On Tue, Nov 18, 2014 at 10:47 AM, Jan Dolezal <dolez...@fel.cvut.cz> wrote:
>
> On 12.11.2014 16:54, Gedare Bloom wrote:
>>
>> On Wed, Nov 12, 2014 at 10:07 AM, Jan Dolezal <dolez...@fel.cvut.cz>
>> wrote:
>>>
>>> ---
>>> c/src/lib/libbsp/i386/pc386/Makefile.am | 2 +
>>> c/src/lib/libbsp/i386/pc386/preinstall.am | 4 +
>>> c/src/lib/libbsp/i386/shared/int16/int16.c | 397
>>> +++++++++++++++++++++++++++++
>>> c/src/lib/libbsp/i386/shared/int16/int16.h | 93 +++++++
>>> 4 files changed, 496 insertions(+)
>>> create mode 100644 c/src/lib/libbsp/i386/shared/int16/int16.c
>>> create mode 100644 c/src/lib/libbsp/i386/shared/int16/int16.h
>>
>> These new files should probably go under i386/shared/irq ?
>
> I am using i386/shared/realmode_int/realmode_int.* now as suggested
> in conversation with Mr. Pisa
>
>
>>
>>>
>>> diff --git a/c/src/lib/libbsp/i386/pc386/Makefile.am
>>> b/c/src/lib/libbsp/i386/pc386/Makefile.am
>>> index 9c901df..6042b5b 100644
>>> --- a/c/src/lib/libbsp/i386/pc386/Makefile.am
>>> +++ b/c/src/lib/libbsp/i386/pc386/Makefile.am
>>> @@ -29,6 +29,7 @@ SUBDIRS = . tools
>>> include_bsp_HEADERS = ../../i386/shared/irq/irq.h
>>> include_bsp_HEADERS += ../../i386/shared/irq/irq_asm.h
>>> include_bsp_HEADERS += ../../i386/shared/comm/tty_drv.h
>>> +include_bsp_HEADERS += ../../i386/shared/int16/int16.h
>>> include_bsp_HEADERS += ../../shared/include/irq-generic.h
>>> include_bsp_HEADERS += ../../shared/include/irq-info.h
>>> include_bsp_HEADERS += console/rtd316.h
>>> @@ -94,6 +95,7 @@ libbsp_a_SOURCES += console/kbd_parser.c
>>> libbsp_a_SOURCES += console/serial_mouse_config.c
>>> libbsp_a_SOURCES += ../../i386/shared/comm/uart.c
>>> libbsp_a_SOURCES += ../../i386/shared/comm/tty_drv.c
>>> +libbsp_a_SOURCES += ../../i386/shared/int16/int16.c
>>> libbsp_a_SOURCES += ../../shared/console.c
>>> libbsp_a_SOURCES += console/console_select.c
>>> libbsp_a_SOURCES += ../../shared/console_read.c
>>> diff --git a/c/src/lib/libbsp/i386/pc386/preinstall.am
>>> b/c/src/lib/libbsp/i386/pc386/preinstall.am
>>> index aff01dc..1ff9fb8 100644
>>> --- a/c/src/lib/libbsp/i386/pc386/preinstall.am
>>> +++ b/c/src/lib/libbsp/i386/pc386/preinstall.am
>>> @@ -69,6 +69,10 @@ $(PROJECT_INCLUDE)/bsp/tty_drv.h:
>>> ../../i386/shared/comm/tty_drv.h $(PROJECT_INC
>>> $(INSTALL_DATA) $< $(PROJECT_INCLUDE)/bsp/tty_drv.h
>>> PREINSTALL_FILES += $(PROJECT_INCLUDE)/bsp/tty_drv.h
>>>
>>> +$(PROJECT_INCLUDE)/bsp/int16.h: ../../i386/shared/int16/int16.h
>>> $(PROJECT_INCLUDE)/bsp/$(dirstamp)
>>> + $(INSTALL_DATA) $< $(PROJECT_INCLUDE)/bsp/int16.h
>>> +PREINSTALL_FILES += $(PROJECT_INCLUDE)/bsp/int16.h
>>> +
>>> $(PROJECT_INCLUDE)/bsp/irq-generic.h:
>>> ../../shared/include/irq-generic.h $(PROJECT_INCLUDE)/bsp/$(dirstamp)
>>> $(INSTALL_DATA) $< $(PROJECT_INCLUDE)/bsp/irq-generic.h
>>> PREINSTALL_FILES += $(PROJECT_INCLUDE)/bsp/irq-generic.h
>>> diff --git a/c/src/lib/libbsp/i386/shared/int16/int16.c
>>> b/c/src/lib/libbsp/i386/shared/int16/int16.c
>>> new file mode 100644
>>> index 0000000..380188f
>>> --- /dev/null
>>> +++ b/c/src/lib/libbsp/i386/shared/int16/int16.c
>>> @@ -0,0 +1,397 @@
>>> +/*
>>> + * Realmode interrupt call implementation.
