[038e1dba] | 1 | /** |
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| 2 | * @file realmode_int.c |
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[586c86c7] | 3 | * |
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[038e1dba] | 4 | * @ingroup i386_shared |
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[586c86c7] | 5 | * |
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[038e1dba] | 6 | * @brief Real mode interrupt call implementation |
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| 7 | */ |
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| 8 | |
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| 9 | /* |
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| 10 | * Copyright (c) 2014 - CTU in Prague |
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| 11 | * Jan DoleÅŸal ( dolezj21@fel.cvut.cz ) |
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[586c86c7] | 12 | * |
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| 13 | * The license and distribution terms for this file may be |
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| 14 | * found in the file LICENSE in this distribution or at |
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| 15 | * http://www.rtems.org/license/LICENSE. |
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| 16 | */ |
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| 17 | |
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| 18 | #include <bsp/realmode_int.h> |
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| 19 | #include <string.h> |
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| 20 | #include <rtems/score/cpu.h> |
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| 21 | |
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[038e1dba] | 22 | /* |
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| 23 | * offsets to \a i386_realmode_interrupt_registers declared in realmode_int.h |
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| 24 | * used in inline assmbler for better readability |
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| 25 | */ |
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[586c86c7] | 26 | #define IR_EAX_OFF "0x00" |
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| 27 | #define IR_EBX_OFF "0x04" |
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| 28 | #define IR_ECX_OFF "0x08" |
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| 29 | #define IR_EDX_OFF "0x0C" |
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| 30 | #define IR_ESI_OFF "0x10" |
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| 31 | #define IR_EDI_OFF "0x14" |
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| 32 | #define IR_DS_OFF "0x18" |
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| 33 | #define IR_ES_OFF "0x1A" |
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| 34 | #define IR_FS_OFF "0x1C" |
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| 35 | #define IR_GS_OFF "0x1E" |
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| 36 | |
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[038e1dba] | 37 | /* |
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| 38 | * offsets to \a rm_int_regs_bkp_param |
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| 39 | */ |
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[586c86c7] | 40 | #define BKP_ESP_OFF "0x20" |
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| 41 | #define BKP_SS_OFF "0x24" |
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| 42 | #define BKP_DS_OFF "0x26" |
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| 43 | #define RM_ENTRY "0x28" |
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| 44 | #define PM_ENTRY "0x2C" |
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| 45 | |
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[038e1dba] | 46 | /** |
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| 47 | * @brief parameters, results, backup values accessible in real mode |
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| 48 | * |
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| 49 | * @note Struct members not necessarily used in C. This serves also as |
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| 50 | * layout of memory and it is used within inline assembler. |
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| 51 | */ |
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[586c86c7] | 52 | typedef struct { |
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| 53 | i386_realmode_interrupt_registers inoutregs; |
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[038e1dba] | 54 | /** spot for back up of protected mode stack pointer */ |
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[586c86c7] | 55 | uint32_t pm_esp_bkp; |
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[038e1dba] | 56 | /** spot for back up of protected mode stack selector */ |
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[586c86c7] | 57 | uint16_t pm_ss_bkp; |
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[038e1dba] | 58 | /** spot for back up of protected mode data selector */ |
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[586c86c7] | 59 | uint16_t ds_bkp; |
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[038e1dba] | 60 | /** spot for setting up long indirect jump offset |
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| 61 | to real mode from 16bit protected mode */ |
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[586c86c7] | 62 | uint16_t rm_entry; |
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[038e1dba] | 63 | /** spot for setting up long indirect jump segment |
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| 64 | to real mode from 16bit protected mode */ |
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[586c86c7] | 65 | uint16_t rm_code_segment; |
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[038e1dba] | 66 | /** returning offset for long indirect jump back |
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| 67 | to 32bit protected mode */ |
