Copying utility headers from optee_os.

Provides an interface for the following common tasks:
  - defining functions in assembly
  - setting function and variable attributes
  - safe integer operations

The files in this commit were forked from optee_os, keeping the
original license header intact:
    tag name: v3.10.0
    tagged commit: d1c635434c55b7d75eadf471bde04926bd1e50a7

From 'lib/libutils/ext/include/' of optee_os to
    'components/common/utils/include/':
        asm.S
        compiler.h
        util.h

Change-Id: I5d83618fa157a4b14f86e522c5def40c74c4ad95
Signed-off-by: Imre Kis <imre.kis@arm.com>
diff --git a/components/common/utils/include/compiler.h b/components/common/utils/include/compiler.h
new file mode 100644
index 0000000..c363df9
--- /dev/null
+++ b/components/common/utils/include/compiler.h
@@ -0,0 +1,250 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (c) 2014, STMicroelectronics International N.V.
+ */
+
+#ifndef COMPILER_H
+#define COMPILER_H
+
+/*
+ * Macros that should be used instead of using __attribute__ directly to
+ * ease portability and make the code easier to read.
+ *
+ * Some of the defines below is known to sometimes cause conflicts when
+ * this file is included from xtest in normal world. It is assumed that
+ * the conflicting defines has the same meaning in that environment.
+ * Surrounding the troublesome defines with #ifndef should be enough.
+ */
+#define __deprecated	__attribute__((deprecated))
+#ifndef __packed
+#define __packed	__attribute__((packed))
+#endif
+#define __weak		__attribute__((weak))
+#ifndef __noreturn
+#define __noreturn	__attribute__((__noreturn__))
+#endif
+#define __pure		__attribute__((pure))
+#define __aligned(x)	__attribute__((aligned(x)))
+#define __printf(a, b)	__attribute__((format(printf, a, b)))
+#define __noinline	__attribute__((noinline))
+#define __attr_const	__attribute__((__const__))
+#ifndef __unused
+#define __unused	__attribute__((unused))
+#endif
+#define __maybe_unused	__attribute__((unused))
+#ifndef __used
+#define __used		__attribute__((__used__))
+#endif
+#define __must_check	__attribute__((warn_unused_result))
+#define __cold		__attribute__((__cold__))
+#define __section(x)	__attribute__((section(x)))
+#define __data		__section(".data")
+#define __bss		__section(".bss")
+#ifdef __clang__
+#define __SECTION_FLAGS_RODATA
+#else
+/*
+ * Override sections flags/type generated by the C compiler to make sure they
+ * are: "a",%progbits (thus creating an allocatable, non-writeable, non-
+ * executable data section).
+ * The trailing '//' comments out the flags generated by the compiler.
+ * This avoids a harmless warning with GCC.
+ */
+#define __SECTION_FLAGS_RODATA ",\"a\",%progbits //"
+#endif
+#define __rodata	__section(".rodata" __SECTION_FLAGS_RODATA)
+#define __rodata_unpaged __section(".rodata.__unpaged" __SECTION_FLAGS_RODATA)
+#ifdef CFG_VIRTUALIZATION
+#define __nex_bss		__section(".nex_bss")
+#define __nex_data		__section(".nex_data")
+#else  /* CFG_VIRTUALIZATION */
+#define __nex_bss
+#define __nex_data
+#endif	/* CFG_VIRTUALIZATION */
+#define __noprof	__attribute__((no_instrument_function))
+#define __nostackcheck	__attribute__((no_instrument_function))
+
+#define __compiler_bswap64(x)	__builtin_bswap64((x))
+#define __compiler_bswap32(x)	__builtin_bswap32((x))
+#define __compiler_bswap16(x)	__builtin_bswap16((x))
+