>>> + *
>>> + *
>>> + * Copyright (c) 2014 - CTU in Prague
>>> + * Jan Doležal ( dolez...@fel.cvut.cz )
>>> + *
>>> + * The license and distribution terms for this file may be
>>> + * found in the file LICENSE in this distribution or at
>>> + * http://www.rtems.org/license/LICENSE.
>>> + *
>>> + */
>>> +
>>> +#include <bsp/int16.h>
>>> +#include <string.h>
>>
>> Why include string.h?
>
> It is here because later there are used functions memset() and memcpy(),
> which have their prototypes in string.h
>
>>
>> I have more comments below in the .h file. I am not reviewing this .c
>> file due to time constraints and my lack of confidence in x86
>> assembly, but I will say if the below macros and struct defines are
>> useful outside this file, then they should go into a header file
>> instead. Also, I think we use __volatile__ for declaring ASM blocks.
>> (We ought to have an RTEMS macro for this, e.g. RTEMS_INLINE_ASM(),
>> but I don't think we do.)
>
> I don't think these macros are useful outside, they are used in inline
> asm and defined only for better readability of the inline asm.
>
> Quick grep over whole rtems source directory shows that
> '__asm__ __volatile__' is used ~110 times and
> '__asm__ volatile' is used ~680 times, but if __volatile__ is a better
> choice I will gladly use that one.
>
I guess it may not matter then.
>
>>
>>> +#include <rtems/score/cpu.h>
>>> +
>>> +#define IR_EAX_OFF "0x00"
>>> +#define IR_EBX_OFF "0x04"
>>> +#define IR_ECX_OFF "0x08"
>>> +#define IR_EDX_OFF "0x0C"
>>> +#define IR_ESI_OFF "0x10"
>>> +#define IR_EDI_OFF "0x14"
>>> +#define IR_DS_OFF "0x18"
>>> +#define IR_ES_OFF "0x1A"
>>> +#define IR_FS_OFF "0x1C"
>>> +#define IR_GS_OFF "0x1E"
>>> +
>>> +#define BKP_ESP_OFF "0x20"
>>> +#define BKP_SS_OFF "0x24"
>>> +#define BKP_DS_OFF "0x26"
>>> +#define RM_ENTRY "0x28"
>>> +#define PM_ENTRY "0x2C"
>>> +
>>> +/* parameters, results, backup values accessible in real mode */
>>> +struct rm_int_regs_bkp_param {
>>> + struct interrupt_registers inoutregs;
>>> + uint32_t pm_esp_bkp;
>>> + uint16_t pm_ss_bkp;
>>> + uint16_t ds_bkp;
>>> + uint16_t rm_entry;
>>> + uint16_t rm_code_segment;
>>> + uint32_t pm_entry;
>>> + uint16_t pm_code_selector;
>>> + /* if modifying update offset definitions as well */
>>> +}__attribute__((__packed__));
>>> +
>>> +#define BKP_IDTR_LIM "0x00"
>>> +#define BKP_IDTR_BASE "0x02"
>>> +#define BKP_ES_OFF "0x06"
>>> +#define BKP_FS_OFF "0x08"
>>> +#define BKP_GS_OFF "0x0A"
>>> +#define RML_ENTRY "0x0C"
>>> +#define RML_D_SEL "0x12"
>>> +#define RM_SS "0x14"
>>> +#define RM_SP "0x16"
>>> +#define RM_DS "0x18"
>>> +/* backup values, pointers/parameters accessible in protected mode */
>>> +struct pm_bkp_and_param {
>>> + uint16_t idtr_lim_bkp;
>>> + uint32_t idtr_base_bkp;
>>> + uint16_t es_bkp;
>>> + uint16_t fs_bkp;
>>> + uint16_t gs_bkp;
>>> + uint32_t rml_entry;
>>> + uint16_t rml_code_selector;
>>> + uint16_t rml_data_selector;
>>> + uint16_t rm_stack_segment;
>>> + uint16_t rm_stack_pointer;
>>> + uint16_t rm_data_segment;
>>> +}__attribute__((__packed__));
>>> +
>>> +/* addresses where we are going to put Interrupt buffer,
>>> + * parameter/returned/preserved values, stack and copy code
>>> + * for calling BIOS interrupt real mode interface
>>> + * The value is chosen arbitrarily in the first 640kB
>>> + * to be accessible for real mode. It should be out of range
>>> + * used by RTEMS because its base address is above 1MB.
