[linux-block.git] / arch / arm / vfp / vfphw.S

/*
 *  linux/arch/arm/vfp/vfphw.S
 *
 *  Copyright (C) 2004 ARM Limited.
 *  Written by Deep Blue Solutions Limited.
 *
 * 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.
 *
 * This code is called from the kernel's undefined instruction trap.
 * r9 holds the return address for successful handling.
 * lr holds the return address for unrecognised instructions.
 * r10 points at the start of the private FP workspace in the thread structure
 * sp points to a struct pt_regs (as defined in include/asm/proc/ptrace.h)
 */
#include <asm/thread_info.h>
#include <asm/vfpmacros.h>
#include "../kernel/entry-header.S"

	.macro	DBGSTR, str
#ifdef DEBUG
	stmfd	sp!, {r0-r3, ip, lr}
	add	r0, pc, #4
	bl	printk
	b	1f
	.asciz  "<7>VFP: \str\n"
	.balign 4
1:	ldmfd	sp!, {r0-r3, ip, lr}
#endif
	.endm

	.macro  DBGSTR1, str, arg
#ifdef DEBUG
	stmfd	sp!, {r0-r3, ip, lr}
	mov	r1, \arg
	add	r0, pc, #4
	bl	printk
	b	1f
	.asciz  "<7>VFP: \str\n"
	.balign 4
1:	ldmfd	sp!, {r0-r3, ip, lr}
#endif
	.endm

	.macro  DBGSTR3, str, arg1, arg2, arg3
#ifdef DEBUG
	stmfd	sp!, {r0-r3, ip, lr}
	mov	r3, \arg3
	mov	r2, \arg2
	mov	r1, \arg1
	add	r0, pc, #4
	bl	printk
	b	1f
	.asciz  "<7>VFP: \str\n"
	.balign 4
1:	ldmfd	sp!, {r0-r3, ip, lr}
#endif
	.endm


@ VFP hardware support entry point.
@
@  r0  = faulted instruction
@  r2  = faulted PC+4
@  r9  = successful return
@  r10 = vfp_state union
@  r11 = CPU number
@  lr  = failure return

	.globl	vfp_support_entry
vfp_support_entry:
	DBGSTR3	"instr %08x pc %08x state %p", r0, r2, r10

	VFPFMRX	r1, FPEXC		@ Is the VFP enabled?
	DBGSTR1	"fpexc %08x", r1
	tst	r1, #FPEXC_EN
	bne	look_for_VFP_exceptions	@ VFP is already enabled

	DBGSTR1 "enable %x", r10
	ldr	r3, last_VFP_context_address
	orr	r1, r1, #FPEXC_EN	@ user FPEXC has the enable bit set
	ldr	r4, [r3, r11, lsl #2]	@ last_VFP_context pointer
	bic	r5, r1, #FPEXC_EX	@ make sure exceptions are disabled
	cmp	r4, r10
	beq	check_for_exception	@ we are returning to the same
					@ process, so the registers are
					@ still there.  In this case, we do
					@ not want to drop a pending exception.

	VFPFMXR	FPEXC, r5		@ enable VFP, disable any pending
					@ exceptions, so we can get at the
					@ rest of it

#ifndef CONFIG_SMP
	@ Save out the current registers to the old thread state
	@ No need for SMP since this is not done lazily

	DBGSTR1	"save old state %p", r4
	cmp	r4, #0
	beq	no_old_VFP_process
	VFPFSTMIA r4, r5		@ save the working registers
	VFPFMRX	r5, FPSCR		@ current status
	tst	r1, #FPEXC_EX		@ is there additional state to save?
	VFPFMRX	r6, FPINST, NE		@ FPINST (only if FPEXC.EX is set)
	tstne	r1, #FPEXC_FP2V		@ is there an FPINST2 to read?
	VFPFMRX	r8, FPINST2, NE		@ FPINST2 if needed (and present)
	stmia	r4, {r1, r5, r6, r8}	@ save FPEXC, FPSCR, FPINST, FPINST2
					@ and point r4 at the word at the
					@ start of the register dump
#endif

