Can be used to pad other options so that they are aligned to the word boundary; is not followed by length byte
1
Subnet mask
4 octets
Client's subnet mask as perRFC 950. If both the subnet mask and the router option (option 3) are included, the subnet mask option must be first.
2
Time offset
4 octets
Time offset of the client's subnet in seconds from Coordinated Universal Time (UTC). The offset is expressed as a two's complement 32-bit integer. A positive offset indicates a location east of the zero meridian and a negative offset indicates a location west of the zero meridian.
3
Router
Multiples of 4 octets
Available routers, should be listed in order of preference
4
Time server
Multiples of 4 octets
AvailableTime Protocolservers to synchronise with, should be listed in order of preference
5
Name server
Multiples of 4 octets
AvailableIEN 116name servers, should be listed in order of preference
6
Domain name server
Multiples of 4 octets
AvailableDNSservers, should be listed in order of preference
7
Log server
Multiples of 4 octets
Available log servers, should be listed in order of preference
8
Cookie server
Multiples of 4 octets
Cookiein this case means "fortune cookie" or "quote of the day", a pithy or humorous anecdote often sent as part of a logon process on large computers; it has nothing to do withcookies sent by websites.
This appendix contains DHCP options and BOOTP vendor extensions from RFC 2132, and includes the validation type for each option, as indicated in Table 10: DHCPv4 Options by Number , on page 23.
The following sections describe the DHCP options in detail: • RFC 1497 Vendor Extensions, on page 1
DHCP option 43 / 25DHCP (Dynamic Host Configuration Protocol) 에는 클라이언트가 DHCP 서버로부터 정보를 요청할 때 클라이언트에게 송신할 수 있는 많은 구성 옵션이 있습니다. 검색 도구를 사용하여 모든 DHCP 옵션을 볼 수 있습니다.
DHCP 옵션은 DHCP 서버가 IP 주소와 함께 클라이언트에게 전달하는 추가적인 구성 데이터를 정의합니다. 일반적인 옵션에는 서브네트 마스크, 도메인명, 라우터 IP 주소, 도메인명 서버 IP 주소 및 정적 라우트가 포함됩니다.
RFC 2132: DHCP 옵션 및 BOOTP 공급업체 확장의 정의를 기반으로 하는 표준 DHCP 옵션이 다음 표에 설명되어 있습니다. IBM Navigator FOR I의 DHCP 옵션 표시를 사용하여 사용자 지정 옵션을 구성할 수도 있습니다.
__bss_start = .; .bss : { bss = .; *(.bss) } . = ALIGN(4096); /* align to page size */ __bss_end = .; __bss_size = __bss_end - __bss_start; __end = .; } : 저 변수들은 실제 저안에서 사용된다기 보다는 소스 코드(C 파일 혹은 어셈블리어 파일)상에서 사용되면서 의미가 부여된다. 저 변수들을 소스 코드상에서 불러 오려면 어떻게 해야 할까? 아래의 코드를 보자.
