linux/tools
Zhangjin Wu 1733675515 tools/nolibc: add new crt.h with _start_c
As the environ and _auxv support added for nolibc, the assembly _start
function becomes more and more complex and therefore makes the porting
of nolibc to new architectures harder and harder.

To simplify portability, this C version of _start_c() is added to do
most of the assembly start operations in C, which reduces the complexity
a lot and will eventually simplify the porting of nolibc to the new
architectures.

The new _start_c() only requires a stack pointer argument, it will find
argc, argv, envp/environ and _auxv for us, and then call main(),
finally, it exit() with main's return status. With this new _start_c(),
the future new architectures only require to add very few assembly
instructions.

As suggested by Thomas, users may use a different signature of main
(e.g. void main(void)), a _nolibc_main alias is added for main to
silence the warning about potential conflicting types.

As suggested by Willy, the code is carefully polished for both smaller
size and better readability with local variables and the right types.

Suggested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/lkml/20230715095729.GC24086@1wt.eu/
Suggested-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/lkml/90fdd255-32f4-4caf-90ff-06456b53dac3@t-8ch.de/
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
2023-08-23 04:40:22 +02:00
..
accounting delayacct: track delays from IRQ/SOFTIRQ 2023-04-18 16:39:34 -07:00
arch asm-generic updates for 6.5 2023-07-06 10:06:04 -07:00
bootconfig
bpf tools/resolve_btfids: Fix setting HOSTCFLAGS 2023-06-05 15:44:47 -07:00
build
certs
cgroup
counter tools/counter: Makefile: Remove lingering 'include' directories on make clean 2023-05-09 19:17:17 -04:00
debugging
edid
firewire
firmware
gpio tools: gpio: fix debounce_period_us output of lsgpio 2023-05-11 10:56:24 +02:00
hv
iio
include tools/nolibc: add new crt.h with _start_c 2023-08-23 04:40:22 +02:00
io_uring
kvm/kvm_stat
laptop
leds
lib perf tools changes and fixes for v6.5: 1st batch 2023-06-30 11:35:41 -07:00
memory-model LKMM scripting updates for v6.4 2023-04-24 12:02:25 -07:00
mm slab changes for 6.4 2023-04-25 13:00:41 -07:00
net/ynl tools: ynl: add display-hint support to ynl 2023-06-24 15:45:49 -07:00
objtool objtool: Remove btrfs_assertfail() from the noreturn exceptions list 2023-06-29 17:27:47 -07:00
pci
pcmcia
perf perf tools changes and fixes for v6.5: 2nd batch 2023-07-08 10:21:51 -07:00
power platform-drivers-x86 for v6.5-1 2023-06-30 14:50:00 -07:00
rcu
scripts sh updates for v6.4 2023-04-27 17:41:23 -07:00
spi spi: spidev_test Add three missing spi mode bits 2023-05-30 15:20:12 +01:00
testing selftests/nolibc: avoid gaps in test numbers 2023-08-23 04:40:22 +02:00
thermal
time
tracing rtla/timerlat_hist: Add timerlat user-space support 2023-06-13 16:41:14 -04:00
usb usbip: Use _FORTIFY_SOURCE=2 instead of (implicitly) =1 2023-05-29 15:11:30 +01:00
verification rv: Fix addition on an uninitialized variable 'run' 2023-04-25 17:02:13 -04:00
virtio tools/virtio: fix build break for aarch64 2023-06-27 10:47:08 -04:00
wmi
workqueue workqueue: Track and monitor per-workqueue CPU time usage 2023-05-17 17:02:09 -10:00
Makefile tools/Makefile: do missed s/vm/mm/ 2023-04-18 14:22:12 -07:00