>>> + * It has to be above first 4kB (or better 64kB) which could
>>> + * be used by BIOS.
>>> + */
>>> +#define REAL_MODE_SPOT 0x12000
>>> +/* REAL_MODE_SPOT value is also top of real mode stack */
>>> +
>>> +/* buffers positions and lengths */
>>> +#define DEFAULT_BUFFER_SIZE 512
>>> +static void *first_rm_buffer_spot = (void *)REAL_MODE_SPOT;
>>> +static uint16_t first_rm_buffer_size = DEFAULT_BUFFER_SIZE;
>>> +
>>> +/* real mode stack */
>>> +#define STACK_SIZE 8192
>>> +#define INT_STACK_TOP REAL_MODE_SPOT
>>> +
>>> +/******************************
>>> + * STACK * *
>>> + ****************************** REAL_MODE_SPOT
>>> + * INT_BUF * 512 B *
>>> + ******************************
>>> + * INT_REGs * 50 B *
>>> + ******************************
>>> + * INT_FNC *~149 B *
>>> + ******************************/
>>> +
>>> +#define __DP_TYPE uint8_t
>>> +#define __DP_YES ((__DP_TYPE)1)
>>> +#define __DP_NO ((__DP_TYPE)-1)
>>> +#define __DP_FAIL ((__DP_TYPE)0)
>>> +static __DP_TYPE descsPrepared = __DP_NO;
>>> +
>>> +/* rml - real mode alike */
>>> +#define rml_limit 0xFFFF
>>> +static uint16_t rml_code_dsc_index = 0;
>>> +static uint16_t rml_data_dsc_index = 0;
>>> +
>>> +/*
>>> + * Prepares real-mode like descriptors to be used for switching
>>> + * to real mode.
>>> + *
>>> + * @return __DP_YES descriptors are prepared
>>> + * @return __DP_FAIL descriptors allocation failed (GDT too small)
>>> + */
>>> +static __DP_TYPE prepareRMDescriptors (void *base32) {
>>> + static void *prevBase = (void *)-1;
>>> + /* check if descriptors were prepared already */
>>> + if (descsPrepared == __DP_YES && prevBase == base32)
>>> + return descsPrepared;
>>> +
>>> + if (descsPrepared == __DP_FAIL)
>>> + return descsPrepared;
>>> +
>>> + /* create 'real mode like' segment descriptors, for switching to
>>> real mode */
>>> + rml_code_dsc_index = i386_next_empty_gdt_entry();
>>> + if (rml_code_dsc_index == 0)
>>> + {
>>> + /* not enough space in GDT */
>>> + descsPrepared = __DP_FAIL;
>>> + return descsPrepared;
>>> + }
>>> +
>>> + segment_descriptors flags_desc;
>>> + memset(&flags_desc, 0, sizeof(flags_desc));
>>> + flags_desc.type = 0xE; /* bits 4 */
>>> + flags_desc.descriptor_type = 0x1; /* bits 1 */
>>> + flags_desc.privilege = 0x0; /* bits 2 */
>>> + flags_desc.present = 0x1; /* bits 1 */
>>> + flags_desc.available = 0x0; /* bits 1 */
>>> + flags_desc.fixed_value_bits = 0x0; /* bits 1 */
>>> + flags_desc.operation_size = 0x0; /* bits 1 */
>>> + flags_desc.granularity = 0x0; /* bits 1 */
>>> + i386_fill_segment_desc_base((unsigned)base32, &flags_desc);
