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@@ -1,6 +1,7 @@
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/* brk system call for Linux/i386.
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Copyright (C) 1995, 1996, 2000 Free Software Foundation, Inc.
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- This file is part of the GNU C Library.
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+ Copyright (c) 2015 mirabilos <tg@mirbsd.org>
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+ This file is part of uclibc-ng, derived from the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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@@ -27,15 +28,18 @@ int brk(void *addr)
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{
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void *newbrk;
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- /* %ebx is used in PIC code, need to save/restore it manually.
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- * gcc won't do it for us if we will request it in constraints
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+ /*
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+ * EBC is used in PIC code, we need to save/restore it manually.
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+ * Unfortunately, GCC won't do that for us even if we use con-
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+ * straints, and we cannot push it either as ESP clobbers are
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+ * silently ignored, but EDX is preserved, so it's scratch space.
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*/
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- __asm__("pushl %%ebx\n"
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- "movl %2, %%ebx\n"
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- "int $0x80\n"
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- "popl %%ebx\n"
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+ __asm__("xchgl %%edx,%%ebx"
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+ "\n int $0x80"
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+ "\n xchgl %%edx,%%ebx"
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: "=a" (newbrk)
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- : "0" (__NR_brk), "g" (addr)
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+ : "0" (__NR_brk), "d" (addr)
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+ : "cc"
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);
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__curbrk = newbrk;
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mirabilos