no_old_VFP_process:
	DBGSTR1	"load state %p", r10
	str	r10, [r3, r11, lsl #2]	@ update the last_VFP_context pointer
					@ Load the saved state back into the VFP
	VFPFLDMIA r10, r5		@ reload the working registers while
					@ FPEXC is in a safe state
	ldmia	r10, {r1, r5, r6, r8}	@ load FPEXC, FPSCR, FPINST, FPINST2
	tst	r1, #FPEXC_EX		@ is there additional state to restore?
	VFPFMXR	FPINST, r6, NE		@ restore FPINST (only if FPEXC.EX is set)
	tstne	r1, #FPEXC_FP2V		@ is there an FPINST2 to write?
	VFPFMXR	FPINST2, r8, NE		@ FPINST2 if needed (and present)
	VFPFMXR	FPSCR, r5		@ restore status

check_for_exception:
	tst	r1, #FPEXC_EX
	bne	process_exception	@ might as well handle the pending
					@ exception before retrying branch
					@ out before setting an FPEXC that
					@ stops us reading stuff
	VFPFMXR	FPEXC, r1		@ restore FPEXC last
	sub	r2, r2, #4
	str	r2, [sp, #S_PC]		@ retry the instruction
	mov	pc, r9			@ we think we have handled things


look_for_VFP_exceptions:
	@ Check for synchronous or asynchronous exception
	tst	r1, #FPEXC_EX | FPEXC_DEX
	bne	process_exception
	@ On some implementations of the VFP subarch 1, setting FPSCR.IXE
	@ causes all the CDP instructions to be bounced synchronously without
	@ setting the FPEXC.EX bit
	VFPFMRX	r5, FPSCR
	tst	r5, #FPSCR_IXE
	bne	process_exception

	@ Fall into hand on to next handler - appropriate coproc instr
	@ not recognised by VFP

	DBGSTR	"not VFP"
	mov	pc, lr

process_exception:
	DBGSTR	"bounce"
	mov	r2, sp			@ nothing stacked - regdump is at TOS
	mov	lr, r9			@ setup for a return to the user code.

	@ Now call the C code to package up the bounce to the support code
	@   r0 holds the trigger instruction
	@   r1 holds the FPEXC value
	@   r2 pointer to register dump
	b	VFP_bounce		@ we have handled this - the support
					@ code will raise an exception if
					@ required. If not, the user code will
					@ retry the faulted instruction

#ifdef CONFIG_SMP
	.globl	vfp_save_state
	.type	vfp_save_state, %function
vfp_save_state:
	@ Save the current VFP state
	@ r0 - save location
	@ r1 - FPEXC
	DBGSTR1	"save VFP state %p", r0
	VFPFSTMIA r0, r2		@ save the working registers
	VFPFMRX	r2, FPSCR		@ current status
	tst	r1, #FPEXC_EX		@ is there additional state to save?
	VFPFMRX	r3, FPINST, NE		@ FPINST (only if FPEXC.EX is set)
	tstne	r1, #FPEXC_FP2V		@ is there an FPINST2 to read?
	VFPFMRX	r12, FPINST2, NE	@ FPINST2 if needed (and present)
	stmia	r0, {r1, r2, r3, r12}	@ save FPEXC, FPSCR, FPINST, FPINST2
	mov	pc, lr
#endif

last_VFP_context_address:
	.word	last_VFP_context

	.globl	vfp_get_float
vfp_get_float:
	add	pc, pc, r0, lsl #3
	mov	r0, r0
	.irp	dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
	mrc	p10, 0, r0, c\dr, c0, 0	@ fmrs	r0, s0
	mov	pc, lr
	mrc	p10, 0, r0, c\dr, c0, 4	@ fmrs	r0, s1
	mov	pc, lr
	.endr

	.globl	vfp_put_float
vfp_put_float:
	add	pc, pc, r1, lsl #3
	mov	r0, r0
	.irp	dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
	mcr	p10, 0, r0, c\dr, c0, 0	@ fmsr	r0, s0
	mov	pc, lr
	mcr	p10, 0, r0, c\dr, c0, 4	@ fmsr	r0, s1
	mov	pc, lr
	.endr