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[586c86c7] | 68 | uint32_t pm_entry; |
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[038e1dba] | 69 | /** returning selector for long indirect jump back |
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| 70 | to 32bit protected mode */ |
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[586c86c7] | 71 | uint16_t pm_code_selector; |
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[038e1dba] | 72 | /* if this struct is to be modified update offset definitions as well */ |
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[586c86c7] | 73 | } RTEMS_COMPILER_PACKED_ATTRIBUTE rm_int_regs_bkp_param; |
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| 74 | |
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[038e1dba] | 75 | /* offsets to \a pm_bkp_and_param */ |
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[586c86c7] | 76 | #define BKP_IDTR_LIM "0x00" |
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| 77 | #define BKP_IDTR_BASE "0x02" |
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| 78 | #define BKP_ES_OFF "0x06" |
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| 79 | #define BKP_FS_OFF "0x08" |
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| 80 | #define BKP_GS_OFF "0x0A" |
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| 81 | #define RML_ENTRY "0x0C" |
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| 82 | #define RML_D_SEL "0x12" |
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| 83 | #define RM_SS "0x14" |
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| 84 | #define RM_SP "0x16" |
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| 85 | #define RM_DS "0x18" |
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[038e1dba] | 86 | |
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| 87 | /** |
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| 88 | * @brief backup values, pointers/parameters accessible in protected mode |
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| 89 | * |
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| 90 | * @note Struct members not necessarily used in C. This serves also as |
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| 91 | * layout of memory and it is used within inline assembler. |
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| 92 | */ |
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[586c86c7] | 93 | typedef struct { |
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[038e1dba] | 94 | /** spot for backup protected mode interrupt descriptor table register */ |
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[586c86c7] | 95 | uint16_t idtr_lim_bkp; |
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[038e1dba] | 96 | /** @see idtr_lim_bkp */ |
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[586c86c7] | 97 | uint32_t idtr_base_bkp; |
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[038e1dba] | 98 | /** spot to backup of ES register value in 32bit protected mode */ |
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[586c86c7] | 99 | uint16_t es_bkp; |
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[038e1dba] | 100 | /** spot to backup of FS register value in 32bit protected mode */ |
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[586c86c7] | 101 | uint16_t fs_bkp; |
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[038e1dba] | 102 | /** spot to backup of GS register value in 32bit protected mode */ |
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[586c86c7] | 103 | uint16_t gs_bkp; |
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[038e1dba] | 104 | /** values for indirect jump to 16bit protected mode */ |
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[586c86c7] | 105 | uint32_t rml_entry; |
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[038e1dba] | 106 | /** @see rml_entry */ |
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[586c86c7] | 107 | uint16_t rml_code_selector; |
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[038e1dba] | 108 | /** data selector for 16bit protected mode */ |
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[586c86c7] | 109 | uint16_t rml_data_selector; |
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[038e1dba] | 110 | /** values determinig location of real mode stack */ |
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[586c86c7] | 111 | uint16_t rm_stack_segment; |
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[038e1dba] | 112 | /** @see rm_stack_segment */ |
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[586c86c7] | 113 | uint16_t rm_stack_pointer; |
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[038e1dba] | 114 | /** data segment for real mode */ |
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[586c86c7] | 115 | uint16_t rm_data_segment; |
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| 116 | } RTEMS_COMPILER_PACKED_ATTRIBUTE pm_bkp_and_param; |
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| 117 | |
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| 118 | /* addresses where we are going to put Interrupt buffer, |
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| 119 | * parameter/returned/preserved values, stack and copy code |
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| 120 | * for calling BIOS interrupt real mode interface |
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| 121 | * The value is chosen arbitrarily in the first 640kB |
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| 122 | * to be accessible for real mode. It should be out of range |
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| 123 | * used by RTEMS because its base address is above 1MB. |
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| 124 | * It has to be above first 4kB (or better 64kB) which could |
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| 125 | * be used by BIOS. |
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| 126 | */ |
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| 127 | #define REAL_MODE_SPOT 0x12000 |
