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[/] [openrisc/] [trunk/] [rtos/] [rtems/] [c/] [src/] [lib/] [libcpu/] [i386/] [cpu.c] - Rev 778
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/* * cpu.c - This file contains implementation of C function to * instantiate IDT entries. More detailled information can be found * on Intel site and more precisely in the following book : * * Pentium Processor family * Developper's Manual * * Volume 3 : Architecture and Programming Manual * * Copyright (C) 1998 Eric Valette (valette@crf.canon.fr) * Canon Centre Recherche France. * * The license and distribution terms for this file may be * found in found in the file LICENSE in this distribution or at * http://www.OARcorp.com/rtems/license.html. * * $Id: cpu.c,v 1.2 2001-09-27 12:01:22 chris Exp $ */ #include <libcpu/cpu.h> #include <irq.h> static rtems_raw_irq_connect_data* raw_irq_table; static rtems_raw_irq_connect_data default_raw_irq_entry; static interrupt_gate_descriptor default_idt_entry; static rtems_raw_irq_global_settings* local_settings; void create_interrupt_gate_descriptor (interrupt_gate_descriptor* idtEntry, rtems_raw_irq_hdl hdl) { idtEntry->low_offsets_bits = (((unsigned) hdl) & 0xffff); idtEntry->segment_selector = i386_get_cs(); idtEntry->fixed_value_bits = 0; idtEntry->gate_type = 0xe; idtEntry->privilege = 0; idtEntry->present = 1; idtEntry->high_offsets_bits = ((((unsigned) hdl) >> 16) & 0xffff); } rtems_raw_irq_hdl get_hdl_from_vector(rtems_vector_offset index) { rtems_raw_irq_hdl hdl; interrupt_gate_descriptor* idt_entry_tbl; unsigned limit; i386_get_info_from_IDTR (&idt_entry_tbl, &limit); /* Convert limit into number of entries */ limit = (limit + 1) / sizeof(interrupt_gate_descriptor); if(index >= limit) { return 0; } * ((unsigned int*) &hdl) = (idt_entry_tbl[index].low_offsets_bits | (idt_entry_tbl[index].high_offsets_bits << 16)); return hdl; } int i386_set_idt_entry (const rtems_raw_irq_connect_data* irq) { interrupt_gate_descriptor* idt_entry_tbl; unsigned limit; unsigned int level; i386_get_info_from_IDTR (&idt_entry_tbl, &limit); /* Convert limit into number of entries */ limit = (limit + 1) / sizeof(interrupt_gate_descriptor); if (irq->idtIndex >= limit) { return 0; } /* * Check if default handler is actually connected. If not issue an error. * You must first get the current handler via i386_get_current_idt_entry * and then disconnect it using i386_delete_idt_entry. * RATIONALE : to always have the same transition by forcing the user * to get the previous handler before accepting to disconnect. */ if (get_hdl_from_vector(irq->idtIndex) != default_raw_irq_entry.hdl) { return 0; } _CPU_ISR_Disable(level); raw_irq_table [irq->idtIndex] = *irq; create_interrupt_gate_descriptor (&idt_entry_tbl[irq->idtIndex], irq->hdl); irq->on(irq); _CPU_ISR_Enable(level); return 1; } void _CPU_ISR_install_vector (unsigned vector, void* hdl, void** oldHdl) { interrupt_gate_descriptor* idt_entry_tbl; unsigned limit; interrupt_gate_descriptor new; unsigned int level; i386_get_info_from_IDTR (&idt_entry_tbl, &limit); /* Convert limit into number of entries */ limit = (limit + 1) / sizeof(interrupt_gate_descriptor); if (vector >= limit) { return; } _CPU_ISR_Disable(level) * ((unsigned int *) oldHdl) = idt_entry_tbl[vector].low_offsets_bits | (idt_entry_tbl[vector].high_offsets_bits << 16); create_interrupt_gate_descriptor(&new, hdl); idt_entry_tbl[vector] = new; _CPU_ISR_Enable(level); } int i386_get_current_idt_entry (rtems_raw_irq_connect_data* irq) { interrupt_gate_descriptor* idt_entry_tbl; unsigned limit; i386_get_info_from_IDTR (&idt_entry_tbl, &limit); /* Convert limit into number of entries */ limit = (limit + 1) / sizeof(interrupt_gate_descriptor); if (irq->idtIndex >= limit) { return 