>>> + i386_fill_segment_desc_limit(rml_limit, &flags_desc);
>>> + if (i386_raw_gdt_entry(rml_code_dsc_index, &flags_desc) == 0)
>>> + {
>>> + /* selector to GDT out of range */
>>> + descsPrepared = __DP_FAIL;
>>> + return descsPrepared;
>>> + }
>>> +
>>> + rml_data_dsc_index = i386_next_empty_gdt_entry();
>>> + if (rml_data_dsc_index == 0)
>>> + {
>>> + /* not enough space in GDT for both descriptors */
>>> + descsPrepared = __DP_FAIL;
>>> + return descsPrepared;
>>> + }
>>> +
>>> + flags_desc.type = 0x2; /* bits 4 */
>>> + if (i386_raw_gdt_entry(rml_data_dsc_index, &flags_desc) == 0)
>>> + {
>>> + /* selector to GDT out of range */
>>> + descsPrepared = __DP_FAIL;
>>> + return descsPrepared;
>>> + }
>>> + prevBase = base32;
>>> + descsPrepared = __DP_YES;
>>> + return descsPrepared;
>>> +}
>>> +
>>> +inline void *i386_get_primary_rm_buffer() {
>>> + return first_rm_buffer_spot;
>>> +}
>>> +
>>> +inline uint16_t i386_get_primary_rm_buffer_size() {
>>> + return first_rm_buffer_size;
>>> +}
>>> +
>>> +int i386_real_interrupt_call(uint8_t interruptNumber, struct
>>> interrupt_registers *ir){
>>> + uint32_t pagingon;
>>> + struct rm_int_regs_bkp_param *int_passed_regs_spot;
>>> + /* place where the code switching to realmode and executing
>>> + interrupt is coppied */
>>> + void *rm_swtch_code_dst;
>>> + void *rm_stack_top;
>>> +
>>> + size_t cpLength;
>>> + void *cpBeg;
>>> +
>>> + /* values that can be passed from protected mode are stored in this
>>> struct
>>> + and they are passed later to the inline assembler executing
>>> interrupt */
>>> + volatile struct pm_bkp_and_param pm_bkp, *pm_bkp_addr;
>>> + unsigned short unused_offset;
>>> +
>>> + __asm__ volatile( "\t"
>>> + "movl %%cr0, %%eax\n\t"
>>> + "andl %1, %%eax\n"
>>> + : "=a"(pagingon)
>>> + : "i"(CR0_PAGING)
>>> + );
>>> + if (pagingon)
>>> + return 0;
>>> +
>>> + /* located under 1MB for real mode to be able to get/set values */
>>> + int_passed_regs_spot = (struct rm_int_regs_bkp_param *)
>>> +
>>> (first_rm_buffer_spot+first_rm_buffer_size);
>>> + /* position for real mode code reallocation to the first 1MB of RAM
>>> */
>>> + rm_swtch_code_dst = (void
>>> *)((uint32_t)int_passed_regs_spot+sizeof(*int_passed_regs_spot));
>>> + rm_stack_top = (void *)INT_STACK_TOP;
>>> +
>>> + if (prepareRMDescriptors(int_passed_regs_spot) != __DP_YES)
>>> + return 0;
>>> +
>>> + pm_bkp_addr = &pm_bkp;
>>> + i386_Physical_to_real_mode_ptr(
>>> + rm_stack_top - STACK_SIZE,
>>> + (unsigned short *)&pm_bkp.rm_stack_segment,
