coreboot-kgpe-d16/src/lib/rmodule.ld
Julius Werner ec5e5e0db2 New mechanism to define SRAM/memory map with automatic bounds checking
This patch creates a new mechanism to define the static memory layout
(primarily in SRAM) for a given board, superseding the brittle mass of
Kconfigs that we were using before. The core part is a memlayout.ld file
in the mainboard directory (although boards are expected to just include
the SoC default in most cases), which is the primary linker script for
all stages (though not rmodules for now). It uses preprocessor macros
from <memlayout.h> to form a different valid linker script for all
stages while looking like a declarative, boilerplate-free map of memory
addresses to the programmer. Linker asserts will automatically guarantee
that the defined regions cannot overlap. Stages are defined with a
maximum size that will be enforced by the linker. The file serves to
both define and document the memory layout, so that the documentation
cannot go missing or out of date.

The mechanism is implemented for all boards in the ARM, ARM64 and MIPS
architectures, and should be extended onto all systems using SRAM in the
future. The CAR/XIP environment on x86 has very different requirements
and the layout is generally not as static, so it will stay like it is
and be unaffected by this patch (save for aligning some symbol names for
consistency and sharing the new common ramstage linker script include).

BUG=None
TEST=Booted normally and in recovery mode, checked suspend/resume and
the CBMEM console on Falco, Blaze (both normal and vboot2), Pinky and
Pit. Compiled Ryu, Storm and Urara, manually compared the disassemblies
with ToT and looked for red flags.

Change-Id: Ifd2276417f2036cbe9c056f17e42f051bcd20e81
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: f1e2028e7ebceeb2d71ff366150a37564595e614
Original-Change-Id: I005506add4e8fcdb74db6d5e6cb2d4cb1bd3cda5
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/213370
Reviewed-on: http://review.coreboot.org/9283
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Tauner <stefan.tauner@gmx.at>
Reviewed-by: Aaron Durbin <adurbin@google.com>
2015-04-06 22:05:01 +02:00

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2.4 KiB
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/*
* This linker script is used to link rmodules (relocatable modules). It
* links at zero so that relocation fixups are easy when placing the binaries
* anywhere in the address space.
*
* NOTE: The program's loadable sections (text, module_params, and data) are
* packed into the flat blob. The rmodule loader assumes the entire program
* resides in one contiguous address space. Therefore, alignment for a given
* section (if required) needs to be done at the end of the preceeding section.
* e.g. if the data section should be aligned to an 8 byte address the text
* section should have ALIGN(8) at the end of its section. Otherwise there
* won't be a consistent mapping between the flat blob and the loaded program.
*/
BASE_ADDRESS = 0x00000;
ENTRY(__rmodule_entry);
SECTIONS
{
. = BASE_ADDRESS;
.payload : {
/* C code of the module. */
_program = .;
*(.text._start);
*(.text.stage_entry);
*(.text);
*(.text.*);
/* C read-only data. */
. = ALIGN(16);
#ifdef CONFIG_COVERAGE
__CTOR_LIST__ = .;
*(.ctors);
LONG(0);
LONG(0);
__CTOR_END__ = .;
#endif
/* The driver sections are to allow linking coreboot's
* ramstage with the rmodule linker. Any changes made in
* ramstage.ld should be made here as well. */
. = ALIGN(8);
pci_drivers = . ;
KEEP(*(.rodata.pci_driver));
epci_drivers = . ;
. = ALIGN(8);
cpu_drivers = . ;
KEEP(*(.rodata.cpu_driver));
ecpu_drivers = . ;
. = ALIGN(8);
_bs_init_begin = .;
KEEP(*(.bs_init));
LONG(0);
LONG(0);
_bs_init_end = .;
. = ALIGN(8);
*(.rodata);
*(.rodata.*);
. = ALIGN(8);
/* The parameters section can be used to pass parameters
* to a module, however there has to be an prior agreement
* on how to interpret the parameters. */
_module_params_begin = .;
KEEP(*(.module_parameters));
_module_params_end = .;
. = ALIGN(8);
/* Data section. */
. = ALIGN(64); /* Mirror cache line alignment from ramstage. */
_sdata = .;
*(.data);
*(.data.*);
. = ALIGN(8);
_edata = .;
. = ALIGN(8);
}
.bss (NOLOAD) : {
/* C uninitialized data of the module. */
_bss = .;
*(.bss);
*(.bss.*)
*(.sbss)
*(.sbss.*)
*(COMMON);
. = ALIGN(8);
_ebss = .;
/*
* Place the heap after BSS. The heap size is passed in by
* by way of ld --defsym=__heap_size=<>
*/
_heap = .;
. = . + __heap_size;
_eheap = .;
_eprogram = .;
}
/DISCARD/ : {
/* Drop unnecessary sections. */
*(.eh_frame);
*(.note);
*(.note.*);
}
}