WebSVN - shark - Blame - Rev 299 - /shark/trunk/oslib/kl/timeint.s

Rev	Author	Line No.	Line
2	pj	1	/* Project: OSLib
		2	* Description: The OS Construction Kit
		3	* Date: 1.6.2000
		4	* Idea by: Luca Abeni & Gerardo Lamastra
		5	*
		6	* OSLib is an SO project aimed at developing a common, easy-to-use
		7	* low-level infrastructure for developing OS kernels and Embedded
		8	* Applications; it partially derives from the HARTIK project but it
		9	* currently is independently developed.
		10	*
		11	* OSLib is distributed under GPL License, and some of its code has
		12	* been derived from the Linux kernel source; also some important
		13	* ideas come from studying the DJGPP go32 extender.
		14	*
		15	* We acknowledge the Linux Community, Free Software Foundation,
		16	* D.J. Delorie and all the other developers who believe in the
		17	* freedom of software and ideas.
		18	*
		19	* For legalese, check out the included GPL license.
		20	*/
		21
		22	/* Safe abort routine & timer asm handler */
		23
		24	.title "Timer.S"
		25
		26	#include <ll/i386/sel.h>
		27	#include <ll/i386/linkage.h>
		28	#include <ll/i386/defs.h>
		29
		30	#include <ll/sys/ll/exc.h>
		31
		32	.data
		33
		34	ASMFILE(TimerHandler)
		35
		36	.extern JmpSel
		37	.extern JmpZone
		38	.globl SYMBOL_NAME(ll_clock)
		39	.globl SYMBOL_NAME(last_handler)
		40
		41	/* Used as JMP entry point to check if a real */
		42	/* context switch is necessary */
		43
		44	SYMBOL_NAME_LABEL(ll_clock) .int 0
		45	SYMBOL_NAME_LABEL(last_handler) .long 0
		46
		47	.extern SYMBOL_NAME(periodic_wake_up)
		48	.extern SYMBOL_NAME(oneshot_wake_up)
299	giacomo	49	.extern SYMBOL_NAME(ack_APIC_irq)
2	pj	50
		51	.text
299	giacomo	52	.globl SYMBOL_NAME(ll_apic_timer)
		53	/* APIC ll_timer */
		54
		55	SYMBOL_NAME_LABEL(ll_apic_timer)
		56	pushal
		57	pushw %ds
		58	pushw %es
		59	pushw %fs
		60	pushw %gs
		61
		62	movw $(X_FLATDATA_SEL),%ax
		63	movw %ax,%ds
		64	movw %ax,%es
		65
		66	/* Send EOI to APIC */
		67	movl $0xFEE000B0,%ebx
		68	movl $0,(%ebx)
		69
		70	/* Call wake_up(actual_context) */
		71
		72	movl SYMBOL_NAME(ll_clock),%eax
		73	incl %eax
		74	movl %eax,SYMBOL_NAME(ll_clock)
		75
		76	/* The following could be optimized a little... */
		77	xorl %ebx, %ebx
		78	movw %ss, %bx
		79	/* We must switch to a ``safe stack'' */
		80	/*
		81	* OK, this is the idea: in %esp we have the address of the
		82	* stack pointer in the APPLICATION address space...
		83	* We assume that address spaces are implemented through segments...
		84	* What we have to do is to add the segment base to %esp:
		85	* - Load the GDT base in a register
		86	* - Add DS * 8 to that value
		87	* - Read the corresponding GDT entry (the segment descriptor)
		88	* - Compute the base...
