parisc: add parisc code patching (620a53d5) · Commits · 戴 / test

arch/parisc/include/asm/patch.h

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		/* SPDX-License-Identifier: GPL-2.0 */
		#ifndef _PARISC_KERNEL_PATCH_H
		#define _PARISC_KERNEL_PATCH_H

		/* stop machine and patch kernel text */
		void patch_text(void *addr, unsigned int insn);

		/* patch kernel text with machine already stopped (e.g. in kgdb) */
		void __patch_text(void *addr, unsigned int insn);

		#endif

arch/parisc/kernel/Makefile

+2 −1

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		@@ -9,7 +9,8 @@ obj-y := cache.o pacache.o setup.o pdt.o traps.o time.o irq.o \
		pa7300lc.o syscall.o entry.o sys_parisc.o firmware.o \
		ptrace.o hardware.o inventory.o drivers.o alternative.o \
		signal.o hpmc.o real2.o parisc_ksyms.o unaligned.o \
		process.o processor.o pdc_cons.o pdc_chassis.o unwind.o
		process.o processor.o pdc_cons.o pdc_chassis.o unwind.o \
		patch.o

		ifdef CONFIG_FUNCTION_TRACER
		# Do not profile debug and lowlevel utilities

arch/parisc/kernel/patch.c

0 → 100644

+78 −0

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		// SPDX-License-Identifier: GPL-2.0
		/*
		* functions to patch RO kernel text during runtime
		*
		* Copyright (c) 2019 Sven Schnelle <svens@stackframe.org>
		*/

		#include <linux/kernel.h>
		#include <linux/spinlock.h>
		#include <linux/kprobes.h>
		#include <linux/mm.h>
		#include <linux/stop_machine.h>

		#include <asm/cacheflush.h>
		#include <asm/fixmap.h>
		#include <asm/patch.h>

		struct patch {
		void *addr;
		unsigned int insn;
		};

		static void __kprobes patch_map(void addr, int fixmap, unsigned long *flags)
		{
		unsigned long uintaddr = (uintptr_t) addr;
		bool module = !core_kernel_text(uintaddr);
		struct page *page;

		if (module && IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
		page = vmalloc_to_page(addr);
		else if (!module && IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
		page = virt_to_page(addr);
		else
		return addr;

		set_fixmap(fixmap, page_to_phys(page));

		return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));
		}

		static void __kprobes patch_unmap(int fixmap, unsigned long *flags)
		{
		clear_fixmap(fixmap);
		}

		void __kprobes __patch_text(void *addr, unsigned int insn)
		{
		unsigned long flags;
		void *waddr = addr;
		int size;

		waddr = patch_map(addr, FIX_TEXT_POKE0, &flags);
		(u32 )waddr = insn;
		size = sizeof(u32);
		flush_kernel_vmap_range(waddr, size);
		patch_unmap(FIX_TEXT_POKE0, &flags);
		flush_icache_range((uintptr_t)(addr),
		(uintptr_t)(addr) + size);
		}

		static int __kprobes patch_text_stop_machine(void *data)
		{
		struct patch *patch = data;

		__patch_text(patch->addr, patch->insn);

		return 0;
		}

		void __kprobes patch_text(void *addr, unsigned int insn)
		{
		struct patch patch = {
		.addr = addr,
		.insn = insn,
		};

		stop_machine_cpuslocked(patch_text_stop_machine, &patch, NULL);
		}

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