	.globl	vfp_get_double
vfp_get_double:
	add	pc, pc, r0, lsl #3
	mov	r0, r0
	.irp	dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
	fmrrd	r0, r1, d\dr
	mov	pc, lr
	.endr
#ifdef CONFIG_VFPv3
	@ d16 - d31 registers
	.irp	dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
	mrrc	p11, 3, r0, r1, c\dr	@ fmrrd	r0, r1, d\dr
	mov	pc, lr
	.endr
#endif

	@ virtual register 16 (or 32 if VFPv3) for compare with zero
	mov	r0, #0
	mov	r1, #0
	mov	pc, lr

	.globl	vfp_put_double
vfp_put_double:
	add	pc, pc, r2, lsl #3
	mov	r0, r0
	.irp	dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
	fmdrr	d\dr, r0, r1
	mov	pc, lr
	.endr
#ifdef CONFIG_VFPv3
	@ d16 - d31 registers
	.irp	dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
	mcrr	p11, 3, r1, r2, c\dr	@ fmdrr	r1, r2, d\dr
	mov	pc, lr
	.endr
#endif
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/arm/vfp/vfphw.S
	3	*
	4	* Copyright (C) 2004 ARM Limited.
	5	* Written by Deep Blue Solutions Limited.
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*
	11	* This code is called from the kernel's undefined instruction trap.
	12	* r9 holds the return address for successful handling.
	13	* lr holds the return address for unrecognised instructions.
	14	* r10 points at the start of the private FP workspace in the thread structure
	15	* sp points to a struct pt_regs (as defined in include/asm/proc/ptrace.h)
	16	*/
	17	#include <asm/thread_info.h>
	18	#include <asm/vfpmacros.h>
	19	#include "../kernel/entry-header.S"
	20
	21	.macro DBGSTR, str
	22	#ifdef DEBUG
	23	stmfd sp!, {r0-r3, ip, lr}
	24	add r0, pc, #4
	25	bl printk
	26	b 1f
	27	.asciz "<7>VFP: \str\n"
	28	.balign 4
	29	1: ldmfd sp!, {r0-r3, ip, lr}
	30	#endif
	31	.endm
	32
	33	.macro DBGSTR1, str, arg
	34	#ifdef DEBUG
	35	stmfd sp!, {r0-r3, ip, lr}
	36	mov r1, \arg
	37	add r0, pc, #4
	38	bl printk
	39	b 1f
	40	.asciz "<7>VFP: \str\n"
	41	.balign 4
	42	1: ldmfd sp!, {r0-r3, ip, lr}
	43	#endif
	44	.endm
	45
	46	.macro DBGSTR3, str, arg1, arg2, arg3
	47	#ifdef DEBUG
	48	stmfd sp!, {r0-r3, ip, lr}
	49	mov r3, \arg3
	50	mov r2, \arg2
	51	mov r1, \arg1
	52	add r0, pc, #4
	53	bl printk
	54	b 1f
	55	.asciz "<7>VFP: \str\n"
	56	.balign 4
	57	1: ldmfd sp!, {r0-r3, ip, lr}
	58	#endif
	59	.endm
	60
	61
	62	@ VFP hardware support entry point.
	63	@
	64	@ r0 = faulted instruction
65	@ r2 = faulted PC+4
66	@ r9 = successful return
67	@ r10 = vfp_state union
c6428464	68	@ r11 = CPU number
1da177e4 LT	69	@ lr = failure return
	70
	71	.globl vfp_support_entry
	72	vfp_support_entry:
	73	DBGSTR3 "instr %08x pc %08x state %p", r0, r2, r10
	74
	75	VFPFMRX r1, FPEXC @ Is the VFP enabled?
	76	DBGSTR1 "fpexc %08x", r1
228adef1	77	tst r1, #FPEXC_EN
1da177e4 LT	78	bne look_for_VFP_exceptions @ VFP is already enabled
	79
	80	DBGSTR1 "enable %x", r10
	81	ldr r3, last_VFP_context_address
228adef1	82	orr r1, r1, #FPEXC_EN @ user FPEXC has the enable bit set
c6428464	83	ldr r4, [r3, r11, lsl #2] @ last_VFP_context pointer
228adef1	84	bic r5, r1, #FPEXC_EX @ make sure exceptions are disabled