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| 128 | /* REAL_MODE_SPOT value is also top of real mode stack */ |
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| 129 | |
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| 130 | /* buffers positions and lengths */ |
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| 131 | #define DEFAULT_BUFFER_SIZE 512 |
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| 132 | static void *default_rm_buffer_spot = (void *)REAL_MODE_SPOT; |
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| 133 | static uint16_t default_rm_buffer_size = DEFAULT_BUFFER_SIZE; |
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| 134 | |
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| 135 | /* real mode stack */ |
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| 136 | #define STACK_SIZE 8192 |
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| 137 | #define INT_STACK_TOP REAL_MODE_SPOT |
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| 138 | |
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| 139 | /****************************** |
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| 140 | * STACK * * |
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| 141 | ****************************** REAL_MODE_SPOT |
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| 142 | * INT_BUF * 512 B * |
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| 143 | ****************************** |
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| 144 | * INT_REGs * 50 B * |
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| 145 | ****************************** |
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| 146 | * INT_FNC *~149 B * |
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| 147 | ******************************/ |
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| 148 | |
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| 149 | #define __DP_TYPE uint8_t |
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| 150 | #define __DP_YES ((__DP_TYPE)1) |
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| 151 | #define __DP_NO ((__DP_TYPE)-1) |
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| 152 | #define __DP_FAIL ((__DP_TYPE)0) |
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| 153 | static __DP_TYPE descsPrepared = __DP_NO; |
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| 154 | |
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| 155 | /* rml - real mode alike */ |
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| 156 | #define rml_limit 0xFFFF |
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| 157 | static uint16_t rml_code_dsc_index = 0; |
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| 158 | static uint16_t rml_data_dsc_index = 0; |
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| 159 | |
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[038e1dba] | 160 | /** |
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| 161 | * @brief Prepares real-mode like descriptors to be used for switching |
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[586c86c7] | 162 | * to real mode. |
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| 163 | * |
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[038e1dba] | 164 | * Descriptors will be placed to the GDT. |
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| 165 | * |
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| 166 | * @param[in] base32 32-bit physical address to be used as base for 16-bit |
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| 167 | * protected mode descriptors |
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[586c86c7] | 168 | * @retval __DP_YES descriptors are prepared |
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| 169 | * @retval __DP_FAIL descriptors allocation failed (GDT too small) |
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| 170 | */ |
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| 171 | static __DP_TYPE prepareRMDescriptors (void *base32) { |
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| 172 | static void *prevBase = (void *)-1; |
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| 173 | /* check if descriptors were prepared already */ |
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| 174 | if (descsPrepared == __DP_YES && prevBase == base32) |
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| 175 | return descsPrepared; |
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| 176 | |
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| 177 | if (descsPrepared == __DP_FAIL) |
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| 178 | return descsPrepared; |
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| 179 | |
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| 180 | /* create 'real mode like' segment descriptors, for switching to real mode */ |
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| 181 | rml_code_dsc_index = i386_next_empty_gdt_entry(); |
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| 182 | if (rml_code_dsc_index == 0) |
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| 183 | { |
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| 184 | /* not enough space in GDT */ |
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| 185 | descsPrepared = __DP_FAIL; |
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| 186 | return descsPrepared; |
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| 187 | } |
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| 188 | |
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| 189 | segment_descriptors flags_desc; |
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| 190 | memset(&flags_desc, 0, sizeof(flags_desc)); |
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| 191 | flags_desc.type = 0xE; /* bits 4 */ |
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| 192 | flags_desc.descriptor_type = 0x1; /* bits 1 */ |
