Commit 303d6da1 authored by Ard Biesheuvel's avatar Ard Biesheuvel
Browse files

ARM: iwmmxt: Use undef hook to enable coprocessor for task 



Define a undef hook to deal with undef exceptions triggered by iwmmxt
instructions that were issued with the coprocessor disabled. This
removes the dependency on the coprocessor dispatch code in entry-armv.S,
which will be made NWFPE-only in a subsequent patch.

Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
parent 8bcba70c

arch/arm/include/asm/thread_info.h

+16 −0
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ struct task_struct; 
DECLARE_PER_CPU(struct task_struct *, __entry_task);



#include <asm/types.h>

#include <asm/traps.h>



struct cpu_context_save {

	__u32	r4;
@@ -104,6 +105,21 @@ extern void iwmmxt_task_restore(struct thread_info *, void *); 
extern void iwmmxt_task_release(struct thread_info *);

extern void iwmmxt_task_switch(struct thread_info *);



extern int iwmmxt_undef_handler(struct pt_regs *, u32);



static inline void register_iwmmxt_undef_handler(void)

{

	static struct undef_hook iwmmxt_undef_hook = {

		.instr_mask	= 0x0c000e00,

		.instr_val	= 0x0c000000,

		.cpsr_mask	= MODE_MASK | PSR_T_BIT,

		.cpsr_val	= USR_MODE,

		.fn		= iwmmxt_undef_handler,

	};



	register_undef_hook(&iwmmxt_undef_hook);

}



extern void vfp_sync_hwstate(struct thread_info *);

extern void vfp_flush_hwstate(struct thread_info *);

arch/arm/kernel/entry-armv.S

+1 −0
Original line number Diff line number Diff line
@@ -507,6 +507,7 @@ ARM_BE8(rev r0, r0) @ little endian instruction 
	ldr	r5, [r10, #TI_FLAGS]

	rsbs	r7, r8, #(1 << 8)		@ CP 0 or 1 only

	movscs	r7, r5, lsr #(TIF_USING_IWMMXT + 1)

	movcs	r0, sp				@ pass struct pt_regs

	bcs	iwmmxt_task_enable

#endif

 ARM(	add	pc, pc, r8, lsr #6	)

arch/arm/kernel/iwmmxt.S

+14 −4
Original line number Diff line number Diff line
@@ -58,9 +58,19 @@ 
	.text

	.arm



ENTRY(iwmmxt_undef_handler)

	push		{r9, r10, lr}

	get_thread_info	r10

	mov		r9, pc

	b		iwmmxt_task_enable

	mov		r0, #0

	pop		{r9, r10, pc}

ENDPROC(iwmmxt_undef_handler)



/*

 * Lazy switching of Concan coprocessor context

 *

 * r0  = struct pt_regs pointer

 * r10 = struct thread_info pointer

 * r9  = ret_from_exception

 * lr  = undefined instr exit
@@ -84,12 +94,12 @@ ENTRY(iwmmxt_task_enable) 
	PJ4(mcr	p15, 0, r2, c1, c0, 2)



	ldr	r3, =concan_owner

	add	r0, r10, #TI_IWMMXT_STATE	@ get task Concan save area

	ldr	r2, [sp, #60]			@ current task pc value

	ldr	r2, [r0, #S_PC]			@ current task pc value

	ldr	r1, [r3]			@ get current Concan owner

	str	r0, [r3]			@ this task now owns Concan regs

	sub	r2, r2, #4			@ adjust pc back

	str	r2, [sp, #60]

	str	r2, [r0, #S_PC]

	add	r0, r10, #TI_IWMMXT_STATE	@ get task Concan save area

	str	r0, [r3]			@ this task now owns Concan regs



	mrc	p15, 0, r2, c2, c0, 0

	mov	r2, r2				@ cpwait

arch/arm/kernel/pj4-cp0.c

+1 −0
Original line number Diff line number Diff line
@@ -126,6 +126,7 @@ static int __init pj4_cp0_init(void) 
	pr_info("PJ4 iWMMXt v%d coprocessor enabled.\n", vers);

	elf_hwcap |= HWCAP_IWMMXT;

	thread_register_notifier(&iwmmxt_notifier_block);

	register_iwmmxt_undef_handler();

#endif



	return 0;

arch/arm/kernel/xscale-cp0.c

+1 −0
Original line number Diff line number Diff line
@@ -166,6 +166,7 @@ static int __init xscale_cp0_init(void) 
		pr_info("XScale iWMMXt coprocessor detected.\n");

		elf_hwcap |= HWCAP_IWMMXT;

		thread_register_notifier(&iwmmxt_notifier_block);

		register_iwmmxt_undef_handler();

#endif

	} else {

		pr_info("XScale DSP coprocessor detected.\n");