/* # Developer notes
- Symbols that start with a double underscore (__) are considered "private"
- Symbols that start with a single underscore (_) are considered "semi-public"; they can be
overridden in a user linker script, but should not be referred from user code (e.g. `extern "C" {
static mut __sbss }`).
- `EXTERN` forces the linker to keep a symbol in the final binary. We use this to make sure a
symbol if not dropped if it appears in or near the front of the linker arguments and "it's not
needed" by any of the preceding objects (linker arguments)
- `PROVIDE` is used to provide default values that can be overridden by a user linker script
- On alignment: it's important for correctness that the VMA boundaries of both .bss and .data *and*
the LMA of .data are all 4-byte aligned. These alignments are assumed by the RAM initialization
routine. There's also a second benefit: 4-byte aligned boundaries means that you won't see
"Address (..) is out of bounds" in the disassembly produced by `objdump`.
*/
/* Provides information about the memory layout of the device */
/* This will be provided by the user (see `memory.x`) or by a Board Support Crate */
INCLUDE memory.x
/* # Entry point = reset vector */
ENTRY(Reset);
EXTERN(__RESET_VECTOR); /* depends on the `Reset` symbol */
/* # Exception vectors */
/* This is effectively weak aliasing at the linker level */
/* The user can override any of these aliases by defining the corresponding symbol themselves (cf.
the `exception!` macro) */
EXTERN(__EXCEPTIONS); /* depends on all the these PROVIDED symbols */
EXTERN(DefaultHandler);
PROVIDE(NonMaskableInt = DefaultHandler);
EXTERN(HardFaultTrampoline);
PROVIDE(MemoryManagement = DefaultHandler);
PROVIDE(BusFault = DefaultHandler);
PROVIDE(UsageFault = DefaultHandler);
PROVIDE(SecureFault = DefaultHandler);
PROVIDE(SVCall = DefaultHandler);
PROVIDE(DebugMonitor = DefaultHandler);
PROVIDE(PendSV = DefaultHandler);
PROVIDE(SysTick = DefaultHandler);
PROVIDE(DefaultHandler = DefaultHandler_);
PROVIDE(HardFault = HardFault_);
/* # Interrupt vectors */
EXTERN(__INTERRUPTS); /* `static` variable similar to `__EXCEPTIONS` */
/* # Pre-initialization function */
/* If the user overrides this using the `pre_init!` macro or by creating a `__pre_init` function,
then the function this points to will be called before the RAM is initialized. */
PROVIDE(__pre_init = DefaultPreInit);
/* # Sections */
SECTIONS
{
PROVIDE(_stack_start = ORIGIN(RAM) + LENGTH(RAM));
/* ## Sections in FLASH */
/* ### Vector table */
.vector_table ORIGIN(FLASH) :
{
/* Initial Stack Pointer (SP) value */
LONG(_stack_start);
/* Reset vector */
KEEP(*(.vector_table.reset_vector)); /* this is the `__RESET_VECTOR` symbol */
__reset_vector = .;
/* Exceptions */
KEEP(*(.vector_table.exceptions)); /* this is the `__EXCEPTIONS` symbol */
__eexceptions = .;
/* Device specific interrupts */
KEEP(*(.vector_table.interrupts)); /* this is the `__INTERRUPTS` symbol */
} > FLASH
PROVIDE(_stext = ADDR(.vector_table) + SIZEOF(.vector_table));
/* ### .text */
.text _stext :
{
/* place these 2 close to each other or the `b` instruction will fail to link */
*(.PreResetTrampoline);
*(.Reset);
*(.text .text.*);
*(.HardFaultTrampoline);
*(.HardFault.*);
. = ALIGN(4);
__etext = .;
} > FLASH
/* ### .rodata */
.rodata __etext : ALIGN(4)
{
*(.rodata .rodata.*);
/* 4-byte align the end (VMA) of this section.
