X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?p=pintos-anon;a=blobdiff_plain;f=src%2Fthreads%2Finterrupt.c;h=9ffd873540b803ca3414b83f10c6da4e8c4b2f54;hp=7559447307db9ee59f672bf042e7e5f88a5b868c;hb=ed04361f6ec91e4f0db1550c2cc487a461b2d17b;hpb=c9c283cb3e26a5b6d918ee47dcf8efe28522b18d diff --git a/src/threads/interrupt.c b/src/threads/interrupt.c index 7559447..9ffd873 100644 --- a/src/threads/interrupt.c +++ b/src/threads/interrupt.c @@ -1,20 +1,30 @@ -#include "interrupt.h" +#include "threads/interrupt.h" +#include #include #include -#include "intr-stubs.h" -#include "debug.h" -#include "gdt.h" -#include "io.h" -#include "lib.h" -#include "mmu.h" -#include "thread.h" -#include "timer.h" +#include +#include "threads/flags.h" +#include "threads/intr-stubs.h" +#include "threads/io.h" +#include "threads/thread.h" +#include "threads/vaddr.h" +#include "devices/timer.h" + +/* Programmable Interrupt Controller (PIC) registers. + A PC has two PICs, called the master and slave PICs, with the + slave attached ("cascaded") to the master IRQ line 2. */ +#define PIC0_CTRL 0x20 /* Master PIC control register address. */ +#define PIC0_DATA 0x21 /* Master PIC data register address. */ +#define PIC1_CTRL 0xa0 /* Slave PIC control register address. */ +#define PIC1_DATA 0xa1 /* Slave PIC data register address. */ /* Number of x86 interrupts. */ #define INTR_CNT 256 /* The Interrupt Descriptor Table (IDT). The format is fixed by - the CPU. See [IA32-v3] sections 5.10, 5.11, 5.12.1.2. */ + the CPU. See [IA32-v3a] sections 5.10 "Interrupt Descriptor + Table (IDT)", 5.11 "IDT Descriptors", 5.12.1.2 "Flag Usage By + Exception- or Interrupt-Handler Procedure". */ static uint64_t idt[INTR_CNT]; /* Interrupt handler functions for each interrupt. */ @@ -40,19 +50,22 @@ static void pic_end_of_interrupt (int irq); /* Interrupt Descriptor Table helpers. */ static uint64_t make_intr_gate (void (*) (void), int dpl); static uint64_t make_trap_gate (void (*) (void), int dpl); +static inline uint64_t make_idtr_operand (uint16_t limit, void *base); /* Interrupt handlers. */ void intr_handler (struct intr_frame *args); -static intr_handler_func panic NO_RETURN; -static intr_handler_func kill NO_RETURN; /* Returns the current interrupt status. */ enum intr_level intr_get_level (void) { uint32_t flags; - - asm ("pushfl; popl %0" : "=g" (flags)); + + /* Push the flags register on the processor stack, then pop the + value off the stack into `flags'. See [IA32-v2b] "PUSHF" + and "POP" and [IA32-v3a] 5.8.1 "Masking Maskable Hardware + Interrupts". */ + asm volatile ("pushfl; popl %0" : "=g" (flags)); return flags & FLAG_IF ? INTR_ON : INTR_OFF; } @@ -70,7 +83,14 @@ enum intr_level intr_enable (void) { enum intr_level old_level = intr_get_level (); + ASSERT (!intr_context ()); + + /* Enable interrupts by setting the interrupt flag. + + See [IA32-v2b] "STI" and [IA32-v3a] 5.8.1 "Masking Maskable + Hardware Interrupts". */ asm volatile ("sti"); + return old_level; } @@ -79,7 +99,12 @@ enum intr_level intr_disable (void) { enum intr_level old_level = intr_get_level (); - asm volatile ("cli"); + + /* Disable interrupts by clearing the interrupt flag. + See [IA32-v2b] "CLI" and [IA32-v3a] 5.8.1 "Masking Maskable + Hardware Interrupts". */ + asm volatile ("cli" : : : "memory"); + return old_level; } @@ -90,45 +115,74 @@ intr_init (void) uint64_t idtr_operand; int i; + /* Initialize interrupt controller. */ pic_init (); + /* Initialize IDT. */ + for (i = 0; i < INTR_CNT; i++) + idt[i] = make_intr_gate (intr_stubs[i], 0); + + /* Load IDT register. + See [IA32-v2a] "LIDT" and [IA32-v3a] 5.10 "Interrupt + Descriptor Table (IDT)". */ + idtr_operand = make_idtr_operand (sizeof idt - 1, idt); + asm volatile ("lidt %0" : : "m" (idtr_operand)); + /* Initialize intr_names. */ for (i = 0; i < INTR_CNT; i++) intr_names[i] = "unknown"; + intr_names[0] = "#DE Divide Error"; + intr_names[1] = "#DB Debug Exception"; + intr_names[2] = "NMI Interrupt"; + intr_names[3] = "#BP Breakpoint Exception"; + intr_names[4] = "#OF Overflow Exception"; + intr_names[5] = "#BR BOUND Range Exceeded Exception"; + intr_names[6] = "#UD Invalid Opcode Exception"; + intr_names[7] = "#NM Device Not Available Exception"; + intr_names[8] = "#DF Double Fault Exception"; + intr_names[9] = "Coprocessor Segment Overrun"; + intr_names[10] = "#TS Invalid TSS Exception"; + intr_names[11] = "#NP Segment Not Present"; + intr_names[12] = "#SS Stack Fault Exception"; + intr_names[13] = "#GP General Protection Exception"; + intr_names[14] = "#PF Page-Fault Exception"; + intr_names[16] = "#MF x87 FPU Floating-Point Error"; + intr_names[17] = "#AC Alignment Check Exception"; + intr_names[18] = "#MC Machine-Check Exception"; + intr_names[19] = "#XF SIMD Floating-Point Exception"; +} + +/* Registers interrupt VEC_NO to invoke HANDLER with descriptor + privilege level DPL. Names the interrupt NAME for debugging + purposes. The interrupt handler will be invoked with + interrupt status set to LEVEL. */ +static void +register_handler (uint8_t vec_no, int dpl, enum intr_level level, + intr_handler_func *handler, const char *name) +{ + ASSERT (intr_handlers[vec_no] == NULL); + if (level == INTR_ON) + idt[vec_no] = make_trap_gate (intr_stubs[vec_no], dpl); + else + idt[vec_no] = make_intr_gate (intr_stubs[vec_no], dpl); + intr_handlers[vec_no] = handler; + intr_names[vec_no] = name; +} - /* Most exceptions require ring 0. - Exceptions 3, 4, and 5 can be caused by ring 3 directly. */ - intr_register (0, 0, INTR_ON, kill, "#DE Divide Error"); - intr_register (1, 0, INTR_ON, kill, "#DB Debug Exception"); - intr_register (2, 0, INTR_ON, panic, "NMI Interrupt"); - intr_register (3, 3, INTR_ON, kill, "#BP Breakpoint Exception"); - intr_register (4, 3, INTR_ON, kill, "#OF Overflow Exception"); - intr_register (5, 3, INTR_ON, kill, "#BR BOUND Range Exceeded Exception"); - intr_register (6, 0, INTR_ON, kill, "#UD Invalid Opcode Exception"); - intr_register (7, 0, INTR_ON, kill, "#NM Device Not Available Exception"); - intr_register (8, 0, INTR_ON, panic, "#DF Double Fault Exception"); - intr_register (9, 0, INTR_ON, panic, "Coprocessor Segment Overrun"); - intr_register (10, 0, INTR_ON, panic, "#TS Invalid TSS Exception"); - intr_register (11, 0, INTR_ON, kill, "#NP Segment Not Present"); - intr_register (12, 0, INTR_ON, kill, "#SS Stack Fault Exception"); - intr_register (13, 0, INTR_ON, kill, "#GP General Protection Exception"); - intr_register (16, 0, INTR_ON, kill, "#MF x87 FPU Floating-Point Error"); - intr_register (17, 0, INTR_ON, panic, "#AC Alignment Check Exception"); - intr_register (18, 0, INTR_ON, panic, "#MC Machine-Check Exception"); - intr_register (19, 0, INTR_ON, kill, "#XF SIMD Floating-Point Exception"); - - /* Most exceptions can be handled with interrupts turned on. - We need to disable interrupts for page faults because the - fault address is stored in CR2 and needs to be preserved. */ - intr_register (14, 0, INTR_OFF, kill, "#PF Page-Fault Exception"); - - idtr_operand = make_dtr_operand (sizeof idt - 1, idt); - asm volatile ("lidt %0" :: "m" (idtr_operand)); +/* Registers external interrupt VEC_NO to invoke HANDLER, which + is named NAME for debugging purposes. The handler will + execute with interrupts disabled. */ +void +intr_register_ext (uint8_t