[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / arc / kernel / unaligned.c

/*
 * Copyright (C) 2011-2012 Synopsys (www.synopsys.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * vineetg : May 2011
 *  -Adapted (from .26 to .35)
 *  -original contribution by Tim.yao@amlogic.com
 *
 */

#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/uaccess.h>
#include <asm/disasm.h>

#define __get8_unaligned_check(val, addr, err)		\
	__asm__(					\
	"1:	ldb.ab	%1, [%2, 1]\n"			\
	"2:\n"						\
	"	.section .fixup,\"ax\"\n"		\
	"	.align	4\n"				\
	"3:	mov	%0, 1\n"			\
	"	b	2b\n"				\
	"	.previous\n"				\
	"	.section __ex_table,\"a\"\n"		\
	"	.align	4\n"				\
	"	.long	1b, 3b\n"			\
	"	.previous\n"				\
	: "=r" (err), "=&r" (val), "=r" (addr)		\
	: "0" (err), "2" (addr))

#define get16_unaligned_check(val, addr)		\
	do {						\
		unsigned int err = 0, v, a = addr;	\
		__get8_unaligned_check(v, a, err);	\
		val =  v ;				\
		__get8_unaligned_check(v, a, err);	\
		val |= v << 8;				\
		if (err)				\
			goto fault;			\
	} while (0)

#define get32_unaligned_check(val, addr)		\
	do {						\
		unsigned int err = 0, v, a = addr;	\
		__get8_unaligned_check(v, a, err);	\
		val =  v << 0;				\
		__get8_unaligned_check(v, a, err);	\
		val |= v << 8;				\
		__get8_unaligned_check(v, a, err);	\
		val |= v << 16;				\
		__get8_unaligned_check(v, a, err);	\
		val |= v << 24;				\
		if (err)				\
			goto fault;			\
	} while (0)

#define put16_unaligned_check(val, addr)		\
	do {						\
		unsigned int err = 0, v = val, a = addr;\
							\
		__asm__(				\
		"1:	stb.ab	%1, [%2, 1]\n"		\
		"	lsr %1, %1, 8\n"		\
		"2:	stb	%1, [%2]\n"		\
		"3:\n"					\
		"	.section .fixup,\"ax\"\n"	\
		"	.align	4\n"			\
		"4:	mov	%0, 1\n"		\
		"	b	3b\n"			\
		"	.previous\n"			\
		"	.section __ex_table,\"a\"\n"	\
		"	.align	4\n"			\
		"	.long	1b, 4b\n"		\
		"	.long	2b, 4b\n"		\
		"	.previous\n"			\
		: "=r" (err), "=&r" (v), "=&r" (a)	\
		: "0" (err), "1" (v), "2" (a));		\
							\
		if (err)				\
			goto fault;			\
	} while (0)

#define put32_unaligned_check(val, addr)		\
	do {						\
		unsigned int err = 0, v = val, a = addr;\
		__asm__(				\
							\
		"1:	stb.ab	%1, [%2, 1]\n"		\
		"	lsr %1, %1, 8\n"		\
		"2:	stb.ab	%1, [%2, 1]\n"		\
		"	lsr %1, %1, 8\n"		\
		"3:	stb.ab	%1, [%2, 1]\n"		\
		"	lsr %1, %1, 8\n"		\
		"4:	stb	%1, [%2]\n"		\
		"5:\n"					\
		"	.section .fixup,\"ax\"\n"	\
		"	.align	4\n"			\
		"6:	mov	%0, 1\n"		\
		"	b	5b\n"			\
		"	.previous\n"			\
		"	.section __ex_table,\"a\"\n"	\
		"	.align	4\n"			\
		"	.long	1b, 6b\n"		\
		"	.long	2b, 6b\n"		\
		"	.long	3b, 6b\n"		\
		"	.long	4b, 6b\n"		\
		"	.previous\n"			\
		: "=r" (err), "=&r" (v), "=&r" (a)	\
		: "0" (err), "1" (v), "2" (a));		\
							\
		if (err)				\
			goto fault;			\
	} while (0)

