diff options
author | Sven Schnelle <svens@stackframe.org> | 2019-04-04 21:14:09 +0200 |
---|---|---|
committer | Helge Deller <deller@gmx.de> | 2019-05-03 23:47:38 +0200 |
commit | 620a53d522ba007a79fffc444bd75e8d3775f5b8 (patch) | |
tree | c2931055351578f8912c41f629d44c500bba7fde /arch/parisc/kernel | |
parent | ccfbc68d41c2db8f5e88128427fb5bfe3855ff9b (diff) |
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>
Diffstat (limited to 'arch/parisc/kernel')
-rw-r--r-- | arch/parisc/kernel/Makefile | 3 | ||||
-rw-r--r-- | arch/parisc/kernel/patch.c | 78 |
2 files changed, 80 insertions, 1 deletions
diff --git a/arch/parisc/kernel/Makefile b/arch/parisc/kernel/Makefile index 8e5f1ab65c68..d29bbd1a73b2 100644 --- a/arch/parisc/kernel/Makefile +++ b/arch/parisc/kernel/Makefile @@ -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 diff --git a/arch/parisc/kernel/patch.c b/arch/parisc/kernel/patch.c new file mode 100644 index 000000000000..8c5ee684cb16 --- /dev/null +++ b/arch/parisc/kernel/patch.c @@ -0,0 +1,78 @@ +// 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); +} |