/* ****************************************************************************** ** ** File : LinkerScript.ld ** ** Author : STM32CubeIDE ** ** Abstract : Linker script for STM32H7 series ** 1024Kbytes FLASH ** 800Kbytes RAM ** ** Set heap size, stack size and stack location according ** to application requirements. ** ** Set memory bank area and size if external memory is used. ** ** Target : STMicroelectronics STM32 ** ** Distribution: The file is distributed as is without any warranty ** of any kind. ** ***************************************************************************** ** @attention ** ** Copyright (c) 2024 STMicroelectronics. ** All rights reserved. ** ** This software is licensed under terms that can be found in the LICENSE file ** in the root directory of this software component. ** If no LICENSE file comes with this software, it is provided AS-IS. ** ***************************************************************************** */
/* Entry Point */ ENTRY(Reset_Handler)
/* Highest address of the user mode stack */ _estack = ORIGIN(RAM_D1) + LENGTH(RAM_D1); /* end of "RAM_D1" Ram type memory */
_Min_Heap_Size = 0x200; /* required amount of heap */ _Min_Stack_Size = 0x400; /* required amount of stack */
/* Sections */ SECTIONS { /* The startup code into "FLASH" Rom type memory */ .isr_vector : { . = ALIGN(4); KEEP(*(.isr_vector)) /* Startup code */ . = ALIGN(4); } >FLASH
/* The program code and other data into "FLASH" Rom type memory */ .text : { . = ALIGN(4); *(.text) /* .text sections (code) */ *(.text*) /* .text* sections (code) */ *(.glue_7) /* glue arm to thumb code */ *(.glue_7t) /* glue thumb to arm code */ *(.eh_frame)
KEEP (*(.init)) KEEP (*(.fini))
. = ALIGN(4); _etext = .; /* define a global symbols at end of code */ } >FLASH
/* Constant data into "FLASH" Rom type memory */ .rodata : { . = ALIGN(4); *(.rodata) /* .rodata sections (constants, strings, etc.) */ *(.rodata*) /* .rodata* sections (constants, strings, etc.) */ . = ALIGN(4); } >FLASH
.ARM.extab (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */ { . = ALIGN(4); *(.ARM.extab* .gnu.linkonce.armextab.*) . = ALIGN(4); } >FLASH .ARM (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */ { . = ALIGN(4); __exidx_start = .; *(.ARM.exidx*) __exidx_end = .; . = ALIGN(4); } >FLASH
.preinit_array (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */ { . = ALIGN(4); PROVIDE_HIDDEN (__preinit_array_start = .); KEEP (*(.preinit_array*)) PROVIDE_HIDDEN (__preinit_array_end = .); . = ALIGN(4); } >FLASH
.init_array (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */ { . = ALIGN(4); PROVIDE_HIDDEN (__init_array_start = .); KEEP (*(SORT(.init_array.*))) KEEP (*(.init_array*)) PROVIDE_HIDDEN (__init_array_end = .); . = ALIGN(4); } >FLASH
.fini_array (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */ { . = ALIGN(4); PROVIDE_HIDDEN (__fini_array_start = .); KEEP (*(SORT(.fini_array.*))) KEEP (*(.fini_array*)) PROVIDE_HIDDEN (__fini_array_end = .); . = ALIGN(4); } >FLASH
/* Used by the startup to initialize data */ _sidata = LOADADDR(.data);
/* Initialized data sections into "RAM" Ram type memory */ .data : { . = ALIGN(4); _sdata = .; /* create a global symbol at data start */ *(.data) /* .data sections */ *(.data*) /* .data* sections */ *(.RamFunc) /* .RamFunc sections */ *(.RamFunc*) /* .RamFunc* sections */
. = ALIGN(4); _edata = .; /* define a global symbol at data end */ } >RAM_D1 AT> FLASH
/* Uninitialized data section into "RAM" Ram type memory */ . = ALIGN(4); .bss : { /* This is used by the startup in order to initialize the .bss section */ _sbss = .; /* define a global symbol at bss start */ __bss_start__ = _sbss; *(.bss) *(.bss*) *(COMMON)
. = ALIGN(4); _ebss = .; /* define a global symbol at bss end */ __bss_end__ = _ebss; } >RAM_D1
/* User_heap_stack section, used to check that there is enough "RAM" Ram type memory left */ ._user_heap_stack : { . = ALIGN(8); PROVIDE ( end = . ); PROVIDE ( _end = . ); . = . + _Min_Heap_Size; . = . + _Min_Stack_Size; . = ALIGN(8); } >RAM_D1
/* Remove information from the compiler libraries */ /DISCARD/ : { libc.a ( * ) libm.a ( * ) libgcc.a ( * ) }
.ARM.attributes 0 : { *(.ARM.attributes) } }
CM4 ld
