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Diffstat (limited to 'kernel/support.c')
| -rw-r--r-- | kernel/support.c | 285 |
1 files changed, 0 insertions, 285 deletions
diff --git a/kernel/support.c b/kernel/support.c deleted file mode 100644 index 89834ee..0000000 --- a/kernel/support.c +++ /dev/null @@ -1,285 +0,0 @@ -/* -** SCCS ID: @(#)support.c 2.6 1/22/25 -** -** @file support.c -** -** @author 4003-506 class of 20003 -** @authors K. Reek, Warren R. Carithers -** -** Miscellaneous system initialization functions, interrupt -** support routines, and data structures. -*/ - -#include <common.h> - -#include <support.h> -#include <cio.h> -#include <x86/arch.h> -#include <x86/pic.h> -#include <x86/ops.h> -#include <bootstrap.h> -#include <syscalls.h> - -/* -** Global variables and local data types. -*/ - -/* -** This is the table that contains pointers to the C-language ISR for -** each interrupt. These functions are called from the isr stub based -** on the interrupt number. -*/ -void (*isr_table[256])(int vector, int code); - -/* -** Format of an IDT entry. -*/ -typedef struct { - short offset_15_0; - short segment_selector; - short flags; - short offset_31_16; -} IDT_Gate; - -/* -** LOCAL ROUTINES - not intended to be used outside this module. -*/ - -/** -** unexpected_handler -** -** This routine catches interrupts that we do not expect to ever occur. -** It handles them by (optionally) reporting them and then calling panic(). -** -** @param vector vector number for the interrupt that occurred -** @param code error code, or a dummy value -** -** Does not return. -*/ -#ifdef RPT_INT_UNEXP -/* add any header includes you need here */ -#endif -static void unexpected_handler(int vector, int code) -{ -#ifdef RPT_INT_UNEXP - cio_printf("\n** UNEXPECTED vector %d code %d\n", vector, code); -#endif - panic("Unexpected interrupt"); -} - -/** -** default_handler -** -** Default handler for interrupts we expect may occur but are not -** handling (yet). We just reset the PIC and return. -** -** @param vector vector number for the interrupt that occurred -** @param code error code, or a dummy value -*/ -static void default_handler(int vector, int code) -{ -#ifdef RPT_INT_UNEXP - cio_printf("\n** vector %d code %d\n", vector, code); -#endif - if (vector >= 0x20 && vector < 0x30) { - if (vector > 0x27) { - // must also ACK the secondary PIC - outb(PIC2_CMD, PIC_EOI); - } - outb(PIC1_CMD, PIC_EOI); - } else { - /* - ** All the "expected" interrupts will be handled by the - ** code above. If we get down here, the isr table may - ** have been corrupted. Print a message and don't return. - */ - panic("Unexpected \"expected\" interrupt!"); - } -} - -/** -** mystery_handler -** -** Default handler for the "mystery" interrupt that comes through vector -** 0x27. This is a non-repeatable interrupt whose source has not been -** identified, but it appears to be the famous "spurious level 7 interrupt" -** source. -** -** @param vector vector number for the interrupt that occurred -** @param code error code, or a dummy value -*/ -static void mystery_handler(int vector, int code) -{ -#if defined(RPT_INT_MYSTERY) || defined(RPT_INT_UNEXP) - cio_printf("\nMystery interrupt!