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To allow the ftrace trampoline code to reuse the PLT entry routines, factor it out and move it into asm/module.h. Cc: <stable@vger.kernel.org> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
93 lines
2.7 KiB
C
93 lines
2.7 KiB
C
/*
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* Copyright (C) 2012 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __ASM_MODULE_H
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#define __ASM_MODULE_H
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#include <asm-generic/module.h>
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#define MODULE_ARCH_VERMAGIC "aarch64"
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#ifdef CONFIG_ARM64_MODULE_PLTS
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struct mod_plt_sec {
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struct elf64_shdr *plt;
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int plt_num_entries;
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int plt_max_entries;
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};
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struct mod_arch_specific {
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struct mod_plt_sec core;
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struct mod_plt_sec init;
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/* for CONFIG_DYNAMIC_FTRACE */
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void *ftrace_trampoline;
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};
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#endif
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u64 module_emit_plt_entry(struct module *mod, void *loc, const Elf64_Rela *rela,
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Elf64_Sym *sym);
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#ifdef CONFIG_RANDOMIZE_BASE
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extern u64 module_alloc_base;
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#else
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#define module_alloc_base ((u64)_etext - MODULES_VSIZE)
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#endif
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struct plt_entry {
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/*
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* A program that conforms to the AArch64 Procedure Call Standard
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* (AAPCS64) must assume that a veneer that alters IP0 (x16) and/or
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* IP1 (x17) may be inserted at any branch instruction that is
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* exposed to a relocation that supports long branches. Since that
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* is exactly what we are dealing with here, we are free to use x16
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* as a scratch register in the PLT veneers.
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*/
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__le32 mov0; /* movn x16, #0x.... */
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__le32 mov1; /* movk x16, #0x...., lsl #16 */
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__le32 mov2; /* movk x16, #0x...., lsl #32 */
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__le32 br; /* br x16 */
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};
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static inline struct plt_entry get_plt_entry(u64 val)
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{
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/*
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* MOVK/MOVN/MOVZ opcode:
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* +--------+------------+--------+-----------+-------------+---------+
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* | sf[31] | opc[30:29] | 100101 | hw[22:21] | imm16[20:5] | Rd[4:0] |
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* +--------+------------+--------+-----------+-------------+---------+
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*
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* Rd := 0x10 (x16)
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* hw := 0b00 (no shift), 0b01 (lsl #16), 0b10 (lsl #32)
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* opc := 0b11 (MOVK), 0b00 (MOVN), 0b10 (MOVZ)
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* sf := 1 (64-bit variant)
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*/
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return (struct plt_entry){
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cpu_to_le32(0x92800010 | (((~val ) & 0xffff)) << 5),
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cpu_to_le32(0xf2a00010 | ((( val >> 16) & 0xffff)) << 5),
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cpu_to_le32(0xf2c00010 | ((( val >> 32) & 0xffff)) << 5),
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cpu_to_le32(0xd61f0200)
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};
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}
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static inline bool plt_entries_equal(const struct plt_entry *a,
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const struct plt_entry *b)
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{
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return a->mov0 == b->mov0 &&
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a->mov1 == b->mov1 &&
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a->mov2 == b->mov2;
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}
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#endif /* __ASM_MODULE_H */
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