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| 193 | flags_desc.privilege = 0x0; /* bits 2 */ |
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| 194 | flags_desc.present = 0x1; /* bits 1 */ |
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| 195 | flags_desc.available = 0x0; /* bits 1 */ |
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| 196 | flags_desc.fixed_value_bits = 0x0; /* bits 1 */ |
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| 197 | flags_desc.operation_size = 0x0; /* bits 1 */ |
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| 198 | flags_desc.granularity = 0x0; /* bits 1 */ |
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| 199 | i386_fill_segment_desc_base((unsigned)base32, &flags_desc); |
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| 200 | i386_fill_segment_desc_limit(rml_limit, &flags_desc); |
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| 201 | if (i386_raw_gdt_entry(rml_code_dsc_index, &flags_desc) == 0) |
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| 202 | { |
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| 203 | /* selector to GDT out of range */ |
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| 204 | descsPrepared = __DP_FAIL; |
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| 205 | return descsPrepared; |
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| 206 | } |
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| 207 | |
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| 208 | rml_data_dsc_index = i386_next_empty_gdt_entry(); |
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| 209 | if (rml_data_dsc_index == 0) |
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| 210 | { |
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| 211 | /* not enough space in GDT for both descriptors */ |
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| 212 | descsPrepared = __DP_FAIL; |
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| 213 | return descsPrepared; |
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| 214 | } |
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| 215 | |
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| 216 | flags_desc.type = 0x2; /* bits 4 */ |
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| 217 | if (i386_raw_gdt_entry(rml_data_dsc_index, &flags_desc) == 0) |
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| 218 | { |
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| 219 | /* selector to GDT out of range */ |
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| 220 | descsPrepared = __DP_FAIL; |
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| 221 | return descsPrepared; |
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| 222 | } |
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| 223 | prevBase = base32; |
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| 224 | descsPrepared = __DP_YES; |
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| 225 | return descsPrepared; |
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| 226 | } |
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| 227 | |
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| 228 | void *i386_get_default_rm_buffer(uint16_t *size) { |
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| 229 | *size = default_rm_buffer_size; |
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| 230 | return default_rm_buffer_spot; |
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| 231 | } |
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| 232 | |
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[d78eac6] | 233 | int i386_real_interrupt_call(uint8_t interrupt_number, |
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[586c86c7] | 234 | i386_realmode_interrupt_registers *ir) |
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| 235 | { |
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| 236 | uint32_t pagingon; |
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| 237 | rm_int_regs_bkp_param *int_passed_regs_spot; |
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| 238 | /* place where the code switching to realmode and executing |
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| 239 | interrupt is coppied */ |
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| 240 | void *rm_swtch_code_dst; |
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| 241 | void *rm_stack_top; |
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| 242 | |
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| 243 | size_t cpLength; |
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| 244 | void *cpBeg; |
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| 245 | |
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| 246 | /* values that can be passed from protected mode are stored in this struct |
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| 247 | and they are passed later to the inline assembler executing interrupt */ |
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| 248 | volatile pm_bkp_and_param pm_bkp, *pm_bkp_addr; |
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| 249 | unsigned short unused_offset; |
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| 250 | |
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| 251 | __asm__ volatile( "\t" |
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| 252 | "movl %%cr0, %%eax\n\t" |
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| 253 | "andl %1, %%eax\n" |
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| 254 | : "=a"(pagingon) |
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| 255 | : "i"(CR0_PAGING) |
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| 256 | ); |
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| 257 | if (pagingon) |
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| 258 | return 0; |
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| 259 | |
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| 260 | /* located under 1MB for real mode to be able to get/set values */ |
