/* * Mach Operating System * Copyright (c) 1991,1990,1989, 1988 Carnegie Mellon University * All Rights Reserved. * * Permission to use, copy, modify and distribute this software and its * documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie Mellon * the rights to redistribute these changes. */ /* * File: model_dep.c * Author: Avadis Tevanian, Jr., Michael Wayne Young * * Copyright (C) 1986, Avadis Tevanian, Jr., Michael Wayne Young * * Basic initialization for I386 - ISA bus machines. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* Location of the kernel's symbol table. Both of these are 0 if none is available. */ #if MACH_KDB static vm_offset_t kern_sym_start, kern_sym_end; #else #define kern_sym_start 0 #define kern_sym_end 0 #endif /* These indicate the total extent of physical memory addresses we're using. They are page-aligned. */ vm_offset_t phys_first_addr = 0; vm_offset_t phys_last_addr; /* Virtual address of physical memory, for the kvtophys/phystokv macros. */ vm_offset_t phys_mem_va; /* A copy of the multiboot info structure passed by the boot loader. */ struct multiboot_info boot_info; /* Command line supplied to kernel. */ char *kernel_cmdline = ""; /* This is used for memory initialization: it gets bumped up through physical memory that exists and is not occupied by boot gunk. It is not necessarily page-aligned. */ static vm_offset_t avail_next = 0x1000; /* XX end of BIOS data area */ /* Possibly overestimated amount of available memory still remaining to be handed to the VM system. */ static vm_size_t avail_remaining; extern char version[]; extern void setup_main(); void halt_all_cpus (boolean_t reboot) __attribute__ ((noreturn)); void halt_cpu (void) __attribute__ ((noreturn)); void inittodr(); /* forward */ int rebootflag = 0; /* exported to kdintr */ /* XX interrupt stack pointer and highwater mark, for locore.S. */ vm_offset_t int_stack_top, int_stack_high; #ifdef LINUX_DEV extern void linux_init(void); #endif /* * Find devices. The system is alive. */ void machine_init(void) { /* * Initialize the console. */ cninit(); /* * Set up to use floating point. */ init_fpu(); #ifdef LINUX_DEV /* * Initialize Linux drivers. */ linux_init(); #endif /* * Find the devices */ probeio(); /* * Get the time */ inittodr(); /* * Tell the BIOS not to clear and test memory. */ *(unsigned short *)phystokv(0x472) = 0x1234; /* * Unmap page 0 to trap NULL references. */ pmap_unmap_page_zero(); } /* Conserve power on processor CPU. */ void machine_idle (int cpu) { assert (cpu == cpu_number ()); asm volatile ("hlt" : : : "memory"); } /* * Halt a cpu. */ void halt_cpu(void) { asm volatile("cli"); while (TRUE) machine_idle (cpu_number ()); } /* * Halt the system or reboot. */ void halt_all_cpus(reboot) boolean_t reboot; { if (reboot) { kdreboot(); } else { rebootflag = 1; printf("In tight loop: hit ctl-alt-del to reboot\n"); (void) spl0(); } while (TRUE) machine_idle (cpu_number ()); } void exit(int rc) { halt_all_cpus(0); } void db_reset_cpu(void) { halt_all_cpus(1); } /* * Compute physical memory size and other parameters. */ void mem_size_init(void) { vm_size_t phys_last_kb; /* Physical memory on all PCs starts at physical address 0. XX make it a constant. */ phys_first_addr = 0; phys_last_kb = 0x400 + boot_info.mem_upper; /* Avoid 4GiB overflow. */ if (phys_last_kb < 0x400 || phys_last_kb >= 0x400000) phys_last_kb = 0x400000 - 1; phys_last_addr = phys_last_kb * 0x400; avail_remaining = phys_last_addr - (0x100000 - (boot_info.mem_lower * 0x400) - 0x1000); printf("AT386 boot: physical memory from 0x%x to 0x%x\n", phys_first_addr, phys_last_addr); /* Reserve 1/16 of the memory address space for virtual mappings. * Yes, this loses memory. Blame i386. */ if (phys_last_addr > (VM_MAX_KERNEL_ADDRESS / 16) * 15) phys_last_addr = (VM_MAX_KERNEL_ADDRESS / 16) * 15; phys_first_addr = round_page(phys_first_addr); phys_last_addr = trunc_page(phys_last_addr); } /* * Basic PC VM initialization. * Turns on paging and changes