0; } raw_irq_table [irq->idtIndex].hdl = get_hdl_from_vector(irq->idtIndex); *irq = raw_irq_table [irq->idtIndex]; return 1; } int i386_delete_idt_entry (const rtems_raw_irq_connect_data* irq) { interrupt_gate_descriptor* idt_entry_tbl; unsigned limit; unsigned int level; i386_get_info_from_IDTR (&idt_entry_tbl, &limit); /* Convert limit into number of entries */ limit = (limit + 1) / sizeof(interrupt_gate_descriptor); if (irq->idtIndex >= limit) { return 0; } /* * Check if handler passed is actually connected. If not issue an error. * You must first get the current handler via i386_get_current_idt_entry * and then disconnect it using i386_delete_idt_entry. * RATIONALE : to always have the same transition by forcing the user * to get the previous handler before accepting to disconnect. */ if (get_hdl_from_vector(irq->idtIndex) != irq->hdl){ return 0; } _CPU_ISR_Disable(level); idt_entry_tbl[irq->idtIndex] = default_idt_entry; irq->off(irq); raw_irq_table[irq->idtIndex] = default_raw_irq_entry; raw_irq_table[irq->idtIndex].idtIndex = irq->idtIndex; _CPU_ISR_Enable(level); return 1; } /* * Caution this function assumes the IDTR has been already set. */ int i386_init_idt (rtems_raw_irq_global_settings* config) { unsigned limit; unsigned i; unsigned level; interrupt_gate_descriptor* idt_entry_tbl; i386_get_info_from_IDTR (&idt_entry_tbl, &limit); /* Convert limit into number of entries */ limit = (limit + 1) / sizeof(interrupt_gate_descriptor); if (config->idtSize != limit) { return 0; } /* * store various accelarators */ raw_irq_table = config->rawIrqHdlTbl; local_settings = config; default_raw_irq_entry = config->defaultRawEntry; _CPU_ISR_Disable(level); create_interrupt_gate_descriptor (&default_idt_entry, default_raw_irq_entry.hdl); for (i=0; i < limit; i++) { interrupt_gate_descriptor new; create_interrupt_gate_descriptor (&new, raw_irq_table[i].hdl); idt_entry_tbl[i] = new; if (raw_irq_table[i].hdl != default_raw_irq_entry.hdl) { raw_irq_table[i].on(&raw_irq_table[i]); } else { raw_irq_table[i].off(&raw_irq_table[i]); } } _CPU_ISR_Enable(level); return 1; } int i386_get_idt_config (rtems_raw_irq_global_settings** config) { *config = local_settings; return 1; } /* * Caution this function assumes the GDTR has been already set. */ int i386_set_gdt_entry (unsigned short segment_selector, unsigned base, unsigned limit) { unsigned gdt_limit; unsigned short tmp_segment = 0; unsigned int limit_adjusted; segment_descriptors* gdt_entry_tbl; i386_get_info_from_GDTR (&gdt_entry_tbl, &gdt_limit); if (segment_selector > limit) { return 0; } /* * set up limit first */ limit_adjusted = limit; if ( limit > 4095 ) { gdt_entry_tbl[segment_selector].granularity = 1; limit_adjusted /= 4096; } gdt_entry_tbl[segment_selector].limit_15_0 = limit_adjusted & 0xffff; gdt_entry_tbl[segment_selector].limit_19_16 = (limit_adjusted >> 16) & 0xf; /* * set up base */ gdt_entry_tbl[segment_selector].base_address_15_0 = base & 0xffff; gdt_entry_tbl[segment_selector].base_address_23_16 = (base >> 16) & 0xff; gdt_entry_tbl[segment_selector].base_address_31_24 = (base >> 24) & 0xff; /* * set up descriptor type (this may well becomes a parameter if needed) */ gdt_entry_tbl[segment_selector].type = 2; /* Data R/W */ gdt_entry_tbl[segment_selector].descriptor_type = 1; /* Code or Data */ gdt_entry_tbl[segment_selector].privilege = 0; /* ring 0 */ gdt_entry_tbl[segment_selector].present = 1; /* not present */ /* * Now, reload all segment registers so the limit takes effect. */ asm volatile( "movw %%ds,%0 ; movw %0,%%ds movw %%es,%0 ; movw %0,%%es movw %%fs,%0 ; movw %0,%%fs movw %%gs,%0 ; movw %0,%%gs movw %%ss,%0 ; movw %0,%%ss" : "=r" (tmp_segment) : "0" (tmp_segment) ); return 1; }
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