vec_no, intr_handler_func *handler, + const char *name) +{ + ASSERT (vec_no >= 0x20 && vec_no <= 0x2f); + register_handler (vec_no, 0, INTR_OFF, handler, name); } -/* Registers interrupt VEC_NO to invoke HANDLER, which is named - NAME for debugging purposes. The interrupt handler will be - invoked with interrupt status set to LEVEL. +/* Registers internal interrupt VEC_NO to invoke HANDLER, which + is named NAME for debugging purposes. The interrupt handler + will be invoked with interrupt status LEVEL. The handler will have descriptor privilege level DPL, meaning that it can be invoked intentionally when the processor is in @@ -136,29 +190,15 @@ intr_init (void) user mode to invoke the interrupts and DPL==0 prevents such invocation. Faults and exceptions that occur in user mode still cause interrupts with DPL==0 to be invoked. See - [IA32-v3] sections 4.5 and 4.8.1.1 for further discussion. */ + [IA32-v3a] sections 4.5 "Privilege Levels" and 4.8.1.1 + "Accessing Nonconforming Code Segments" for further + discussion. */ void -intr_register (uint8_t vec_no, int dpl, enum intr_level level, - intr_handler_func *handler, - const char *name) +intr_register_int (uint8_t vec_no, int dpl, enum intr_level level, + intr_handler_func *handler, const char *name) { - /* Make sure this handler isn't already registered to someone - else. */ - ASSERT (intr_handlers[vec_no] == NULL); - - /* Interrupts generated by external hardware (0x20 <= VEC_NO <= - 0x2f) should specify INTR_OFF for LEVEL. Otherwise a timer - interrupt could cause a task switch during interrupt - handling. Most other interrupts can and should be handled - with interrupts enabled. */ - ASSERT (vec_no < 0x20 || vec_no > 0x2f || level == INTR_OFF); - - if (level == INTR_ON) - idt[vec_no] = make_trap_gate (intr_stubs[vec_no], dpl); - else - idt[vec_no] = make_intr_gate (intr_stubs[vec_no], dpl); - intr_handlers[vec_no] = handler; - intr_names[vec_no] = name; + ASSERT (vec_no < 0x20 || vec_no > 0x2f); + register_handler (vec_no, dpl, level, handler, name); } /* Returns true during processing of an external interrupt @@ -182,42 +222,35 @@ intr_yield_on_return (void) /* 8259A Programmable Interrupt Controller. */ -/* Every PC has two 8259A Programmable Interrupt Controller (PIC) - chips. One is a "master" accessible at ports 0x20 and 0x21. - The other is a "slave" cascaded onto the master's IRQ 2 line - and accessible at ports 0xa0 and 0xa1. Accesses to port 0x20 - set the A0 line to 0 and accesses to 0x21 set the A1 line to - 1. The situation is similar for the slave PIC. +/* Initializes the PICs. Refer to [8259A] for details. By default, interrupts 0...15 delivered by the PICs will go to - interrupt vectors 0...15. Unfortunately, those vectors are - also used for CPU traps and exceptions. We reprogram the PICs - so that interrupts 0...15 are delivered to interrupt vectors - 32...47 (0x20...0x2f) instead. */ - -/* Initializes the PICs. Refer to [8259A] for details. */ + interrupt vectors 0...15. Those vectors are also used for CPU + traps and exceptions, so we reprogram the PICs so that + interrupts 0...15 are delivered to interrupt vectors 32...47 + (0x20...0x2f) instead. */ static void pic_init (void) { /* Mask all interrupts on both PICs. */ - outb (0x21, 0xff); - outb (0xa1, 0xff); + outb (PIC0_DATA, 0xff); + outb (PIC1_DATA, 0xff); /* Initialize master. */ - outb (0x20, 0x11); /* ICW1: single mode, edge triggered, expect ICW4. */ - outb (0x21, 0x20); /* ICW2: line IR0...7 -> irq 0x20...0x27. */ - outb (0x21, 0x04); /* ICW3: slave PIC on line IR2. */ - outb (0x21, 0x01); /* ICW4: 8086 mode, normal EOI, non-buffered. */ + outb (PIC0_CTRL, 0x11); /* ICW1: single mode, edge triggered, expect ICW4. */ + outb (PIC0_DATA, 0x20); /* ICW2: line IR0...7 -> irq 0x20...0x27. */ + outb (PIC0_DATA, 0x04); /* ICW3: slave PIC on line IR2. */ + outb (PIC0_DATA, 0x01); /* ICW4: 8086 mode, normal EOI, non-buffered. */ /* Initialize slave. */ - outb (0xa0, 0x11); /* ICW1: single mode, edge triggered, expect ICW4. */ - outb (0xa1, 0x28); /* ICW2: line IR0...7 -> irq 0x28...0x2f. */ - outb (0xa1, 0x02); /* ICW3: slave ID is 2. */ - outb (0xa1, 0x01); /* ICW4: 8086 mode, normal EOI, non-buffered. */ + outb (PIC1_CTRL, 0x11); /* ICW1: single mode, edge triggered, expect ICW4. */ + outb (PIC1_DATA, 0x28); /* ICW2: line IR0...7 -> irq 0x28...0x2f. */ + outb (PIC1_DATA, 0x02); /* ICW3: slave ID is 2. */ + outb (PIC1_DATA, 0x01); /* ICW4: 8086 mode, normal EOI, non-buffered. */ /* Unmask all interrupts. */ - outb (0x21, 0x00); - outb (0xa1, 0x00); + outb (PIC0_DATA, 0x00); + outb (PIC1_DATA, 0x00); } /* Sends an end-of-interrupt signal to the PIC for the given IRQ. @@ -243,13 +276,15 @@ pic_end_of_interrupt (int irq) or lower-numbered ring. In practice, DPL==3 allows user mode to call into the gate and DPL==0 prevents such calls. Faults and exceptions that occur in user mode still cause gates with - DPL==0 to be invoked. See [IA32-v3] sections 4.5 and 4.8.1.1 + DPL==0 to be invoked. See [IA32-v3a] sections 4.5 "Privilege + Levels" and 4.8.1.1 "Accessing Nonconforming Code Segments" for further discussion. TYPE must be either 14 (for an interrupt gate) or 15 (for a trap gate). The difference is that entering an interrupt gate disables interrupts, but entering a trap gate does not. See - [IA32-v3] section 5.12.1.2 for discussion. */ + [IA32-v3a] section 5.12.1.2 "Flag Usage By Exception- or + Interrupt-Handler Procedure" for discussion. */ static uint64_t make_gate (void (*function) (void), int dpl, int type) { @@ -286,22 +321,32 @@ make_trap_gate (void (*function) (void), int dpl) { return make_gate (function, dpl, 15); } + +/* Returns a descriptor that yields the given LIMIT and BASE when + used as an operand for the LIDT instruction. */ +static inline uint64_t +make_idtr_operand (uint16_t limit, void *base) +{ + return limit | ((uint64_t) (uint32_t) base << 16); +} /* Interrupt handlers. */ -static void dump_intr_frame (struct intr_frame *); - /* Handler for all interrupts, faults, and exceptions. This function is called by the assembly language interrupt stubs in - intr-stubs.S (see intr-stubs.pl). ARGS describes the - interrupt and the interrupted thread's registers. */ + intr-stubs.S. FRAME describes the interrupt and the + interrupted thread's registers. */ void -intr_handler (struct intr_frame *args) +intr_handler (struct intr_frame *frame) { bool external; intr_handler_func *handler; - external = args->vec_no >= 0x20 && args->vec_no < 0x30; + /* External interrupts are special. + We only handle one at a time (so interrupts must be off) + and they need to be acknowledged on the PIC (see below). + An external interrupt handler cannot sleep. */ + external = frame->vec_no >= 0x20 && frame->vec_no < 0x30; if (external) { ASSERT (intr_get_level () == INTR_OFF); @@ -311,13 +356,23 @@ intr_handler (struct intr_frame *args) yield_on_return = false; } - /* Invoke the interrupt's handler. - If there is no handler, invoke the unexpected interrupt - handler. */ - handler = intr_handlers[args->vec_no]; - if (handler == NULL) - handler = panic; - handler (args); + /* Invoke the interrupt's handler. */ + handler = intr_handlers[frame->vec_no]; + if (handler != NULL) + handler (frame); + else if (frame->vec_no == 0x27 || frame->vec_no == 