tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
parisc: add parisc code patching
Instead of re-mapping the whole kernel text with RWX rights
add a patch_text() which can be used to replace instructions
in the kernel .text section. Based on the ARM implementation.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>
authored by
Sven Schnelle
and committed by
Helge Deller
620a53d5
ccfbc68d
+91
-1
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arch/parisc/include/asm/patch.h
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arch/parisc/include/asm/patch.h
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _PARISC_KERNEL_PATCH_H
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#define _PARISC_KERNEL_PATCH_H
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/* stop machine and patch kernel text */
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void patch_text(void *addr, unsigned int insn);
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/* patch kernel text with machine already stopped (e.g. in kgdb) */
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void __patch_text(void *addr, unsigned int insn);
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#endif
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arch/parisc/kernel/Makefile
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arch/parisc/kernel/Makefile
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pa7300lc.o syscall.o entry.o sys_parisc.o firmware.o \
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ptrace.o hardware.o inventory.o drivers.o alternative.o \
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signal.o hpmc.o real2.o parisc_ksyms.o unaligned.o \
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process.o processor.o pdc_cons.o pdc_chassis.o unwind.o
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process.o processor.o pdc_cons.o pdc_chassis.o unwind.o \
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patch.o
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ifdef CONFIG_FUNCTION_TRACER
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# Do not profile debug and lowlevel utilities
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arch/parisc/kernel/patch.c
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arch/parisc/kernel/patch.c
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// SPDX-License-Identifier: GPL-2.0
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/*
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* functions to patch RO kernel text during runtime
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*
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* Copyright (c) 2019 Sven Schnelle <svens@stackframe.org>
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*/
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#include <linux/kernel.h>
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#include <linux/spinlock.h>
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#include <linux/kprobes.h>
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#include <linux/mm.h>
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#include <linux/stop_machine.h>
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#include <asm/cacheflush.h>
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#include <asm/fixmap.h>
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#include <asm/patch.h>
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struct patch {
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void *addr;
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unsigned int insn;
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};
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static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags)
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{
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unsigned long uintaddr = (uintptr_t) addr;
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bool module = !core_kernel_text(uintaddr);
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struct page *page;
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if (module && IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
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page = vmalloc_to_page(addr);
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else if (!module && IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
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page = virt_to_page(addr);
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else
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return addr;
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set_fixmap(fixmap, page_to_phys(page));
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return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));
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}
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static void __kprobes patch_unmap(int fixmap, unsigned long *flags)
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{
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clear_fixmap(fixmap);
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}
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void __kprobes __patch_text(void *addr, unsigned int insn)
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{
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unsigned long flags;
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void *waddr = addr;
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int size;
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waddr = patch_map(addr, FIX_TEXT_POKE0, &flags);
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*(u32 *)waddr = insn;
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size = sizeof(u32);
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flush_kernel_vmap_range(waddr, size);
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patch_unmap(FIX_TEXT_POKE0, &flags);
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flush_icache_range((uintptr_t)(addr),
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(uintptr_t)(addr) + size);
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}
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static int __kprobes patch_text_stop_machine(void *data)
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{
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struct patch *patch = data;
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__patch_text(patch->addr, patch->insn);
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return 0;
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}
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void __kprobes patch_text(void *addr, unsigned int insn)
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{
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struct patch patch = {
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.addr = addr,
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.insn = insn,
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};
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stop_machine_cpuslocked(patch_text_stop_machine, &patch, NULL);
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}