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128 lines
2.9 KiB
128 lines
2.9 KiB
// SPDX-License-Identifier: GPL-2.0 |
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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/smp_plat.h> |
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#include <asm/opcodes.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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#ifdef CONFIG_MMU |
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static DEFINE_RAW_SPINLOCK(patch_lock); |
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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 int 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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if (flags) |
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raw_spin_lock_irqsave(&patch_lock, *flags); |
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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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if (flags) |
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raw_spin_unlock_irqrestore(&patch_lock, *flags); |
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} |
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#else |
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static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags) |
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{ |
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return addr; |
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} |
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static void __kprobes patch_unmap(int fixmap, unsigned long *flags) { } |
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#endif |
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void __kprobes __patch_text_real(void *addr, unsigned int insn, bool remap) |
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{ |
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bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL); |
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unsigned int uintaddr = (uintptr_t) addr; |
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bool twopage = false; |
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unsigned long flags; |
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void *waddr = addr; |
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int size; |
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if (remap) |
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waddr = patch_map(addr, FIX_TEXT_POKE0, &flags); |
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if (thumb2 && __opcode_is_thumb16(insn)) { |
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*(u16 *)waddr = __opcode_to_mem_thumb16(insn); |
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size = sizeof(u16); |
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} else if (thumb2 && (uintaddr & 2)) { |
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u16 first = __opcode_thumb32_first(insn); |
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u16 second = __opcode_thumb32_second(insn); |
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u16 *addrh0 = waddr; |
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u16 *addrh1 = waddr + 2; |
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twopage = (uintaddr & ~PAGE_MASK) == PAGE_SIZE - 2; |
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if (twopage && remap) |
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addrh1 = patch_map(addr + 2, FIX_TEXT_POKE1, NULL); |
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*addrh0 = __opcode_to_mem_thumb16(first); |
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*addrh1 = __opcode_to_mem_thumb16(second); |
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if (twopage && addrh1 != addr + 2) { |
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flush_kernel_vmap_range(addrh1, 2); |
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patch_unmap(FIX_TEXT_POKE1, NULL); |
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} |
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size = sizeof(u32); |
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} else { |
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if (thumb2) |
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insn = __opcode_to_mem_thumb32(insn); |
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else |
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insn = __opcode_to_mem_arm(insn); |
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*(u32 *)waddr = insn; |
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size = sizeof(u32); |
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} |
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if (waddr != addr) { |
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flush_kernel_vmap_range(waddr, twopage ? size / 2 : size); |
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patch_unmap(FIX_TEXT_POKE0, &flags); |
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} |
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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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}
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