path: root/arch/arm/kvm/interrupts_head.S

#include <linux/irqchip/arm-gic.h>

#define VCPU_USR_REG(_reg_nr)	(VCPU_USR_REGS + (_reg_nr * 4))
#define VCPU_USR_SP		(VCPU_USR_REG(13))
#define VCPU_USR_LR		(VCPU_USR_REG(14))
#define CP15_OFFSET(_cp15_reg_idx) (VCPU_CP15 + (_cp15_reg_idx * 4))

/*
 * Many of these macros need to access the VCPU structure, which is always
 * held in r0. These macros should never clobber r1, as it is used to hold the
 * exception code on the return path (except of course the macro that switches
 * all the registers before the final jump to the VM).
 */
vcpu	.req	r0		@ vcpu pointer always in r0

/* Clobbers {r2-r6} */
.macro store_vfp_state vfp_base
	@ The VFPFMRX and VFPFMXR macros are the VMRS and VMSR instructions
	VFPFMRX	r2, FPEXC
	@ Make sure VFP is enabled so we can touch the registers.
	orr	r6, r2, #FPEXC_EN
	VFPFMXR	FPEXC, r6

	VFPFMRX	r3, FPSCR
	tst	r2, #FPEXC_EX		@ Check for VFP Subarchitecture
	beq	1f
	@ If FPEXC_EX is 0, then FPINST/FPINST2 reads are upredictable, so
	@ we only need to save them if FPEXC_EX is set.
	VFPFMRX r4, FPINST
	tst	r2, #FPEXC_FP2V
	VFPFMRX r5, FPINST2, ne		@ vmrsne
	bic	r6, r2, #FPEXC_EX	@ FPEXC_EX disable
	VFPFMXR	FPEXC, r6
1:
	VFPFSTMIA \vfp_base, r6		@ Save VFP registers
	stm	\vfp_base, {r2-r5}	@ Save FPEXC, FPSCR, FPINST, FPINST2
.endm

/* Assume FPEXC_EN is on and FPEXC_EX is off, clobbers {r2-r6} */
.macro restore_vfp_state vfp_base
	VFPFLDMIA \vfp_base, r6		@ Load VFP registers
	ldm	\vfp_base, {r2-r5}	@ Load FPEXC, FPSCR, FPINST, FPINST2

	VFPFMXR FPSCR, r3
	tst	r2, #FPEXC_EX		@ Check for VFP Subarchitecture
	beq	1f
	VFPFMXR FPINST, r4
	tst	r2, #FPEXC_FP2V
	VFPFMXR FPINST2, r5, ne
1:
	VFPFMXR FPEXC, r2	@ FPEXC	(last, in case !EN)
.endm

/* These are simply for the macros to work - value don't have meaning */
.equ usr, 0
.equ svc, 1
.equ abt, 2
.equ und, 3
.equ irq, 4
.equ fiq, 5

.macro push_host_regs_mode mode
	mrs	r2, SP_\mode
	mrs	r3, LR_\mode
	mrs	r4, SPSR_\mode
	push	{r2, r3, r4}
.endm

/*
 * Store all host persistent registers on the stack.
 * Clobbers all registers, in all modes, except r0 and r1.
 */
.macro save_host_regs
	/* Hyp regs. Only ELR_hyp (SPSR_hyp already saved) */
	mrs	r2, ELR_hyp
	push	{r2}

	/* usr regs */
	push	{r4-r12}	@ r0-r3 are always clobbered
	mrs	r2, SP_usr
	mov	r3, lr
	push	{r2, r3}

	push_host_regs_mode svc
	push_host_regs_mode abt
	push_host_regs_mode und
	push_host_regs_mode irq

	/* fiq regs */
	mrs	r2, r8_fiq
	mrs	r3, r9_fiq
	mrs	r4, r10_fiq
	mrs	r5, r11_fiq
	mrs	r6, r12_fiq
	mrs	r7, SP_fiq
	mrs	r8, LR_fiq
	mrs	r9, SPSR_fiq
	push	{r2-r9}
.endm

.macro pop_host_regs_mode mode
	pop	{r2, r3, r4}
	msr	SP_\mode, r2
	msr	LR_\mode, r3
	msr	SPSR_\mode, r4
.endm