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| 261 | int_passed_regs_spot = (rm_int_regs_bkp_param *) |
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| 262 | (default_rm_buffer_spot+default_rm_buffer_size); |
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| 263 | /* position for real mode code reallocation to the first 1MB of RAM */ |
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| 264 | rm_swtch_code_dst = (void *)((uint32_t)int_passed_regs_spot + |
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| 265 | sizeof(*int_passed_regs_spot)); |
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| 266 | rm_stack_top = (void *)INT_STACK_TOP; |
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| 267 | |
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| 268 | if (prepareRMDescriptors(int_passed_regs_spot) != __DP_YES) |
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| 269 | return 0; |
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| 270 | |
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| 271 | pm_bkp_addr = &pm_bkp; |
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| 272 | i386_Physical_to_real( |
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| 273 | rm_stack_top - STACK_SIZE, |
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| 274 | (unsigned short *)&pm_bkp.rm_stack_segment, |
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| 275 | (unsigned short *)&pm_bkp.rm_stack_pointer |
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| 276 | ); |
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| 277 | pm_bkp.rm_stack_pointer += STACK_SIZE; |
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| 278 | pm_bkp.rml_code_selector = (rml_code_dsc_index<<3); |
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| 279 | pm_bkp.rml_entry = ((uint32_t)rm_swtch_code_dst - |
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| 280 | (uint32_t)int_passed_regs_spot); |
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| 281 | pm_bkp.rml_data_selector = (rml_data_dsc_index<<3); |
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| 282 | i386_Physical_to_real( |
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| 283 | int_passed_regs_spot, |
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| 284 | (unsigned short *)&pm_bkp.rm_data_segment, |
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| 285 | &unused_offset |
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| 286 | ); |
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| 287 | |
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| 288 | int_passed_regs_spot->inoutregs = *ir; |
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| 289 | /* offset from the beginning of coppied code */ |
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| 290 | uint16_t rm_entry_offset; |
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| 291 | __asm__ volatile( |
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| 292 | "movw $(rment-cp_beg), %0\n\t" |
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| 293 | : "=r"(rm_entry_offset) |
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| 294 | ); |
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| 295 | i386_Physical_to_real( |
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| 296 | rm_swtch_code_dst+rm_entry_offset, |
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| 297 | (unsigned short *)&int_passed_regs_spot->rm_code_segment, |
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| 298 | (unsigned short *)&int_passed_regs_spot->rm_entry |
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| 299 | ); |
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| 300 | __asm__ volatile( |
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| 301 | "movl $(cp_end), %0\n\t" |
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| 302 | "movw %%cs, %1\n\t" |
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| 303 | : "=mr"(int_passed_regs_spot->pm_entry), |
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| 304 | "=mr"(int_passed_regs_spot->pm_code_selector) |
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| 305 | ); |
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| 306 | /* copy code for switch to real mode and |
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| 307 | executing interrupt to first MB of RAM */ |
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| 308 | __asm__ volatile( "\t" |
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| 309 | "mov $cp_end-cp_beg, %0\n\t" |
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| 310 | "mov $cp_beg, %1\n\t" |
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| 311 | : "=rm"(cpLength), "=rm"(cpBeg) |
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| 312 | ); |
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| 313 | memcpy(rm_swtch_code_dst, cpBeg, cpLength); |
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| 314 | /* write interrupt number to be executed */ |
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| 315 | uint16_t interrupt_number_off; |
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| 316 | uint8_t *interrupt_number_ptr; |
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| 317 | __asm__ volatile( "\t" |
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| 318 | "movw $intnum-cp_beg, %0\n\t" |
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| 319 | : "=rm"(interrupt_number_off) |
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| 320 | ); |
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| 321 | interrupt_number_ptr = (uint8_t *)(rm_swtch_code_dst+interrupt_number_off); |
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[d78eac6] | 322 | *interrupt_number_ptr = interrupt_number; |
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[586c86c7] | 323 | /* execute code that jumps to coppied function, which switches to real mode, |
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| 324 | loads registers with values passed to interrupt and executes interrupt */ |