>>> + (unsigned short *)&pm_bkp.rm_stack_pointer
>>> + );
>>> + pm_bkp.rm_stack_pointer += STACK_SIZE;
>>> + pm_bkp.rml_code_selector = (rml_code_dsc_index<<3);
>>> + pm_bkp.rml_entry =
>>> ((uint32_t)rm_swtch_code_dst-(uint32_t)int_passed_regs_spot);
>>> + pm_bkp.rml_data_selector = (rml_data_dsc_index<<3);
>>> + i386_Physical_to_real_mode_ptr(
>>> + int_passed_regs_spot,
>>> + (unsigned short *)&pm_bkp.rm_data_segment,
>>> + &unused_offset
>>> + );
>>> +
>>> + int_passed_regs_spot->inoutregs = *ir;
>>> + /* offset from the beginning of coppied code */
>>> + uint16_t rm_entry_offset;
>>> + __asm__ volatile(
>>> + "movw $(rment-cp_beg), %0\n\t"
>>> + : "=r"(rm_entry_offset)
>>> + );
>>> + i386_Physical_to_real_mode_ptr(
>>> + rm_swtch_code_dst+rm_entry_offset,
>>> + (unsigned short *)&int_passed_regs_spot->rm_code_segment,
>>> + (unsigned short *)&int_passed_regs_spot->rm_entry
>>> + );
>>> + __asm__ volatile(
>>> + "movl $(cp_end), %0\n\t"
>>> + "movw %%cs, %1\n\t"
>>> + : "=mr"(int_passed_regs_spot->pm_entry),
>>> "=mr"(int_passed_regs_spot->pm_code_selector)
>>> + );
>>> + /* copy code for switch to real mode and executing interrupt to
>>> first MB of RAM */
>>> + __asm__ volatile( "\t"
>>> + "mov $cp_end-cp_beg, %0\n\t"
>>> + "mov $cp_beg, %1\n\t"
>>> + : "=rm"(cpLength), "=rm"(cpBeg)
>>> + );
>>> + memcpy(rm_swtch_code_dst, cpBeg, cpLength);
>>> + /* write interrupt number to be executed */
>>> + uint16_t interrupt_number_off;
>>> + uint8_t *interrupt_number_ptr;
>>> + __asm__ volatile( "\t"
>>> + "movw $intnum-cp_beg, %0\n\t"
>>> + : "=rm"(interrupt_number_off)
>>> + );
>>> + interrupt_number_ptr = (uint8_t *)
>>> (rm_swtch_code_dst+interrupt_number_off);
>>> + *interrupt_number_ptr = interruptNumber;
>>> + /* execute code that jumps to coppied function, which switches to
>>> real mode,
>>> + loads registers with values passed to interrupt and executes
>>> interrupt */
>>> + __asm__ volatile( "\t"
>>> + /* backup stack */
>>> + "movl %[regs_spot], %%ebx\n\t"
>>> + "movl %%esp, "BKP_ESP_OFF"(%%ebx)\n\t"
>>> + "movw %%ss, "BKP_SS_OFF"(%%ebx)\n\t"
>>> + /* backup data selector */
>>> + "movw %%ds, "BKP_DS_OFF"(%%ebx)\n\t"
>>> + /* backup other selectors */
>>> + "movl %[pm_bkp], %%esi\n\t"
>>> + "movw %%es, "BKP_ES_OFF"(%%esi)\n\t"
>>> + "movw %%fs, "BKP_FS_OFF"(%%esi)\n\t"
>>> + "movw %%gs, "BKP_GS_OFF"(%%esi)\n\t"
>>> + /* hopefully loader does not damage interrupt table on the
>>> beginning of memory; that means length: 0x3FF, base: 0x0 */
>>> + /* preserve idtr */
>>> + "movl %%esi, %%eax\n\t"
>>> + "addl $"BKP_IDTR_LIM", %%eax\n\t"