/*
 * Restore all host registers from the stack.
 * Clobbers all registers, in all modes, except r0 and r1.
 */
.macro restore_host_regs
	pop	{r2-r9}
	msr	r8_fiq, r2
	msr	r9_fiq, r3
	msr	r10_fiq, r4
	msr	r11_fiq, r5
	msr	r12_fiq, r6
	msr	SP_fiq, r7
	msr	LR_fiq, r8
	msr	SPSR_fiq, r9

	pop_host_regs_mode irq
	pop_host_regs_mode und
	pop_host_regs_mode abt
	pop_host_regs_mode svc

	pop	{r2, r3}
	msr	SP_usr, r2
	mov	lr, r3
	pop	{r4-r12}

	pop	{r2}
	msr	ELR_hyp, r2
.endm

/*
 * Restore SP, LR and SPSR for a given mode. offset is the offset of
 * this mode's registers from the VCPU base.
 *
 * Assumes vcpu pointer in vcpu reg
 *
 * Clobbers r1, r2, r3, r4.
 */
.macro restore_guest_regs_mode mode, offset
	add	r1, vcpu, \offset
	ldm	r1, {r2, r3, r4}
	msr	SP_\mode, r2
	msr	LR_\mode, r3
	msr	SPSR_\mode, r4
.endm

/*
 * Restore all guest registers from the vcpu struct.
 *
 * Assumes vcpu pointer in vcpu reg
 *
 * Clobbers *all* registers.
 */
.macro restore_guest_regs
	restore_guest_regs_mode svc, #VCPU_SVC_REGS
	restore_guest_regs_mode abt, #VCPU_ABT_REGS
	restore_guest_regs_mode und, #VCPU_UND_REGS
	restore_guest_regs_mode irq, #VCPU_IRQ_REGS

	add	r1, vcpu, #VCPU_FIQ_REGS
	ldm	r1, {r2-r9}
	msr	r8_fiq, r2
	msr	r9_fiq, r3
	msr	r10_fiq, r4
	msr	r11_fiq, r5
	msr	r12_fiq, r6
	msr	SP_fiq, r7
	msr	LR_fiq, r8
	msr	SPSR_fiq, r9

	@ Load return state
	ldr	r2, [vcpu, #VCPU_PC]
	ldr	r3, [vcpu, #VCPU_CPSR]
	msr	ELR_hyp, r2
	msr	SPSR_cxsf, r3

	@ Load user registers
	ldr	r2, [vcpu, #VCPU_USR_SP]
	ldr	r3, [vcpu, #VCPU_USR_LR]
	msr	SP_usr, r2
	mov	lr, r3
	add	vcpu, vcpu, #(VCPU_USR_REGS)
	ldm	vcpu, {r0-r12}
.endm

/*
 * Save SP, LR and SPSR for a given mode. offset is the offset of
 * this mode's registers from the VCPU base.
 *
 * Assumes vcpu pointer in vcpu reg
 *
 * Clobbers r2, r3, r4, r5.
 */
.macro save_guest_regs_mode mode, offset
	add	r2, vcpu, \offset
	mrs	r3, SP_\mode
	mrs	r4, LR_\mode
	mrs	r5, SPSR_\mode
	stm	r2, {r3, r4, r5}
.endm

/*
 * Save all guest registers to the vcpu struct
 * Expects guest's r0, r1, r2 on the stack.
 *
 * Assumes vcpu pointer in vcpu reg
 *
 * Clobbers r2, r3, r4, r5.
 */
.macro save_guest_regs
	@ Store usr registers
	add	r2, vcpu, #VCPU_USR_REG(3)
	stm	r2, {r3-r12}
	add	r2, vcpu, #VCPU_USR_REG(0)
	pop	{r3, r4, r5}		@ r0, r1, r2
	stm	r2, {r3, r4, r5}
	mrs	r2, SP_usr
	mov	r3, lr
	str	r2, [vcpu, #VCPU_USR_SP]
	str	r3, [vcpu, #VCPU_USR_LR]

	@ Store return state
	mrs	r2, ELR_hyp
	mrs	r3, spsr
	str	r2, [vcpu, #VCPU_PC]
	str	r3, [vcpu, #VCPU_CPSR]

	@ Store other guest registers
	save_guest_regs_mode svc, #VCPU_SVC_REGS
	save_guest_regs_mode abt, #VCPU_ABT_REGS
	save_guest_regs_mode