+#define __GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + \
+		       __GNUC_PATCHLEVEL__)
+
+#if __GCC_VERSION >= 50100 && !defined(__CHECKER__)
+#define __HAVE_BUILTIN_OVERFLOW 1
+#endif
+
+#ifdef __HAVE_BUILTIN_OVERFLOW
+#define __compiler_add_overflow(a, b, res) \
+	__builtin_add_overflow((a), (b), (res))
+
+#define __compiler_sub_overflow(a, b, res) \
+	__builtin_sub_overflow((a), (b), (res))
+
+#define __compiler_mul_overflow(a, b, res) \
+	__builtin_mul_overflow((a), (b), (res))
+#else /*!__HAVE_BUILTIN_OVERFLOW*/
+
+/*
+ * Copied/inspired from https://www.fefe.de/intof.html
+ */
+
+#define __INTOF_ASSIGN(dest, src) (__extension__({ \
+	typeof(src) __intof_x = (src); \
+	typeof(dest) __intof_y = __intof_x; \
+	(((uintmax_t)__intof_x == (uintmax_t)__intof_y) && \
+	 ((__intof_x < 1) == (__intof_y < 1)) ? \
+		(void)((dest) = __intof_y) , 0 : 1); \
+}))
+
+#define __INTOF_ADD(c, a, b) (__extension__({ \
+	typeof(a) __intofa_a = (a); \
+	typeof(b) __intofa_b = (b); \
+	intmax_t __intofa_a_signed = __intofa_a; \
+	uintmax_t __intofa_a_unsigned = __intofa_a; \
+	intmax_t __intofa_b_signed = __intofa_b; \
+	uintmax_t __intofa_b_unsigned = __intofa_b; \
+	\
+	__intofa_b < 1 ? \
+		__intofa_a < 1 ? \
+			((INTMAX_MIN - __intofa_b_signed <= \
+			  __intofa_a_signed)) ? \
+				__INTOF_ASSIGN((c), __intofa_a_signed + \
+						    __intofa_b_signed) : 1 \
+		: \
+			((__intofa_a_unsigned >= (uintmax_t)-__intofa_b) ? \
+				__INTOF_ASSIGN((c), __intofa_a_unsigned + \
+						    __intofa_b_signed) \
+			: \
+				__INTOF_ASSIGN((c), \
+					(intmax_t)(__intofa_a_unsigned + \
+						   __intofa_b_signed))) \
+	: \
+		__intofa_a < 1 ? \
+			((__intofa_b_unsigned >= (uintmax_t)-__intofa_a) ? \
+				__INTOF_ASSIGN((c), __intofa_a_signed + \
+						    __intofa_b_unsigned) \
+			: \
+				__INTOF_ASSIGN((c), \
+					(intmax_t)(__intofa_a_signed + \
+						   __intofa_b_unsigned))) \
+		: \
+			((UINTMAX_MAX - __intofa_b_unsigned >= \
+			  __intofa_a_unsigned) ? \
+				__INTOF_ASSIGN((c), __intofa_a_unsigned + \
+						    __intofa_b_unsigned) : 1); \
+}))
+
+#define __INTOF_SUB(c, a, b) (__extension__({ \
+	typeof(a) __intofs_a = a; \
+	typeof(b) __intofs_b = b; \
+	intmax_t __intofs_a_signed = __intofs_a; \
+	uintmax_t __intofs_a_unsigned = __intofs_a; \
+	intmax_t __intofs_b_signed = __intofs_b; \
+	uintmax_t __intofs_b_unsigned = __intofs_b; \
+	\
+	__intofs_b < 1 ? \
+		__intofs_a < 1 ? \
+			((INTMAX_MAX + __intofs_b_signed >= \
+			  __intofs_a_signed) ? \
+				__INTOF_ASSIGN((c), __intofs_a_signed - \
+						    __intofs_b_signed) : 1) \
+		: \
+			(((uintmax_t)(UINTMAX_MAX + __intofs_b_signed) >= \
+			  __intofs_a_unsigned) ? \
+				__INTOF_ASSIGN((c), __intofs_a - \
+						    __intofs_b) : 1) \
+	: \
+		__intofs_a < 1 ? \
+			(((intmax_t)(INTMAX_MIN + __intofs_b) <= \
+			  __intofs_a_signed) ? \
+				__INTOF_ASSIGN((c), \
+					(intmax_t)(__intofs_a_signed - \
+						   __intofs_b_unsigned)) : 1) \
+		: \
+			((__intofs_b_unsigned <= __intofs_a_unsigned) ? \
+				__INTOF_ASSIGN((c), __intofs_a_unsigned - \
+						    __intofs_b_unsigned) \
+			: \
+				__INTOF_ASSIGN((c), \
+					(intmax_t)(__intofs_a_unsigned - \
+						   __intofs_b_unsigned))); \
+}))
+
+/*
+ * Dealing with detecting overflow in multiplication of integers.
+ *
+ * First step is to remove two corner cases with the minum signed integer
+ * which can't be represented as a positive integer + sign.
