diff options
| author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 | 
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 | 
| commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
| tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/mm/alignment.c | |
| download | olio-linux-3.10-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz olio-linux-3.10-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip  | |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/arm/mm/alignment.c')
| -rw-r--r-- | arch/arm/mm/alignment.c | 756 | 
1 files changed, 756 insertions, 0 deletions
diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c new file mode 100644 index 00000000000..81f4a8a2d34 --- /dev/null +++ b/arch/arm/mm/alignment.c @@ -0,0 +1,756 @@ +/* + *  linux/arch/arm/mm/alignment.c + * + *  Copyright (C) 1995  Linus Torvalds + *  Modifications for ARM processor (c) 1995-2001 Russell King + *  Thumb aligment fault fixups (c) 2004 MontaVista Software, Inc. + *  - Adapted from gdb/sim/arm/thumbemu.c -- Thumb instruction emulation. + *    Copyright (C) 1996, Cygnus Software Technologies Ltd. + * + * 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. + */ +#include <linux/config.h> +#include <linux/compiler.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <linux/ptrace.h> +#include <linux/proc_fs.h> +#include <linux/init.h> + +#include <asm/uaccess.h> +#include <asm/unaligned.h> + +#include "fault.h" + +/* + * 32-bit misaligned trap handler (c) 1998 San Mehat (CCC) -July 1998 + * /proc/sys/debug/alignment, modified and integrated into + * Linux 2.1 by Russell King + * + * Speed optimisations and better fault handling by Russell King. + * + * *** NOTE *** + * This code is not portable to processors with late data abort handling. + */ +#define CODING_BITS(i)	(i & 0x0e000000) + +#define LDST_I_BIT(i)	(i & (1 << 26))		/* Immediate constant	*/ +#define LDST_P_BIT(i)	(i & (1 << 24))		/* Preindex		*/ +#define LDST_U_BIT(i)	(i & (1 << 23))		/* Add offset		*/ +#define LDST_W_BIT(i)	(i & (1 << 21))		/* Writeback		*/ +#define LDST_L_BIT(i)	(i & (1 << 20))		/* Load			*/ + +#define LDST_P_EQ_U(i)	((((i) ^ ((i) >> 1)) & (1 << 23)) == 0) + +#define LDSTH_I_BIT(i)	(i & (1 << 22))		/* half-word immed	*/ +#define LDM_S_BIT(i)	(i & (1 << 22))		/* write CPSR from SPSR	*/ + +#define RN_BITS(i)	((i >> 16) & 15)	/* Rn			*/ +#define RD_BITS(i)	((i >> 12) & 15)	/* Rd			*/ +#define RM_BITS(i)	(i & 15)		/* Rm			*/ + +#define REGMASK_BITS(i)	(i & 0xffff) +#define OFFSET_BITS(i)	(i & 0x0fff) + +#define IS_SHIFT(i)	(i & 0x0ff0) +#define SHIFT_BITS(i)	((i >> 7) & 0x1f) +#define SHIFT_TYPE(i)	(i & 0x60) +#define SHIFT_LSL	0x00 +#define SHIFT_LSR	0x20 +#define SHIFT_ASR	0x40 +#define SHIFT_RORRRX	0x60 + +static unsigned long ai_user; +static unsigned long ai_sys; +static unsigned long ai_skipped; +static unsigned long ai_half; +static unsigned long ai_word; +static unsigned long ai_multi; +static int ai_usermode; + +#ifdef CONFIG_PROC_FS +static const char *usermode_action[] = { +	"ignored", +	"warn", +	"fixup", +	"fixup+warn", +	"signal", +	"signal+warn" +}; + +static int +proc_alignment_read(char *page, char **start, off_t off, int count, int *eof, +		    void *data) +{ +	char *p = page; +	int len; + +	p += sprintf(p, "User:\t\t%lu\n", ai_user); +	p += sprintf(p, "System:\t\t%lu\n", ai_sys); +	p += sprintf(p, "Skipped:\t%lu\n", ai_skipped); +	p += sprintf(p, "Half:\t\t%lu\n", ai_half); +	p += sprintf(p, "Word:\t\t%lu\n", ai_word); +	p += sprintf(p, "Multi:\t\t%lu\n", ai_multi); +	p += sprintf(p, "User faults:\t%i (%s)\n", ai_usermode, +			usermode_action[ai_usermode]); + +	len = (p - page) - off; +	if (len < 0) +		len = 0; + +	*eof = (len <= count) ? 