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Commit 0983b318 authored by Yoshinori Sato's avatar Yoshinori Sato Committed by Paul Mundt
Browse files

sh: Wire up division and address error exceptions on SH-2A. 



SH-2A has special division hardware as opposed to a full-fledged FPU,
wire up the exception handlers for this.

Signed-off-by: default avatarYoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 9d4436a6

arch/sh/kernel/traps.c

+79 −9
Original line number Diff line number Diff line
@@ -35,6 +35,11 @@ 
#ifdef CONFIG_CPU_SH2

# define TRAP_RESERVED_INST	4

# define TRAP_ILLEGAL_SLOT_INST	6

# define TRAP_ADDRESS_ERROR	9

# ifdef CONFIG_CPU_SH2A

#  define TRAP_DIVZERO_ERROR	17

#  define TRAP_DIVOVF_ERROR	18

# endif

#else

#define TRAP_RESERVED_INST	12

#define TRAP_ILLEGAL_SLOT_INST	13
@@ -479,6 +484,14 @@ static int handle_unaligned_access(u16 instruction, struct pt_regs *regs) 
	return ret;

}



#ifdef CONFIG_CPU_HAS_SR_RB

#define lookup_exception_vector(x)	\

	__asm__ __volatile__ ("stc r2_bank, %0\n\t" : "=r" ((x)))

#else

#define lookup_exception_vector(x)	\

	__asm__ __volatile__ ("mov r4, %0\n\t" : "=r" ((x)))

#endif



/*

 * Handle various address error exceptions

 */
@@ -486,24 +499,37 @@ asmlinkage void do_address_error(struct pt_regs *regs, 
				 unsigned long writeaccess,

				 unsigned long address)

{

	unsigned long error_code;

	unsigned long error_code = 0;

	mm_segment_t oldfs;

	u16 instruction;

	int tmp;



	asm volatile("stc       r2_bank,%0": "=r" (error_code));

	/* Intentional ifdef */

#ifdef CONFIG_CPU_HAS_SR_RB

	lookup_exception_vector(error_code);

#endif



	oldfs = get_fs();



	if (user_mode(regs)) {

		local_irq_enable();

		current->thread.error_code = error_code;

#ifdef CONFIG_CPU_SH2

		/*

		 * On the SH-2, we only have a single vector for address

		 * errors, there's no differentiating between a load error

		 * and a store error.

		 */

		current->thread.trap_no = 9;

#else

		current->thread.trap_no = (writeaccess) ? 8 : 7;

#endif



		/* bad PC is not something we can fix */

		if (regs->pc & 1)

			goto uspace_segv;



#ifndef CONFIG_CPU_SH2A

		set_fs(USER_DS);

		if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) {

			/* Argh. Fault on the instruction itself.
@@ -518,6 +544,7 @@ asmlinkage void do_address_error(struct pt_regs *regs, 


		if (tmp==0)

			return; /* sorted */

#endif



	uspace_segv:

		printk(KERN_NOTICE "Killing process \"%s\" due to unaligned access\n", current->comm);
@@ -526,6 +553,7 @@ asmlinkage void do_address_error(struct pt_regs *regs, 
		if (regs->pc & 1)

			die("unaligned program counter", regs, error_code);



#ifndef CONFIG_CPU_SH2A

		set_fs(KERNEL_DS);

		if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) {

			/* Argh. Fault on the instruction itself.
@@ -537,6 +565,10 @@ asmlinkage void do_address_error(struct pt_regs *regs, 


		handle_unaligned_access(instruction, regs);

		set_fs(oldfs);

#else

		printk(KERN_NOTICE "Killing process \"%s\" due to unaligned access\n", current->comm);

		force_sig(SIGSEGV, current);

#endif

	}

}
@@ -569,6 +601,29 @@ int is_dsp_inst(struct pt_regs *regs) 
#define is_dsp_inst(regs)	(0)

#endif /* CONFIG_SH_DSP */



#ifdef CONFIG_CPU_SH2A

asmlinkage void do_divide_error(unsigned long r4, unsigned long r5,

				unsigned long r6, unsigned long r7,

				struct pt_regs regs)

{

	siginfo_t info;



	current->thread.trap_no = r4;

	current->thread.error_code = 0;



	switch (r4) {

	case TRAP_DIVZERO_ERROR:

		info.si_code = FPE_INTDIV;

		break;

	case TRAP_DIVOVF_ERROR:

		info.si_code = FPE_INTOVF;

		break;

	}



	force_sig_info(SIGFPE, &info, current);

}

#endif



/* arch/sh/kernel/cpu/sh4/fpu.c */

extern int do_fpu_inst(unsigned short, struct pt_regs *);

extern asmlinkage void do_fpu_state_restore(unsigned long r4, unsigned long r5,
@@ -582,7 +637,7 @@ asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5, 
	struct task_struct *tsk = current;



#ifdef CONFIG_SH_FPU_EMU

	unsigned short inst;

	unsigned short inst = 0;

	int err;



	get_user(inst, (unsigned short*)regs.pc);
@@ -604,7 +659,8 @@ asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5, 
	}

#endif



	asm volatile("stc	r2_bank, %0": "=r" (error_code));

	lookup_exception_vector(error_code);



	local_irq_enable();

	tsk->thread.error_code = error_code;

	tsk->thread.trap_no = TRAP_RESERVED_INST;
@@ -663,7 +719,7 @@ asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5, 
	unsigned long error_code;

	struct task_struct *tsk = current;

#ifdef CONFIG_SH_FPU_EMU

	unsigned short inst;

	unsigned short inst = 0;



	get_user(inst, (unsigned short *)regs.pc + 1);

	if (!do_fpu_inst(inst, &regs)) {
@@ -675,7 +731,8 @@ asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5, 
	/* not a FPU inst. */

#endif



	asm volatile("stc	r2_bank, %0": "=r" (error_code));

	lookup_exception_vector(error_code);



	local_irq_enable();

	tsk->thread.error_code = error_code;

	tsk->thread.trap_no = TRAP_RESERVED_INST;
@@ -689,7 +746,8 @@ asmlinkage void do_exception_error(unsigned long r4, unsigned long r5, 
				   struct pt_regs regs)

{

	long ex;

	asm volatile("stc	r2_bank, %0" : "=r" (ex));



	lookup_exception_vector(ex);

	die_if_kernel("exception", &regs, ex);

}
@@ -741,6 +799,10 @@ void *set_exception_table_vec(unsigned int vec, void *handler) 
	return old_handler;

}



extern asmlinkage void address_error_handler(unsigned long r4, unsigned long r5,

					     unsigned long r6, unsigned long r7,

					     struct pt_regs regs);



void __init trap_init(void)

{

	set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst);
@@ -760,6 +822,14 @@ void __init trap_init(void) 
	set_exception_table_evt(0x820, do_fpu_state_restore);

#endif



#ifdef CONFIG_CPU_SH2

	set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_handler);

#endif

#ifdef CONFIG_CPU_SH2A

	set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error);

	set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error);

#endif

		

	/* Setup VBR for boot cpu */

	per_cpu_trap_init();

}