7523e4dc50
Makes it easier to handle init vs core cleanly, though the change is fairly invasive across random architectures. It simplifies the rbtree code immediately, however, while keeping the core data together in the same cachline (now iff the rbtree code is enabled). Acked-by: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
92 lines
2.5 KiB
C
92 lines
2.5 KiB
C
/*
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* livepatch.c - x86-specific Kernel Live Patching Core
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*
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* Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
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* Copyright (C) 2014 SUSE
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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 2
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* of the License, or (at your option) any later version.
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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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#include <linux/module.h>
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#include <linux/uaccess.h>
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#include <asm/cacheflush.h>
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#include <asm/page_types.h>
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#include <asm/elf.h>
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#include <asm/livepatch.h>
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/**
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* klp_write_module_reloc() - write a relocation in a module
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* @mod: module in which the section to be modified is found
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* @type: ELF relocation type (see asm/elf.h)
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* @loc: address that the relocation should be written to
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* @value: relocation value (sym address + addend)
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*
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* This function writes a relocation to the specified location for
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* a particular module.
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*/
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int klp_write_module_reloc(struct module *mod, unsigned long type,
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unsigned long loc, unsigned long value)
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{
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int ret, numpages, size = 4;
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bool readonly;
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unsigned long val;
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unsigned long core = (unsigned long)mod->core_layout.base;
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unsigned long core_size = mod->core_layout.size;
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switch (type) {
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case R_X86_64_NONE:
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return 0;
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case R_X86_64_64:
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val = value;
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size = 8;
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break;
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case R_X86_64_32:
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val = (u32)value;
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break;
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case R_X86_64_32S:
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val = (s32)value;
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break;
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case R_X86_64_PC32:
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val = (u32)(value - loc);
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break;
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default:
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/* unsupported relocation type */
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return -EINVAL;
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}
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if (loc < core || loc >= core + core_size)
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/* loc does not point to any symbol inside the module */
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return -EINVAL;
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readonly = false;
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#ifdef CONFIG_DEBUG_SET_MODULE_RONX
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if (loc < core + mod->core_layout.ro_size)
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readonly = true;
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#endif
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/* determine if the relocation spans a page boundary */
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numpages = ((loc & PAGE_MASK) == ((loc + size) & PAGE_MASK)) ? 1 : 2;
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if (readonly)
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set_memory_rw(loc & PAGE_MASK, numpages);
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ret = probe_kernel_write((void *)loc, &val, size);
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if (readonly)
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set_memory_ro(loc & PAGE_MASK, numpages);
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return ret;
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}
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