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001 /* Copyright (C) 2004 The SOS Team 001 /* Copyright (C) 2004 The SOS Team 002 Copyright (C) 1999 Free Software Foundatio 002 Copyright (C) 1999 Free Software Foundation, Inc. 003 003 004 This program is free software; you can redi 004 This program is free software; you can redistribute it and/or 005 modify it under the terms of the GNU Genera 005 modify it under the terms of the GNU General Public License 006 as published by the Free Software Foundatio 006 as published by the Free Software Foundation; either version 2 007 of the License, or (at your option) any lat 007 of the License, or (at your option) any later version. 008 008 009 This program is distributed in the hope tha 009 This program is distributed in the hope that it will be useful, 010 but WITHOUT ANY WARRANTY; without even the 010 but WITHOUT ANY WARRANTY; without even the implied warranty of 011 MERCHANTABILITY or FITNESS FOR A PARTICULAR 011 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 012 GNU General Public License for more details 012 GNU General Public License for more details. 013 013 014 You should have received a copy of the GNU 014 You should have received a copy of the GNU General Public License 015 along with this program; if not, write to t 015 along with this program; if not, write to the Free Software 016 Foundation, Inc., 59 Temple Place - Suite 3 016 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 017 USA. 017 USA. 018 */ 018 */ 019 019 020 /* Include definitions of the multiboot standa 020 /* Include definitions of the multiboot standard */ 021 #include <bootstrap/multiboot.h> 021 #include <bootstrap/multiboot.h> 022 #include <hwcore/idt.h> 022 #include <hwcore/idt.h> 023 #include <hwcore/gdt.h> 023 #include <hwcore/gdt.h> 024 #include <hwcore/irq.h> 024 #include <hwcore/irq.h> 025 #include <hwcore/exception.h> 025 #include <hwcore/exception.h> 026 #include <hwcore/i8254.h> 026 #include <hwcore/i8254.h> 027 #include <sos/list.h> << 028 #include <sos/physmem.h> << 029 #include <hwcore/paging.h> << 030 #include <sos/list.h> << 031 #include <sos/klibc.h> 027 #include <sos/klibc.h> 032 #include <sos/assert.h> 028 #include <sos/assert.h> 033 #include <drivers/x86_videomem.h> 029 #include <drivers/x86_videomem.h> 034 #include <drivers/bochs.h> 030 #include <drivers/bochs.h> 035 031 036 032 037 /* Helper function to display each bits of a 3 033 /* Helper function to display each bits of a 32bits integer on the 038 screen as dark or light carrets */ 034 screen as dark or light carrets */ 039 static void display_bits(unsigned char row, un 035 static void display_bits(unsigned char row, unsigned char col, 040 unsigned char attribu 036 unsigned char attribute, 041 sos_ui32_t integer) 037 sos_ui32_t integer) 042 { 038 { 043 int i; 039 int i; 044 /* Scan each bit of the integer, MSb first * 040 /* Scan each bit of the integer, MSb first */ 045 for (i = 31 ; i >= 0 ; i--) 041 for (i = 31 ; i >= 0 ; i--) 046 { 042 { 047 /* Test if bit i of 'integer' is set */ 043 /* Test if bit i of 'integer' is set */ 048 int bit_i = (integer & (1 << i)); 044 int bit_i = (integer & (1 << i)); 049 /* Ascii 219 => dark carret, Ascii 177 = 045 /* Ascii 219 => dark carret, Ascii 177 => light carret */ 050 unsigned char ascii_code = bit_i?219:177 046 unsigned char ascii_code = bit_i?219:177; 051 sos_x86_videomem_putchar(row, col++, 047 sos_x86_videomem_putchar(row, col++, 052 attribute, 048 attribute, 053 ascii_code); 049 ascii_code); 054 } 050 } 055 } 051 } 056 052 057 053 058 /* Clock IRQ handler */ 054 /* Clock IRQ handler */ 059 static void clk_it(int intid) 055 static void clk_it(int intid) 060 { 056 { 061 static sos_ui32_t clock_count = 0; 057 static sos_ui32_t clock_count = 0; 062 058 063 display_bits(0, 48, 059 display_bits(0, 48, 064 SOS_X86_VIDEO_FG_LTGREEN | SOS_ 060 SOS_X86_VIDEO_FG_LTGREEN | SOS_X86_VIDEO_BG_BLUE, 065 clock_count); 061 clock_count); 066 clock_count++; 062 clock_count++; 067 063 068 } 064 } 069 065 070 /* Page fault exception handler */ !! 066 /* Division by zero exception handler */ 071 static void pgflt_ex(int exid) !! 067 static void divide_ex(int exid) 072 { 068 { 073 sos_bochs_printf("Got page fault\n"); !! 069 static sos_ui32_t div_count = 0; 074 sos_x86_videomem_printf(10, 30, !! 070 display_bits(0, 0, 075 SOS_X86_VIDEO_FG_LTR !! 071 SOS_X86_VIDEO_FG_LTRED | SOS_X86_VIDEO_BG_BLUE, 076 "Got EXPECTED (?) Pa !! 072 div_count); 077 for (;;) ; !! 073 div_count++; 078 } << 079 << 080 static void test_paging(sos_vaddr_t sos_kernel << 081 { << 082 /* The (linear) address of the page holding << 083 currently executing */ << 084 sos_vaddr_t vpage_code = SOS_PAGE_ALIGN_INF( << 085 << 086 /* The new physical page that will hold the << 087 sos_paddr_t ppage_new; << 088 << 089 /* Where this page will be mapped temporaril << 090 code into it: right after the kernel code << 091 sos_vaddr_t vpage_tmp = sos_kernel_core_top_ << 092 << 093 unsigned i; << 094 << 095 /* Bind the page fault exception to one of o << 096 sos_exception_set_routine(SOS_EXCEPT_PAGE_FA << 097 pgflt_ex); << 098 << 099 /* << 100 * Test 1: move the page where we execute th << 101 * physical memory << 102 */ << 103 sos_x86_videomem_printf(4, 0, << 104 SOS_X86_VIDEO_FG_LTG << 105 "Moving current code << 106 << 107 << 108 /* Allocate a new physical page */ << 109 ppage_new = sos_physmem_ref_physpage_new(FAL << 110 if (! ppage_new) << 111 { << 112 /* STOP ! No memory left */ << 113 sos_x86_videomem_putstring(20, 0, << 114 SOS_X86_VIDEO << 115 | SOS_X86_V << 116 "test_paging << 117 return; << 118 } << 119 << 120 sos_x86_videomem_printf(5, 0, << 121 SOS_X86_VIDEO_FG_YEL << 122 "Hello from the addr << 123 sos_paging_get_paddr << 124 << 125 sos_x86_videomem_printf(6, 0, << 126 SOS_X86_VIDEO_FG_YEL << 127 "Transfer vpage 0x%x << 128 vpage_code, << 129 sos_paging_get_paddr << 130 ppage_new, << 131 (unsigned)vpage_tmp) << 132 << 133 /* Map the page somewhere (right after the k << 134 to copy the code we are currently executi << 135 sos_paging_map(ppage_new, vpage_tmp, << 136 FALSE, << 137 SOS_VM_MAP_ATOMIC << 138 | SOS_VM_MAP_PROT_READ << 139 | SOS_VM_MAP_PROT_WRITE); << 140 << 141 /* Ok, the new page is referenced by the map << 142 reference to it */ << 143 sos_physmem_unref_physpage(ppage_new); << 144 << 145 /* Copy the contents of the current page of << 146 mapping */ << 147 memcpy((void*)vpage_tmp, << 148 (void*)vpage_code, << 149 SOS_PAGE_SIZE); << 150 << 151 /* Transfer the mapping of the current page << 152 sos_paging_map(ppage_new, vpage_code, << 153 FALSE, << 154 SOS_VM_MAP_ATOMIC << 155 | SOS_VM_MAP_PROT_READ << 156 | SOS_VM_MAP_PROT_WRITE); << 157 << 158 /* Ok, here we are: we have changed the phys << 159 code we are executing ;). However, this n << 160 virtual addresses: << 161 - vpage_tmp << 162 - vpage_code << 163 We can safely unmap it from sos_kernel_co << 164 still keeping the vpage_code mapping */ << 165 sos_paging_unmap(vpage_tmp); << 166 << 167 sos_x86_videomem_printf(7, 0, << 168 SOS_X86_VIDEO_FG_YEL << 169 "Hello from the addr << 170 sos_paging_get_paddr << 171 << 172 sos_x86_videomem_printf(9, 0, << 173 SOS_X86_VIDEO_FG_LTG << 174 "Provoking a page fa << 175 << 176 /* << 177 * Test 2: make sure the #PF handler works << 178 */ << 179 << 180 /* Scan part of the kernel up to a page faul << 181 should occur on the first page unmapped a << 182 which is exactly the page we temporarily << 183 (vpage_tmp) above to move the kernel code << 184 for (i = vpage_code ; /* none */ ; i += SOS_ << 185 { << 186 unsigned *pint = (unsigned *)SOS_PAGE_AL << 187 sos_bochs_printf("Test vaddr 0x%x : val= << 188 sos_x86_videomem_printf(10, 0, << 189 SOS_X86_VIDEO_FG << 190 "Test vaddr 0x%x << 191 (unsigned)pint); << 192 sos_bochs_printf("0x%x\n", *pint); << 193 sos_x86_videomem_printf(10, 30, << 194 SOS_X86_VIDEO_FG << 195 "0x%x " << 196 } << 197 << 198 /* BAD ! Did not get the page fault... */ << 199 sos_x86_videomem_printf(20, 0, << 200 SOS_X86_VIDEO_FG_LTR << 201 "We should have had << 202 vpage_tmp); << 203 } 074 } 204 075 205 /* The C entry point of our operating system * 076 /* The C entry point of our operating system */ 206 void sos_main(unsigned long magic, unsigned lo 077 void sos_main(unsigned long magic, unsigned long addr) 207 { 078 { 208 unsigned i; 079 unsigned i; 209 sos_paddr_t sos_kernel_core_base_paddr, sos_ << 210 080 211 /* Grub sends us a structure, called multibo 081 /* Grub sends us a structure, called multiboot_info_t with a lot of 212 precious informations about the system, s 082 precious informations about the system, see the multiboot 213 documentation for more information. */ 083 documentation for more information. */ 214 multiboot_info_t *mbi; 084 multiboot_info_t *mbi; 215 mbi = (multiboot_info_t *) addr; 085 mbi = (multiboot_info_t *) addr; 216 086 217 /* Setup bochs and console, and clear the co 087 /* Setup bochs and console, and clear the console */ 218 sos_bochs_setup(); 088 sos_bochs_setup(); 219 089 220 sos_x86_videomem_setup(); 090 sos_x86_videomem_setup(); 221 sos_x86_videomem_cls(SOS_X86_VIDEO_BG_BLUE); 091 sos_x86_videomem_cls(SOS_X86_VIDEO_BG_BLUE); 222 092 223 /* Greetings from SOS */ 093 /* Greetings from SOS */ 224 if (magic == MULTIBOOT_BOOTLOADER_MAGIC) 094 if (magic == MULTIBOOT_BOOTLOADER_MAGIC) 225 /* Loaded with Grub */ 095 /* Loaded with Grub */ 226 sos_x86_videomem_printf(1, 0, 096 sos_x86_videomem_printf(1, 0, 227 SOS_X86_VIDEO_FG_Y 097 SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE, 228 "Welcome From GRUB 098 "Welcome From GRUB to %s%c RAM is %dMB (upper mem = 0x%x kB)", 229 "SOS", ',', 099 "SOS", ',', 230 (unsigned)(mbi->me 100 (unsigned)(mbi->mem_upper >> 10) + 1, 231 (unsigned)mbi->mem 101 (unsigned)mbi->mem_upper); 232 else 102 else 233 /* Not loaded with grub */ 103 /* Not loaded with grub */ 234 sos_x86_videomem_printf(1, 0, 104 sos_x86_videomem_printf(1, 0, 235 SOS_X86_VIDEO_FG_Y 105 SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE, 236 "Welcome to SOS"); 106 "Welcome to SOS"); 237 107 238 sos_bochs_putstring("Message in a bochs\n"); 108 sos_bochs_putstring("Message in a bochs\n"); 239 109 240 /* Setup CPU segmentation and IRQ subsystem 110 /* Setup CPU segmentation and IRQ subsystem */ 241 sos_gdt_setup(); 111 sos_gdt_setup(); 242 sos_idt_setup(); 112 sos_idt_setup(); 243 113 244 /* Setup SOS IRQs and exceptions subsystem * 114 /* Setup SOS IRQs and exceptions subsystem */ 245 sos_exceptions_setup(); 115 sos_exceptions_setup(); 246 sos_irq_setup(); 116 sos_irq_setup(); 247 117 248 /* Configure the timer so as to raise the IR 118 /* Configure the timer so as to raise the IRQ0 at a 100Hz rate */ 249 sos_i8254_set_frequency(100); 119 sos_i8254_set_frequency(100); 250 120 251 << 252 /* We need a multiboot-compliant boot loader << 253 if (magic != MULTIBOOT_BOOTLOADER_MAGIC) << 254 { << 255 sos_x86_videomem_putstring(20, 0, << 256 SOS_X86_VIDEO << 257 | SOS_X86_V << 258 | SOS_X86_V << 259 "I'm not load << 260 /* STOP ! */ << 261 for (;;) << 262 continue; << 263 } << 264 << 265 /* Binding some HW interrupts and exceptions 121 /* Binding some HW interrupts and exceptions to software routines */ 266 sos_irq_set_routine(SOS_IRQ_TIMER, 122 sos_irq_set_routine(SOS_IRQ_TIMER, 267 clk_it); 123 clk_it); >> 124 sos_exception_set_routine(SOS_EXCEPT_DIVIDE_ERROR, >> 125 divide_ex); 268 /* Enabling the HW interrupts here, this wil 126 /* Enabling the HW interrupts here, this will make the timer HW 269 interrupt call our clk_it handler */ 127 interrupt call our clk_it handler */ 270 asm volatile ("sti\n"); 128 asm volatile ("sti\n"); 271 /* Multiboot says: "The value returned for u !! 129 272 the address of the first upper memory hol !! 130 /* Raise a rafale of 'division by 0' exceptions. All this code is 273 also adds: "It is not guaranteed to be th !! 131 not really needed (equivalent to a bare "i=1/0;"), except when 274 sos_physmem_setup((mbi->mem_upper<<10) + (1< !! 132 compiling with -O3: "i=1/0;" is considered dead code with gcc 275 & sos_kernel_core_base_pad !! 133 -O3. */ 276 & sos_kernel_core_top_padd !! 134 i = 10; 277 !! 135 while (1) 278 /* !! 136 { 279 * Switch to paged-memory mode !! 137 /* Stupid function call to fool gcc optimizations */ 280 */ !! 138 sos_bochs_printf("i = 1 / %d...\n", i); 281 !! 139 i = 1 / i; 282 /* Disabling interrupts should seem more cor !! 140 } 283 necessary at this stage */ !! 141 284 if (sos_paging_setup(sos_kernel_core_base_pa !! 142 /* Will never print this since the "divide by zero" exception always 285 sos_kernel_core_top_pad !! 143 returns to the faulting instruction (see Intel x86 doc vol 3, 286 sos_bochs_printf("Could not setup paged me !! 144 section 5.12), thus re-evaluating the "divide-by-zero" exprssion 287 sos_x86_videomem_printf(2, 0, !! 145 and raising the "divide by zero" exception again and again... */ 288 SOS_X86_VIDEO_FG_YEL !! 146 sos_x86_videomem_putstring(2, 0, 289 "Paged-memory mode i !! 147 SOS_X86_VIDEO_FG_LTRED | SOS_X86_VIDEO_BG_BLUE, 290 !! 148 "Invisible"); 291 test_paging(sos_kernel_core_top_paddr); << 292 << 293 /* An operatig system never ends */ << 294 for (;;) << 295 continue; << 296 149 297 return; 150 return; 298 } 151 }
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