>>> + "cli\n\t"
>>> + "sidt (%%eax)\n\t"
>>> + "movl $rmidt, %%eax\n\t"
>>> + "lidt (%%eax)\n\t"
>>> + /* prepare 'real mode like' data selector */
>>> + "movw "RML_D_SEL"(%%esi), %%ax\n\t"
>>> + /* prepare real mode data segment value */
>>> + "xorl %%edx,%%edx\n\t"
>>> + "movw "RM_DS"(%%esi), %%dx\n\t"
>>> + /* prepare real mode stack values */
>>> + "movw "RM_SS"(%%esi), %%cx\n\t"
>>> + "movzwl "RM_SP"(%%esi), %%esp\n\t"
>>> + /* jump to copied function and */
>>> + /* load 'real mode like' code selector */
>>> + "ljmp *"RML_ENTRY"(%%esi)\n"
>>> +"rmidt:"/* limit and base for realmode interrupt descriptor table */
>>> + ".word 0x3FF\n\t"
>>> + ".long 0\n\t"
>>> + /* load 'real mode like' data selectors */
>>> +"cp_beg: .code16\n\t"
>>> + "movw %%ax, %%ss\n\t"
>>> + "movw %%ax, %%ds\n\t"
>>> + "movw %%ax, %%es\n\t"
>>> + "movw %%ax, %%fs\n\t"
>>> + "movw %%ax, %%gs\n\t"
>>> + /* disable protected mode */
>>> + "movl %%cr0, %%eax\n\t"
>>> + "and %[cr0_prot_dis], %%ax\n\t"
>>> + "movl %%eax, %%cr0\n\t"
>>> + /* base for data selector of 16-bit protected mode is at
>>> beginning of passed regs */
>>> + /* flush prefetch queue by far jumping */
>>> + "ljmp *"RM_ENTRY"\n\t"
>>> +"rment: "
>>> + /* establish rm stack - esp was already set in 32-bit protected
>>> mode*/
>>> + "movw %%cx, %%ss\n\t"
>>> + /* set data segment (value prepared in 32-bit prot mode) */
>>> + "movw %%dx, %%ds\n\t"
>>> + /* count real mode pointer so we don't need to overuse address
>>> prefix (by using 32bit address) */
>>> + "shll $4,%%edx\n\t"
>>> + "subl %%edx,%%ebx\n\t"
>>> + /* prepare values to be used after interrupt call */
>>> + "pushw %%bx\n\t"
>>> + "pushw %%ds\n\t"
>>> + /* fill registers with parameters */
>>> + "movw " IR_DS_OFF"(%%bx), %%ax\n\t"
>>> + "pushw %%ax\n\t"
>>> + "movl "IR_EAX_OFF"(%%bx), %%eax\n\t"
>>> + "movl "IR_ECX_OFF"(%%bx), %%ecx\n\t"
>>> + "movl "IR_EDX_OFF"(%%bx), %%edx\n\t"
>>> + "movl "IR_EDI_OFF"(%%bx), %%edi\n\t"
>>> + "movl "IR_ESI_OFF"(%%bx), %%esi\n\t"
>>> + "movw " IR_ES_OFF"(%%bx), %%es\n\t"
>>> + "movw " IR_FS_OFF"(%%bx), %%fs\n\t"
>>> + "movw " IR_GS_OFF"(%%bx), %%gs\n\t"
>>> + /* prepare ebx register */
>>> + "movl "IR_EBX_OFF"(%%bx), %%ebx\n\t"
>>> + /* prepare ds */
>>> + "popw %%ds\n\t"
>>> + /* interrupt instruction */
>>> + ".byte 0xCD\n\t"
>>> +"intnum: .byte 0x0\n\t"
>>> + /* fill return structure */
>>> + "pushw %%ds\n\t"
>>> + "pushl %%ebx\n\t"
>>> + "movw 0x6(%%esp), %%ds\n\t"
>>> + "movw 0x8(%%esp),%%bx\n\t" /* regs_spot */
>>> + "movl %%eax,"IR_EAX_OFF"(%%bx)\n\t"
>>> + "popl %%eax\n\t"