1 : 0; +	*start = page + off; + +	return len; +} + +static int proc_alignment_write(struct file *file, const char __user *buffer, +			       unsigned long count, void *data) +{ +	char mode; + +	if (count > 0) { +		if (get_user(mode, buffer)) +			return -EFAULT; +		if (mode >= '0' && mode <= '5') +			   ai_usermode = mode - '0'; +	} +	return count; +} + +#endif /* CONFIG_PROC_FS */ + +union offset_union { +	unsigned long un; +	  signed long sn; +}; + +#define TYPE_ERROR	0 +#define TYPE_FAULT	1 +#define TYPE_LDST	2 +#define TYPE_DONE	3 + +#ifdef __ARMEB__ +#define BE		1 +#define FIRST_BYTE_16	"mov	%1, %1, ror #8\n" +#define FIRST_BYTE_32	"mov	%1, %1, ror #24\n" +#define NEXT_BYTE	"ror #24" +#else +#define BE		0 +#define FIRST_BYTE_16 +#define FIRST_BYTE_32 +#define NEXT_BYTE	"lsr #8" +#endif + +#define __get8_unaligned_check(ins,val,addr,err)	\ +	__asm__(					\ +	"1:	"ins"	%1, [%2], #1\n"			\ +	"2:\n"						\ +	"	.section .fixup,\"ax\"\n"		\ +	"	.align	2\n"				\ +	"3:	mov	%0, #1\n"			\ +	"	b	2b\n"				\ +	"	.previous\n"				\ +	"	.section __ex_table,\"a\"\n"		\ +	"	.align	3\n"				\ +	"	.long	1b, 3b\n"			\ +	"	.previous\n"				\ +	: "=r" (err), "=&r" (val), "=r" (addr)		\ +	: "0" (err), "2" (addr)) + +#define __get16_unaligned_check(ins,val,addr)			\ +	do {							\ +		unsigned int err = 0, v, a = addr;		\ +		__get8_unaligned_check(ins,v,a,err);		\ +		val =  v << ((BE) ? 8 : 0);			\ +		__get8_unaligned_check(ins,v,a,err);		\ +		val |= v << ((BE) ? 0 : 8);			\ +		if (err)					\ +			goto fault;				\ +	} while (0) + +#define get16_unaligned_check(val,addr) \ +	__get16_unaligned_check("ldrb",val,addr) + +#define get16t_unaligned_check(val,addr) \ +	__get16_unaligned_check("ldrbt",val,addr) + +#define __get32_unaligned_check(ins,val,addr)			\ +	do {							\ +		unsigned int err = 0, v, a = addr;		\ +		__get8_unaligned_check(ins,v,a,err);		\ +		val =  v << ((BE) ? 24 :  0);			\ +		__get8_unaligned_check(ins,v,a,err);		\ +		val |= v << ((BE) ? 16 :  8);			\ +		__get8_unaligned_check(ins,v,a,err);		\ +		val |= v << ((BE) ?  8 : 16);			\ +		__get8_unaligned_check(ins,v,a,err);		\ +		val |= v << ((BE) ?  0 : 24);			\ +		if (err)					\ +			goto fault;				\ +	} while (0) + +#define get32_unaligned_check(val,addr) \ +	__get32_unaligned_check("ldrb",val,addr) + +#define get32t_unaligned_check(val,addr) \ +	__get32_unaligned_check("ldrbt",val,addr) + +#define __put16_unaligned_check(ins,val,addr)			\ +	do {							\ +		unsigned int err = 0, v = val, a = addr;	\ +		__asm__( FIRST_BYTE_16				\ +		"1:	"ins"	%1, [%2], #1\n"			\ +		"	mov	%1, %1, "NEXT_BYTE"\n"		\ +		"2:	"ins"	%1, [%2]\n"			\ +		"3:\n"						\ +		"	.section .fixup,\"ax\"\n"		\ +		"	.align	2\n"				\ +		"4:	mov	%0, #1\n"			\ +		"	b	3b\n"				\ +		"	.previous\n"				\ +		"	.section __ex_table,\"a\"\n"		\ +		"	.align	3\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 put16_unaligned_check(val,addr)  \ +	__put16_unaligned_check("strb",val,addr) + +#define put16t_unaligned_check(val,addr) \ +	__put16_unaligned_check("strbt",val,addr) + +#define __put32_unaligned_check(ins,val,addr)			\ +	do {							\ +		unsigned int err = 0, v = val, a = addr;	\ +		__asm__( FIRST_BYTE_32				\ +		"1:	"ins"	%1, [%2], #1\n"			\ +		"	mov	%1, %1, "NEXT_BYTE"\n"		\ +		"2:	"ins"	%1, [%2], #1\n"			\ +		"	mov	%1, %1, "NEXT_BYTE"\n"		\ +		"3:	"ins"	%1, [%2], #1\n"			\ +		"	mov	%1, %1, "NEXT_BYTE"\n"		\ +		"4:	"ins"	%1, [%2]\n"			\ +		"5:\n"						\ +		"	.section .fixup,\"ax\"\n"		\ +		"	.align	2\n"				\ +		"6:	mov	%0, #1\n"			\ +		"	b	5b\n"				\ +		"	.previous\n"				\ +		"	.section __ex_table,\"a\"\n"		\ +		"	.align	3\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) + +#define put32_unaligned_check(val,addr)	 \ +	__put32_unaligned_check("strb", val, addr) + +#define put32t_unaligned_check(val,addr) \ +	__put32_unaligned_check("strbt", val, addr) + +static void +do_alignment_finish_ldst(unsigned long addr, unsigned long instr, struct pt_regs *regs, union offset_union offset) +{ +	if (!LDST_U_BIT(instr)) +		offset.un = -offset.un; + +	if (!LDST_P_BIT(instr)) +		addr += offset.un; + +	if (!LDST_P_BIT(instr) || LDST_W_BIT(instr)) +		regs->uregs[RN_BITS(instr)] = addr; +} + +static int +do_alignment_ldrhstrh(unsigned long addr, unsigned long instr, struct pt_regs *regs) +{ +	unsigned int rd = RD_BITS(instr); + +	if ((instr & 0x01f00ff0) == 0x01000090) +		goto swp; + +	if ((instr & 0x90) != 0x90 || (instr & 0x60) == 0) +		goto bad; + +	ai_half += 1; + +	if (user_mode(regs)) +		goto user; + +	if (LDST_L_BIT(instr)) { +		unsigned long val; +		get16_unaligned_check(val, addr); + +		/* signed half-word? */ +		if (instr & 0x40) +			val = (signed long)((signed short) val); + +		regs->uregs[rd] = val; +	} else +		put16_unaligned_check(regs->uregs[rd], addr); + +	return TYPE_LDST; + + user: + 	if (LDST_L_BIT(instr)) { + 		unsigned long val; + 		get16t_unaligned_check(val, addr); + + 		/* signed half-word? */ + 		if (instr & 0x40) + 			val = (signed long)((signed short) val); + + 		regs->uregs[rd] = val; + 	} else + 		put16t_unaligned_check(regs->uregs[rd], addr); + + 	return TYPE_LDST; + + swp: +	printk(KERN_ERR "Alignment trap: not handling swp instruction\n"); + bad: +	return TYPE_ERROR; + + fault: +	return TYPE_FAULT; +} + +static int +do_alignment_ldrstr(unsigned long addr, unsigned long instr, struct pt_regs *regs) +{ +	unsigned int rd = RD_BITS(instr); + +	ai_word += 1; + +	if ((!LDST_P_BIT(instr) && LDST_W_BIT(instr)) || user_mode(regs)) +		goto trans; + +	if (LDST_L_BIT(instr)) { +		unsigned int val; +		get32_unaligned_check(val, addr); +		regs->uregs[rd] = val; +	} else +		put32_unaligned_check(regs->uregs[rd], addr); +	return TYPE_LDST; + + trans: +	if (LDST_L_BIT(instr)) { +		unsigned int val; +		get32t_unaligned_check(val, addr); +		regs->uregs[rd] = val; +	} else +		put32t_unaligned_check(regs->uregs[rd], addr); +	return TYPE_LDST; + + fault: +	return TYPE_FAULT; +} + +/* + * LDM/STM alignment handler. + * + * There are 4 variants of this instruction: + * + * B = rn pointer before instruction, A = rn pointer after instruction + *              ------ increasing address -----> + *	        |    | r0 | r1 | ... | rx |    | + * PU = 01             B                    A + * PU = 11        B                    A + * PU = 00        A                    B + * PU = 10             A                    B + */ +static int +do_alignment_ldmstm(unsigned long