1da177e4 LT	85	cmp r4, r10
	86	beq check_for_exception @ we are returning to the same
	87	@ process, so the registers are
	88	@ still there. In this case, we do
	89	@ not want to drop a pending exception.
	90
	91	VFPFMXR FPEXC, r5 @ enable VFP, disable any pending
	92	@ exceptions, so we can get at the
	93	@ rest of it
	94
c6428464	95	#ifndef CONFIG_SMP
1da177e4	96	@ Save out the current registers to the old thread state
c6428464	97	@ No need for SMP since this is not done lazily
1da177e4 LT	98
	99	DBGSTR1 "save old state %p", r4
	100	cmp r4, #0
	101	beq no_old_VFP_process
25ebee02	102	VFPFSTMIA r4, r5 @ save the working registers
1da177e4	103	VFPFMRX r5, FPSCR @ current status
c98929c0 CM	104	tst r1, #FPEXC_EX @ is there additional state to save?
	105	VFPFMRX r6, FPINST, NE @ FPINST (only if FPEXC.EX is set)
	106	tstne r1, #FPEXC_FP2V @ is there an FPINST2 to read?
	107	VFPFMRX r8, FPINST2, NE @ FPINST2 if needed (and present)
1da177e4 LT	108	stmia r4, {r1, r5, r6, r8} @ save FPEXC, FPSCR, FPINST, FPINST2
	109	@ and point r4 at the word at the
	110	@ start of the register dump
c6428464	111	#endif
1da177e4 LT	112
	113	no_old_VFP_process:
	114	DBGSTR1 "load state %p", r10
c6428464	115	str r10, [r3, r11, lsl #2] @ update the last_VFP_context pointer
1da177e4	116	@ Load the saved state back into the VFP
25ebee02	117	VFPFLDMIA r10, r5 @ reload the working registers while
1da177e4	118	@ FPEXC is in a safe state
80ed3547	119	ldmia r10, {r1, r5, r6, r8} @ load FPEXC, FPSCR, FPINST, FPINST2
c98929c0 CM	120	tst r1, #FPEXC_EX @ is there additional state to restore?
	121	VFPFMXR FPINST, r6, NE @ restore FPINST (only if FPEXC.EX is set)
	122	tstne r1, #FPEXC_FP2V @ is there an FPINST2 to write?
	123	VFPFMXR FPINST2, r8, NE @ FPINST2 if needed (and present)
1da177e4 LT	124	VFPFMXR FPSCR, r5 @ restore status
	125
	126	check_for_exception:
228adef1	127	tst r1, #FPEXC_EX
1da177e4 LT	128	bne process_exception @ might as well handle the pending
	129	@ exception before retrying branch
	130	@ out before setting an FPEXC that
	131	@ stops us reading stuff
	132	VFPFMXR FPEXC, r1 @ restore FPEXC last
	133	sub r2, r2, #4
	134	str r2, [sp, #S_PC] @ retry the instruction
	135	mov pc, r9 @ we think we have handled things
	136
	137
	138	look_for_VFP_exceptions:
c98929c0 CM	139	@ Check for synchronous or asynchronous exception
c98929c0 CM	140	tst r1, #FPEXC_EX \| FPEXC_DEX
1da177e4	141	bne process_exception
c98929c0 CM	142	@ On some implementations of the VFP subarch 1, setting FPSCR.IXE
	143	@ causes all the CDP instructions to be bounced synchronously without
	144	@ setting the FPEXC.EX bit
1da177e4	145	VFPFMRX r5, FPSCR
c98929c0	146	tst r5, #FPSCR_IXE
1da177e4 LT	147	bne process_exception
	148
	149	@ Fall into hand on to next handler - appropriate coproc instr
	150	@ not recognised by VFP
	151
	152	DBGSTR "not VFP"
	153	mov pc, lr
	154
	155	process_exception:
	156	DBGSTR "bounce"
1da177e4 LT	157	mov r2, sp @ nothing stacked - regdump is at TOS
