libc: Provide ucontext_t/mcontext_t/<sys/ucontext.h>
This patch updates the C library headers to provide ucontext_t
definitions for three architectures.
+ Fix <signal.h> to always define 'struct sigcontext'.
The new declarations are announced with new macros defined in
<sys/cdefs.h> in order to make it easier to adapt client code
that already defines its own, incompatible, versions of the
structures seen here.
http://code.google.com/p/android/issues/detail?id=34784
Change-Id: Ie78c48690a4ce61c50593f6c39639be7fead3596
diff --git a/libc/arch-mips/include/machine/ucontext.h b/libc/arch-mips/include/machine/ucontext.h
new file mode 100644
index 0000000..df3b64b
--- /dev/null
+++ b/libc/arch-mips/include/machine/ucontext.h
@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#ifndef _ARCH_MIPS_SYS_UCONTEXT_H_
+#define _ARCH_MIPS_SYS_UCONTEXT_H_
+
+#include <signal.h>
+#include <stdint.h>
+
+__BEGIN_DECLS
+
+/* Technical note:
+ *
+ * On MIPS, there are differences in the way GLibc and the Linux kernel declare
+ * ucontext_t:
+ *
+ * - The kernel implements 'uc_mcontext' with a 'struct sigcontext',
+ * while GLibc defines 'mcontext_t' in a binary-compatible way
+ * (same size, same binary layout), but with different field naming/access
+ * convention.
+ *
+ * The biggest difference is the naming of the fields. The kernel uses
+ * a 'sc_' prefix (e.g. "sc_gregs[]"), while GLibc does not ("gregs[]").
+ *
+ * For maximum portability of existing client code, this header follows
+ * the GLibc convention. Client code, and the C library, should never
+ * try to include <asm/ucontext.h>
+ *
+ * Apart from that, all floating point state is stored in uc_mcontext
+ * in the same way, which is much simpler than ARM and x86 schemes for it.
+ * As such, there is no _libc_fpstate.
+ *
+ * Reference source files:
+ * $KERNEL/arch/mips/include/asm/sigcontext.h
+ * $KERNEL/arch/mips/include/asm/ucontext.h
+ *
+ * $GLIBC/sysdeps/unix/sysv/linux/mips/getcontext.S
+ * $GLIBC/sysdeps/unix/sysv/linux/mips/setcontext.S
+ * $GLIBC/sysdeps/unix/sysv/linux/mips/sys/ucontext.h
+ */
+
+/* First, the kernel-compatible version, for reference. */
+typedef struct __kernel_ucontext {
+ unsigned long uc_flags;
+ struct __kernel_ucontext* uc_link;
+ stack_t uc_stack;
+ struct sigcontext uc_mcontext;
+ __kernel_sigset_t uc_sigmask;
+} __kernel_ucontext_t;
+
+/* Second, the GLibc-compatible version */
+
+__extension__ /* Required to build in ANSI C mode */
+typedef unsigned long long greg_t;
+
+#define NGREG 32
+#define NFPREG 32
+
+typedef greg_t gregset_t[NGREG];
+
+typedef struct fpregset {
+ union {
+ double fp_dregs[NFPREG];
+ struct {
+ float _fp_fregs;
+ unsigned _fp_pad;
+ } fp_fregs[NFPREG];
+ } fp_r;
+} fpregset_t;
+
+#ifndef _MIPS_SIM
+#error "_MIPS_SIM should be defined by your Android MIPS toolchain!"
+#endif
+
+#ifndef _OABI32
+#error "_OABI32 should be defined by your Android MIPS toolchain!"
+#endif
+
+#if _MIPS_SIM != _OABI32
+#error "Only _OABI32 is supported on Android MIPS!"
+#endif
+
+typedef struct {
+ unsigned regmask;
+ unsigned status;
+ greg_t pc;
+ gregset_t gregs;
+ fpregset_t fpregs;
+ unsigned fp_owned;
+ unsigned fpc_csr;
+ unsigned fpc_eir;
+ unsigned used_math;
+ unsigned dsp;
+ greg_t mdhi;
+ greg_t mdlo;
+ unsigned hi1;
+ unsigned lo1;
+ unsigned hi2;
+ unsigned lo2;
+ unsigned hi3;
+ unsigned lo3;
+} mcontext_t;
+
+typedef struct ucontext {
+ uint32_t uc_flags;
+ struct ucontext* uc_link;
+ stack_t uc_stack;
+ mcontext_t uc_mcontext;
+ /* Only expose the signals in Bionic's 32-bit sigset_t.
+ * The _unused field is required padding from the kernel. */
+ sigset_t uc_sigmask;
+ char _unused[sizeof(__kernel_sigset_t) - sizeof(sigset_t)];
+} ucontext_t;
+
+__END_DECLS
+
+#endif /* _ARCH_MIPS_SYS_UCONTEXT_H_ */