Add build system scaffolding and libc headers

1 files changed, 53 insertions, 0 deletions

diff --git a/include/arch/x86_64/linux/const.h b/include/arch/x86_64/linux/const.h
new file mode 100644
index 00000000..f1694e63
--- /dev/null
+++ b/include/arch/x86_64/linux/const.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/* const.h: Macros for dealing with constants.  */
+
+#ifndef _LINUX_CONST_H
+#define _LINUX_CONST_H
+
+/* Some constant macros are used in both assembler and
+ * C code.  Therefore we cannot annotate them always with
+ * 'UL' and other type specifiers unilaterally.  We
+ * use the following macros to deal with this.
+ *
+ * Similarly, _AT() will cast an expression with a type in C, but
+ * leave it unchanged in asm.
+ */
+
+#ifdef __ASSEMBLY__
+#define _AC(X, Y) X
+#define _AT(T, X) X
+#else
+#define __AC(X, Y) (X##Y)
+#define _AC(X, Y)  __AC(X, Y)
+#define _AT(T, X)  ((T)(X))
+#endif
+
+#define _UL(x)	(_AC(x, UL))
+#define _ULL(x) (_AC(x, ULL))
+
+#define _BITUL(x)  (_UL(1) << (x))
+#define _BITULL(x) (_ULL(1) << (x))
+
+#if !defined(__ASSEMBLY__)
+/*
+ * Missing __asm__ support
+ *
+ * __BIT128() would not work in the __asm__ code, as it shifts an
+ * 'unsigned __int128' data type as direct representation of
+ * 128 bit constants is not supported in the gcc compiler, as
+ * they get silently truncated.
+ *
+ * TODO: Please revisit this implementation when gcc compiler
+ * starts representing 128 bit constants directly like long
+ * and unsigned long etc. Subsequently drop the comment for
+ * GENMASK_U128() which would then start supporting __asm__ code.
+ */
+#define _BIT128(x) ((unsigned __int128)(1) << (x))
+#endif
+
+#define __ALIGN_KERNEL(x, a)	     __ALIGN_KERNEL_MASK(x, (__typeof__(x))(a) - 1)
+#define __ALIGN_KERNEL_MASK(x, mask) (((x) + (mask)) & ~(mask))
+
+#define __KERNEL_DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
+
+#endif /* _LINUX_CONST_H */