xref: /openbmc/linux/arch/arm64/include/asm/module.h (revision d7955ce4)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2012 ARM Ltd.
4  */
5 #ifndef __ASM_MODULE_H
6 #define __ASM_MODULE_H
7 
8 #include <asm-generic/module.h>
9 
10 struct mod_plt_sec {
11 	int			plt_shndx;
12 	int			plt_num_entries;
13 	int			plt_max_entries;
14 };
15 
16 struct mod_arch_specific {
17 	struct mod_plt_sec	core;
18 	struct mod_plt_sec	init;
19 
20 	/* for CONFIG_DYNAMIC_FTRACE */
21 	struct plt_entry	*ftrace_trampolines;
22 };
23 
24 u64 module_emit_plt_entry(struct module *mod, Elf64_Shdr *sechdrs,
25 			  void *loc, const Elf64_Rela *rela,
26 			  Elf64_Sym *sym);
27 
28 u64 module_emit_veneer_for_adrp(struct module *mod, Elf64_Shdr *sechdrs,
29 				void *loc, u64 val);
30 
31 struct plt_entry {
32 	/*
33 	 * A program that conforms to the AArch64 Procedure Call Standard
34 	 * (AAPCS64) must assume that a veneer that alters IP0 (x16) and/or
35 	 * IP1 (x17) may be inserted at any branch instruction that is
36 	 * exposed to a relocation that supports long branches. Since that
37 	 * is exactly what we are dealing with here, we are free to use x16
38 	 * as a scratch register in the PLT veneers.
39 	 */
40 	__le32	adrp;	/* adrp	x16, ....			*/
41 	__le32	add;	/* add	x16, x16, #0x....		*/
42 	__le32	br;	/* br	x16				*/
43 };
44 
45 static inline bool is_forbidden_offset_for_adrp(void *place)
46 {
47 	return IS_ENABLED(CONFIG_ARM64_ERRATUM_843419) &&
48 	       cpus_have_const_cap(ARM64_WORKAROUND_843419) &&
49 	       ((u64)place & 0xfff) >= 0xff8;
50 }
51 
52 struct plt_entry get_plt_entry(u64 dst, void *pc);
53 
54 static inline const Elf_Shdr *find_section(const Elf_Ehdr *hdr,
55 				    const Elf_Shdr *sechdrs,
56 				    const char *name)
57 {
58 	const Elf_Shdr *s, *se;
59 	const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
60 
61 	for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) {
62 		if (strcmp(name, secstrs + s->sh_name) == 0)
63 			return s;
64 	}
65 
66 	return NULL;
67 }
68 
69 #endif /* __ASM_MODULE_H */
70