[people/arne_f/kernel.git] / arch / arm / kernel / patch.c

#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/patch.h>

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

static DEFINE_RAW_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)
		raw_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)
		raw_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 *)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);
	} else
		__release(&patch_lock);

	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(patch_text_stop_machine, &patch, NULL);
}
Commit	Line	Data
b21d55e9	1	#include <linux/kernel.h>
ab0615e2	2	#include <linux/spinlock.h>
b21d55e9	3	#include <linux/kprobes.h>
ab0615e2	4	#include <linux/mm.h>
b21d55e9 RV	5	#include <linux/stop_machine.h>
	6
	7	#include <asm/cacheflush.h>
ab0615e2	8	#include <asm/fixmap.h>
b21d55e9 RV	9	#include <asm/smp_plat.h>
b21d55e9 RV	10	#include <asm/opcodes.h>
fca08f32	11	#include <asm/patch.h>
b21d55e9 RV	12
	13	struct patch {
	14	void *addr;
	15	unsigned int insn;
	16	};
	17
a0594831	18	static DEFINE_RAW_SPINLOCK(patch_lock);
ab0615e2 RV	19
	20	static void __kprobes patch_map(void addr, int fixmap, unsigned long *flags)
	21	__acquires(&patch_lock)
	22	{
	23	unsigned int uintaddr = (uintptr_t) addr;
	24	bool module = !core_kernel_text(uintaddr);
	25	struct page *page;
	26
	27	if (module && IS_ENABLED(CONFIG_DEBUG_SET_MODULE_RONX))
	28	page = vmalloc_to_page(addr);
	29	else if (!module && IS_ENABLED(CONFIG_DEBUG_RODATA))
	30	page = virt_to_page(addr);
	31	else
	32	return addr;
	33
	34	if (flags)
a0594831	35	raw_spin_lock_irqsave(&patch_lock, *flags);
ab0615e2 RV	36	else
	37	__acquire(&patch_lock);
	38
	39	set_fixmap(fixmap, page_to_phys(page));
	40
	41	return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));
	42	}
	43
	44	static void __kprobes patch_unmap(int fixmap, unsigned long *flags)
	45	__releases(&patch_lock)
	46	{
	47	clear_fixmap(fixmap);
	48
	49	if (flags)
a0594831	50	raw_spin_unlock_irqrestore(&patch_lock, *flags);
ab0615e2 RV	51	else
	52	__release(&patch_lock);
	53	}
	54
	55	void __kprobes __patch_text_real(void *addr, unsigned int insn, bool remap)
b21d55e9 RV	56	{
b21d55e9 RV	57	bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL);
ab0615e2 RV	58	unsigned int uintaddr = (uintptr_t) addr;
	59	bool twopage = false;
	60	unsigned long flags;
	61	void *waddr = addr;
b21d55e9 RV	62	int size;
b21d55e9 RV	63
ab0615e2 RV	64	if (remap)
	65	waddr = patch_map(addr, FIX_TEXT_POKE0, &flags);
	66	else
	67	__acquire(&patch_lock);
	68
b21d55e9	69	if (thumb2 && __opcode_is_thumb16(insn)) {
ab0615e2	70	(u16 )waddr = __opcode_to_mem_thumb16(insn);
b21d55e9	71	size = sizeof(u16);
ab0615e2	72	} else if (thumb2 && (uintaddr & 2)) {
b21d55e9 RV	73	u16 first = __opcode_thumb32_first(insn);
b21d55e9 RV	74	u16 second = __opcode_thumb32_second(insn);
ab0615e2 RV	75	u16 *addrh0 = waddr;
	76	u16 *addrh1 = waddr + 2;
	77
	78	twopage = (uintaddr & ~PAGE_MASK) == PAGE_SIZE - 2;
	79	if (twopage && remap)
	80	addrh1 = patch_map(addr + 2, FIX_TEXT_POKE1, NULL);
	81
	82	*addrh0 = __opcode_to_mem_thumb16(first);
	83	*addrh1 = __opcode_to_mem_thumb16(second);
b21d55e9	84
ab0615e2 RV	85	if (twopage && addrh1 != addr + 2) {
	86	flush_kernel_vmap_range(addrh1, 2);
	87	patch_unmap(FIX_TEXT_POKE1, NULL);
	88	}
b21d55e9 RV	89
	90	size = sizeof(u32);
	91	} else {
	92	if (thumb2)
	93	insn = __opcode_to_mem_thumb32(insn);
	94	else
	95	insn = __opcode_to_mem_arm(insn);
	96
ab0615e2	97	(u32 )waddr = insn;
b21d55e9 RV	98	size = sizeof(u32);
	99	}
	100
ab0615e2 RV	101	if (waddr != addr) {
	102	flush_kernel_vmap_range(waddr, twopage ? size / 2 : size);
	103	patch_unmap(FIX_TEXT_POKE0, &flags);
	104	} else
	105	__release(&patch_lock);
	106
b21d55e9 RV	107	flush_icache_range((uintptr_t)(addr),
	108	(uintptr_t)(addr) + size);
	109	}
	110
	111	static int __kprobes patch_text_stop_machine(void *data)
	112	{
	113	struct patch *patch = data;
	114
	115	__patch_text(patch->addr, patch->insn);
	116
	117	return 0;
	118	}
	119
	120	void __kprobes patch_text(void *addr, unsigned int insn)
	121	{
	122	struct patch patch = {
	123	.addr = addr,
	124	.insn = insn,
	125	};
	126
ab0615e2	127	stop_machine(patch_text_stop_machine, &patch, NULL);
b21d55e9	128	}