This is required by LLD to ensure the LMA of the following .data
section will have the correct alignment. */
. = ALIGN(4);
__erodata = .;
} > FLASH
/* ## Sections in RAM */
/* ### .data */
.data : AT(__erodata) ALIGN(4)
{
. = ALIGN(4);
__sdata = .;
*(.data .data.*);
. = ALIGN(4); /* 4-byte align the end (VMA) of this section */
__edata = .;
} > RAM
/* LMA of .data */
__sidata = LOADADDR(.data);
/* ### .bss */
.bss : ALIGN(4)
{
. = ALIGN(4);
__sbss = .;
*(.bss .bss.*);
. = ALIGN(4); /* 4-byte align the end (VMA) of this section */
__ebss = .;
} > RAM
/* ### .uninit */
.uninit (NOLOAD) : ALIGN(4)
{
. = ALIGN(4);
*(.uninit .uninit.*);
. = ALIGN(4);
} > RAM
/* Place the heap right after `.uninit` */
. = ALIGN(4);
__sheap = .;
/* ## .got */
/* Dynamic relocations are unsupported. This section is only used to detect relocatable code in
the input files and raise an error if relocatable code is found */
.got (NOLOAD) :
{
KEEP(*(.got .got.*));
}
/* ## Discarded sections */
/DISCARD/ :
{
/* Unused exception related info that only wastes space */
*(.ARM.exidx);
*(.ARM.exidx.*);
*(.ARM.extab.*);
}
}
/* Do not exceed this mark in the error messages below | */
/* # Alignment checks */
ASSERT(ORIGIN(FLASH) % 4 == 0, "
ERROR(cortex-m-rt): the start of the FLASH region must be 4-byte aligned");
ASSERT(ORIGIN(RAM) % 4 == 0, "
ERROR(cortex-m-rt): the start of the RAM region must be 4-byte aligned");
ASSERT(__sdata % 4 == 0 && __edata % 4 == 0, "
BUG(cortex-m-rt): .data is not 4-byte aligned");
ASSERT(__sidata % 4 == 0, "
BUG(cortex-m-rt): the LMA of .data is not 4-byte aligned");
ASSERT(__sbss % 4 == 0 && __ebss % 4 == 0, "
BUG(cortex-m-rt): .bss is not 4-byte aligned");
ASSERT(__sheap % 4 == 0, "
BUG(cortex-m-rt): start of .heap is not 4-byte aligned");
/* # Position checks */
/* ## .vector_table */
ASSERT(__reset_vector == ADDR(.vector_table) + 0x8, "
BUG(cortex-m-rt): the reset vector is missing");
ASSERT(__eexceptions == ADDR(.vector_table) + 0x40, "
BUG(cortex-m-rt): the exception vectors are missing");
ASSERT(SIZEOF(.vector_table) > 0x40, "
ERROR(cortex-m-rt): The interrupt vectors are missing.
Possible solutions, from most likely to less likely:
- Link to a svd2rust generated device crate
- Disable the 'device' feature of cortex-m-rt to build a generic application (a dependency
may be enabling it)
- Supply the interrupt handlers yourself. Check the documentation for details.");
/* ## .text */
ASSERT(ADDR(.vector_table) + SIZEOF(.vector_table) <= _stext, "
ERROR(cortex-m-rt): The .text section can't be placed inside the .vector_table section
Set _stext to an address greater than the end of .vector_table (See output of `nm`)");
ASSERT(_stext + SIZEOF(.text) < ORIGIN(FLASH) + LENGTH(FLASH), "
ERROR(cortex-m-rt): The .text section must be placed inside the FLASH memory.
Set _stext to an address smaller than 'ORIGIN(FLASH) + LENGTH(FLASH)'");
/* # Other checks */
ASSERT(SIZEOF(.got) == 0, "
ERROR(cortex-m-rt): .got section detected in the input object files
Dynamic relocations are not supported. If you are linking to C code compiled using
the 'cc' crate then modify your build script to compile the C code _without_
the -fPIC flag. See the documentation of the `cc::Build.pic` method for details.");
/* Do not exceed this mark in the error messages above | */