/* sysctl hooks */
int unaligned_enabled __read_mostly = 1;	/* Enabled by default */
int no_unaligned_warning __read_mostly = 1;	/* Only 1 warning by default */

static void fixup_load(struct disasm_state *state, struct pt_regs *regs,
			struct callee_regs *cregs)
{
	int val;

	/* register write back */
	if ((state->aa == 1) || (state->aa == 2)) {
		set_reg(state->wb_reg, state->src1 + state->src2, regs, cregs);

		if (state->aa == 2)
			state->src2 = 0;
	}

	if (state->zz == 0) {
		get32_unaligned_check(val, state->src1 + state->src2);
	} else {
		get16_unaligned_check(val, state->src1 + state->src2);

		if (state->x)
			val = (val << 16) >> 16;
	}

	if (state->pref == 0)
		set_reg(state->dest, val, regs, cregs);

	return;

fault:	state->fault = 1;
}

static void fixup_store(struct disasm_state *state, struct pt_regs *regs,
			struct callee_regs *cregs)
{
	/* register write back */
	if ((state->aa == 1) || (state->aa == 2)) {
		set_reg(state->wb_reg, state->src2 + state->src3, regs, cregs);

		if (state->aa == 3)
			state->src3 = 0;
	} else if (state->aa == 3) {
		if (state->zz == 2) {
			set_reg(state->wb_reg, state->src2 + (state->src3 << 1),
				regs, cregs);
		} else if (!state->zz) {
			set_reg(state->wb_reg, state->src2 + (state->src3 << 2),
				regs, cregs);
		} else {
			goto fault;
		}
	}

	/* write fix-up */
	if (!state->zz)
		put32_unaligned_check(state->src1, state->src2 + state->src3);
	else
		put16_unaligned_check(state->src1, state->src2 + state->src3);

	return;

fault:	state->fault = 1;
}

/*
 * Handle an unaligned access
 * Returns 0 if successfully handled, 1 if some error happened
 */
int misaligned_fixup(unsigned long address, struct pt_regs *regs,
		     unsigned long cause, struct callee_regs *cregs)
{
	struct disasm_state state;
	char buf[TASK_COMM_LEN];

	/* handle user mode only and only if enabled by sysadmin */
	if (!user_mode(regs) || !unaligned_enabled)
		return 1;

	if (no_unaligned_warning) {
		pr_warn_once("%s(%d) made unaligned access which was emulated"
			     " by kernel assist\n. This can degrade application"
			     " performance significantly\n. To enable further"
			     " logging of such instances, please \n"
			     " echo 0 > /proc/sys/kernel/ignore-unaligned-usertrap\n",
			     get_task_comm(buf, current), task_pid_nr(current));
	} else {
		/* Add rate limiting if it gets down to it */
		pr_warn("%s(%d): unaligned access to/from 0x%lx by PC: 0x%lx\n",
			get_task_comm(buf, current), task_pid_nr(current),
			address, regs->ret);

	}

	disasm_instr(regs->ret, &state, 1, regs, cregs);

	if (state.fault)
		goto fault;

	/* ldb/stb should not have unaligned exception */
	if ((state.zz == 1) || (state.di))
		goto fault;

	if (!state.write)
		fixup_load(&state, regs, cregs);
	else
		fixup_store(&state, regs, cregs);

	if (state.fault)
		goto fault;

	/* clear any remanants of delay slot */
	if (delay_mode(regs)) {
		regs->ret = regs->bta & ~1U;
		regs->status32 &= ~STATUS_DE_MASK;
	} else {
		regs->ret += state.instr_len;

		/* handle zero-overhead-loop */
		if ((regs->ret == regs->lp_end) && (regs->lp_count)) {
			regs->ret = regs->lp_start;
			regs->lp_count--;
		}
	}

	return 0;

fault:
	pr_err("Alignment trap: fault in fix-up %08lx at [<%08lx>]\n",
		state.words[0], address);