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| 325 | __asm__ volatile( "\t" |
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| 326 | /* backup stack */ |
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| 327 | "movl %[regs_spot], %%ebx\n\t" |
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| 328 | "movl %%esp, "BKP_ESP_OFF"(%%ebx)\n\t" |
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| 329 | "movw %%ss, "BKP_SS_OFF"(%%ebx)\n\t" |
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| 330 | /* backup data selector */ |
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| 331 | "movw %%ds, "BKP_DS_OFF"(%%ebx)\n\t" |
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| 332 | /* backup other selectors */ |
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| 333 | "movl %[pm_bkp], %%esi\n\t" |
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| 334 | "movw %%es, "BKP_ES_OFF"(%%esi)\n\t" |
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| 335 | "movw %%fs, "BKP_FS_OFF"(%%esi)\n\t" |
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| 336 | "movw %%gs, "BKP_GS_OFF"(%%esi)\n\t" |
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| 337 | /* hopefully loader does not damage interrupt table on the beginning of |
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| 338 | memory; that means length: 0x3FF, base: 0x0 */ |
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| 339 | /* preserve idtr */ |
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| 340 | "movl %%esi, %%eax\n\t" |
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| 341 | "addl $"BKP_IDTR_LIM", %%eax\n\t" |
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| 342 | "cli\n\t" |
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| 343 | "sidt (%%eax)\n\t" |
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| 344 | "movl $rmidt, %%eax\n\t" |
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| 345 | "lidt (%%eax)\n\t" |
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| 346 | /* prepare 'real mode like' data selector */ |
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| 347 | "movw "RML_D_SEL"(%%esi), %%ax\n\t" |
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| 348 | /* prepare real mode data segment value */ |
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| 349 | "xorl %%edx,%%edx\n\t" |
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| 350 | "movw "RM_DS"(%%esi), %%dx\n\t" |
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| 351 | /* prepare real mode stack values */ |
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| 352 | "movw "RM_SS"(%%esi), %%cx\n\t" |
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| 353 | "movzwl "RM_SP"(%%esi), %%esp\n\t" |
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| 354 | /* jump to copied function and */ |
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| 355 | /* load 'real mode like' code selector */ |
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| 356 | "ljmp *"RML_ENTRY"(%%esi)\n" |
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| 357 | "rmidt:"/* limit and base for realmode interrupt descriptor table */ |
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| 358 | ".word 0x3FF\n\t" |
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| 359 | ".long 0\n\t" |
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| 360 | /* load 'real mode like' data selectors */ |
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| 361 | "cp_beg: .code16\n\t" |
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| 362 | "movw %%ax, %%ss\n\t" |
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| 363 | "movw %%ax, %%ds\n\t" |
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| 364 | "movw %%ax, %%es\n\t" |
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| 365 | "movw %%ax, %%fs\n\t" |
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| 366 | "movw %%ax, %%gs\n\t" |
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| 367 | /* disable protected mode */ |
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| 368 | "movl %%cr0, %%eax\n\t" |
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| 369 | "and %[cr0_prot_dis], %%ax\n\t" |
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| 370 | "movl %%eax, %%cr0\n\t" |
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| 371 | /* base for data selector of 16-bit protected mode is |
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| 372 | at beginning of passed regs */ |
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| 373 | /* flush prefetch queue by far jumping */ |
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| 374 | "ljmp *"RM_ENTRY"\n\t" |
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| 375 | "rment: " |
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| 376 | /* establish rm stack - esp was already set in 32-bit protected mode*/ |
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| 377 | "movw %%cx, %%ss\n\t" |
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| 378 | /* set data segment (value prepared in 32-bit prot mode) */ |
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| 379 | "movw %%dx, %%ds\n\t" |
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| 380 | /* count real mode pointer so we don't need to overuse address |
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| 381 | prefix (by using 32bit addresses in 16bit context) */ |
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| 382 | "shll $4,%%edx\n\t" |
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| 383 | "subl %%edx,%%ebx\n\t" |
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| 384 | /* prepare values to be used after interrupt call */ |
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| 385 | "pushw %%bx\n\t" |
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| 386 | "pushw %%ds\n\t" |
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| 387 | /* fill registers with parameters */ |
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| 388 | "movw " IR_DS_OFF"(%%bx), %%ax\n\t" |
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| 389 | "pushw %%ax\n\t" |
