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authorMike Frysinger <vapier@gentoo.org>2008-01-05 10:05:27 +0000
committerMike Frysinger <vapier@gentoo.org>2008-01-05 10:05:27 +0000
commit124ec188720b6bdea85ade49e7ea195161b12fce (patch)
tree2bce39bc1e51bd587e010a61419b47d122be3165 /libc/sysdeps/linux/xtensa/bits/syscalls.h
parent9c95d5d28d8d40f7b826c9399f5ce781bbc61567 (diff)
Chris Zankel writes:
The following patches add support for the Xtensa processor architecture to uClibc. They are based on a recent SVN checkout (12/05/2007). The first patch (attached to this post) adds Xtensa support to various shared configuration and make files. The following patches then include the Xtensa specific files and directories. I welcome any feedback and would appreciate it if you could include the patches into the mainline tree. I am certainly committed to maintain the port. Bob Wilson was kind enough to review the patches. Some notes about the architecture: Xtensa is a configurable and extensible processor architecture developed by Tensilica. For more information, please visit: www.linux-xtensa.org.
Diffstat (limited to 'libc/sysdeps/linux/xtensa/bits/syscalls.h')
-rw-r--r--libc/sysdeps/linux/xtensa/bits/syscalls.h140
1 files changed, 140 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/xtensa/bits/syscalls.h b/libc/sysdeps/linux/xtensa/bits/syscalls.h
new file mode 100644
index 000000000..76bcf404f
--- /dev/null
+++ b/libc/sysdeps/linux/xtensa/bits/syscalls.h
@@ -0,0 +1,140 @@
+#ifndef _BITS_SYSCALLS_H
+#define _BITS_SYSCALLS_H
+#ifndef _SYSCALL_H
+# error "Never use <bits/syscalls.h> directly; include <sys/syscall.h> instead."
+#endif
+
+/*
+ Some of the sneaky macros in the code were taken from
+ glibc .../sysdeps/unix/sysv/linux/xtensa/sysdep.h
+*/
+
+#define SYS_ify(syscall_name) __NR_##syscall_name
+
+#ifdef __ASSEMBLER__
+
+/* The register layout upon entering the function is:
+
+ return addr stack ptr arg0, arg1, arg2, arg3, arg4, arg5
+ ----------- --------- ----------------------------------
+ a0 a1 a2, a3, a4, a5, a6, a7
+
+ (Of course a function with say 3 arguments does not have entries for
+ arguments 4, 5, and 6.)
+
+ Linux takes system-call arguments in registers. The ABI and Xtensa
+ software conventions require the system-call number in a2. We move any
+ argument that was in a2 to a7, and a7 to a8 if we have all 6 arguments.
+ Note that for improved efficiency, we do NOT shift all parameters down
+ one register to maintain the original order.
+
+ syscall number arg0, arg1, arg2, arg3, arg4, arg5
+ -------------- ----------------------------------
+ a2 a6, a3, a4, a5, a8, a9
+
+ Upon return, a2 and a3 are clobbered; all other registers are preserved. */
+
+#undef DO_CALL
+#define DO_CALL(syscall_name, nargs) \
+ DO_ARGS_##nargs \
+ movi a2, SYS_ify (syscall_name); \
+ syscall
+
+#define DO_ARGS_0
+#define DO_ARGS_1 mov a6, a2;
+#define DO_ARGS_2 mov a6, a2;
+#define DO_ARGS_3 mov a6, a2;
+#define DO_ARGS_4 mov a6, a2;
+#define DO_ARGS_5 mov a8, a6; mov a6, a2;
+#define DO_ARGS_6 mov a9, a7; mov a8, a6; mov a6, a2;
+
+#else /* not __ASSEMBLER__ */
+