/* ****************************************************************************** ** ** File : LinkerScript.ld ** ** Author : STM32CubeIDE ** ** Abstract : Linker script for STM32H7 series ** 1024Kbytes FLASH and 288Kbytes RAM ** ** Set heap size, stack size and stack location according ** to application requirements. ** ** Set memory bank area and size if external memory is used. ** ** Target : STMicroelectronics STM32 ** ** Distribution: The file is distributed as is, without any warranty ** of any kind. ** ***************************************************************************** ** @attention ** ** Copyright (c) 2024 STMicroelectronics. ** All rights reserved. ** ** This software is licensed under terms that can be found in the LICENSE file ** in the root directory of this software component. ** If no LICENSE file comes with this software, it is provided AS-IS. ** **************************************************************************** */
/* Entry Point */ ENTRY(Reset_Handler)
/* Highest address of the user mode stack */ _estack = ORIGIN(RAM) + LENGTH(RAM); /* end of RAM */ /* Generate a link error if heap and stack don't fit into RAM */ _Min_Heap_Size = 0x200; /* required amount of heap */ _Min_Stack_Size = 0x400; /* required amount of stack */
/* The program code and other data goes into FLASH */ .text : { . = ALIGN(4); *(.text) /* .text sections (code) */ *(.text*) /* .text* sections (code) */ *(.glue_7) /* glue arm to thumb code */ *(.glue_7t) /* glue thumb to arm code */ *(.eh_frame)
KEEP (*(.init)) KEEP (*(.fini))
. = ALIGN(4); _etext = .; /* define a global symbols at end of code */ } >FLASH
.ARM.extab (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */ { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH .ARM (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */ { __exidx_start = .; *(.ARM.exidx*) __exidx_end = .; } >FLASH
.preinit_array (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */ { PROVIDE_HIDDEN (__preinit_array_start = .); KEEP (*(.preinit_array*)) PROVIDE_HIDDEN (__preinit_array_end = .); } >FLASH .init_array (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */ { PROVIDE_HIDDEN (__init_array_start = .); KEEP (*(SORT(.init_array.*))) KEEP (*(.init_array*)) PROVIDE_HIDDEN (__init_array_end = .); } >FLASH .fini_array (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */ { PROVIDE_HIDDEN (__fini_array_start = .); KEEP (*(SORT(.fini_array.*))) KEEP (*(.fini_array*)) PROVIDE_HIDDEN (__fini_array_end = .); } >FLASH
/* used by the startup to initialize data */ _sidata = LOADADDR(.data);
/* Initialized data sections goes into RAM, load LMA copy after code */ .data : { . = ALIGN(4); _sdata = .; /* create a global symbol at data start */ *(.data) /* .data sections */ *(.data*) /* .data* sections */ *(.RamFunc) /* .RamFunc sections */ *(.RamFunc*) /* .RamFunc* sections */
. = ALIGN(4); _edata = .; /* define a global symbol at data end */ } >RAM AT> FLASH
/* Uninitialized data section */ . = ALIGN(4); .bss : { /* This is used by the startup in order to initialize the .bss section */ _sbss = .; /* define a global symbol at bss start */ __bss_start__ = _sbss; *(.bss) *(.bss*) *(COMMON)
. = ALIGN(4); _ebss = .; /* define a global symbol at bss end */ __bss_end__ = _ebss; } >RAM
/* User_heap_stack section, used to check that there is enough RAM left */ ._user_heap_stack : { . = ALIGN(8); PROVIDE ( end = . ); PROVIDE ( _end = . ); . = . + _Min_Heap_Size; . = . + _Min_Stack_Size; . = ALIGN(8); } >RAM
/* Remove information from the standard libraries */ /DISCARD/ : { libc.a ( * ) libm.a ( * ) libgcc.a ( * ) }
D2 domain 에는 Cortex-M4에 가까운 SRAM1 128K(I-bus) / SRAM2 128K(D-bus) / SRAM3 32K(S-bus)가 존재한다.
D3 domain 에는 SRAM4 64K / Backup SRAM 4K 가 존재한다.(얘네는 링커에 없다)
3.3.3 Embedded SRAM All devices feature around 1 Mbyte of RAM with hardware ECC. The RAM is divided as follows: • 512 Kbytes of AXI-SRAM mapped onto AXI bus on D1 domain. • SRAM1 mapped on D2 domain: 128 Kbytes • SRAM2 mapped on D2 domain: 128 Kbytes • SRAM3 mapped on D2 domain: 32 Kbytes • SRAM4 mapped on D3 domain: 64 Kbytes • 4 Kbytes of backup SRAM The content of this area is protected against possible unwanted write accesses, and is retained in Standby or VBAT mode. • RAM mapped to TCM interface (ITCM and DTCM): Both ITCM and DTCM RAMs are 0 wait state memories. They can be accessed either from the Arm® Cortex®-M7 CPU or the MDMA (even in Sleep mode) through a specific AHB slave of the Cortex®-M7(AHBS): – 64 Kbytes of ITCM-RAM (instruction RAM) This RAM is connected to ITCM 64-bit interface designed for execution of critical real-times routines by the Cortex®-M7. – 128 Kbytes of DTCM-RAM (2x 64-Kbyte DTCM-RAMs on 2x32-bit DTCM ports) The DTCM-RAM could be used for critical real-time data, such as interrupt service routines or stack/heap memory. Both DTCM-RAMs can be used in parallel (for load/store operations) thanks to the Cortex®-M7 dual issue capability. The MDMA can be used to load code or data in ITCM or DTCM RAMs.
