[deliverable/linux.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 "patch.h"

struct patch {
	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 *)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>
	10	#include <asm/opcodes.h>
	11
	12	#include "patch.h"
	13
	14	struct patch {
	15	void *addr;
	16	unsigned int insn;
	17	};
	18
ab0615e2 RV	19	static DEFINE_SPINLOCK(patch_lock);
	20
	21	static void __kprobes patch_map(void addr, int fixmap, unsigned long *flags)
	22	__acquires(&patch_lock)
	23	{
	24	unsigned int uintaddr = (uintptr_t) addr;
	25	bool module = !core_kernel_text(uintaddr);
	26	struct page *page;
	27
	28	if (module && IS_ENABLED(CONFIG_DEBUG_SET_MODULE_RONX))
	29	page = vmalloc_to_page(addr);
	30	else if (!module && IS_ENABLED(CONFIG_DEBUG_RODATA))
	31	page = virt_to_page(addr);
	32	else
	33	return addr;
	34
	35	if (flags)
	36	spin_lock_irqsave(&patch_lock, *flags);
	37	else
	38	__acquire(&patch_lock);
	39
	40	set_fixmap(fixmap, page_to_phys(page));
	41
	42	return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));
	43	}
	44
	45	static void __kprobes patch_unmap(int fixmap, unsigned long *flags)
	46	__releases(&patch_lock)
	47	{
	48	clear_fixmap(fixmap);
	49
	50	if (flags)
	51	spin_unlock_irqrestore(&patch_lock, *flags);
	52	else
	53	__release(&patch_lock);
	54	}
	55
	56	void __kprobes __patch_text_real(void *addr, unsigned int insn, bool remap)
b21d55e9 RV	57	{
b21d55e9 RV	58	bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL);
ab0615e2 RV	59	unsigned int uintaddr = (uintptr_t) addr;
	60	bool twopage = false;
	61	unsigned long flags;
	62	void *waddr = addr;
b21d55e9 RV	63	int size;
b21d55e9 RV	64
ab0615e2 RV	65	if (remap)
	66	waddr = patch_map(addr, FIX_TEXT_POKE0, &flags);
	67	else
	68	__acquire(&patch_lock);
	69
b21d55e9	70	if (thumb2 && __opcode_is_thumb16(insn)) {
ab0615e2	71	(u16 )waddr = __opcode_to_mem_thumb16(insn);
b21d55e9	72	size = sizeof(u16);
ab0615e2	73	} else if (thumb2 && (uintaddr & 2)) {
b21d55e9 RV	74	u16 first = __opcode_thumb32_first(insn);
b21d55e9 RV	75	u16 second = __opcode_thumb32_second(insn);
ab0615e2 RV	76	u16 *addrh0 = waddr;
	77	u16 *addrh1 = waddr + 2;
	78
	79	twopage = (uintaddr & ~PAGE_MASK) == PAGE_SIZE - 2;
	80	if (twopage && remap)
	81	addrh1 = patch_map(addr + 2, FIX_TEXT_POKE1, NULL);
	82
	83	*addrh0 = __opcode_to_mem_thumb16(first);
	84	*addrh1 = __opcode_to_mem_thumb16(second);
b21d55e9	85
ab0615e2 RV	86	if (twopage && addrh1 != addr + 2) {
	87	flush_kernel_vmap_range(addrh1, 2);
	88	patch_unmap(FIX_TEXT_POKE1, NULL);
	89	}
b21d55e9 RV	90
	91	size = sizeof(u32);
	92	} else {
	93	if (thumb2)
	94	insn = __opcode_to_mem_thumb32(insn);
	95	else
	96	insn = __opcode_to_mem_arm(insn);
	97
ab0615e2	98	(u32 )waddr = insn;
b21d55e9 RV	99	size = sizeof(u32);
	100	}
	101
ab0615e2 RV	102	if (waddr != addr) {
	103	flush_kernel_vmap_range(waddr, twopage ? size / 2 : size);
	104	patch_unmap(FIX_TEXT_POKE0, &flags);
	105	} else
	106	__release(&patch_lock);
	107
b21d55e9 RV	108	flush_icache_range((uintptr_t)(addr),
	109	(uintptr_t)(addr) + size);
	110	}
	111
	112	static int __kprobes patch_text_stop_machine(void *data)
	113	{
	114	struct patch *patch = data;
	115
	116	__patch_text(patch->addr, patch->insn);
	117
	118	return 0;
	119	}
	120
	121	void __kprobes patch_text(void *addr, unsigned int insn)
	122	{
	123	struct patch patch = {
	124	.addr = addr,
	125	.insn = insn,
	126	};
	127
ab0615e2	128	stop_machine(patch_text_stop_machine, &patch, NULL);
b21d55e9	129	}