>>> + "movl %%eax,"IR_EBX_OFF"(%%bx)\n\t"
>>> + "movl %%ecx,"IR_ECX_OFF"(%%bx)\n\t"
>>> + "movl %%edx,"IR_EDX_OFF"(%%bx)\n\t"
>>> + "movl %%esi,"IR_ESI_OFF"(%%bx)\n\t"
>>> + "movl %%edi,"IR_EDI_OFF"(%%bx)\n\t"
>>> + "popw %%ax\n\t"
>>> + "movw %%ax, " IR_DS_OFF"(%%bx)\n\t"
>>> + "movw %%es, " IR_ES_OFF"(%%bx)\n\t"
>>> + "movw %%fs, " IR_FS_OFF"(%%bx)\n\t"
>>> + "movw %%gs, " IR_GS_OFF"(%%bx)\n\t"
>>> + /* prepare protected mode data segment */
>>> + "movw "BKP_DS_OFF"(%%bx), %%ax\n\t"
>>> + /* restore protected mode stack values */
>>> + "movl "BKP_ESP_OFF"(%%bx),%%esp\n\t"
>>> + "movw "BKP_SS_OFF"(%%bx), %%dx\n\t"
>>> + /* return to protected mode */
>>> + "movl %%cr0, %%ecx \n\t"
>>> + "or %[cr0_prot_ena], %%cx\n\t"
>>> + "movl %%ecx, %%cr0 \n\t"
>>> + "ljmpl *"PM_ENTRY"(%%bx)\n\t"
>>> + ".code32\n"
>>> + /* reload segmentation registers */
>>> +"cp_end:"
>>> + "movw %%ax, %%ds\n\t"
>>> + /* restore stack segment in protected mode context */
>>> + "movw %%dx, %%ss\n\t"
>>> + "movl %[pm_bkp], %%esi\n\t"
>>> + "movw "BKP_ES_OFF"(%%esi), %%es\n\t"
>>> + "movw "BKP_FS_OFF"(%%esi), %%fs\n\t"
>>> + "movw "BKP_GS_OFF"(%%esi), %%gs\n\t"
>>> + /* restore IDTR */
>>> + "addl $"BKP_IDTR_LIM", %%esi\n\t"
>>> + "lidt (%%esi)\n\t"
>>> + :
>>> + : [regs_spot]"m"(int_passed_regs_spot),
>>> [pm_bkp]"m"(pm_bkp_addr), [cr0_prot_ena]"i"(CR0_PROTECTION_ENABLE),
>>> [cr0_prot_dis]"i"(~CR0_PROTECTION_ENABLE)
>>> + : "memory", "ebx", "ecx", "edx", "esi", "edi"
>>> + );
>>> + *ir = int_passed_regs_spot->inoutregs;
>>> + return 1;
>>> +}
>>> +
>>> diff --git a/c/src/lib/libbsp/i386/shared/int16/int16.h
>>> b/c/src/lib/libbsp/i386/shared/int16/int16.h
>>> new file mode 100644
>>> index 0000000..96025ef
>>> --- /dev/null
>>> +++ b/c/src/lib/libbsp/i386/shared/int16/int16.h
>>> @@ -0,0 +1,93 @@
>>> +/**
>>> + * @file int16.h
>>> + *
>>> + * @ingroup i386_shared
>>> + *
>>> + * @brief Definitioins supporting real mode interrupt calls.
>>> + */
>>> +
>>> +/*
>>> + * Interface allows calling given interrupt number with content of the
>>> + * registers defined. For passing or receiving higher amounts of the
>>> data
>>> + * there is a buffer accessible from real mode available. Real mode
>>> pointer
>>> + * to this buffer is passed to the interrupt in the registers.
>>> + *
>>> + * Copyright (C) 2014 Jan Doležal (dolez...@fel.cvut.cz)
>>> + * CTU in Prague.
>>> + *
>>> + * The license and distribution terms for this file may be
>>> + * found in the file LICENSE in this distribution or at
>>> + * http://www.rtems.org/license/LICENSE.
