arch/arm64/include/asm/module.h

/*
 * Copyright (C) 2012 ARM Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef __ASM_MODULE_H
#define __ASM_MODULE_H

#include <asm-generic/module.h>

#define MODULE_ARCH_VERMAGIC	"aarch64"

#ifdef CONFIG_ARM64_MODULE_PLTS
struct mod_plt_sec {
	int			plt_shndx;
	int			plt_num_entries;
	int			plt_max_entries;
};

struct mod_arch_specific {
	struct mod_plt_sec	core;
	struct mod_plt_sec	init;

	/* for CONFIG_DYNAMIC_FTRACE */
	struct plt_entry 	*ftrace_trampoline;
};
#endif

u64 module_emit_plt_entry(struct module *mod, Elf64_Shdr *sechdrs,
			  void *loc, const Elf64_Rela *rela,
			  Elf64_Sym *sym);

u64 module_emit_veneer_for_adrp(struct module *mod, Elf64_Shdr *sechdrs,
				void *loc, u64 val);

#ifdef CONFIG_RANDOMIZE_BASE
extern u64 module_alloc_base;
#else
#define module_alloc_base	((u64)_etext - MODULES_VSIZE)
#endif

struct plt_entry {
	/*
	 * A program that conforms to the AArch64 Procedure Call Standard
	 * (AAPCS64) must assume that a veneer that alters IP0 (x16) and/or
	 * IP1 (x17) may be inserted at any branch instruction that is
	 * exposed to a relocation that supports long branches. Since that
	 * is exactly what we are dealing with here, we are free to use x16
	 * as a scratch register in the PLT veneers.
	 */
	__le32	adrp;	/* adrp	x16, ....			*/
	__le32	add;	/* add	x16, x16, #0x....		*/
	__le32	br;	/* br	x16				*/
};

static inline bool is_forbidden_offset_for_adrp(void *place)
{
	return IS_ENABLED(CONFIG_ARM64_ERRATUM_843419) &&
	       cpus_have_const_cap(ARM64_WORKAROUND_843419) &&
	       ((u64)place & 0xfff) >= 0xff8;
}

struct plt_entry get_plt_entry(u64 dst, void *pc);
bool plt_entries_equal(const struct plt_entry *a, const struct plt_entry *b);

#endif /* __ASM_MODULE_H */