tools/nolibc: add auxiliary vector retrieval for s390
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: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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@ -160,6 +160,7 @@ struct sys_stat_struct {
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})
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char **environ __attribute__((weak));
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const unsigned long *_auxv __attribute__((weak));
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/* startup code */
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void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void)
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@ -179,6 +180,15 @@ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void)
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"larl %r1,environ\n"
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"stg %r4,0(%r1)\n"
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/* search for auxv */
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"lgr %r5,%r4\n" /* start at envp */
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"1:\n"
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"clg %r0,0(%r5)\n" /* entry zero? */
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"la %r5,8(%r5)\n" /* advance pointer */
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"jnz 1b\n" /* no -> test next pointer */
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"larl %r1,_auxv\n" /* yes -> store value in _auxv */
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"stg %r5,0(%r1)\n"
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"aghi %r15,-160\n" /* allocate new stackframe */
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"xc 0(8,%r15),0(%r15)\n" /* clear backchain */
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"brasl %r14,main\n" /* ret value of main is arg to exit */
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