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| 390 | "movl "IR_EAX_OFF"(%%bx), %%eax\n\t" |
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| 391 | "movl "IR_ECX_OFF"(%%bx), %%ecx\n\t" |
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| 392 | "movl "IR_EDX_OFF"(%%bx), %%edx\n\t" |
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| 393 | "movl "IR_EDI_OFF"(%%bx), %%edi\n\t" |
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| 394 | "movl "IR_ESI_OFF"(%%bx), %%esi\n\t" |
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| 395 | "movw " IR_ES_OFF"(%%bx), %%es\n\t" |
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| 396 | "movw " IR_FS_OFF"(%%bx), %%fs\n\t" |
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| 397 | "movw " IR_GS_OFF"(%%bx), %%gs\n\t" |
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| 398 | /* prepare ebx register */ |
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| 399 | "movl "IR_EBX_OFF"(%%bx), %%ebx\n\t" |
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| 400 | /* prepare ds */ |
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| 401 | "popw %%ds\n\t" |
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| 402 | /* interrupt instruction */ |
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| 403 | ".byte 0xCD\n\t" |
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| 404 | "intnum: .byte 0x0\n\t" |
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| 405 | /* fill return structure */ |
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| 406 | "pushw %%ds\n\t" |
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| 407 | "pushl %%ebx\n\t" |
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| 408 | "movw 0x6(%%esp), %%ds\n\t" |
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| 409 | "movw 0x8(%%esp),%%bx\n\t" /* regs_spot */ |
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| 410 | "movl %%eax,"IR_EAX_OFF"(%%bx)\n\t" |
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| 411 | "popl %%eax\n\t" |
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| 412 | "movl %%eax,"IR_EBX_OFF"(%%bx)\n\t" |
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| 413 | "movl %%ecx,"IR_ECX_OFF"(%%bx)\n\t" |
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| 414 | "movl %%edx,"IR_EDX_OFF"(%%bx)\n\t" |
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| 415 | "movl %%esi,"IR_ESI_OFF"(%%bx)\n\t" |
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| 416 | "movl %%edi,"IR_EDI_OFF"(%%bx)\n\t" |
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| 417 | "popw %%ax\n\t" |
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| 418 | "movw %%ax, " IR_DS_OFF"(%%bx)\n\t" |
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| 419 | "movw %%es, " IR_ES_OFF"(%%bx)\n\t" |
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| 420 | "movw %%fs, " IR_FS_OFF"(%%bx)\n\t" |
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| 421 | "movw %%gs, " IR_GS_OFF"(%%bx)\n\t" |
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| 422 | /* prepare protected mode data segment */ |
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| 423 | "movw "BKP_DS_OFF"(%%bx), %%ax\n\t" |
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| 424 | /* restore protected mode stack values */ |
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| 425 | "movl "BKP_ESP_OFF"(%%bx),%%esp\n\t" |
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| 426 | "movw "BKP_SS_OFF"(%%bx), %%dx\n\t" |
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| 427 | /* return to protected mode */ |
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| 428 | "movl %%cr0, %%ecx \n\t" |
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| 429 | "or %[cr0_prot_ena], %%cx\n\t" |
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| 430 | "movl %%ecx, %%cr0 \n\t" |
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| 431 | "ljmpl *"PM_ENTRY"(%%bx)\n\t" |
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| 432 | ".code32\n" |
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| 433 | /* reload segmentation registers */ |
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| 434 | "cp_end:" |
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| 435 | "movw %%ax, %%ds\n\t" |
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| 436 | /* restore stack segment in protected mode context */ |
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| 437 | "movw %%dx, %%ss\n\t" |
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| 438 | "movl %[pm_bkp], %%esi\n\t" |
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| 439 | "movw "BKP_ES_OFF"(%%esi), %%es\n\t" |
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| 440 | "movw "BKP_FS_OFF"(%%esi), %%fs\n\t" |
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| 441 | "movw "BKP_GS_OFF"(%%esi), %%gs\n\t" |
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| 442 | /* restore IDTR */ |
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| 443 | "addl $"BKP_IDTR_LIM", %%esi\n\t" |
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| 444 | "lidt (%%esi)\n\t" |
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| 445 | : |
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| 446 | : [regs_spot]"m"(int_passed_regs_spot), |
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| 447 | [pm_bkp]"m"(pm_bkp_addr), |
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| 448 | [cr0_prot_ena]"i"(CR0_PROTECTION_ENABLE), |
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| 449 | [cr0_prot_dis]"i"(~CR0_PROTECTION_ENABLE) |
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| 450 | : "memory", "ebx", "ecx", "edx", "esi", "edi" |
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| 451 | ); |
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| 452 | *ir = int_passed_regs_spot->inoutregs; |
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| 453 | return 1; |
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| 454 | } |
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