addr, unsigned long instr, struct pt_regs *regs) +{ +	unsigned int rd, rn, correction, nr_regs, regbits; +	unsigned long eaddr, newaddr; + +	if (LDM_S_BIT(instr)) +		goto bad; + +	correction = 4; /* processor implementation defined */ +	regs->ARM_pc += correction; + +	ai_multi += 1; + +	/* count the number of registers in the mask to be transferred */ +	nr_regs = hweight16(REGMASK_BITS(instr)) * 4; + +	rn = RN_BITS(instr); +	newaddr = eaddr = regs->uregs[rn]; + +	if (!LDST_U_BIT(instr)) +		nr_regs = -nr_regs; +	newaddr += nr_regs; +	if (!LDST_U_BIT(instr)) +		eaddr = newaddr; + +	if (LDST_P_EQ_U(instr))	/* U = P */ +		eaddr += 4; + +	/*  +	 * For alignment faults on the ARM922T/ARM920T the MMU  makes +	 * the FSR (and hence addr) equal to the updated base address +	 * of the multiple access rather than the restored value. +	 * Switch this message off if we've got a ARM92[02], otherwise +	 * [ls]dm alignment faults are noisy! +	 */ +#if !(defined CONFIG_CPU_ARM922T)  && !(defined CONFIG_CPU_ARM920T) +	/* +	 * This is a "hint" - we already have eaddr worked out by the +	 * processor for us. +	 */ +	if (addr != eaddr) { +		printk(KERN_ERR "LDMSTM: PC = %08lx, instr = %08lx, " +			"addr = %08lx, eaddr = %08lx\n", +			 instruction_pointer(regs), instr, addr, eaddr); +		show_regs(regs); +	} +#endif + +	if (user_mode(regs)) { +		for (regbits = REGMASK_BITS(instr), rd = 0; regbits; +		     regbits >>= 1, rd += 1) +			if (regbits & 1) { +				if (LDST_L_BIT(instr)) { +					unsigned int val; +					get32t_unaligned_check(val, eaddr); +					regs->uregs[rd] = val; +				} else +					put32t_unaligned_check(regs->uregs[rd], eaddr); +				eaddr += 4; +			} +	} else { +		for (regbits = REGMASK_BITS(instr), rd = 0; regbits; +		     regbits >>= 1, rd += 1) +			if (regbits & 1) { +				if (LDST_L_BIT(instr)) { +					unsigned int val; +					get32_unaligned_check(val, eaddr); +					regs->uregs[rd] = val; +				} else +					put32_unaligned_check(regs->uregs[rd], eaddr); +				eaddr += 4; +			} +	} + +	if (LDST_W_BIT(instr)) +		regs->uregs[rn] = newaddr; +	if (!LDST_L_BIT(instr) || !(REGMASK_BITS(instr) & (1 << 15))) +		regs->ARM_pc -= correction; +	return TYPE_DONE; + +fault: +	regs->ARM_pc -= correction; +	return TYPE_FAULT; + +bad: +	printk(KERN_ERR "Alignment trap: not handling ldm with s-bit set\n"); +	return TYPE_ERROR; +} + +/* + * Convert Thumb ld/st instruction forms to equivalent ARM instructions so + * we can reuse ARM userland alignment fault fixups for Thumb. + * + * This implementation was initially based on the algorithm found in + * gdb/sim/arm/thumbemu.c. It is basically just a code reduction of same + * to convert only Thumb ld/st instruction forms to equivalent ARM forms. + * + * NOTES: + * 1. Comments below refer to ARM ARM DDI0100E Thumb Instruction sections. + * 2. If for some reason we're passed an non-ld/st Thumb instruction to + *    decode, we return 0xdeadc0de. This should never happen under normal + *    circumstances but if it does, we've got other problems to deal with + *    elsewhere and we obviously can't fix those problems here. + */ + +static unsigned long +thumb2arm(u16 tinstr) +{ +	u32 L = (tinstr & (1<<11)) >> 11; + +	switch ((tinstr & 0xf800) >> 11) { +	/* 6.5.1 Format 1: */ +	case 0x6000 >> 11:				/* 7.1.52 STR(1) */ +	case 0x6800 >> 11:				/* 7.1.26 LDR(1) */ +	case 0x7000 >> 11:				/* 7.1.55 STRB(1) */ +	case 0x7800 >> 11:				/* 7.1.30 LDRB(1) */ +		return 0xe5800000 | +			((tinstr & (1<<12)) << (22-12)) |	/* fixup */ +			(L<<20) |				/* L==1? */ +			((tinstr & (7<<0)) << (12-0)) |		/* Rd */ +			((tinstr & (7<<3)) << (16-3)) |		/* Rn */ +			((tinstr & (31<<6)) >>			/* immed_5 */ +				(6 - ((tinstr & (1<<12)) ? 