		89	* It is (p & 0xFC) \| ((p +1) & 0x0F) << 16) \| *(p + 2)
		90	*/
		91	movl SYMBOL_NAME(GDT_base), %edi
		92	addl %ebx, %edi
		93	xorl %ebx, %ebx
		94	movb 7(%edi), %bh
		95	movb 4(%edi), %bl
		96	shl $16, %ebx
		97	movw 2(%edi), %bx
		98	/* Is it correct? I think so... Test it!!! */
		99	addl %ebx, %esp
		100	/* Save EBX for returning to our stack... */
		101	movw %ds, %cx
		102	movw %ss, %dx
		103	movw %cx, %ss
		104	pushl %ebx
		105	pushl %edx
		106	cld
		107	movl SYMBOL_NAME(timermode), %eax
		108	cmpl $1, %eax
		109	je apic_oneshot
		110	call SYMBOL_NAME(periodic_wake_up)
		111	jmp apic_Timer_OK
		112	apic_oneshot: call SYMBOL_NAME(oneshot_wake_up)
		113	apic_Timer_OK:
		114	/* Restore ESP */
		115	popl %edx
		116	popl %ebx /* We must subtract it from ESP...*/
		117	subl %ebx, %esp
		118	movw %dx, %ss
		119
		120	#ifdef __VIRCSW__
		121
		122	movw SYMBOL_NAME(currCtx), %ax
		123	cmpw %ax,JmpSel
		124	je apic_NoPreempt2
		125	movw %ax,JmpSel
		126	ljmp JmpZone /* DISPATCH! */
		127	#endif
		128	apic_NoPreempt2:
		129
		130	cmpl $0, SYMBOL_NAME(last_handler)
		131	je apic_nohandler
		132	movl SYMBOL_NAME(last_handler), %ebx
		133	call *%ebx
		134	apic_nohandler:
		135	popw %gs
		136	popw %fs
		137	popw %es
		138	popw %ds
		139	popal
		140	iret
		141
2	pj	142	.globl SYMBOL_NAME(ll_timer)
		143	/* This is the timer handler; it reloads for safety the DS register; this */
		144	/* prevents from mess when timer interrupts linear access to memory (not in */
		145	/* ELF address space); then EOI is sent in order to detect timer overrun */
		146	/* The high level kernel procedure wake_up() is called to perform the */
		147	/* preeption at higher level (process descriptos); the resulting context */
		148	/* if different from the old one is used to trigger the task activation. */
		149
		150	SYMBOL_NAME_LABEL(ll_timer)
		151	pushal
		152	pushw %ds
		153	pushw %es
		154	pushw %fs
		155	pushw %gs
		156
		157	movw $(X_FLATDATA_SEL),%ax
		158	movw %ax,%ds
		159	movw %ax,%es
		160
		161	/* Send EOI to master PIC */
		162	/* to perform later the overrun test */
		163	movb $0x20,%al
		164	movl $0x20,%edx
		165	outb %al,%dx
		166
		167	/* Call wake_up(actual_context) */
		168
		169	movl SYMBOL_NAME(ll_clock),%eax
		170	incl %eax
		171	movl %eax,SYMBOL_NAME(ll_clock)
		172
		173	/* The following could be optimized a little... */
		174	xorl %ebx, %ebx
		175	movw %ss, %bx
		176	/* We must switch to a ``safe stack'' */
		177	/*
		178	* OK, this is the idea: in %esp we have the address of the
		179	* stack pointer in the APPLICATION address space...
		180	* We assume that address spaces are implemented through segments...
		181	* What we have to do is to add the segment base to %esp:
		182	* - Load the GDT base in a register
		183	* - Add DS * 8 to that value
		184	* - Read the corresponding GDT entry (the segment descriptor)
		185	* - Compute the base...
		186	* It is (p & 0xFC) \| ((p +1) & 0x0F) << 16) \| *(p + 2)
		187	*/
		188	movl SYMBOL_NAME(GDT_base), %edi
		189	addl %ebx, %edi
		190	xorl %ebx, %ebx
		191	movb 7(%edi), %bh
		192	movb 4(%edi), %bl
		193	shl $16, %ebx
		194	movw 2(%edi), %bx
		195	/* Is it correct? I think so... Test it!!! */
		196	addl %ebx, %esp
		197	/* Save EBX for returning to our stack... */
		198	movw %ds, %cx
		199	movw %ss, %dx
		200	movw %cx, %ss
		201	pushl %ebx
		202	pushl %edx
		203	cld
		204	movl SYMBOL_NAME(timermode), %eax
		205	cmpl $1, %eax
		206	je oneshot
		207	call SYMBOL_NAME(periodic_wake_up)
		208	jmp goon
		209	oneshot: call SYMBOL_NAME(oneshot_wake_up)
227	giacomo	210	jmp Timer_OK
2	pj	211	goon:
		212	/* This is the overrun test */
		213	/* Do it after sending EOI to master PIC */
		214
		215	movb $0x0A,%al
		216	movl $0x020,%edx
		217	outb %al,%dx
		218	inb %dx,%al
		219	testb $1,%al
		220	jz Timer_OK
		221	movl $(CLOCK_OVERRUN),%eax
		222	pushl %eax
		223	call SYMBOL_NAME(ll_abort)
		224
		225	Timer_OK:
		226	/* Restore ESP */
		227	popl %edx
		228	popl %ebx /* We must subtract it from ESP...*/
		229	subl %ebx, %esp
		230	movw %dx, %ss
40	pj	231
2	pj	232	#ifdef __VIRCSW__
		233
		234	movw SYMBOL_NAME(currCtx), %ax
		235	cmpw %ax,JmpSel
		236	je NoPreempt2
		237	movw %ax,JmpSel
		238	ljmp JmpZone /* DISPATCH! */
		239	#endif
		240	NoPreempt2:
		241
		242	cmpl $0, SYMBOL_NAME(last_handler)
		243	je nohandler
		244	movl SYMBOL_NAME(last_handler), %ebx
		245	call *%ebx
		246	nohandler:
		247	popw %gs
		248	popw %fs
		249	popw %es
		250	popw %ds
		251	popal
		252	iret

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