Fix x86 system calls made from ELF preinit.
Used by CFI, so broke cfi_test#early_init@x86, but I've added a specific
test for this (and a similar test for getauxval from preinit, which this
patch does not fix).
Bug: http://b/35885875
Test: ran tests
Change-Id: I43885bedfb88c0a26b4474bd3c27a87dec7bbc97
diff --git a/libc/bionic/libc_init_common.cpp b/libc/bionic/libc_init_common.cpp
index e5654c3..9094fc5 100644
--- a/libc/bionic/libc_init_common.cpp
+++ b/libc/bionic/libc_init_common.cpp
@@ -62,7 +62,11 @@
char** environ;
#if defined(__i386__)
-__LIBC_HIDDEN__ void* __libc_sysinfo = nullptr;
+__attribute__((__naked__)) static void __libc_int0x80() {
+ __asm__ volatile("int $0x80; ret");
+}
+
+__LIBC_HIDDEN__ void* __libc_sysinfo = reinterpret_cast<void*>(__libc_int0x80);
__LIBC_HIDDEN__ void __libc_init_sysinfo(KernelArgumentBlock& args) {
__libc_sysinfo = reinterpret_cast<void*>(args.getauxval(AT_SYSINFO));