1 // Handler for int 0x15 "system" calls
3 // Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
4 // Copyright (C) 2002 MandrakeSoft S.A.
6 // This file may be distributed under the terms of the GNU LGPLv3 license.
8 #include "util.h" // memcpy_far
9 #include "biosvar.h" // BIOS_CONFIG_TABLE
10 #include "ioport.h" // inb
11 #include "memmap.h" // E820_RAM
12 #include "pic.h" // eoi_pic2
13 #include "bregs.h" // struct bregs
15 // Use PS2 System Control port A to set A20 enable
19 // get current setting first
20 u8 newval, oldval = inb(PORT_A20);
22 newval = oldval | A20_ENABLE_BIT;
24 newval = oldval & ~A20_ENABLE_BIT;
25 outb(newval, PORT_A20);
27 return (oldval & A20_ENABLE_BIT) != 0;
31 handle_152400(struct bregs *regs)
34 set_code_success(regs);
38 handle_152401(struct bregs *regs)
41 set_code_success(regs);
45 handle_152402(struct bregs *regs)
47 regs->al = (inb(PORT_A20) & A20_ENABLE_BIT) != 0;
48 set_code_success(regs);
52 handle_152403(struct bregs *regs)
55 set_code_success(regs);
59 handle_1524XX(struct bregs *regs)
61 set_code_unimplemented(regs, RET_EUNSUPPORTED);
65 handle_1524(struct bregs *regs)
68 case 0x00: handle_152400(regs); break;
69 case 0x01: handle_152401(regs); break;
70 case 0x02: handle_152402(regs); break;
71 case 0x03: handle_152403(regs); break;
72 default: handle_1524XX(regs); break;
76 // removable media eject
78 handle_1552(struct bregs *regs)
80 set_code_success(regs);
84 handle_1587(struct bregs *regs)
86 // +++ should probably have descriptor checks
87 // +++ should have exception handlers
89 u8 prev_a20_enable = set_a20(1); // enable A20 line
91 // 128K max of transfer on 386+ ???
92 // source == destination ???
94 // ES:SI points to descriptor table
95 // offset use initially comments
96 // ==============================================
97 // 00..07 Unused zeros Null descriptor
98 // 08..0f GDT zeros filled in by BIOS
99 // 10..17 source ssssssss source of data
100 // 18..1f dest dddddddd destination of data
101 // 20..27 CS zeros filled in by BIOS
102 // 28..2f SS zeros filled in by BIOS
104 // check for access rights of source & dest here
106 // Initialize GDT descriptor
108 u64 *gdt_far = (void*)si;
109 u16 gdt_seg = regs->es;
110 u32 loc = (u32)MAKE_FLATPTR(gdt_seg, gdt_far);
111 SET_FARVAR(gdt_seg, gdt_far[1], GDT_DATA | GDT_LIMIT((6*sizeof(u64))-1)
113 // Initialize CS descriptor
114 SET_FARVAR(gdt_seg, gdt_far[4], GDT_CODE | GDT_LIMIT(BUILD_BIOS_SIZE-1)
115 | GDT_BASE(BUILD_BIOS_ADDR));
116 // Initialize SS descriptor
117 loc = (u32)MAKE_FLATPTR(GET_SEG(SS), 0);
118 SET_FARVAR(gdt_seg, gdt_far[5], GDT_DATA | GDT_LIMIT(0x0ffff)
121 u16 count = regs->cx;
123 // Load new descriptor tables
124 " lgdtw %%es:(1<<3)(%%si)\n"
125 " lidtw %%cs:pmode_IDT_info\n"
127 // Enable protected mode
128 " movl %%cr0, %%eax\n"
129 " orl $" __stringify(CR0_PE) ", %%eax\n"
130 " movl %%eax, %%cr0\n"
132 // far jump to flush CPU queue after transition to protected mode
133 " ljmpw $(4<<3), $1f\n"
135 // GDT points to valid descriptor table, now load DS, ES
136 "1:movw $(2<<3), %%ax\n" // 2nd descriptor in table, TI=GDT, RPL=00
138 " movw $(3<<3), %%ax\n" // 3rd descriptor in table, TI=GDT, RPL=00
141 // move CX words from DS:SI to ES:DI
146 // Restore DS and ES segment limits to 0xffff
147 " movw $(5<<3), %%ax\n" // 5th descriptor in table (SS)
151 // Disable protected mode
152 " movl %%cr0, %%eax\n"
153 " andl $~" __stringify(CR0_PE) ", %%eax\n"
154 " movl %%eax, %%cr0\n"
156 // far jump to flush CPU queue after transition to real mode
157 " ljmpw $" __stringify(SEG_BIOS) ", $2f\n"
159 // restore IDT to normal real-mode defaults
160 "2:lidtw %%cs:rmode_IDT_info\n"
162 // Restore %ds (from %ss)
165 : "+c"(count), "+S"(si)
166 : : "eax", "di", "cc"); // XXX - also clobbers %es
168 set_a20(prev_a20_enable);
170 set_code_success(regs);
173 // Get the amount of extended memory (above 1M)
175 handle_1588(struct bregs *regs)
177 u32 rs = GET_GLOBAL(RamSize);
179 // According to Ralf Brown's interrupt the limit should be 15M,
180 // but real machines mostly return max. 63M.