0x2f) + { + /* There is no handler, but this interrupt can trigger + spuriously due to a hardware fault or hardware race + condition. Ignore it. */ + } + else + { + /* No handler and not spurious. Invoke the unexpected + interrupt handler. */ + intr_dump_frame (frame); + PANIC ("Unexpected interrupt"); + } /* Complete the processing of an external interrupt. */ if (external) @@ -326,78 +381,40 @@ intr_handler (struct intr_frame *args) ASSERT (intr_context ()); in_external_intr = false; - pic_end_of_interrupt (args->vec_no); + pic_end_of_interrupt (frame->vec_no); if (yield_on_return) thread_yield (); } } -/* Handler for an interrupt that should not have been invoked. */ -static void -panic (struct intr_frame *regs) -{ - dump_intr_frame (regs); - PANIC ("Panic!"); -} - -/* Handler for an exception (probably) caused by a user process. */ -static void -kill (struct intr_frame *f) -{ - /* This interrupt is one (probably) caused by a user process. - For example, the process might have tried to access unmapped - virtual memory (a page fault). For now, we simply kill the - user process. Later, we'll want to handle page faults in - the kernel. Real Unix-like operating systems pass most - exceptions back to the process via signals, but we don't - implement them. */ - - /* The interrupt frame's code segment value tells us where the - exception originated. */ - switch (f->cs) - { - case SEL_UCSEG: - /* User's code segment, so it's a user exception, as we - expected. */ - printk ("%s: dying due to interrupt %#04x (%s).\n", - thread_name (thread_current ()), - f->vec_no, intr_names[f->vec_no]); - dump_intr_frame (f); - thread_exit (); - - case SEL_KCSEG: - /* Kernel's code segment, which indicates a kernel bug. - Kernel code shouldn't throw exceptions. (Page faults - may cause kernel exceptions--but they shouldn't arrive - here.) */ - printk ("Kernel bug - unexpected interrupt in kernel\n"); - panic (f); - - default: - /* Some other code segment? Shouldn't happen. */ - printk ("Interrupt %#04x (%s) in unknown segment %04x\n", - f->vec_no, intr_names[f->vec_no], f->cs); - thread_exit (); - } -} - /* Dumps interrupt frame F to the console, for debugging. */ -static void -dump_intr_frame (struct intr_frame *f) +void +intr_dump_frame (const struct intr_frame *f) { - uint32_t cr2, ss; + uint32_t cr2; + + /* Store current value of CR2 into `cr2'. + CR2 is the linear address of the last page fault. + See [IA32-v2a] "MOV--Move to/from Control Registers" and + [IA32-v3a] 5.14 "Interrupt 14--Page Fault Exception + (#PF)". */ asm ("movl %%cr2, %0" : "=r" (cr2)); - asm ("movl %%ss, %0" : "=r" (ss)); - printk ("Interrupt %#04x (%s) at eip=%p\n", + printf ("Interrupt %#04x (%s) at eip=%p\n", f->vec_no, intr_names[f->vec_no], f->eip); - printk (" cr2=%08"PRIx32" error=%08"PRIx32"\n", cr2, f->error_code); - printk (" eax=%08"PRIx32" ebx=%08"PRIx32" ecx=%08"PRIx32" edx=%08"PRIx32"\n", + printf (" cr2=%08"PRIx32" error=%08"PRIx32"\n", cr2, f->error_code); + printf (" eax=%08"PRIx32" ebx=%08"PRIx32" ecx=%08"PRIx32" edx=%08"PRIx32"\n", f->eax, f->ebx, f->ecx, f->edx); - printk (" esi=%08"PRIx32" edi=%08"PRIx32" esp=%08"PRIx32" ebp=%08"PRIx32"\n", + printf (" esi=%08"PRIx32" edi=%08"PRIx32" esp=%08"PRIx32" ebp=%08"PRIx32"\n", f->esi, f->edi, (uint32_t) f->esp, f->ebp); - printk (" cs=%04"PRIx16" ds=%04"PRIx16" es=%04"PRIx16" ss=%04"PRIx16"\n", - f->cs, f->ds, f->es, f->cs != SEL_KCSEG ? f->ss : ss); + printf (" cs=%04"PRIx16" ds=%04"PRIx16" es=%04"PRIx16" ss=%04"PRIx16"\n", + f->cs, f->ds, f->es, f->ss); } +/* Returns the name of interrupt VEC. */ +const char * +intr_name (uint8_t vec) +{ + return intr_names[vec]; +}