arch/powerpc/kernel/vector.S - linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 */
 #include <asm/processor.h>
 #include <asm/ppc_asm.h>
 #include <asm/reg.h>
 #include <asm/asm-offsets.h>
 #include <asm/cputable.h>
 #include <asm/thread_info.h>
 #include <asm/page.h>
 #include <asm/ptrace.h>
 #include <asm/export.h>
 #include <asm/asm-compat.h>

 /*
  * Load state from memory into VMX registers including VSCR.
  * Assumes the caller has enabled VMX in the MSR.
  */
 _GLOBAL(load_vr_state)
 	li	r4,VRSTATE_VSCR
 	lvx	v0,r4,r3
 	mtvscr	v0
 	REST_32VRS(0,r4,r3)
 	blr
 EXPORT_SYMBOL(load_vr_state)
 _ASM_NOKPROBE_SYMBOL(load_vr_state); /* used by restore_math */

 /*
  * Store VMX state into memory, including VSCR.
  * Assumes the caller has enabled VMX in the MSR.
  */
 _GLOBAL(store_vr_state)
 	SAVE_32VRS(0, r4, r3)
 	mfvscr	v0
 	li	r4, VRSTATE_VSCR
 	stvx	v0, r4, r3
 	blr
 EXPORT_SYMBOL(store_vr_state)

 /*
  * Disable VMX for the task which had it previously,
  * and save its vector registers in its thread_struct.
  * Enables the VMX for use in the kernel on return.
  * On SMP we know the VMX is free, since we give it up every
  * switch (ie, no lazy save of the vector registers).
  *
  * Note that on 32-bit this can only use registers that will be
  * restored by fast_exception_return, i.e. r3 - r6, r10 and r11.
  */
 _GLOBAL(load_up_altivec)
 	mfmsr	r5			/* grab the current MSR */
 	oris	r5,r5,MSR_VEC@h
 	MTMSRD(r5)			/* enable use of AltiVec now */
 	isync

 	/*
 	 * While userspace in general ignores VRSAVE, glibc uses it as a boolean
 	 * to optimise userspace context save/restore. Whenever we take an
 	 * altivec unavailable exception we must set VRSAVE to something non
 	 * zero. Set it to all 1s. See also the programming note in the ISA.
 	 */
 	mfspr	r4,SPRN_VRSAVE
 	cmpwi	0,r4,0
 	bne+	1f
 	li	r4,-1
 	mtspr	SPRN_VRSAVE,r4
 1:
 	/* enable use of VMX after return */
 #ifdef CONFIG_PPC32
 	mfspr	r5,SPRN_SPRG_THREAD		/* current task's THREAD (phys) */
 	oris	r9,r9,MSR_VEC@h
 #else
 	ld	r4,PACACURRENT(r13)
 	addi	r5,r4,THREAD		/* Get THREAD */
 	oris	r12,r12,MSR_VEC@h
 	std	r12,_MSR(r1)
 #endif
 	/* Don't care if r4 overflows, this is desired behaviour */
 	lbz	r4,THREAD_LOAD_VEC(r5)
 	addi	r4,r4,1
 	stb	r4,THREAD_LOAD_VEC(r5)
 	addi	r6,r5,THREAD_VRSTATE
 	li	r4,1
 	li	r10,VRSTATE_VSCR
 	stw	r4,THREAD_USED_VR(r5)
 	lvx	v0,r10,r6
 	mtvscr	v0
 	REST_32VRS(0,r4,r6)
 	/* restore registers and return */
 	blr

 /*
  * save_altivec(tsk)
  * Save the vector registers to its thread_struct
  */
 _GLOBAL(save_altivec)
 	addi	r3,r3,THREAD		/* want THREAD of task */
 	PPC_LL	r7,THREAD_VRSAVEAREA(r3)
 	PPC_LL	r5,PT_REGS(r3)
 	PPC_LCMPI	0,r7,0
 	bne	2f
 	addi	r7,r3,THREAD_VRSTATE
 2:	SAVE_32VRS(0,r4,r7)
 	mfvscr	v0
 	li	r4,VRSTATE_VSCR
 	stvx	v0,r4,r7
 	blr

