coreboot-kgpe-d16/payloads/libpayload
Yidi Lin eabdd0252a libpayload/libc/time: Fix possible overflow in multiplication
The value from raw_read_cntfrq_el0() could be large enough to cause
overflow when multiplied by USECS_PER_SEC. To prevent this, both
USECS_PER_SEC and hz can be reduced by dividing them by their GCD.

This patch also modifies the return type of `timer_hz()` from
`uint64_t` to `uint32_t`, assuming that in practice the timestamp
counter should never be that fast.

BUG=b:307790895
TEST=boot to kernel and check the timestamps from `cbmem`

Change-Id: Ia55532490651fcf47128b83a8554751f050bcc89
Signed-off-by: Yidi Lin <yidilin@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78888
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2023-11-07 19:25:23 +00:00
..
arch libpayload: Skip unknown arguments to clang 2023-08-26 21:06:30 +00:00
bin libpayload: bin/lpgcc allow to call without files 2023-03-07 17:10:36 +00:00
configs payloads/libpayload/configs: drop config.galileo 2023-05-27 00:26:59 +00:00
crypto
curses payloads/libpayload: Don't use old style function definition 2023-08-28 17:09:46 +00:00
drivers libpayload/libc/time: Fix possible overflow in multiplication 2023-11-07 19:25:23 +00:00
gdb
include libpayload/libc/time: Fix possible overflow in multiplication 2023-11-07 19:25:23 +00:00
libc libpayload/libc/time: Fix possible overflow in multiplication 2023-11-07 19:25:23 +00:00
libcbfs libpayload/libcbfs: Add VBOOT_CBFS_INTEGRATION support 2023-09-18 15:43:45 +00:00
liblz4
liblzma
libpci
sample
tests libpayload/vboot: Add vboot context initialization and management code 2023-09-18 15:40:40 +00:00
vboot libpayload/libcbfs: Add VBOOT_CBFS_INTEGRATION support 2023-09-18 15:43:45 +00:00
.gitignore
Doxyfile
Kconfig libpayload;arch,cpu/x86: drop USE_MARCH_586 Kconfig option 2023-05-27 00:29:02 +00:00
LICENSES
LICENSE_GPL
Makefile
Makefile.inc libpayload/Makefile.inc: Initialize vboot submodule 2022-06-20 13:54:31 +00:00
Makefile.payload libpayload/Makefile.payload: Fix CFLAGS 2022-06-15 18:06:39 +00:00
README

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.