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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129// SPDX-License-Identifier: GPL-2.0#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/smp_plat.h>#include <asm/opcodes.h>#include <asm/text-patching.h>
struct patch { void *addr; unsigned int insn;};
#ifdef CONFIG_MMUstatic DEFINE_RAW_SPINLOCK(patch_lock);
static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags){ unsigned int 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;
if (flags) raw_spin_lock_irqsave(&patch_lock, *flags);
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);
if (flags) raw_spin_unlock_irqrestore(&patch_lock, *flags);}#elsestatic void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags){ return addr;}static void __kprobes patch_unmap(int fixmap, unsigned long *flags) { }#endif
void __kprobes __patch_text_real(void *addr, unsigned int insn, bool remap){ bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL); unsigned int uintaddr = (uintptr_t) addr; bool twopage = false; unsigned long flags; void *waddr = addr; int size;
if (remap) waddr = patch_map(addr, FIX_TEXT_POKE0, &flags);
if (thumb2 && __opcode_is_thumb16(insn)) { *(u16 *)waddr = __opcode_to_mem_thumb16(insn); size = sizeof(u16); } else if (thumb2 && (uintaddr & 2)) { u16 first = __opcode_thumb32_first(insn); u16 second = __opcode_thumb32_second(insn); u16 *addrh0 = waddr; u16 *addrh1 = waddr + 2;
twopage = (uintaddr & ~PAGE_MASK) == PAGE_SIZE - 2; if (twopage && remap) addrh1 = patch_map(addr + 2, FIX_TEXT_POKE1, NULL);
*addrh0 = __opcode_to_mem_thumb16(first); *addrh1 = __opcode_to_mem_thumb16(second);
if (twopage && addrh1 != addr + 2) { flush_kernel_vmap_range(addrh1, 2); patch_unmap(FIX_TEXT_POKE1, NULL); }
size = sizeof(u32); } else { if (thumb2) insn = __opcode_to_mem_thumb32(insn); else insn = __opcode_to_mem_arm(insn);
*(u32 *)waddr = insn; size = sizeof(u32); }
if (waddr != addr) { flush_kernel_vmap_range(waddr, twopage ? size / 2 : 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);}