M4가 M7 보다 메모리 어드레스 비트가 낮은가? 아무튼 아래와 같이 연결이 된다고 한다.
cortex-M7
cortex-M4
AXI SRAM
0x2400 0000
?
SRAM1
0x3000 0000
0x1000 0000
SRAM2
0x3002 0000
0x1002 0000
SRAM3
0x3004 0000
0x1004 0000
SRAM4
0x3800 0000
?
2.2.1 Embedded SRAM The STM32H7 dual‑core devices feature: • Up to 864 Kbytes of System SRAM • 128 Kbytes of data TCM RAM, DTCM RAM • 64 Kbytes of instruction TCM RAM, ITCM RAM • 4 Kbytes of backup SRAM The embedded system SRAM is split into five blocks over the three power domains: AXI SRAM, AHB SRAM1, AHB SRAM2, AHB SRAM3 and AHB SRAM4. • D1 domain, AXI SRAM: – AXI SRAM is accessible through D1 domain AXI bus matrix. It is mapped at address 0x2400 0000 and accessible by all system masters except BDMA. AXI SRAM can be used for application data which are not allocated in DTCM RAM or reserved for graphic objects (such as frame buffers) • D2 domain, AHB SRAM: – AHB SRAM1 is accessible through D2 domain AHB matrix. It is mapped at address 0x3000 0000 and accessible by all system masters except BDMA. The AHB SRAMs of the D2 domain are also aliased to an address range below 0x2000 0000 to maintain the Cortex®‑M4 Harvard architecture. The AHB SRAM1 also mapped at address 0x1000 0000. The AHB SRAM2 also mapped at address 0x1002 0000. The AHB SRAM3 also mapped at address 0x1004 0000. All those AHB SRAMs are accessible by all system masters through D2 domain AHB matrix. All those AHB SRAMs are accessible by all system masters through D2 domain AHB matrix. AHB SRAM1 can be used as DMA buffers to store peripheral input/output data in D2 domain, or as code location for Cortex®‑M4 CPU (application code available when D1 is powered off). AHB SRAM1 can be used as DMA buffers to store peripheral input/output data in D2 domain, or as code location for Cortex®‑M4 CPU (application code available when D1 is powered off). – AHB SRAM2 is accessible through D2 domain AHB matrix. It is mapped at address 0x3002 0000 and accessible by all system masters except BDMA. AHB SRAM2 can be used as DMA buffers to store peripheral input/output data in D2 domain, or as readwrite segment for application running on Cortex®‑M4 CPU. – AHB SRAM3 is accessible through D2 domain AHB matrix is mapped at address 0x3004 0000 and accessible by all system masters except BDMA. AHB SRAM3 can be used as buffers to store peripheral input/output data for Ethernet and USB, or as shared memory between the two cores. • D3 domain, AHB SRAM: – AHB SRAM4 is mapped at address 0x3800 0000 and accessible by most of system masters through D3 domain AHB matrix. AHB SRAM4 can be used as BDMA buffers to store peripheral input/output data in D3 domain. It can also be used to retain some application code/data when D1 and D2 domain in DStandby mode, or as shared memory between the two cores. The system AHB SRAM can be accessed as bytes, half‑words (16‑bit units) or words (32‑bit units), while the system AXI SRAM can be accessed as bytes, half‑words, words or doublewords (64‑bit units). These memories can be addressed at maximum system clock frequency without wait state.