 #ifdef CONFIG_VSX

 #ifdef CONFIG_PPC32
 #error This asm code isn't ready for 32-bit kernels
 #endif

 /*
  * load_up_vsx(unused, unused, tsk)
  * Disable VSX for the task which had it previously,
  * and save its vector registers in its thread_struct.
  * Reuse the fp and vsx saves, but first check to see if they have
  * been saved already.
  */
 _GLOBAL(load_up_vsx)
 /* Load FP and VSX registers if they haven't been done yet */
 	andi.	r5,r12,MSR_FP
 	beql+	load_up_fpu		/* skip if already loaded */
 	andis.	r5,r12,MSR_VEC@h
 	beql+	load_up_altivec		/* skip if already loaded */

 	ld	r4,PACACURRENT(r13)
 	addi	r4,r4,THREAD		/* Get THREAD */
 	li	r6,1
 	stw	r6,THREAD_USED_VSR(r4) /* ... also set thread used vsr */
 	/* enable use of VSX after return */
 	oris	r12,r12,MSR_VSX@h
 	std	r12,_MSR(r1)
 	b	fast_exception_return

 #endif /* CONFIG_VSX */


 /*
  * The routines below are in assembler so we can closely control the
  * usage of floating-point registers.  These routines must be called
  * with preempt disabled.
  */
 #ifdef CONFIG_PPC32
 	.data
 fpzero:
 	.long	0
 fpone:
 	.long	0x3f800000	/* 1.0 in single-precision FP */
 fphalf:
 	.long	0x3f000000	/* 0.5 in single-precision FP */

 #define LDCONST(fr, name)	\
 	lis	r11,name@ha;	\
 	lfs	fr,name@l(r11)
 #else

 	.section ".toc","aw"
 fpzero:
 	.tc	FD_0_0[TC],0
 fpone:
 	.tc	FD_3ff00000_0[TC],0x3ff0000000000000	/* 1.0 */
 fphalf:
 	.tc	FD_3fe00000_0[TC],0x3fe0000000000000	/* 0.5 */

 #define LDCONST(fr, name)	\
 	lfd	fr,name@toc(r2)
 #endif

 	.text
 /*
  * Internal routine to enable floating point and set FPSCR to 0.
  * Don't call it from C; it doesn't use the normal calling convention.
  */
 fpenable:
 #ifdef CONFIG_PPC32
 	stwu	r1,-64(r1)
 #else
 	stdu	r1,-64(r1)
 #endif
 	mfmsr	r10
 	ori	r11,r10,MSR_FP
 	mtmsr	r11
 	isync
 	stfd	fr0,24(r1)
 	stfd	fr1,16(r1)
 	stfd	fr31,8(r1)
 	LDCONST(fr1, fpzero)
 	mffs	fr31
 	MTFSF_L(fr1)
 	blr

 fpdisable:
 	mtlr	r12
 	MTFSF_L(fr31)
 	lfd	fr31,8(r1)
 	lfd	fr1,16(r1)
 	lfd	fr0,24(r1)
 	mtmsr	r10
 	isync
 	addi	r1,r1,64
 	blr

 /*
  * Vector add, floating point.
  */
 _GLOBAL(vaddfp)
 	mflr	r12
 	bl	fpenable
 	li	r0,4
 	mtctr	r0
 	li	r6,0
 1:	lfsx	fr0,r4,r6
 	lfsx	fr1,r5,r6
 	fadds	fr0,fr0,fr1
 	stfsx	fr0,r3,r6
 	addi	r6,r6,4
 	bdnz	1b
 	b	fpdisable

 /*
  * Vector subtract, floating point.
  */
 _GLOBAL(vsubfp)
 	mflr	r12
 	bl	fpenable
 	li	r0,4
 	mtctr	r0
 	li	r6,0
 1:	lfsx	fr0,r4,r6
 	lfsx	fr1,r5,r6
 	fsubs	fr0,fr0,fr1
 	stfsx	fr0,r3,r6
 	addi	r6,r6,4
 	bdnz	1b
 	b	fpdisable

 /*
  * Vector multiply and add, floating point.
  */
 _GLOBAL(vmaddfp)
 	mflr	r12
 	bl	fpenable
 	stfd	fr2,32(r1)
 	li	r0,4
 	mtctr	r0
 	li	r7,0
 1:	lfsx	fr0,r4,r7
 	lfsx	fr1,r5,r7
 	lfsx	fr2,r6,r7
 	fmadds	fr0,fr0,fr2,fr1
 	stfsx	fr0,r3,r7
 	addi	r7,r7,4
 	bdnz	1b
 	lfd	fr2,32(r1)
 	b	fpdisable