0 : 2))); +	case 0x8000 >> 11:				/* 7.1.57 STRH(1) */ +	case 0x8800 >> 11:				/* 7.1.32 LDRH(1) */ +		return 0xe1c000b0 | +			(L<<20) |				/* L==1? */ +			((tinstr & (7<<0)) << (12-0)) |		/* Rd */ +			((tinstr & (7<<3)) << (16-3)) |		/* Rn */ +			((tinstr & (7<<6)) >> (6-1)) |	 /* immed_5[2:0] */ +			((tinstr & (3<<9)) >> (9-8));	 /* immed_5[4:3] */ + +	/* 6.5.1 Format 2: */ +	case 0x5000 >> 11: +	case 0x5800 >> 11: +		{ +			static const u32 subset[8] = { +				0xe7800000,		/* 7.1.53 STR(2) */ +				0xe18000b0,		/* 7.1.58 STRH(2) */ +				0xe7c00000,		/* 7.1.56 STRB(2) */ +				0xe19000d0,		/* 7.1.34 LDRSB */ +				0xe7900000,		/* 7.1.27 LDR(2) */ +				0xe19000b0,		/* 7.1.33 LDRH(2) */ +				0xe7d00000,		/* 7.1.31 LDRB(2) */ +				0xe19000f0		/* 7.1.35 LDRSH */ +			}; +			return subset[(tinstr & (7<<9)) >> 9] | +			    ((tinstr & (7<<0)) << (12-0)) |	/* Rd */ +			    ((tinstr & (7<<3)) << (16-3)) |	/* Rn */ +			    ((tinstr & (7<<6)) >> (6-0));	/* Rm */ +		} + +	/* 6.5.1 Format 3: */ +	case 0x4800 >> 11:				/* 7.1.28 LDR(3) */ +		/* NOTE: This case is not technically possible. We're +		 * 	 loading 32-bit memory data via PC relative +		 *	 addressing mode. So we can and should eliminate +		 *	 this case. But I'll leave it here for now. +		 */ +		return 0xe59f0000 | +		    ((tinstr & (7<<8)) << (12-8)) |		/* Rd */ +		    ((tinstr & 255) << (2-0));			/* immed_8 */ + +	/* 6.5.1 Format 4: */ +	case 0x9000 >> 11:				/* 7.1.54 STR(3) */ +	case 0x9800 >> 11:				/* 7.1.29 LDR(4) */ +		return 0xe58d0000 | +			(L<<20) |				/* L==1? */ +			((tinstr & (7<<8)) << (12-8)) |		/* Rd */ +			((tinstr & 255) << 2);			/* immed_8 */ + +	/* 6.6.1 Format 1: */ +	case 0xc000 >> 11:				/* 7.1.51 STMIA */ +	case 0xc800 >> 11:				/* 7.1.25 LDMIA */ +		{ +			u32 Rn = (tinstr & (7<<8)) >> 8; +			u32 W = ((L<<Rn) & (tinstr&255)) ? 0 : 1<<21; + +			return 0xe8800000 | W | (L<<20) | (Rn<<16) | +				(tinstr&255); +		} + +	/* 6.6.1 Format 2: */ +	case 0xb000 >> 11:				/* 7.1.48 PUSH */ +	case 0xb800 >> 11:				/* 7.1.47 POP */ +		if ((tinstr & (3 << 9)) == 0x0400) { +			static const u32 subset[4] = { +				0xe92d0000,	/* STMDB sp!,{registers} */ +				0xe92d4000,	/* STMDB sp!,{registers,lr} */ +				0xe8bd0000,	/* LDMIA sp!,{registers} */ +				0xe8bd8000	/* LDMIA sp!,{registers,pc} */ +			}; +			return subset[(L<<1) | ((tinstr & (1<<8)) >> 8)] | +			    (tinstr & 255);		/* register_list */ +		} +		/* Else fall through for illegal instruction case */ + +	default: +		return 0xdeadc0de; +	} +} + +static int +do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs) +{ +	union offset_union offset; +	unsigned long instr = 0, instrptr; +	int (*handler)(unsigned long addr, unsigned long instr, struct pt_regs *regs); +	unsigned int type; +	mm_segment_t fs; +	unsigned int fault; +	u16 tinstr = 0; + +	instrptr = instruction_pointer(regs); + +	fs = get_fs(); +	set_fs(KERNEL_DS); +	if thumb_mode(regs) { +		fault = __get_user(tinstr, (u16 *)(instrptr & ~1)); +		if (!