181 if (rs > 64*1024*1024)
182 regs->ax = 63 * 1024;
184 regs->ax = (rs - 1*1024*1024) / 1024;
188 // Switch to protected mode
190 handle_1589(struct bregs *regs)
194 set_pics(regs->bl, regs->bh);
196 u64 *gdt_far = (void*)(regs->si + 0);
197 u16 gdt_seg = regs->es;
198 SET_FARVAR(gdt_seg, gdt_far[7], GDT_CODE | GDT_LIMIT(BUILD_BIOS_SIZE-1)
199 | GDT_BASE(BUILD_BIOS_ADDR));
201 regs->ds = 3<<3; // 3rd gdt descriptor is %ds
202 regs->es = 4<<3; // 4th gdt descriptor is %es
203 regs->code.seg = 6<<3; // 6th gdt descriptor is %cs
205 set_code_success(regs);
208 // Load new descriptor tables
209 " lgdtw %%es:(1<<3)(%%si)\n"
210 " lidtw %%es:(2<<3)(%%si)\n"
212 // Enable protected mode
213 " movl %%cr0, %%eax\n"
214 " orl $" __stringify(CR0_PE) ", %%eax\n"
215 " movl %%eax, %%cr0\n"
217 // far jump to flush CPU queue after transition to protected mode
218 " ljmpw $(7<<3), $1f\n"
220 // GDT points to valid descriptor table, now load SS
221 "1:movw $(5<<3), %%ax\n"
229 // Device busy interrupt. Called by Int 16h when no key available
231 handle_1590(struct bregs *regs)
235 // Interrupt complete. Called by Int 16h when key becomes available
237 handle_1591(struct bregs *regs)
241 // keyboard intercept
243 handle_154f(struct bregs *regs)
245 set_invalid_silent(regs);
249 handle_15c0(struct bregs *regs)
252 regs->bx = (u32)&BIOS_CONFIG_TABLE;
253 set_code_success(regs);
257 handle_15c1(struct bregs *regs)
259 regs->es = get_ebda_seg();
264 handle_15e801(struct bregs *regs)
266 // my real system sets ax and bx to 0
267 // this is confirmed by Ralph Brown list
268 // but syslinux v1.48 is known to behave
269 // strangely if ax is set to 0
270 // regs.u.r16.ax = 0;
271 // regs.u.r16.bx = 0;
273 u32 rs = GET_GLOBAL(RamSize);
275 // Get the amount of extended memory (above 1M)
276 if (rs > 16*1024*1024) {
279 // Get the amount of extended memory above 16M in 64k blocks
280 regs->dx = (rs - 16*1024*1024) / (64*1024);
282 regs->cx = (rs - 1*1024*1024) / 1024;
286 // Set configured memory equal to extended memory
293 // Info on e820 map location and size.
294 struct e820entry e820_list[CONFIG_MAX_E820] VAR16VISIBLE;
295 int e820_count VAR16VISIBLE;
298 handle_15e820(struct bregs *regs)
300 int count = GET_GLOBAL(e820_count);
301 if (regs->edx != 0x534D4150 || regs->bx >= count
302 || regs->ecx < sizeof(e820_list[0])) {
303 set_code_invalid(regs, RET_EUNSUPPORTED);
307 memcpy_far(regs->es, (void*)(regs->di+0)
308 , get_global_seg(), &e820_list[regs->bx]
309 , sizeof(e820_list[0]));
310 if (regs->bx == count-1)
314 regs->eax = 0x534D4150;
315 regs->ecx = sizeof(e820_list[0]);
320 handle_15e8XX(struct bregs *regs)
322 set_code_unimplemented(regs, RET_EUNSUPPORTED);
326 handle_15e8(struct bregs *regs)
329 case 0x01: handle_15e801(regs); break;
330 case 0x20: handle_15e820(regs); break;
331 default: handle_15e8XX(regs); break;
336 handle_15XX(struct bregs *regs)
338 set_code_unimplemented(regs, RET_EUNSUPPORTED);
341 // INT 15h System Services Entry Point
343 handle_15(struct bregs *regs)
345 debug_enter(regs, DEBUG_HDL_15);
347 case 0x24: handle_1524(regs); break;
348 case 0x4f: handle_154f(regs); break;
349 case 0x52: handle_1552(regs); break;
350 case 0x53: handle_1553(regs); break;
351 case 0x5f: handle_155f(regs); break;
352 case 0x83: handle_1583(regs); break;
353 case 0x86: handle_1586(regs); break;
354 case 0x87: handle_1587(regs); break;
355 case 0x88: handle_1588(regs); break;
356 case 0x89: handle_1589(regs); break;
357 case 0x90: handle_1590(regs); break;
358 case 0x91: handle_1591(regs); break;
359 case 0xc0: handle_15c0(regs); break;
360 case 0xc1: handle_15c1(regs); break;
361 case 0xc2: handle_15c2(regs); break;
362 case 0xe8: handle_15e8(regs); break;
363 default: handle_15XX(regs); break;