 /*
  * Vector negative multiply and subtract, floating point.
  */
 _GLOBAL(vnmsubfp)
 	mflr	r12
 	bl	fpenable
 	stfd	fr2,32(r1)
 	li	r0,4
 	mtctr	r0
 	li	r7,0
 1:	lfsx	fr0,r4,r7
 	lfsx	fr1,r5,r7
 	lfsx	fr2,r6,r7
 	fnmsubs	fr0,fr0,fr2,fr1
 	stfsx	fr0,r3,r7
 	addi	r7,r7,4
 	bdnz	1b
 	lfd	fr2,32(r1)
 	b	fpdisable

 /*
  * Vector reciprocal estimate.  We just compute 1.0/x.
  * r3 -> destination, r4 -> source.
  */
 _GLOBAL(vrefp)
 	mflr	r12
 	bl	fpenable
 	li	r0,4
 	LDCONST(fr1, fpone)
 	mtctr	r0
 	li	r6,0
 1:	lfsx	fr0,r4,r6
 	fdivs	fr0,fr1,fr0
 	stfsx	fr0,r3,r6
 	addi	r6,r6,4
 	bdnz	1b
 	b	fpdisable

 /*
  * Vector reciprocal square-root estimate, floating point.
  * We use the frsqrte instruction for the initial estimate followed
  * by 2 iterations of Newton-Raphson to get sufficient accuracy.
  * r3 -> destination, r4 -> source.
  */
 _GLOBAL(vrsqrtefp)
 	mflr	r12
 	bl	fpenable
 	stfd	fr2,32(r1)
 	stfd	fr3,40(r1)
 	stfd	fr4,48(r1)
 	stfd	fr5,56(r1)
 	li	r0,4
 	LDCONST(fr4, fpone)
 	LDCONST(fr5, fphalf)
 	mtctr	r0
 	li	r6,0
 1:	lfsx	fr0,r4,r6
 	frsqrte	fr1,fr0		/* r = frsqrte(s) */
 	fmuls	fr3,fr1,fr0	/* r * s */
 	fmuls	fr2,fr1,fr5	/* r * 0.5 */
 	fnmsubs	fr3,fr1,fr3,fr4	/* 1 - s * r * r */
 	fmadds	fr1,fr2,fr3,fr1	/* r = r + 0.5 * r * (1 - s * r * r) */
 	fmuls	fr3,fr1,fr0	/* r * s */
 	fmuls	fr2,fr1,fr5	/* r * 0.5 */
 	fnmsubs	fr3,fr1,fr3,fr4	/* 1 - s * r * r */
 	fmadds	fr1,fr2,fr3,fr1	/* r = r + 0.5 * r * (1 - s * r * r) */
 	stfsx	fr1,r3,r6
 	addi	r6,r6,4
 	bdnz	1b
 	lfd	fr5,56(r1)
 	lfd	fr4,48(r1)
 	lfd	fr3,40(r1)
 	lfd	fr2,32(r1)
 	b	fpdisable
	/* SPDX-License-Identifier: GPL-2.0 */
	#include <asm/processor.h>
	#include <asm/ppc_asm.h>
	#include <asm/reg.h>
	#include <asm/asm-offsets.h>
	#include <asm/cputable.h>
	#include <asm/thread_info.h>
	#include <asm/page.h>
	#include <asm/ptrace.h>
	#include <asm/export.h>
	#include <asm/asm-compat.h>

	/*
	* Load state from memory into VMX registers including VSCR.
	* Assumes the caller has enabled VMX in the MSR.
	*/
	_GLOBAL(load_vr_state)
	li r4,VRSTATE_VSCR
	lvx v0,r4,r3
	mtvscr v0
	REST_32VRS(0,r4,r3)
	blr
	EXPORT_SYMBOL(load_vr_state)
	_ASM_NOKPROBE_SYMBOL(load_vr_state); /* used by restore_math */

	/*
	* Store VMX state into memory, including VSCR.
	* Assumes the caller has enabled VMX in the MSR.
	*/
	_GLOBAL(store_vr_state)
	SAVE_32VRS(0, r4, r3)
	mfvscr v0
	li r4, VRSTATE_VSCR
	stvx v0, r4, r3
	blr
	EXPORT_SYMBOL(store_vr_state)

	/*
	* Disable VMX for the task which had it previously,
	* and save its vector registers in its thread_struct.
	* Enables the VMX for use in the kernel on return.
	* On SMP we know the VMX is free, since we give it up every
	* switch (ie, no lazy save of the vector registers).
	*
	* Note that on 32-bit this can only use registers that will be
	* restored by fast_exception_return, i.e. r3 - r6, r10 and r11.
	*/
	_GLOBAL(load_up_altivec)
	mfmsr r5 /* grab the current MSR */
	oris r5,r5,MSR_VEC@h
	MTMSRD(r5) /* enable use of AltiVec now */
	isync