(fault)) +			instr = thumb2arm(tinstr); +	} else +		fault = __get_user(instr, (u32 *)instrptr); +	set_fs(fs); + +	if (fault) { +		type = TYPE_FAULT; + 		goto bad_or_fault; +	} + +	if (user_mode(regs)) +		goto user; + +	ai_sys += 1; + + fixup: + +	regs->ARM_pc += thumb_mode(regs) ? 2 : 4; + +	switch (CODING_BITS(instr)) { +	case 0x00000000:	/* ldrh or strh */ +		if (LDSTH_I_BIT(instr)) +			offset.un = (instr & 0xf00) >> 4 | (instr & 15); +		else +			offset.un = regs->uregs[RM_BITS(instr)]; +		handler = do_alignment_ldrhstrh; +		break; + +	case 0x04000000:	/* ldr or str immediate */ +		offset.un = OFFSET_BITS(instr); +		handler = do_alignment_ldrstr; +		break; + +	case 0x06000000:	/* ldr or str register */ +		offset.un = regs->uregs[RM_BITS(instr)]; + +		if (IS_SHIFT(instr)) { +			unsigned int shiftval = SHIFT_BITS(instr); + +			switch(SHIFT_TYPE(instr)) { +			case SHIFT_LSL: +				offset.un <<= shiftval; +				break; + +			case SHIFT_LSR: +				offset.un >>= shiftval; +				break; + +			case SHIFT_ASR: +				offset.sn >>= shiftval; +				break; + +			case SHIFT_RORRRX: +				if (shiftval == 0) { +					offset.un >>= 1; +					if (regs->ARM_cpsr & PSR_C_BIT) +						offset.un |= 1 << 31; +				} else +					offset.un = offset.un >> shiftval | +							  offset.un << (32 - shiftval); +				break; +			} +		} +		handler = do_alignment_ldrstr; +		break; + +	case 0x08000000:	/* ldm or stm */ +		handler = do_alignment_ldmstm; +		break; + +	default: +		goto bad; +	} + +	type = handler(addr, instr, regs); + +	if (type == TYPE_ERROR || type == TYPE_FAULT) +		goto bad_or_fault; + +	if (type == TYPE_LDST) +		do_alignment_finish_ldst(addr, instr, regs, offset); + +	return 0; + + bad_or_fault: +	if (type == TYPE_ERROR) +		goto bad; +	regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; +	/* +	 * We got a fault - fix it up, or die. +	 */ +	do_bad_area(current, current->mm, addr, fsr, regs); +	return 0; + + bad: +	/* +	 * Oops, we didn't handle the instruction. +	 */ +	printk(KERN_ERR "Alignment trap: not handling instruction " +		"%0*lx at [<%08lx>]\n", +		thumb_mode(regs) ? 4 : 8, +		thumb_mode(regs) ? tinstr : instr, instrptr); +	ai_skipped += 1; +	return 1; + + user: +	ai_user += 1; + +	if (ai_usermode & 1) +		printk("Alignment trap: %s (%d) PC=0x%08lx Instr=0x%0*lx " +		       "Address=0x%08lx FSR 0x%03x\n", current->comm, +			current->pid, instrptr, +		        thumb_mode(regs) ? 4 : 8, +		        thumb_mode(regs) ? tinstr : instr, +		        addr, fsr); + +	if (ai_usermode & 2) +		goto fixup; + +	if (ai_usermode & 4) +		force_sig(SIGBUS, current); +	else +		set_cr(cr_no_alignment); + +	return 0; +} + +/* + * This needs to be done after sysctl_init, otherwise sys/ will be + * overwritten.  Actually, this shouldn't be in sys/ at all since + * it isn't a sysctl, and it doesn't contain sysctl information. + * We now locate it in /proc/cpu/alignment instead. + */ +static int __init alignment_init(void) +{ +#ifdef CONFIG_PROC_FS +	struct proc_dir_entry *res; + +	res = proc_mkdir("cpu", NULL); +	if (!res) +		return -ENOMEM; + +	res = create_proc_entry("alignment", S_IWUSR | S_IRUGO, res); +	if (!res) +		return -ENOMEM; + +	res->read_proc = proc_alignment_read; +	res->write_proc = proc_alignment_write; +#endif + +	hook_fault_code(1, do_alignment, SIGILL, "alignment exception"); +	hook_fault_code(3, do_alignment, SIGILL, "alignment exception"); + +	return 0; +} + +fs_initcall(alignment_init);  |