+ * Multiply with 0 or 1 can't overflow, no checking needed of the operation,
+ * only if it can be assigned to the result.
+ *
+ * After the corner cases are eliminated we convert the two factors to
+ * positive unsigned values, keeping track of the original in another
+ * variable which is used at the end to determine the sign of the product.
+ *
+ * The two terms (a and b) are divided into upper and lower half (x1 upper
+ * and x0 lower), so the product is:
+ * ((a1 << hshift) + a0) * ((b1 << hshift) + b0)
+ * which also is:
+ * ((a1 * b1) << (hshift * 2)) +				(T1)
+ * ((a1 * b0 + a0 * b1) << hshift) +				(T2)
+ * (a0 * b0)							(T3)
+ *
+ * From this we can tell and (a1 * b1) has to be 0 or we'll overflow, that
+ * is, at least one of a1 or b1 has to be 0. Once this has been checked the
+ * addition: ((a1 * b0) << hshift) + ((a0 * b1) << hshift)
+ * isn't an addition as one of the terms will be 0.
+ *
+ * Since each factor in: (a0 * b0)
+ * only uses half the capicity of the underlaying type it can't overflow
+ *
+ * The addition of T2 and T3 can overflow so we use __INTOF_ADD() to
+ * perform that addition. If the addition succeeds without overflow the
+ * result is assigned the required sign and checked for overflow again.
+ */
+
+#define __intof_mul_negate	((__intof_oa < 1) != (__intof_ob < 1))
+#define __intof_mul_hshift	(sizeof(uintmax_t) * 8 / 2)
+#define __intof_mul_hmask	(UINTMAX_MAX >> __intof_mul_hshift)
+#define __intof_mul_a0		((uintmax_t)(__intof_a) >> __intof_mul_hshift)
+#define __intof_mul_b0		((uintmax_t)(__intof_b) >> __intof_mul_hshift)
+#define __intof_mul_a1		((uintmax_t)(__intof_a) & __intof_mul_hmask)
+#define __intof_mul_b1		((uintmax_t)(__intof_b) & __intof_mul_hmask)
+#define __intof_mul_t		(__intof_mul_a1 * __intof_mul_b0 + \
+				 __intof_mul_a0 * __intof_mul_b1)
+
+#define __INTOF_MUL(c, a, b) (__extension__({ \
+	typeof(a) __intof_oa = (a); \
+	typeof(a) __intof_a = __intof_oa < 1 ? -__intof_oa : __intof_oa; \
+	typeof(b) __intof_ob = (b); \
+	typeof(b) __intof_b = __intof_ob < 1 ? -__intof_ob : __intof_ob; \
+	typeof(c) __intof_c; \
+	\
+	__intof_oa == 0 || __intof_ob == 0 || \
+	__intof_oa == 1 || __intof_ob == 1 ? \
+		__INTOF_ASSIGN((c), __intof_oa * __intof_ob) : \
+	(__intof_mul_a0 && __intof_mul_b0) || \
+	 __intof_mul_t > __intof_mul_hmask ?  1 : \
+	__INTOF_ADD((__intof_c), __intof_mul_t << __intof_mul_hshift, \
+				 __intof_mul_a1 * __intof_mul_b1) ? 1 : \
+	__intof_mul_negate ? __INTOF_ASSIGN((c), -__intof_c) : \
+			     __INTOF_ASSIGN((c), __intof_c); \
+}))
+
+#define __compiler_add_overflow(a, b, res) __INTOF_ADD(*(res), (a), (b))
+#define __compiler_sub_overflow(a, b, res) __INTOF_SUB(*(res), (a), (b))
+#define __compiler_mul_overflow(a, b, res) __INTOF_MUL(*(res), (a), (b))
+
+#endif /*!__HAVE_BUILTIN_OVERFLOW*/
+
+#define __compiler_compare_and_swap(p, oval, nval) \
+	__atomic_compare_exchange_n((p), (oval), (nval), true, \
+				    __ATOMIC_ACQUIRE, __ATOMIC_RELAXED) \
+
+#define __compiler_atomic_load(p) __atomic_load_n((p), __ATOMIC_RELAXED)
+#define __compiler_atomic_store(p, val) \
+	__atomic_store_n((p), (val), __ATOMIC_RELAXED)
+
+#endif /*COMPILER_H*/