>>> + */
>>> +
>>> +#ifndef _INT16_H
>>> +#define _INT16_H
>>> +
>>> +#include <libcpu/cpu.h>
>>> +#include <stdint.h>
>>> +
>>> +#ifndef ASM /* ASM */
>>> +
>>> +#ifdef __cplusplus
>>> +extern "C" {
>>> +#endif /* __cplusplus */
>>> +
>>> +/* --- BIOS service interrupt number --- */
>>> +/* number of interrupt servicing video functions */
>>> +#define INTERRUPT_NO_VIDEO_SERVICES 0x10
>>> +
>>> +struct interrupt_registers { /* used for passing parameters, fetching
>>> results and preserving values */
>>> + uint32_t reg_eax;
>>> + uint32_t reg_ebx;
>>> + uint32_t reg_ecx;
>>> + uint32_t reg_edx;
>>> + uint32_t reg_esi;
>>> + uint32_t reg_edi;
>>> + uint16_t reg_ds;
>>> + uint16_t reg_es;
>>> + uint16_t reg_fs;
>>> + uint16_t reg_gs;
>>> +}__attribute__((__packed__));
>>> +
>>
>> RTEMS prefers to use typedef on struct names. Also, the name should be
>> "namespaced", for example, i386_interrupt_registers. Usually I would
>> expect to see this kind of structure in
>> score/cpu/i386/rtems/score/i386.h defined as an interrupt context
>> structure. I think ARM has an example.
>
> I've chosen i386_realmode_interrupt_registers
> I believe the reasons from conversation with Mr. Pisa also apply
> here - to keep this separately from x86 protected mode runtime support.
>
>>
>> Is __packed__ necessary? We avoid compiler attributes where possible,
>> and where necessary we should use a macro e.g. RTEMS_PACKED_STRUCT (or
>> something, if it exists).
>
> for moxie and h8300 there is
> #define nogap __attribute__ ((packed))
> in score - cpu.h
> and for arm bsp
> #define PACKED __attribute__ ((packed))
> in jtypes.h
> but I have not found such thing for i386
>
I'd prefer to see you define a generic macro in
score/include/rtems/score/basedefs.h along the same lines as the other
RTEMS_COMPILER macros, e.g. RTEMS_COMPILER_PACKED_ATTRIBUTE, as a
separate patch to apply before yours.
Time permitting, you could also cleanup the other placed that packed
is used to the new macro.
>>
>>> +/**
>>> + * provides position to real mode buffer, which is buffer
>>> + * accessible from real mode context - it is located below
>>> + * address ~0x100000 in order for it to be accessible
>>> + * This buffer is meant to be pointed to by segReg:GenPurpReg
>>> + * and through this get bigger portion of information to/from
>>> + * interrupt service routine.
>>> + *
>>> + * @return pointer to buffer
>>> + */
>>> +extern void *i386_get_primary_rm_buffer(void);
>>> +
>>
>> avoid abbreviations, use realmode
>>
>> What does "primary" mean? Is there a "secondary"? If not, just use
>> i386_get_realmode_buffer().
>
> If there was ever need to add another buffer this could make things
> easier.
> Is it ok if I use i386_get_default_realmode_buffer()?
>
Seems fine by me.
-Gedare
>>
>>
>>> +/**
>>> + * returns size of real mode buffer
>>> + *
>>> + * @return size of buffer
>>> + */
>>> +extern uint16_t i386_get_primary_rm_buffer_size(void);
>>> +
>>
>> The above two functions can be merged together, where the buffer is
>> returned and the size gets set as a side-effect, if that is useful.
>
> ok
>
>
>>
>>> +/* if there is ever need to have more buffers or setting size of the
>>> buffer,
>>> + * feel free to modify the code */
>>> +
>>> +/**
>>> + * This function allows calling interrupts in real mode and to set
>>> processor
>>> + * registers as desired before interrupt call is made and to retrieve
>>> the
>>> + * registers content after call was made.
>>> + *
>>> + * @param interruptNumber interrupt number to be called
>>> + * @param ir pointer to structure containing registers to be passed to
>>> interrupt
>>> + * and to retrieve register content after call was made.
>>> + * @return 0 call failed (GDT too small or pagin is on)
>>> + * 1 call successful
>>> + */
>>> +extern int i386_real_interrupt_call(uint8_t interruptNumber, struct
>>> interrupt_registers *ir);
>>> +
>>> +#ifdef __cplusplus
>>> +}
>>> +#endif /* __cplusplus */
>>> +
>>> +#endif /* ASM */
>>> +
>>> +#endif /* _INT16_H */
>>> --
>>> 1.9.1
>>>
>>> _______________________________________________
>>> devel mailing list
>>> devel@rtems.org
>>> http://lists.rtems.org/mailman/listinfo/devel
>
>
>
> Thank you,
> Jan Dolezal
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