	return 1;
}
Commit	Line	Data
2e651ea1 VG	1	/*
	2	* Copyright (C) 2011-2012 Synopsys (www.synopsys.com)
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*
	8	* vineetg : May 2011
	9	* -Adapted (from .26 to .35)
	10	* -original contribution by Tim.yao@amlogic.com
	11	*
	12	*/
	13
	14	#include <linux/types.h>
	15	#include <linux/ptrace.h>
	16	#include <linux/uaccess.h>
	17	#include <asm/disasm.h>
	18
	19	#define __get8_unaligned_check(val, addr, err) \
	20	__asm__( \
	21	"1: ldb.ab %1, [%2, 1]\n" \
	22	"2:\n" \
	23	" .section .fixup,\"ax\"\n" \
	24	" .align 4\n" \
	25	"3: mov %0, 1\n" \
	26	" b 2b\n" \
	27	" .previous\n" \
	28	" .section __ex_table,\"a\"\n" \
	29	" .align 4\n" \
	30	" .long 1b, 3b\n" \
	31	" .previous\n" \
	32	: "=r" (err), "=&r" (val), "=r" (addr) \
	33	: "0" (err), "2" (addr))
	34
	35	#define get16_unaligned_check(val, addr) \
	36	do { \
	37	unsigned int err = 0, v, a = addr; \
	38	__get8_unaligned_check(v, a, err); \
	39	val = v ; \
	40	__get8_unaligned_check(v, a, err); \
	41	val \|= v << 8; \
	42	if (err) \
	43	goto fault; \
	44	} while (0)
	45
	46	#define get32_unaligned_check(val, addr) \
	47	do { \
	48	unsigned int err = 0, v, a = addr; \
	49	__get8_unaligned_check(v, a, err); \
	50	val = v << 0; \
	51	__get8_unaligned_check(v, a, err); \
	52	val \|= v << 8; \
	53	__get8_unaligned_check(v, a, err); \
	54	val \|= v << 16; \
	55	__get8_unaligned_check(v, a, err); \
	56	val \|= v << 24; \
	57	if (err) \
	58	goto fault; \
	59	} while (0)
	60
	61	#define put16_unaligned_check(val, addr) \
	62	do { \
	63	unsigned int err = 0, v = val, a = addr;\
	64	\
65	__asm__( \
66	"1: stb.ab %1, [%2, 1]\n" \
67	" lsr %1, %1, 8\n" \
68	"2: stb %1, [%2]\n" \
69	"3:\n" \
70	" .section .fixup,\"ax\"\n" \
71	" .align 4\n" \
72	"4: mov %0, 1\n" \
73	" b 3b\n" \
74	" .previous\n" \
75	" .section __ex_table,\"a\"\n" \
76	" .align 4\n" \
77	" .long 1b, 4b\n" \
78	" .long 2b, 4b\n" \
79	" .previous\n" \
80	: "=r" (err), "=&r" (v), "=&r" (a) \
81	: "0" (err), "1" (v), "2" (a)); \
82	\
83	if (err) \
84	goto fault; \
85	} while (0)
86
87	#define put32_unaligned_check(val, addr) \
88	do { \
89	unsigned int err = 0, v = val, a = addr;\
90	__asm__( \
91	\
92	"1: stb.ab %1, [%2, 1]\n" \
93	" lsr %1, %1, 8\n" \
94	"2: stb.ab %1, [%2, 1]\n" \
95	" lsr %1, %1, 8\n" \
96	"3: stb.ab %1, [%2, 1]\n" \
97	" lsr %1, %1, 8\n" \
98	"4: stb %1, [%2]\n" \
99	"5:\n" \
100	" .section .fixup,\"ax\"\n" \
101	" .align 4\n" \
102	"6: mov %0, 1\n" \
103	" b 5b\n" \
104	" .previous\n" \
105	" .section __ex_table,\"a\"\n" \
106	" .align 4\n" \
107	" .long 1b, 6b\n" \
108	" .long 2b, 6b\n" \
109	" .long 3b, 6b\n" \
110	" .long 4b, 6b\n" \
111	" .previous\n" \
112	: "=r" (err), "=&r" (v), "=&r" (a) \
113	: "0" (err), "1" (v), "2" (a)); \
114	\
115	if (err) \
116	goto fault; \
117	} while (0)
118
119	/* sysctl hooks */
120	int unaligned_enabled __read_mostly = 1; /* Enabled by default */
121	int no_unaligned_warning __read_mostly = 1; /* Only 1 warning by default */
122
123	static void fixup_load(struct disasm_state state, struct pt_regs regs,
124	struct callee_regs *cregs)
125	{
126	int val;
127
128	/* register write back */
129	if ((state->aa == 1) \|\| (state->aa == 2)) {
130	set_reg(state->wb_reg, state->src1 + state->src2, regs, cregs);