	/*
	* While userspace in general ignores VRSAVE, glibc uses it as a boolean
	* to optimise userspace context save/restore. Whenever we take an
	* altivec unavailable exception we must set VRSAVE to something non
	* zero. Set it to all 1s. See also the programming note in the ISA.
	*/
	mfspr r4,SPRN_VRSAVE
	cmpwi 0,r4,0
	bne+ 1f
	li r4,-1
	mtspr SPRN_VRSAVE,r4
	1:
	/* enable use of VMX after return */
	#ifdef CONFIG_PPC32
	mfspr r5,SPRN_SPRG_THREAD /* current task's THREAD (phys) */
	oris r9,r9,MSR_VEC@h
	#else
	ld r4,PACACURRENT(r13)
	addi r5,r4,THREAD /* Get THREAD */
	oris r12,r12,MSR_VEC@h
	std r12,_MSR(r1)
	#endif
	/* Don't care if r4 overflows, this is desired behaviour */
	lbz r4,THREAD_LOAD_VEC(r5)
	addi r4,r4,1
	stb r4,THREAD_LOAD_VEC(r5)
	addi r6,r5,THREAD_VRSTATE
	li r4,1
	li r10,VRSTATE_VSCR
	stw r4,THREAD_USED_VR(r5)
	lvx v0,r10,r6
	mtvscr v0
	REST_32VRS(0,r4,r6)
	/* restore registers and return */
	blr

	/*
	* save_altivec(tsk)
	* Save the vector registers to its thread_struct
	*/
	_GLOBAL(save_altivec)
	addi r3,r3,THREAD /* want THREAD of task */
	PPC_LL r7,THREAD_VRSAVEAREA(r3)
	PPC_LL r5,PT_REGS(r3)
	PPC_LCMPI 0,r7,0
	bne 2f
	addi r7,r3,THREAD_VRSTATE
	2: SAVE_32VRS(0,r4,r7)
	mfvscr v0
	li r4,VRSTATE_VSCR
	stvx v0,r4,r7
	blr

	#ifdef CONFIG_VSX

	#ifdef CONFIG_PPC32
	#error This asm code isn't ready for 32-bit kernels
	#endif

	/*
	* load_up_vsx(unused, unused, tsk)
	* Disable VSX for the task which had it previously,
	* and save its vector registers in its thread_struct.
	* Reuse the fp and vsx saves, but first check to see if they have
	* been saved already.
	*/
	_GLOBAL(load_up_vsx)
	/* Load FP and VSX registers if they haven't been done yet */
	andi. r5,r12,MSR_FP
	beql+ load_up_fpu /* skip if already loaded */
	andis. r5,r12,MSR_VEC@h
	beql+ load_up_altivec /* skip if already loaded */

	ld r4,PACACURRENT(r13)
	addi r4,r4,THREAD /* Get THREAD */
	li r6,1
	stw r6,THREAD_USED_VSR(r4) /* ... also set thread used vsr */
	/* enable use of VSX after return */
	oris r12,r12,MSR_VSX@h
	std r12,_MSR(r1)
	b fast_exception_return

	#endif /* CONFIG_VSX */


	/*
	* The routines below are in assembler so we can closely control the
	* usage of floating-point registers. These routines must be called
	* with preempt disabled.
	*/
	#ifdef CONFIG_PPC32
	.data
	fpzero:
	.long 0
	fpone:
	.long 0x3f800000 /* 1.0 in single-precision FP */
	fphalf:
	.long 0x3f000000 /* 0.5 in single-precision FP */

	#define LDCONST(fr, name) \
	lis r11,name@ha; \
	lfs fr,name@l(r11)
	#else

	.section ".toc","aw"
	fpzero:
	.tc FD_0_0[TC],0
	fpone:
	.tc FD_3ff00000_0[TC],0x3ff0000000000000 /* 1.0 */
	fphalf:
	.tc FD_3fe00000_0[TC],0x3fe0000000000000 /* 0.5 */

	#define LDCONST(fr, name) \
	lfd fr,name@toc(r2)
	#endif

	.text
	/*
	* Internal routine to enable floating point and set FPSCR to 0.
	* Don't call it from C; it doesn't use the normal calling convention.
	*/
	fpenable:
	#ifdef CONFIG_PPC32
	stwu r1,-64(r1)
	#else
	stdu r1,-64(r1)
	#endif
	mfmsr r10
	ori r11,r10,MSR_FP
	mtmsr r11
	isync
	stfd fr0,24(r1)
	stfd fr1,16(r1)
	stfd fr31,8(r1)
	LDCONST(fr1, fpzero)
	mffs fr31
	MTFSF_L(fr1)
	blr

	fpdisable:
	mtlr r12
	MTFSF_L(fr31)
	lfd fr31,8(r1)
	lfd fr1,16(r1)
	lfd fr0,24(r1)
	mtmsr r10
	isync
	addi r1,r1,64
	blr

