x86/vdso/doc: Rename vdso_test.c to vdso_standalone_test_x86.c

This thing is hopelessly x86_64-specific: it's an example of how to
access the vDSO without any runtime support at all.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/3efc170e0e166e15f0150c9fdb37d52488b9c0a4.1402620737.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

diff --git a/Documentation/vDSO/vdso_standalone_test_x86.c b/Documentation/vDSO/vdso_standalone_test_x86.c
new file mode 100644 (file)
index 0000000..1523f5d
--- /dev/null
+++ b/Documentation/vDSO/vdso_standalone_test_x86.c
@@ -0,0 +1,111 @@
+/*
+ * vdso_test.c: Sample code to test parse_vdso.c on x86_64
+ * Copyright (c) 2011 Andy Lutomirski
+ * Subject to the GNU General Public License, version 2
+ *
+ * You can amuse yourself by compiling with:
+ * gcc -std=gnu99 -nostdlib
+ *     -Os -fno-asynchronous-unwind-tables -flto
+ *      vdso_standalone_test_x86.c parse_vdso.c
+ * to generate a small binary with no dependencies at all.
+ */
+
+#include <sys/syscall.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include <stdint.h>
+
+extern void *vdso_sym(const char *version, const char *name);
+extern void vdso_init_from_sysinfo_ehdr(uintptr_t base);
+extern void vdso_init_from_auxv(void *auxv);
+
+/* We need a libc functions... */
+int strcmp(const char *a, const char *b)
+{
+       /* This implementation is buggy: it never returns -1. */
+       while (*a || *b) {
+               if (*a != *b)
+                       return 1;
+               if (*a == 0 || *b == 0)
+                       return 1;
+               a++;
+               b++;
+       }
+
+       return 0;
+}
+
+/* ...and two syscalls.  This is x86_64-specific. */
+static inline long linux_write(int fd, const void *data, size_t len)
+{
+
+       long ret;
+       asm volatile ("syscall" : "=a" (ret) : "a" (__NR_write),
+                     "D" (fd), "S" (data), "d" (len) :
+                     "cc", "memory", "rcx",
+                     "r8", "r9", "r10", "r11" );
+       return ret;
+}
+
+static inline void linux_exit(int code)
+{
+       asm volatile ("syscall" : : "a" (__NR_exit), "D" (code));
+}
+
+void to_base10(char *lastdig, uint64_t n)
+{
+       while (n) {
+               *lastdig = (n % 10) + '0';
+               n /= 10;
+               lastdig--;
+       }
+}
+
+__attribute__((externally_visible)) void c_main(void **stack)
+{
+       /* Parse the stack */
+       long argc = (long)*stack;
+       stack += argc + 2;
+
+       /* Now we're pointing at the environment.  Skip it. */
+       while(*stack)
+               stack++;
+       stack++;
+
+       /* Now we're pointing at auxv.  Initialize the vDSO parser. */
+       vdso_init_from_auxv((void *)stack);
+
+       /* Find gettimeofday. */
+       typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz);
+       gtod_t gtod = (gtod_t)vdso_sym("LINUX_2.6", "__vdso_gettimeofday");
+
+       if (!gtod)
+               linux_exit(1);
+
+       struct timeval tv;
+       long ret = gtod(&tv, 0);
+
+       if (ret == 0) {
+               char buf[] = "The time is                     .000000\n";
+               to_base10(buf + 31, tv.tv_sec);
+               to_base10(buf + 38, tv.tv_usec);
+               linux_write(1, buf, sizeof(buf) - 1);
+       } else {
+               linux_exit(ret);
+       }
+
+       linux_exit(0);
+}
+
+/*
+ * This is the real entry point.  It passes the initial stack into
+ * the C entry point.
+ */
+asm (
+       ".text\n"
+       ".global _start\n"
+        ".type _start,@function\n"
+        "_start:\n\t"
+        "mov %rsp,%rdi\n\t"
+        "jmp c_main"
+       );

diff --git a/Documentation/vDSO/vdso_test.c b/Documentation/vDSO/vdso_test.c
deleted file mode 100644 (file)
index fff6334..0000000
--- a/Documentation/vDSO/vdso_test.c
+++ /dev/null
@@ -1,111 +0,0 @@
-/*
- * vdso_test.c: Sample code to test parse_vdso.c on x86_64
- * Copyright (c) 2011 Andy Lutomirski
- * Subject to the GNU General Public License, version 2
- *
- * You can amuse yourself by compiling with:
- * gcc -std=gnu99 -nostdlib
- *     -Os -fno-asynchronous-unwind-tables -flto
- *      vdso_test.c parse_vdso.c -o vdso_test
- * to generate a small binary with no dependencies at all.
- */
-
-#include <sys/syscall.h>
-#include <sys/time.h>
-#include <unistd.h>
-#include <stdint.h>
-
-extern void *vdso_sym(const char *version, const char *name);
-extern void vdso_init_from_sysinfo_ehdr(uintptr_t base);
-extern void vdso_init_from_auxv(void *auxv);
-
-/* We need a libc functions... */
-int strcmp(const char *a, const char *b)
-{
-       /* This implementation is buggy: it never returns -1. */
-       while (*a || *b) {
-               if (*a != *b)
-                       return 1;
-               if (*a == 0 || *b == 0)
-                       return 1;
-               a++;
-               b++;
-       }
-
-       return 0;
-}
-
-/* ...and two syscalls.  This is x86_64-specific. */
-static inline long linux_write(int fd, const void *data, size_t len)
-{
-
-       long ret;
-       asm volatile ("syscall" : "=a" (ret) : "a" (__NR_write),
-                     "D" (fd), "S" (data), "d" (len) :
-                     "cc", "memory", "rcx",
-                     "r8", "r9", "r10", "r11" );
-       return ret;
-}
-
-static inline void linux_exit(int code)
-{
-       asm volatile ("syscall" : : "a" (__NR_exit), "D" (code));
-}
-
-void to_base10(char *lastdig, uint64_t n)
-{
-       while (n) {
-               *lastdig = (n % 10) + '0';
-               n /= 10;
-               lastdig--;
-       }
-}
-
-__attribute__((externally_visible)) void c_main(void **stack)
-{
-       /* Parse the stack */
-       long argc = (long)*stack;
-       stack += argc + 2;
-
-       /* Now we're pointing at the environment.  Skip it. */
-       while(*stack)
-               stack++;
-       stack++;
-
-       /* Now we're pointing at auxv.  Initialize the vDSO parser. */
-       vdso_init_from_auxv((void *)stack);
-
-       /* Find gettimeofday. */
-       typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz);
-       gtod_t gtod = (gtod_t)vdso_sym("LINUX_2.6", "__vdso_gettimeofday");
-
-       if (!gtod)
-               linux_exit(1);
-
-       struct timeval tv;
-       long ret = gtod(&tv, 0);
-
-       if (ret == 0) {
-               char buf[] = "The time is                     .000000\n";
-               to_base10(buf + 31, tv.tv_sec);
-               to_base10(buf + 38, tv.tv_usec);
-               linux_write(1, buf, sizeof(buf) - 1);
-       } else {
-               linux_exit(ret);
-       }
-
-       linux_exit(0);
-}
-
-/*
- * This is the real entry point.  It passes the initial stack into
- * the C entry point.
- */
-asm (
-       ".text\n"
-       ".global _start\n"
-        ".type _start,@function\n"
-        "_start:\n\t"
-        "mov %rsp,%rdi\n\t"
-        "jmp c_main"
-       );