bootsector.h File Reference
x86 bootsector image format More...
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Functions | |
| FILE_LICENCE (GPL2_OR_LATER_OR_UBDL) | |
| int | call_bootsector (unsigned int segment, unsigned int offset, unsigned int drive) |
| Jump to preloaded bootsector. | |
Detailed Description
x86 bootsector image format
Definition in file bootsector.h.
Function Documentation
◆ FILE_LICENCE()
◆ call_bootsector()
|
extern |
Jump to preloaded bootsector.
- Parameters
-
segment Real-mode segment offset Real-mode offset drive Drive number to pass to boot sector
- Return values
-
rc Return status code
Definition at line 64 of file bootsector.c.
65 {
67
68 /* Reset console, since boot sector will probably use it */
69 console_reset();
70
72
73 /* Hook INTs 18 and 19 to capture failure paths */
75 &int18_vector );
77 &int19_vector );
78
79 /* Boot the loaded sector
80 *
81 * We assume that the boot sector may completely destroy our
82 * real-mode stack, so we preserve everything we need in
83 * static storage.
84 */
86 "popw %%cs:saved_retaddr\n\t"
87 /* Save stack pointer */
88 "movw %%ss, %%ax\n\t"
89 "movw %%ax, %%cs:saved_ss\n\t"
90 "movw %%sp, %%cs:saved_sp\n\t"
91 /* Save frame pointer (gcc bug) */
92 "movl %%ebp, %%cs:saved_ebp\n\t"
93 /* Prepare jump to boot sector */
94 "pushw %%bx\n\t"
95 "pushw %%di\n\t"
96 /* Clear all registers */
97 "xorl %%eax, %%eax\n\t"
98 "xorl %%ebx, %%ebx\n\t"
99 "xorl %%ecx, %%ecx\n\t"
100 /* %edx contains drive number */
101 "xorl %%esi, %%esi\n\t"
102 "xorl %%edi, %%edi\n\t"
103 "xorl %%ebp, %%ebp\n\t"
104 "movw %%ax, %%ds\n\t"
105 "movw %%ax, %%es\n\t"
106 "movw %%ax, %%fs\n\t"
107 "movw %%ax, %%gs\n\t"
108 /* Jump to boot sector */
109 "sti\n\t"
110 "lret\n\t"
111 /* Preserved variables */
112 "\nsaved_ebp: .long 0\n\t"
113 "\nsaved_ss: .word 0\n\t"
114 "\nsaved_sp: .word 0\n\t"
115 "\nsaved_retaddr: .word 0\n\t"
116 /* Boot failure return point */
117 "\nbootsector_exec_fail:\n\t"
118 /* Restore frame pointer (gcc bug) */
119 "movl %%cs:saved_ebp, %%ebp\n\t"
120 /* Restore stack pointer */
121 "movw %%cs:saved_ss, %%ax\n\t"
122 "movw %%ax, %%ss\n\t"
123 "movw %%cs:saved_sp, %%sp\n\t"
124 /* Return via saved address */
125 "jmp *%%cs:saved_retaddr\n\t" )
127 "=d" ( discard_d )
130 : "eax", "ecx", "esi" );
131
133
134 /* Unhook INTs 18 and 19 */
136 &int18_vector );
138 &int19_vector );
139
141}
__asm__ __volatile__("call *%9" :"=a"(result), "=c"(discard_ecx), "=d"(discard_edx) :"d"(0), "a"(code), "b"(0), "c"(in_phys), "D"(0), "S"(out_phys), "m"(hypercall))
void hook_bios_interrupt(unsigned int interrupt, unsigned int handler, struct segoff *chain_vector)
Hook INT vector.
Definition biosint.c:25
int unhook_bios_interrupt(unsigned int interrupt, unsigned int handler, struct segoff *chain_vector)
Unhook INT vector.
Definition biosint.c:70
static struct segoff int19_vector
Vector for storing original INT 19 handler.
Definition bootsector.c:51
static struct segoff int18_vector
Vector for storing original INT 18 handler.
Definition bootsector.c:44
__asm__(".section \".rodata\", \"a\", " PROGBITS "\n\t" "\nprivate_key_data:\n\t" ".size private_key_data, ( . - private_key_data )\n\t" ".equ private_key_len, ( . - private_key_data )\n\t" ".previous\n\t")
References __asm__(), __volatile__(), bootsector_exec_fail(), console_reset(), DBG, discard_D, drive, ECANCELED, hook_bios_interrupt(), int18_vector, int19_vector, offset, REAL_CODE, segment, and unhook_bios_interrupt().
Referenced by int13_boot().
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