Merge tag 'urgent/nolibc.2023.10.16a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull nolibc fixes from Paul McKenney:

 - tools/nolibc: i386: Fix a stack misalign bug on _start

 - MAINTAINERS: nolibc: update tree location

 - tools/nolibc: mark start_c as weak to avoid linker errors

* tag 'urgent/nolibc.2023.10.16a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
  tools/nolibc: mark start_c as weak
  MAINTAINERS: nolibc: update tree location
  tools/nolibc: i386: Fix a stack misalign bug on _start

Author: torvalds

MAINTAINERS

@@ -15131,7 +15131,7 @@ NOLIBC HEADER FILE
 M:	Willy Tarreau <w@1wt.eu>
 M:	Thomas Weißschuh <linux@weissschuh.net>
 S:	Maintained
-T:	git git://git.kernel.org/pub/scm/linux/kernel/git/wtarreau/nolibc.git
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/nolibc/linux-nolibc.git
 F:	tools/include/nolibc/
 F:	tools/testing/selftests/nolibc/
 

tools/include/nolibc/arch-i386.h

@@ -167,7 +167,9 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_
 	__asm__ volatile (
 		"xor  %ebp, %ebp\n"       /* zero the stack frame                                */
 		"mov  %esp, %eax\n"       /* save stack pointer to %eax, as arg1 of _start_c     */
-		"and  $-16, %esp\n"       /* last pushed argument must be 16-byte aligned        */
+		"add  $12, %esp\n"        /* avoid over-estimating after the 'and' & 'sub' below */
+		"and  $-16, %esp\n"       /* the %esp must be 16-byte aligned on 'call'          */
+		"sub  $12, %esp\n"        /* sub 12 to keep it aligned after the push %eax       */
 		"push %eax\n"             /* push arg1 on stack to support plain stack modes too */
 		"call _start_c\n"         /* transfer to c runtime                               */
 		"hlt\n"                   /* ensure it does not return                           */

tools/include/nolibc/crt.h

@@ -13,6 +13,7 @@ const unsigned long *_auxv __attribute__((weak));
 static void __stack_chk_init(void);
 static void exit(int);
 
+__attribute__((weak))
 void _start_c(long *sp)
 {
 	long argc;