cregit-Linux how code gets into the kernel

Release 4.15 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 {
	
struct elf64_shdr	*plt;
	
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, void *loc, const Elf64_Rela *rela,
			  Elf64_Sym *sym);

#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	mov0;	/* movn x16, #0x....                    */
	
__le32	mov1;	/* movk x16, #0x...., lsl #16           */
	
__le32	mov2;	/* movk x16, #0x...., lsl #32           */
	
__le32	br;	/* br   x16                             */
};


static inline struct plt_entry get_plt_entry(u64 val) { /* * MOVK/MOVN/MOVZ opcode: * +--------+------------+--------+-----------+-------------+---------+ * | sf[31] | opc[30:29] | 100101 | hw[22:21] | imm16[20:5] | Rd[4:0] | * +--------+------------+--------+-----------+-------------+---------+ * * Rd := 0x10 (x16) * hw := 0b00 (no shift), 0b01 (lsl #16), 0b10 (lsl #32) * opc := 0b11 (MOVK), 0b00 (MOVN), 0b10 (MOVZ) * sf := 1 (64-bit variant) */ return (struct plt_entry){ cpu_to_le32(0x92800010 | (((~val ) & 0xffff)) << 5), cpu_to_le32(0xf2a00010 | ((( val >> 16) & 0xffff)) << 5), cpu_to_le32(0xf2c00010 | ((( val >> 32) & 0xffff)) << 5), cpu_to_le32(0xd61f0200) }; }

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Ard Biesheuvel80100.00%1100.00%
Total80100.00%1100.00%


static inline bool plt_entries_equal(const struct plt_entry *a, const struct plt_entry *b) { return a->mov0 == b->mov0 && a->mov1 == b->mov1 && a->mov2 == b->mov2; }

Contributors

PersonTokensPropCommitsCommitProp
Ard Biesheuvel44100.00%1100.00%
Total44100.00%1100.00%

#endif /* __ASM_MODULE_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
Ard Biesheuvel22392.92%685.71%
Will Deacon177.08%114.29%
Total240100.00%7100.00%
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