131
132	if (state->aa == 2)
133	state->src2 = 0;
134	}
135
136	if (state->zz == 0) {
137	get32_unaligned_check(val, state->src1 + state->src2);
138	} else {
139	get16_unaligned_check(val, state->src1 + state->src2);
140
141	if (state->x)
142	val = (val << 16) >> 16;
143	}
144
145	if (state->pref == 0)
146	set_reg(state->dest, val, regs, cregs);
147
148	return;
149
150	fault: state->fault = 1;
151	}
152
153	static void fixup_store(struct disasm_state state, struct pt_regs regs,
154	struct callee_regs *cregs)
155	{
156	/* register write back */
157	if ((state->aa == 1) \|\| (state->aa == 2)) {
158	set_reg(state->wb_reg, state->src2 + state->src3, regs, cregs);
159
160	if (state->aa == 3)
161	state->src3 = 0;
162	} else if (state->aa == 3) {
163	if (state->zz == 2) {
164	set_reg(state->wb_reg, state->src2 + (state->src3 << 1),
165	regs, cregs);
166	} else if (!state->zz) {
167	set_reg(state->wb_reg, state->src2 + (state->src3 << 2),
168	regs, cregs);
169	} else {
170	goto fault;
171	}
172	}
173
174	/* write fix-up */
175	if (!state->zz)
176	put32_unaligned_check(state->src1, state->src2 + state->src3);
177	else
178	put16_unaligned_check(state->src1, state->src2 + state->src3);
179
180	return;
181
182	fault: state->fault = 1;
183	}
184
185	/*
186	* Handle an unaligned access
187	* Returns 0 if successfully handled, 1 if some error happened
188	*/
189	int misaligned_fixup(unsigned long address, struct pt_regs *regs,
190	unsigned long cause, struct callee_regs *cregs)
191	{
192	struct disasm_state state;
193	char buf[TASK_COMM_LEN];
194
195	/* handle user mode only and only if enabled by sysadmin */
196	if (!user_mode(regs) \|\| !unaligned_enabled)
197	return 1;
198
199	if (no_unaligned_warning) {
200	pr_warn_once("%s(%d) made unaligned access which was emulated"
201	" by kernel assist\n. This can degrade application"
202	" performance significantly\n. To enable further"
203	" logging of such instances, please \n"
204	" echo 0 > /proc/sys/kernel/ignore-unaligned-usertrap\n",
205	get_task_comm(buf, current), task_pid_nr(current));
206	} else {
207	/* Add rate limiting if it gets down to it */
208	pr_warn("%s(%d): unaligned access to/from 0x%lx by PC: 0x%lx\n",
209	get_task_comm(buf, current), task_pid_nr(current),
210	address, regs->ret);
211
212	}
213
214	disasm_instr(regs->ret, &state, 1, regs, cregs);
215
216	if (state.fault)
217	goto fault;
218
219	/* ldb/stb should not have unaligned exception */
220	if ((state.zz == 1) \|\| (state.di))
221	goto fault;
222
223	if (!state.write)
224	fixup_load(&state, regs, cregs);
225	else
226	fixup_store(&state, regs, cregs);
227
228	if (state.fault)
229	goto fault;
230
b5882ec2	231	/* clear any remanants of delay slot */
2e651ea1	232	if (delay_mode(regs)) {
e2ec1495	233	regs->ret = regs->bta & ~1U;
2e651ea1 VG	234	regs->status32 &= ~STATUS_DE_MASK;
	235	} else {
	236	regs->ret += state.instr_len;
5cd12e77 MJ	237
	238	/* handle zero-overhead-loop */
	239	if ((regs->ret == regs->lp_end) && (regs->lp_count)) {
	240	regs->ret = regs->lp_start;
	241	regs->lp_count--;
	242	}
2e651ea1 VG	243	}
	244
	245	return 0;
	246
	247	fault:
	248	pr_err("Alignment trap: fault in fix-up %08lx at [<%08lx>]\n",
	249	state.words[0], address);
	250
	251	return 1;
	252	}