diff options
| -rw-r--r-- | arch/arm/include/asm/fixmap.h | 4 | ||||
| -rw-r--r-- | arch/arm/kernel/jump_label.c | 2 | ||||
| -rw-r--r-- | arch/arm/kernel/patch.c | 92 | ||||
| -rw-r--r-- | arch/arm/kernel/patch.h | 12 |
4 files changed, 89 insertions, 21 deletions
diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h index 714606f70425..0415eae1df27 100644 --- a/arch/arm/include/asm/fixmap.h +++ b/arch/arm/include/asm/fixmap.h @@ -11,6 +11,10 @@ enum fixed_addresses { FIX_KMAP_BEGIN, FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1, + /* Support writing RO kernel text via kprobes, jump labels, etc. */ + FIX_TEXT_POKE0, + FIX_TEXT_POKE1, + __end_of_fixed_addresses }; diff --git a/arch/arm/kernel/jump_label.c b/arch/arm/kernel/jump_label.c index 4ce4f789446d..afeeb9ea6f43 100644 --- a/arch/arm/kernel/jump_label.c +++ b/arch/arm/kernel/jump_label.c @@ -19,7 +19,7 @@ static void __arch_jump_label_transform(struct jump_entry *entry, insn = arm_gen_nop(); if (is_static) - __patch_text(addr, insn); + __patch_text_early(addr, insn); else patch_text(addr, insn); } diff --git a/arch/arm/kernel/patch.c b/arch/arm/kernel/patch.c index 07314af47733..5038960e3c55 100644 --- a/arch/arm/kernel/patch.c +++ b/arch/arm/kernel/patch.c @@ -1,8 +1,11 @@ #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> @@ -13,21 +16,77 @@ struct patch { unsigned int insn; }; -void __kprobes __patch_text(void *addr, unsigned int insn) +static DEFINE_SPINLOCK(patch_lock); + +static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags) + __acquires(&patch_lock) +{ + unsigned int uintaddr = (uintptr_t) addr; + bool module = !core_kernel_text(uintaddr); + struct page *page; + + if (module && IS_ENABLED(CONFIG_DEBUG_SET_MODULE_RONX)) + page = vmalloc_to_page(addr); + else if (!module && IS_ENABLED(CONFIG_DEBUG_RODATA)) + page = virt_to_page(addr); + else + return addr; + + if (flags) + spin_lock_irqsave(&patch_lock, *flags); + else + __acquire(&patch_lock); + + 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) + __releases(&patch_lock) +{ + clear_fixmap(fixmap); + + if (flags) + spin_unlock_irqrestore(&patch_lock, *flags); + else + __release(&patch_lock); +} + +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); + else + __acquire(&patch_lock); + if (thumb2 && __opcode_is_thumb16(insn)) { - *(u16 *)addr = __opcode_to_mem_thumb16(insn); + *(u16 *)waddr = __opcode_to_mem_thumb16(insn); size = sizeof(u16); - } else if (thumb2 && ((uintptr_t)addr & 2)) { + } else if (thumb2 && (uintaddr & 2)) { u16 first = __opcode_thumb32_first(insn); u16 second = __opcode_thumb32_second(insn); - u16 *addrh = addr; + 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); - addrh[0] = __opcode_to_mem_thumb16(first); - addrh[1] = __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 { @@ -36,10 +95,16 @@ void __kprobes __patch_text(void *addr, unsigned int insn) else insn = __opcode_to_mem_arm(insn); - *(u32 *)addr = 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); + } else + __release(&patch_lock); + flush_icache_range((uintptr_t)(addr), (uintptr_t)(addr) + size); } @@ -60,16 +125,5 @@ void __kprobes patch_text(void *addr, unsigned int insn) .insn = insn, }; - if (cache_ops_need_broadcast()) { - stop_machine(patch_text_stop_machine, &patch, cpu_online_mask); - } else { - bool straddles_word = IS_ENABLED(CONFIG_THUMB2_KERNEL) - && __opcode_is_thumb32(insn) - && ((uintptr_t)addr & 2); - - if (straddles_word) - stop_machine(patch_text_stop_machine, &patch, NULL); - else - __patch_text(addr, insn); - } + stop_machine(patch_text_stop_machine, &patch, NULL); } diff --git a/arch/arm/kernel/patch.h b/arch/arm/kernel/patch.h index b4731f2dac38..77e054c2f6cd 100644 --- a/arch/arm/kernel/patch.h +++ b/arch/arm/kernel/patch.h @@ -2,6 +2,16 @@ #define _ARM_KERNEL_PATCH_H void patch_text(void *addr, unsigned int insn); -void __patch_text(void *addr, unsigned int insn); +void __patch_text_real(void *addr, unsigned int insn, bool remap); + +static inline void __patch_text(void *addr, unsigned int insn) +{ + __patch_text_real(addr, insn, true); +} + +static inline void __patch_text_early(void *addr, unsigned int insn) +{ + __patch_text_real(addr, insn, false); +} #endif |