	/*
	* Vector add, floating point.
	*/
	_GLOBAL(vaddfp)
	mflr r12
	bl fpenable
	li r0,4
	mtctr r0
	li r6,0
	1: lfsx fr0,r4,r6
	lfsx fr1,r5,r6
	fadds fr0,fr0,fr1
	stfsx fr0,r3,r6
	addi r6,r6,4
	bdnz 1b
	b fpdisable

	/*
	* Vector subtract, floating point.
	*/
	_GLOBAL(vsubfp)
	mflr r12
	bl fpenable
	li r0,4
	mtctr r0
	li r6,0
	1: lfsx fr0,r4,r6
	lfsx fr1,r5,r6
	fsubs fr0,fr0,fr1
	stfsx fr0,r3,r6
	addi r6,r6,4
	bdnz 1b
	b fpdisable

	/*
	* Vector multiply and add, floating point.
	*/
	_GLOBAL(vmaddfp)
	mflr r12
	bl fpenable
	stfd fr2,32(r1)
	li r0,4
	mtctr r0
	li r7,0
	1: lfsx fr0,r4,r7
	lfsx fr1,r5,r7
	lfsx fr2,r6,r7
	fmadds fr0,fr0,fr2,fr1
	stfsx fr0,r3,r7
	addi r7,r7,4
	bdnz 1b
	lfd fr2,32(r1)
	b fpdisable

	/*
	* Vector negative multiply and subtract, floating point.
	*/
	_GLOBAL(vnmsubfp)
	mflr r12
	bl fpenable
	stfd fr2,32(r1)
	li r0,4
	mtctr r0
	li r7,0
	1: lfsx fr0,r4,r7
	lfsx fr1,r5,r7
	lfsx fr2,r6,r7
	fnmsubs fr0,fr0,fr2,fr1
	stfsx fr0,r3,r7
	addi r7,r7,4
	bdnz 1b
	lfd fr2,32(r1)
	b fpdisable

	/*
	* Vector reciprocal estimate. We just compute 1.0/x.
	* r3 -> destination, r4 -> source.
	*/
	_GLOBAL(vrefp)
	mflr r12
	bl fpenable
	li r0,4
	LDCONST(fr1, fpone)
	mtctr r0
	li r6,0
	1: lfsx fr0,r4,r6
	fdivs fr0,fr1,fr0
	stfsx fr0,r3,r6
	addi r6,r6,4
	bdnz 1b
	b fpdisable

	/*
	* Vector reciprocal square-root estimate, floating point.
	* We use the frsqrte instruction for the initial estimate followed
	* by 2 iterations of Newton-Raphson to get sufficient accuracy.
	* r3 -> destination, r4 -> source.
	*/
	_GLOBAL(vrsqrtefp)
	mflr r12
	bl fpenable
	stfd fr2,32(r1)
	stfd fr3,40(r1)
	stfd fr4,48(r1)
	stfd fr5,56(r1)
	li r0,4
	LDCONST(fr4, fpone)
	LDCONST(fr5, fphalf)
	mtctr r0
	li r6,0
	1: lfsx fr0,r4,r6
	frsqrte fr1,fr0 /* r = frsqrte(s) */
	fmuls fr3,fr1,fr0 /* r * s */
	fmuls fr2,fr1,fr5 /* r * 0.5 */
	fnmsubs fr3,fr1,fr3,fr4 /* 1 - s * r * r */
	fmadds fr1,fr2,fr3,fr1 /* r = r + 0.5 * r * (1 - s * r * r) */
	fmuls fr3,fr1,fr0 /* r * s */
	fmuls fr2,fr1,fr5 /* r * 0.5 */
	fnmsubs fr3,fr1,fr3,fr4 /* 1 - s * r * r */
	fmadds fr1,fr2,fr3,fr1 /* r = r + 0.5 * r * (1 - s * r * r) */
	stfsx fr1,r3,r6
	addi r6,r6,4
	bdnz 1b
	lfd fr5,56(r1)
	lfd fr4,48(r1)
	lfd fr3,40(r1)
	lfd fr2,32(r1)
	b fpdisable