	158	mov lr, r9 @ setup for a return to the user code.
	159
	160	@ Now call the C code to package up the bounce to the support code
	161	@ r0 holds the trigger instruction
	162	@ r1 holds the FPEXC value
	163	@ r2 pointer to register dump
c98929c0	164	b VFP_bounce @ we have handled this - the support
1da177e4 LT	165	@ code will raise an exception if
	166	@ required. If not, the user code will
	167	@ retry the faulted instruction
	168
c6428464 CM	169	#ifdef CONFIG_SMP
	170	.globl vfp_save_state
	171	.type vfp_save_state, %function
	172	vfp_save_state:
	173	@ Save the current VFP state
	174	@ r0 - save location
	175	@ r1 - FPEXC
	176	DBGSTR1 "save VFP state %p", r0
25ebee02	177	VFPFSTMIA r0, r2 @ save the working registers
c6428464	178	VFPFMRX r2, FPSCR @ current status
c98929c0 CM	179	tst r1, #FPEXC_EX @ is there additional state to save?
	180	VFPFMRX r3, FPINST, NE @ FPINST (only if FPEXC.EX is set)
	181	tstne r1, #FPEXC_FP2V @ is there an FPINST2 to read?
	182	VFPFMRX r12, FPINST2, NE @ FPINST2 if needed (and present)
c6428464 CM	183	stmia r0, {r1, r2, r3, r12} @ save FPEXC, FPSCR, FPINST, FPINST2
	184	mov pc, lr
	185	#endif
	186
1da177e4 LT	187	last_VFP_context_address:
	188	.word last_VFP_context
	189
	190	.globl vfp_get_float
	191	vfp_get_float:
	192	add pc, pc, r0, lsl #3
	193	mov r0, r0
	194	.irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
	195	mrc p10, 0, r0, c\dr, c0, 0 @ fmrs r0, s0
	196	mov pc, lr
	197	mrc p10, 0, r0, c\dr, c0, 4 @ fmrs r0, s1
	198	mov pc, lr
	199	.endr
	200
	201	.globl vfp_put_float
	202	vfp_put_float:
0355b3e0	203	add pc, pc, r1, lsl #3
1da177e4 LT	204	mov r0, r0
1da177e4 LT	205	.irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
0355b3e0	206	mcr p10, 0, r0, c\dr, c0, 0 @ fmsr r0, s0
1da177e4	207	mov pc, lr
0355b3e0	208	mcr p10, 0, r0, c\dr, c0, 4 @ fmsr r0, s1
1da177e4 LT	209	mov pc, lr
	210	.endr
	211
	212	.globl vfp_get_double
	213	vfp_get_double:
1da177e4 LT	214	add pc, pc, r0, lsl #3
	215	mov r0, r0
	216	.irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
1a6be26d	217	fmrrd r0, r1, d\dr
1da177e4 LT	218	mov pc, lr
1da177e4 LT	219	.endr
25ebee02 CM	220	#ifdef CONFIG_VFPv3
	221	@ d16 - d31 registers
	222	.irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
	223	mrrc p11, 3, r0, r1, c\dr @ fmrrd r0, r1, d\dr
	224	mov pc, lr
	225	.endr
	226	#endif
1da177e4	227
25ebee02	228	@ virtual register 16 (or 32 if VFPv3) for compare with zero
1da177e4 LT	229	mov r0, #0
	230	mov r1, #0
	231	mov pc, lr
	232
	233	.globl vfp_put_double
	234	vfp_put_double:
0355b3e0	235	add pc, pc, r2, lsl #3
1da177e4 LT	236	mov r0, r0
1da177e4 LT	237	.irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
0355b3e0	238	fmdrr d\dr, r0, r1
1da177e4 LT	239	mov pc, lr
1da177e4 LT	240	.endr
25ebee02 CM	241	#ifdef CONFIG_VFPv3
	242	@ d16 - d31 registers
	243	.irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
	244	mcrr p11, 3, r1, r2, c\dr @ fmdrr r1, r2, d\dr
	245	mov pc, lr
	246	.endr
	247	#endif