coreboot-kgpe-d16/payloads/libpayload
Julius Werner 6c1a669b44 libpayload: xhci: Do not memcpy registers
memcpy() is meant to be used on normal memory and often implemented with
architecture-specific optimizations to make that as performant as
possible. MMIO registers often have special access restrictions that may
be incompatible with whatever memcpy() does. For example, on arm64 it
uses the LDP (load pair) to load 16 bytes at a time, which makes 4-byte
MMIO registers unhappy.

This patch removes the caching of the XHCI capreg registers and changes
it back to a pointer. The CAP_GET() macro is still accessing a full
(non-bitfield) uint32_t at the end so this should still generate a
4-byte access (which was the goal of the original change in CB:39838).

Signed-off-by: Julius Werner <jwerner@chromium.org>
Change-Id: Id058c8813087a8e8cb85f570399e07fb8a597108
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40895
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
2020-04-30 01:57:05 +00:00
..
arch libpayload: arm64: Keep instruction cache enabled at all times 2020-02-17 15:42:34 +00:00
bin Remove MIPS architecture 2019-11-20 10:10:48 +00:00
configs trogdor: add support for Bubs variant 2020-04-15 19:57:59 +00:00
crypto
curses libpayload: Enable -Wimplicit-fallthrough 2019-07-21 17:17:42 +00:00
drivers libpayload: xhci: Do not memcpy registers 2020-04-30 01:57:05 +00:00
gdb
include libpayload/drivers/nvram: Add function to write RTC 2020-03-23 08:35:31 +00:00
libc libpayload: malloc: Change memcpy() to memmove() in realloc 2020-04-03 19:56:27 +00:00
libcbfs libpayload: cbfs: fix infinite loop in cbfs_get_{handle,attr} 2020-03-02 15:00:24 +00:00
liblz4 lz4: Fix out-of-bounds reads 2020-03-02 15:03:03 +00:00
liblzma libpayload: Fix out-of-bounds read 2020-02-24 12:53:25 +00:00
libpci libpayload: Make pci and endian handling -Wconversion safe 2020-02-05 21:48:36 +00:00
sample Remove MIPS architecture 2019-11-20 10:10:48 +00:00
tests
Doxyfile
Kconfig libpayload: Add uart/serial driver support for trogdor 2020-03-09 22:58:56 +00:00
LICENSES
LICENSE_GPL
Makefile Makefile: Remove romcc 2019-12-27 08:59:59 +00:00
Makefile.inc Remove MIPS architecture 2019-11-20 10:10:48 +00:00
README payloads/libpayload: Update a Makefile for sample libpayload 2019-06-21 09:16:36 +00:00

README

-------------------------------------------------------------------------------
libpayload README
-------------------------------------------------------------------------------

libpayload is a minimal library to support standalone payloads
that can be booted with firmware like coreboot. It handles the setup
code, and provides common C library symbols such as malloc() and printf().

Note: This is _not_ a standard library for use with an operating system,
rather it's only useful for coreboot payload development!
See https://www.coreboot.org for details on coreboot.


Installation
------------

 $ git clone https://review.coreboot.org/coreboot.git

 $ cd coreboot/payloads/libpayload

 $ make menuconfig

 $ make

 $ make install (optional, will install into ./install per default)

On x86 systems, libpayload will always be 32-bit even if your host OS runs
in 64-bit, so you might have to install the 32-bit libgcc version.
On Debian systems you'd do 'apt-get install gcc-multilib' for example.

Run 'make distclean' before switching boards. This command will remove
your current .config file, so you need 'make menuconfig' again or
'make defconfig' in order to set up configuration. Default configuration
is based on 'configs/defconfig'. See the configs/ directory for examples
of configuration.


Usage
-----

Here's an example of a very simple payload (hello.c) and how to build it:

 #include <libpayload.h>

 int main(void)
 {
     printf("Hello, world!\n");
     return 0;
 }

Building the payload using the 'lpgcc' compiler wrapper:

 $ lpgcc -o hello.elf hello.c

Please see the sample/ directory for details.


Website and Mailing List
------------------------

The main website is https://www.coreboot.org/Libpayload.

For additional information, patches, and discussions, please join the
coreboot mailing list at https://www.coreboot.org/Mailinglist, where most
libpayload developers are subscribed.


Copyright and License
---------------------

See LICENSES.