\nVector=0x%02x, code=%d\n", vector, code); -#endif - outb(PIC1_CMD, PIC_EOI); -} - -/** -** init_pic -** -** Initialize the 8259 Programmable Interrupt Controller. -*/ -static void init_pic(void) -{ - /* - ** ICW1: start the init sequence, update ICW4 - */ - outb(PIC1_CMD, PIC_CW1_INIT | PIC_CW1_NEED4); - outb(PIC2_CMD, PIC_CW1_INIT | PIC_CW1_NEED4); - - /* - ** ICW2: primary offset of 0x20 in the IDT, secondary offset of 0x28 - */ - outb(PIC1_DATA, PIC1_CW2_VECBASE); - outb(PIC2_DATA, PIC2_CW2_VECBASE); - - /* - ** ICW3: secondary attached to line 2 of primary, bit mask is 00000100 - ** secondary id is 2 - */ - outb(PIC1_DATA, PIC1_CW3_SEC_IRQ2); - outb(PIC2_DATA, PIC2_CW3_SEC_ID); - - /* - ** ICW4: want 8086 mode, not 8080/8085 mode - */ - outb(PIC1_DATA, PIC_CW4_PM86); - outb(PIC2_DATA, PIC_CW4_PM86); - - /* - ** OCW1: allow interrupts on all lines - */ - outb(PIC1_DATA, PIC_MASK_NONE); - outb(PIC2_DATA, PIC_MASK_NONE); -} - -/** -** set_idt_entry -** -** Construct an entry in the IDT -** -** @param entry the vector number of the interrupt -** @param handler ISR address to be put into the IDT entry -** -** Note: generally, the handler invoked from the IDT will be a "stub" -** that calls the second-level C handler via the isr_table array. -*/ -static void set_idt_entry(int entry, void (*handler)(void)) -{ - IDT_Gate *g = (IDT_Gate *)IDT_ADDR + entry; - - g->offset_15_0 = (int)handler & 0xffff; - g->segment_selector = 0x0010; - g->flags = IDT_PRESENT | IDT_DPL_0 | IDT_INT32_GATE; - g->offset_31_16 = (int)handler >> 16 & 0xffff; -} - -/** -** Name: init_idt -** -** Initialize the Interrupt Descriptor Table (IDT). This makes each of -** the entries in the IDT point to the isr stub for that entry, and -** installs a default handler in the handler table. Temporary handlers -** are then installed for those interrupts we may get before a real -** handler is set up. -*/ -static void init_idt(void) -{ - int i; - extern void (*isr_stub_table[256])(void); - - /* - ** Make each IDT entry point to the stub for that vector. Also - ** make each entry in the ISR table point to the default handler. - */ - for (i = 0; i < 256; i++) { - set_idt_entry(i, isr_stub_table[i]); - install_isr(i, unexpected_handler); - } - - /* - ** Install the handlers for interrupts that have (or will have) a - ** specific handler. Comments indicate which module init function - ** will eventually install the "real" handler. - */ - - install_isr(VEC_KBD, default_handler); // cio_init() - install_isr(VEC_COM1, default_handler); // sio_init() - install_isr(VEC_TIMER, default_handler); // clk_init() - install_isr(VEC_SYSCALL, default_handler); // sys_init() - install_isr(VEC_PAGE_FAULT, default_handler); // vm_init() - - install_isr(VEC_MYSTERY, mystery_handler); -} - -/* -** END OF LOCAL ROUTINES. -** -** Full documentation for globally-visible routines is in the corresponding -** header file. -*/ - -/* -** panic -** -** Called when we find an unrecoverable error. -*/ -void panic(char *reason) -{ - __asm__("cli"); - cio_printf("\nPANIC: %s\nHalting...", reason); - for (;;) { - ; - } -} - -/* -** init_interrupts -** -** (Re)initilizes the interrupt system. -*/ -void init_interrupts(void) -{ - init_idt(); - init_pic(); -} - -/* -** install_isr -** -** Installs a second-level handler for a specific interrupt. -*/ -void (*install_isr(int vector, void (*handler)(int, int)))(int, int) -{ - void (*old_handler)(int vector, int code); - - old_handler = isr_table[vector]; - isr_table[vector] = handler; - return old_handler; -} - -/* -** Name: delay -** -** Notes: The parameter to the delay() function is ambiguous; it -** purports to indicate a delay length, but that isn't really tied -** to any real-world time measurement. -** -** On the original systems we used (dual 500MHz Intel P3 CPUs), each -** "unit" was approximately one tenth of a second, so delay(10) would -** delay for about one second. -** -** On the current machines (Intel Core i5-7500), delay(100) is about -** 2.5 seconds, so each "unit" is roughly 0.025 seconds. -** -** Ultimately, just remember that DELAY VALUES ARE APPROXIMATE AT BEST. -*/ -void delay(int length) -{ - while (--length >= 0) { - for (int i = 0; i < 10000000; ++i) - ; - } -} |