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e71a4e1beb
Currently, dynamic ftrace support in the arm64 kernel assumes that all core kernel code is within range of ordinary branch instructions that occur in module code, which is usually the case, but is no longer guaranteed now that we have support for module PLTs and address space randomization. Since on arm64, all patching of branch instructions involves function calls to the same entry point [ftrace_caller()], we can emit the modules with a trampoline that has unlimited range, and patch both the trampoline itself and the branch instruction to redirect the call via the trampoline. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> [will: minor clarification to smp_wmb() comment] Signed-off-by: Will Deacon <will.deacon@arm.com>
49 lines
1.3 KiB
C
49 lines
1.3 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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#endif /* __ASM_MODULE_H */
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