+#include <errno.h>
+
+#define STR(s) #s
+#define LD_ARG(n,ar) register int _a##n asm (STR(a##n)) = (int) (ar)
+
+#define LD_ARGS_0()
+#define LD_ARGS_1(a0) LD_ARG(6,a0)
+#define LD_ARGS_2(a0,a1) LD_ARGS_1(a0); LD_ARG(3,a1)
+#define LD_ARGS_3(a0,a1,a2) LD_ARGS_2(a0,a1); LD_ARG(4,a2)
+#define LD_ARGS_4(a0,a1,a2,a3) LD_ARGS_3(a0,a1,a2); LD_ARG(5,a3)
+#define LD_ARGS_5(a0,a1,a2,a3,a4) LD_ARGS_4(a0,a1,a2,a3); LD_ARG(8,a4)
+#define LD_ARGS_6(a0,a1,a2,a3,a4,a5) LD_ARGS_5(a0,a1,a2,a3,a4); LD_ARG(9,a5)
+
+#define ASM_ARGS_0 "r"(_a2)
+#define ASM_ARGS_1 ASM_ARGS_0, "r"(_a6)
+#define ASM_ARGS_2 ASM_ARGS_1, "r"(_a3)
+#define ASM_ARGS_3 ASM_ARGS_2, "r"(_a4)
+#define ASM_ARGS_4 ASM_ARGS_3, "r"(_a5)
+#define ASM_ARGS_5 ASM_ARGS_4, "r"(_a8)
+#define ASM_ARGS_6 ASM_ARGS_5, "r"(_a9)
+
+/* Define a macro which expands into the inline wrapper code for a system
+ call. */
+
+#undef INLINE_SYSCALL
+#define INLINE_SYSCALL(name, nr, args...) \
+ ({ unsigned long resultvar = INTERNAL_SYSCALL (name, , nr, args); \
+ if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (resultvar, ), 0)) \
+ { \
+ __set_errno (INTERNAL_SYSCALL_ERRNO (resultvar, )); \
+ resultvar = (unsigned long) -1; \
+ } \
+ (long) resultvar; })
+
+#undef INTERNAL_SYSCALL_DECL
+#define INTERNAL_SYSCALL_DECL(err) do { } while (0)
+
+#define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \
+ ({ LD_ARG(2, name); \
+ LD_ARGS_##nr(args); \
+ asm volatile ("syscall\n" \
+ : "=a" (_a2) \
+ : ASM_ARGS_##nr \
+ : "memory"); \
+ (long) _a2; })
+
+#undef INTERNAL_SYSCALL
+#define INTERNAL_SYSCALL(name, err, nr, args...) \
+ INTERNAL_SYSCALL_NCS (__NR_##name, err, nr, ##args)
+
+#undef INTERNAL_SYSCALL_ERROR_P
+#define INTERNAL_SYSCALL_ERROR_P(val, err) \
+ ((unsigned long) (val) >= -4095L)
+
+#undef INTERNAL_SYSCALL_ERRNO
+#define INTERNAL_SYSCALL_ERRNO(val, err) (-(val))
+
+#define _syscall0(args...) SYSCALL_FUNC (0, args)
+#define _syscall1(args...) SYSCALL_FUNC (1, args)
+#define _syscall2(args...) SYSCALL_FUNC (2, args)
+#define _syscall3(args...) SYSCALL_FUNC (3, args)
+#define _syscall4(args...) SYSCALL_FUNC (4, args)
+#define _syscall5(args...) SYSCALL_FUNC (5, args)
+#define _syscall6(args...) SYSCALL_FUNC (6, args)
+
+#define C_DECL_ARGS_0() void
+#define C_DECL_ARGS_1(t, v) t v
+#define C_DECL_ARGS_2(t, v, args...) t v, C_DECL_ARGS_1(args)
+#define C_DECL_ARGS_3(t, v, args...) t v, C_DECL_ARGS_2(args)
+#define C_DECL_ARGS_4(t, v, args...) t v, C_DECL_ARGS_3(args)
+#define C_DECL_ARGS_5(t, v, args...) t v, C_DECL_ARGS_4(args)
+#define C_DECL_ARGS_6(t, v, args...) t v, C_DECL_ARGS_5(args)
+
+#define C_ARGS_0()
+#define C_ARGS_1(t, v) v
+#define C_ARGS_2(t, v, args...) v, C_ARGS_1 (args)
+#define C_ARGS_3(t, v, args...) v, C_ARGS_2 (args)
+#define C_ARGS_4(t, v, args...) v, C_ARGS_3 (args)
+#define C_ARGS_5(t, v, args...) v, C_ARGS_4 (args)
+#define C_ARGS_6(t, v, args...) v, C_ARGS_5 (args)
+
+#define SYSCALL_FUNC(nargs, type, name, args...) \
+type name (C_DECL_ARGS_##nargs (args)) { \
+ return (type) INLINE_SYSCALL (name, nargs, C_ARGS_##nargs (args)); \
+}
+
+#endif /* not __ASSEMBLER__ */
+#endif /* _BITS_SYSCALLS_H */