the kernel segments to use high linear addresses. */ void i386at_init(void) { /* XXX move to intel/pmap.h */ extern pt_entry_t *kernel_page_dir; /* * Initialize the PIC prior to any possible call to an spl. */ picinit(); /* * Find memory size parameters. */ mem_size_init(); /* * Initialize kernel physical map, mapping the * region from loadpt to avail_start. * Kernel virtual address starts at VM_KERNEL_MIN_ADDRESS. * XXX make the BIOS page (page 0) read-only. */ pmap_bootstrap(); /* * Turn paging on. * We'll have to temporarily install a direct mapping * between physical memory and low linear memory, * until we start using our new kernel segment descriptors. * One page table (4MB) should do the trick. * Also, set the WP bit so that on 486 or better processors * page-level write protection works in kernel mode. */ kernel_page_dir[lin2pdenum(0)] = kernel_page_dir[lin2pdenum(LINEAR_MIN_KERNEL_ADDRESS)]; set_cr3((unsigned)kernel_page_dir); if (CPU_HAS_FEATURE(CPU_FEATURE_PGE)) set_cr4(get_cr4() | CR4_PGE); printf("boot cr0 is %x\n",get_cr0()); set_cr0(get_cr0() | CR0_PG | CR0_WP | CR0_CD | CR0_NW); flush_instr_queue(); /* * Initialize and activate the real i386 protected-mode structures. */ gdt_init(); idt_init(); int_init(); ldt_init(); ktss_init(); /* Get rid of the temporary direct mapping and flush it out of the TLB. */ kernel_page_dir[lin2pdenum(0)] = 0; set_cr3((unsigned)kernel_page_dir); /* XXX We'll just use the initialization stack we're already running on as the interrupt stack for now. Later this will have to change, because the init stack will get freed after bootup. */ asm("movl %%esp,%0" : "=m" (int_stack_top)); /* Interrupt stacks are allocated in physical memory, while kernel stacks are allocated in kernel virtual memory, so phys_last_addr serves as a convenient dividing point. */ int_stack_high = phys_last_addr; } /* * C boot entrypoint - called by boot_entry in boothdr.S. * Running in 32-bit flat mode, but without paging yet. */ void c_boot_entry(vm_offset_t bi) { /* Stash the boot_image_info pointer. */ boot_info = *(struct multiboot_info*)phystokv(bi); int cpu_type; /* XXX we currently assume phys_mem_va is always 0 here - if it isn't, we must tweak the pointers in the boot_info. */ /* Before we do _anything_ else, print the hello message. If there are no initialized console devices yet, it will be stored and printed at the first opportunity. */ printf(version); printf("\n"); /* Find the kernel command line, if there is one. */ if (boot_info.flags & MULTIBOOT_CMDLINE) kernel_cmdline = (char*)phystokv(boot_info.cmdline); #if MACH_KDB /* * Locate the kernel's symbol table, if the boot loader provided it. * We need to do this before i386at_init() * so that the symbol table's memory won't be stomped on. */ if ((boot_info.flags & MULTIBOOT_AOUT_SYMS) && boot_info.syms.a.addr) { vm_size_t symtab_size, strtab_size; kern_sym_start = (vm_offset_t)phystokv(boot_info.syms.a.addr); symtab_size = (vm_offset_t)phystokv(boot_info.syms.a.tabsize); strtab_size = (vm_offset_t)phystokv(boot_info.syms.a.strsize); kern_sym_end = kern_sym_start + 4 + symtab_size + strtab_size; printf("kernel symbol table at %08x-%08x (%d,%d)\n", kern_sym_start, kern_sym_end, symtab_size, strtab_size); } #endif /* MACH_KDB */ cpu_type = discover_x86_cpu_type (); /* * Do basic VM initialization */ i386at_init(); #if MACH_KDB /* * Initialize the kernel debugger's kernel symbol table. */ if (kern_sym_start) { aout_db_sym_init(kern_sym_start, kern_sym_end, "mach", 0); } /* * Cause a breakpoint trap to the debugger before proceeding * any further if the proper option flag was specified * on the kernel's command line. * XXX check for surrounding spaces. */ if (strstr(kernel_cmdline, "-d ")) { cninit(); /* need console for debugger */ Debugger(); } #endif /* MACH_KDB */ machine_slot[0].is_cpu = TRUE; machine_slot[0].running = TRUE; machine_slot[0].cpu_subtype = CPU_SUBTYPE_AT386; switch (cpu_type) { case 3: default: machine_slot[0].cpu_type = CPU_TYPE_I386; break; case 4: machine_slot[0].cpu_type = CPU_TYPE_I486; break; case 5: machine_slot[0].cpu_type = CPU_TYPE_PENTIUM; break; case 6: machine_slot[0].cpu_type = CPU_TYPE_PENTIUMPRO; break; } /* * Start the system. */ setup_main(); } #include #include #include int timemmap(dev,off,prot) vm_prot_t prot; { extern time_value_t *mtime; #ifdef lint dev++; off++; #endif /* lint */ if (prot & VM_PROT_WRITE) return (-1); return (i386_btop(pmap_extract(pmap_kernel(), (vm_offset_t) mtime))); } void startrtclock(void) { clkstart(); } void inittodr(void) { time_value_t new_time; new_time.seconds = 0; new_time.microseconds = 0; (void) readtodc(&new_time.seconds); { spl_t s = splhigh(); time = new_time; splx(s); } } void resettodr(void) { writetodc(); } unsigned int pmap_free_pages(void) { return atop(avail_remaining); } /* Always returns page-aligned regions. */ static boolean_t init_alloc_aligned(vm_size_t size, vm_offset_t *addrp) { vm_offset_t addr; extern char start[], end[]; int i; static int wrapped = 0; /* Memory regions to skip. */ vm_offset_t cmdline_start_pa = boot_info.flags & MULTIBOOT_CMDLINE ? boot_info.cmdline : 0; vm_offset_t cmdline_end_pa = cmdline_start_pa ? cmdline_start_pa+strlen((char*)phystokv(cmdline_start_pa))+1 : 0; vm_offset_t mods_start_pa = boot_info.flags & MULTIBOOT_MODS ? boot_info.mods_addr : 0; vm_offset_t mods_end_pa = mods_start_pa ? mods_start_pa + boot_info.mods_count * sizeof(struct multiboot_module) : 0; retry: /* Page-align the start address. */ avail_next = round_page(avail_next); /* Start with memory above 16MB, reserving the low memory for later. */ if (!wrapped && phys_last_addr > 16 * 1024*1024) { if (avail_next < 16 * 1024*1024) avail_next = 16 * 1024*1024; else if (avail_next == phys_last_addr) { /* We have used all the memory above 16MB, so now start on the low memory. This will wind up at the end of the list of free pages, so it should not have been allocated to any other use in early initialization before the Linux driver glue initialization needs to allocate low memory. */ avail_next = 0x1000; wrapped = 1; } } /* Check if we have reached the end of memory. */ if (avail_next == (wrapped ? 16 * 1024*1024 : phys_last_addr)) return FALSE; /* Tentatively assign the current location to the caller. */ addr = avail_next; /* Bump the pointer past the newly allocated region and see where that puts us. */ avail_next += size; /* Skip past the I/O and ROM area. */ if ((avail_next > (boot_info.mem_lower * 0x400)) && (addr < 0x100000)) { avail_next = 0x100000; goto retry; } /* Skip our own kernel code, data, and bss. */ if ((avail_next > (vm_offset_t)start) && (addr < (vm_offset_t)end)) { avail_next = (vm_offset_t)end; goto retry; } /* Skip any areas occupied by valuable boot_info data. */ if ((avail_next > cmdline_start_pa) && (addr < cmdline_end_pa)) { avail_next = cmdline_end_pa; goto retry; } if ((avail_next > mods_start_pa) && (addr < mods_end_pa)) { avail_next = mods_end_pa; goto retry; } if ((avail_next > kern_sym_start) && (addr < kern_sym_end)) { avail_next = kern_sym_end; goto retry; } if (boot_info.flags & MULTIBOOT_MODS) { struct multiboot_module *m = (struct multiboot_module *) phystokv(boot_info.mods_addr); for (i = 0; i < boot_info.mods_count; i++) { if ((avail_next > m[i].mod_start) && (addr < m[i].mod_end)) { avail_next = m[i].mod_end; goto retry; } /* XXX string */ } } avail_remaining -= size; *addrp = addr; return TRUE; } boolean_t pmap_next_page(addrp) vm_offset_t *addrp; { return init_alloc_aligned(PAGE_SIZE, addrp); } /* Grab a physical page: the standard memory allocation mechanism during system initialization. */ vm_offset_t pmap_grab_page(void) { vm_offset_t addr; if (!pmap_next_page(&addr)) panic("Not enough memory to initialize Mach"); return addr; } boolean_t pmap_valid_page(x) vm_offset_t x; { /* XXX is this OK? What does it matter for? */ return (((phys_first_addr <= x) && (x < phys_last_addr)) && !(((boot_info.mem_lower * 1024) <= x) && (x < 1024*1024))); }