/* SPDX-License-Identifier: GPL-2.0 */

/* Upstream Linux v6.0: arch/x86/include/asm/uaccess_64.h:27-47
 * Exact source lines; kernel context, not a standalone program or book restoration.
 */
static __always_inline __must_check unsigned long
copy_user_generic(void *to, const void *from, unsigned len)
{
	unsigned ret;

	/*
	 * If CPU has ERMS feature, use copy_user_enhanced_fast_string.
	 * Otherwise, if CPU has rep_good feature, use copy_user_generic_string.
	 * Otherwise, use copy_user_generic_unrolled.
	 */
	alternative_call_2(copy_user_generic_unrolled,
			 copy_user_generic_string,
			 X86_FEATURE_REP_GOOD,
			 copy_user_enhanced_fast_string,
			 X86_FEATURE_ERMS,
			 ASM_OUTPUT2("=a" (ret), "=D" (to), "=S" (from),
				     "=d" (len)),
			 "1" (to), "2" (from), "3" (len)
			 : "memory", "rcx", "r8", "r9", "r10", "r11");
	return ret;
}