Commit 2a39a532 authored by Willy Tarreau's avatar Willy Tarreau Committed by Paul E. McKenney
Browse files

tools/nolibc: add auxiliary vector retrieval for arm64 



In the _start block we now iterate over envp to find the auxiliary
vector after the NULL. The pointer is saved into an _auxv variable
that is marked as weak so that it's accessible from multiple units.

Signed-off-by: default avatarWilly Tarreau <w@1wt.eu>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 1cce162a

tools/include/nolibc/arch-aarch64.h

+7 −0
Original line number Diff line number Diff line
@@ -170,6 +170,7 @@ struct sys_stat_struct { 
})



char **environ __attribute__((weak));

const unsigned long *_auxv __attribute__((weak));



/* startup code */

void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void)
@@ -182,6 +183,12 @@ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void) 
		"add x2, x2, x1\n"   //           + argv

		"adrp x3, environ\n"          // x3 = &environ (high bits)

		"str x2, [x3, #:lo12:environ]\n" // store envp into environ

		"mov x4, x2\n"       // search for auxv (follows NULL after last env)

		"0:\n"

		"ldr x5, [x4], 8\n"  // x5 = *x4; x4 += 8

		"cbnz x5, 0b\n"      // and stop at NULL after last env

		"adrp x3, _auxv\n"   // x3 = &_auxv (high bits)

		"str x4, [x3, #:lo12:_auxv]\n" // store x4 into _auxv

		"and sp, x1, -16\n"  // sp must be 16-byte aligned in the callee

		"bl main\n"          // main() returns the status code, we'll exit with it.

		"mov x8, 93\n"       // NR_exit == 93