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Commit f21ee2d4 authored by Steve Longerbeam's avatar Steve Longerbeam Committed by Russell King
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[ARM] 2867/2: unaligned ldrd/strd fixups 



Patch from Steve Longerbeam

Adds an implementation of unaligned LDRD and STRD fixups.
Also fixes a bug where do_alignment() would misinterpret and
fixup an unaligned LDRD/STRD as LDRH/STRH, causing memory
corruption.
This is the same as Patch #2867/1, but with minor whitespace
and comments changes, plus a check for arch-level >= v5TE
before printing ai_dword count in proc_alignment_read().

Signed-off-by: default avatarSteve Longerbeam <stevel@mwwireless.net>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 3618886f

arch/arm/mm/alignment.c

+56 −14
Original line number Diff line number Diff line
@@ -45,7 +45,7 @@ 


#define LDST_P_EQ_U(i)	((((i) ^ ((i) >> 1)) & (1 << 23)) == 0)



#define LDSTH_I_BIT(i)	(i & (1 << 22))		/* half-word immed	*/

#define LDSTHD_I_BIT(i)	(i & (1 << 22))		/* double/half-word immed */

#define LDM_S_BIT(i)	(i & (1 << 22))		/* write CPSR from SPSR	*/



#define RN_BITS(i)	((i >> 16) & 15)	/* Rn			*/
@@ -68,6 +68,7 @@ static unsigned long ai_sys; 
static unsigned long ai_skipped;

static unsigned long ai_half;

static unsigned long ai_word;

static unsigned long ai_dword;

static unsigned long ai_multi;

static int ai_usermode;
@@ -93,6 +94,8 @@ proc_alignment_read(char *page, char **start, off_t off, int count, int *eof, 
	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);

	if (cpu_architecture() >= CPU_ARCH_ARMv5TE)

		p += sprintf(p, "DWord:\t\t%lu\n", ai_dword);

	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]);
@@ -283,12 +286,6 @@ do_alignment_ldrhstrh(unsigned long addr, unsigned long instr, struct pt_regs *r 
{

	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))
@@ -323,10 +320,47 @@ do_alignment_ldrhstrh(unsigned long addr, unsigned long instr, struct pt_regs *r 


 	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_ldrdstrd(unsigned long addr, unsigned long instr,

		      struct pt_regs *regs)

{

	unsigned int rd = RD_BITS(instr);



	ai_dword += 1;



	if (user_mode(regs))

		goto user;



	if ((instr & 0xf0) == 0xd0) {

		unsigned long val;

		get32_unaligned_check(val, addr);

		regs->uregs[rd] = val;

		get32_unaligned_check(val, addr+4);

		regs->uregs[rd+1] = val;

	} else {

		put32_unaligned_check(regs->uregs[rd], addr);

		put32_unaligned_check(regs->uregs[rd+1], addr+4);

	}



	return TYPE_LDST;



 user:

	if ((instr & 0xf0) == 0xd0) {

		unsigned long val;

		get32t_unaligned_check(val, addr);

		regs->uregs[rd] = val;

		get32t_unaligned_check(val, addr+4);

		regs->uregs[rd+1] = val;

	} else {

		put32t_unaligned_check(regs->uregs[rd], addr);

		put32t_unaligned_check(regs->uregs[rd+1], addr+4);

	}



	return TYPE_LDST;



 fault:

	return TYPE_FAULT;
@@ -617,12 +651,20 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs) 
	regs->ARM_pc += thumb_mode(regs) ? 2 : 4;



	switch (CODING_BITS(instr)) {

	case 0x00000000:	/* ldrh or strh */

		if (LDSTH_I_BIT(instr))

	case 0x00000000:	/* 3.13.4 load/store instruction extensions */

		if (LDSTHD_I_BIT(instr))

			offset.un = (instr & 0xf00) >> 4 | (instr & 15);

		else

			offset.un = regs->uregs[RM_BITS(instr)];



		if ((instr & 0x000000f0) == 0x000000b0 || /* LDRH, STRH */

		    (instr & 0x001000f0) == 0x001000f0)   /* LDRSH */

			handler = do_alignment_ldrhstrh;

		else if ((instr & 0x001000f0) == 0x000000d0 || /* LDRD */

			 (instr & 0x001000f0) == 0x000000f0)   /* STRD */

			handler = do_alignment_ldrdstrd;

		else

			goto bad;

		break;



	case 0x04000000:	/* ldr or str immediate */