault occurs during copy_from_uspace()
+ * or copy_to_uspace().
+ *
+ * @param MEMCPY_DST(%esp)	Destination address.
+ * @param MEMCPY_SRC(%esp)	Source address.
+ * @param MEMCPY_SIZE(%esp)	Size.
+ *
+ * @return MEMCPY_SRC(%esp) on success and 0 on failure.
+ */
+memcpy:
+memcpy_from_uspace:
+memcpy_to_uspace:
+	movl %edi, %edx				/* save %edi */
+	movl %esi, %eax				/* save %esi */
+	movl MEMCPY_SIZE(%esp), %ecx
+	shrl $2, %ecx				/* size / 4 */
+	movl MEMCPY_DST(%esp), %edi
+	movl MEMCPY_SRC(%esp), %esi
+	rep movsl				/* copy as much as possible word by word */
+	movl MEMCPY_SIZE(%esp), %ecx
+	andl $3, %ecx				/* size % 4 */
+	jz 0f
+	rep movsb				/* copy the rest byte by byte */
+:
+	movl %edx, %edi
+	movl %eax, %esi
+	movl MEMCPY_SRC(%esp), %eax		/* MEMCPY_SRC(%esp), success */
+	ret
+/*
+ * We got here from as_page_fault() after the memory operations
+ * above had caused a page fault.
+ */
+memcpy_from_uspace_failover_address:
+memcpy_to_uspace_failover_address:
+	movl %edx, %edi
+	movl %eax, %esi
+	xorl %eax, %eax				/* return 0, failure */
+	ret
 ## Turn paging on
+#
 # Enable paging and write-back caching in CR0.
+#
 paging_on:
 	movl %cr0,%edx
 	orl $(1<<31),%edx		# paging on
 	andl $~((1<<30)|(1<<29)),%edx	# clear Cache Disable and not Write Though
 	movl %edx,%cr0
 	jmp 0f
 :
 	ret
 ## Enable local APIC
+#
 # Enable local APIC in MSR.
+#
 enable_l_apic_in_msr:
 	push %eax
 	movl $0x1b, %ecx
 	rdmsr
 	orl $(1<<11),%eax
 	orl $(0xfee00000),%eax
 	wrmsr
 	pop %eax
 	ret
 # Clear nested flag
 # overwrites %ecx
 .macro CLEAR_NT_FLAG
 	pushfl
 	pop %ecx
 	and $0xffffbfff,%ecx
 	push %ecx
 	popfl
 .endm
 ## Declare interrupt handlers
+#
 # Declare interrupt handlers for n interrupt
 # vectors starting at vector i.
+#
 # The handlers setup data segment registers
 # and call exc_dispatch().
+#
 #define INTERRUPT_ALIGN 64
 .macro handler i n
 .ifeq \i-0x30     # Syscall handler
 	push %ds
 	push %es
 	push %fs
 	push %gs
 	# Push arguments on stack
 	push %edi
 	push %esi
 	push %edx
 	push %ecx
 	push %eax
 	# we must fill the data segment registers
 	movw $16,%ax
 	movw %ax,%ds
 	movw %ax,%es
 	sti
 	call syscall_handler   # syscall_handler(ax,cx,dx,si,di)
 	cli
 	addl $20, %esp         # clean-up of parameters
 	pop %gs
 	pop %fs
 	pop %es
 	pop %ds
 	CLEAR_NT_FLAG
 	iret
 .else
 	/*
 	 * This macro distinguishes between two versions of ia32 exceptions.
 	 * One version has error word and the other does not have it.
 	 * The latter version fakes the error word on the stack so that the
 	 * handlers and istate_t can be the same for both types.
 	 */
 	.iflt \i-32
 		.if (1 << \i) & ERROR_WORD_INTERRUPT_LIST
 			/*
 			 * With error word, do nothing
 			 */
                 .else
                         /*
                          * Version without error word,
                          */
 			subl $4, %esp
                 .endif
         .else
                 /*
                  * Version without error word,
                  */
 		subl $4, %esp
 	.endif
 	push %ds
 	push %es
 	push %fs
 	push %gs
 #ifdef CONFIG_DEBUG_ALLREGS
 	push %ebx
 	push %ebp
 	push %edi
 	push %esi
 #else
 	sub $16, %esp
 #endif
 	push %edx
 	push %ecx
 	push %eax
 	# we must fill the data segment registers
 	movw $16,%ax
 	movw %ax,%ds
 	movw %ax,%es
 	pushl %esp          # *istate
 	pushl $(\i)         # intnum
 	call exc_dispatch   # excdispatch(intnum, *istate)
 	addl $8,%esp        # Clear arguments from stack
 	CLEAR_NT_FLAG # Modifies %ecx
 	pop %eax
 	pop %ecx
 	pop %edx
 #ifdef CONFIG_DEBUG_ALLREGS
 	pop %esi
 	pop %edi
 	pop %ebp
 	pop %ebx
 #else
 	add $16, %esp
 #endif
 	pop %gs
 	pop %fs
 	pop %es
 	pop %ds
 	addl $4,%esp	# Skip error word, no matter whether real or fake.
 	iret
 .endif
 	.align INTERRUPT_ALIGN
 	.if (\n-\i)-1
 	handler "(\i+1)",\n
 	.endif
 .endm
 # keep in sync with pm.h !!!
 IDT_ITEMS=64
 .align INTERRUPT_ALIGN
 interrupt_handlers:
 h_start:
 	handler 0 IDT_ITEMS
 h_end:
 .data
 .global interrupt_handler_size
 interrupt_handler_size: .long (h_end-h_start)/IDT_ITEMS

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(root)/kernel/trunk/arch/ia32/src/asm.S – Rev 1278 → 1288