136cd3450a
Currently we generate the module stub for ftrace_caller() at the bottom of apply_relocate_add(). However apply_relocate_add() is potentially called more than once per module, which means we will try to generate the ftrace_caller() stub multiple times. Although the current code deals with that correctly, ie. it only generates a stub the first time, it would be clearer to only try to generate the stub once. Note also on first reading it may appear that we generate a different stub for each section that requires relocation, but that is not the case. The code in stub_for_addr() that searches for an existing stub uses sechdrs[me->arch.stubs_section], ie. the single stub section for this module. A cleaner approach is to only generate the ftrace_caller() stub once, from module_finalize(). Although the original code didn't check to see if the stub was actually generated correctly, it seems prudent to add a check, so do that. And an additional benefit is we can clean the ifdefs up a little. Finally we must propagate the const'ness of some of the pointers passed to module_finalize(), but that is also an improvement. Reviewed-by: Balbir Singh <bsingharora@gmail.com> Reviewed-by: Torsten Duwe <duwe@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
104 lines
2.7 KiB
C
104 lines
2.7 KiB
C
#ifndef _ASM_POWERPC_MODULE_H
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#define _ASM_POWERPC_MODULE_H
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#ifdef __KERNEL__
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/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/list.h>
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#include <asm/bug.h>
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#include <asm-generic/module.h>
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#ifndef __powerpc64__
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/*
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* Thanks to Paul M for explaining this.
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*
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* PPC can only do rel jumps += 32MB, and often the kernel and other
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* modules are furthur away than this. So, we jump to a table of
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* trampolines attached to the module (the Procedure Linkage Table)
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* whenever that happens.
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*/
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struct ppc_plt_entry {
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/* 16 byte jump instruction sequence (4 instructions) */
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unsigned int jump[4];
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};
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#endif /* __powerpc64__ */
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struct mod_arch_specific {
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#ifdef __powerpc64__
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unsigned int stubs_section; /* Index of stubs section in module */
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unsigned int toc_section; /* What section is the TOC? */
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bool toc_fixed; /* Have we fixed up .TOC.? */
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#ifdef CONFIG_DYNAMIC_FTRACE
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unsigned long toc;
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unsigned long tramp;
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#endif
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#else /* powerpc64 */
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/* Indices of PLT sections within module. */
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unsigned int core_plt_section;
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unsigned int init_plt_section;
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#ifdef CONFIG_DYNAMIC_FTRACE
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unsigned long tramp;
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#endif
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#endif /* powerpc64 */
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/* List of BUG addresses, source line numbers and filenames */
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struct list_head bug_list;
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struct bug_entry *bug_table;
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unsigned int num_bugs;
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};
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/*
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* Select ELF headers.
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* Make empty section for module_frob_arch_sections to expand.
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*/
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#ifdef __powerpc64__
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# ifdef MODULE
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asm(".section .stubs,\"ax\",@nobits; .align 3; .previous");
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# endif
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#else
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# ifdef MODULE
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asm(".section .plt,\"ax\",@nobits; .align 3; .previous");
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asm(".section .init.plt,\"ax\",@nobits; .align 3; .previous");
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# endif /* MODULE */
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#endif
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#ifdef CONFIG_DYNAMIC_FTRACE
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# ifdef MODULE
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asm(".section .ftrace.tramp,\"ax\",@nobits; .align 3; .previous");
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# endif /* MODULE */
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#endif
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bool is_module_trampoline(u32 *insns);
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int module_trampoline_target(struct module *mod, u32 *trampoline,
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unsigned long *target);
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#ifdef CONFIG_DYNAMIC_FTRACE
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int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs);
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#else
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static inline int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs)
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{
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return 0;
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}
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#endif
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struct exception_table_entry;
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void sort_ex_table(struct exception_table_entry *start,
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struct exception_table_entry *finish);
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#if defined(CONFIG_MODVERSIONS) && defined(CONFIG_PPC64)
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#define ARCH_RELOCATES_KCRCTAB
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#define reloc_start PHYSICAL_START
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#endif
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_MODULE_H */
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