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Diffstat (limited to 'arch/powerpc/kernel/vector.S')
| -rw-r--r-- | arch/powerpc/kernel/vector.S | 346 |
1 files changed, 346 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/vector.S b/arch/powerpc/kernel/vector.S new file mode 100644 index 000000000..99c1e7084 --- /dev/null +++ b/arch/powerpc/kernel/vector.S @@ -0,0 +1,346 @@ +/* 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 + lvx v0, 0, 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 */ +#ifdef CONFIG_PPC_BOOK3S_64 + /* interrupt doesn't set MSR[RI] and HPT can fault on current access */ + ori r5,r5,MSR_RI +#endif + 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 + addi r5,r2,THREAD + 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) +#ifdef CONFIG_PPC_BOOK3S_64 + li r4,0 + stb r4,PACASRR_VALID(r13) +#endif +#endif + li r4,1 + stb r4,THREAD_LOAD_VEC(r5) + addi r6,r5,THREAD_VRSTATE + 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 +_ASM_NOKPROBE_SYMBOL(load_up_altivec) + +/* + * 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 + lvx v0,0,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 */ + +#ifdef CONFIG_PPC_BOOK3S_64 + /* interrupt doesn't set MSR[RI] and HPT can fault on current access */ + li r5,MSR_RI + mtmsrd r5,1 +#endif + + 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) + li r4,0 + stb r4,PACASRR_VALID(r13) + b fast_interrupt_return_srr + +#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. + */ + .data +#ifdef CONFIG_PPC32 +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 + +fpzero: + .quad 0 +fpone: + .quad 0x3ff0000000000000 /* 1.0 */ +fphalf: + .quad 0x3fe0000000000000 /* 0.5 */ + +#define LDCONST(fr, name) \ + addis r11,r2,name@toc@ha; \ + lfd fr,name@toc@l(r11) +#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 |