diff options
Diffstat (limited to 'arch/powerpc/kernel/fpu.S')
| -rw-r--r-- | arch/powerpc/kernel/fpu.S | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/fpu.S b/arch/powerpc/kernel/fpu.S new file mode 100644 index 000000000..2f8f3f93c --- /dev/null +++ b/arch/powerpc/kernel/fpu.S @@ -0,0 +1,154 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * FPU support code, moved here from head.S so that it can be used + * by chips which use other head-whatever.S files. + * + * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) + * Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu> + * Copyright (C) 1996 Paul Mackerras. + * Copyright (C) 1997 Dan Malek (dmalek@jlc.net). + */ + +#include <linux/export.h> +#include <asm/reg.h> +#include <asm/page.h> +#include <asm/mmu.h> +#include <asm/cputable.h> +#include <asm/cache.h> +#include <asm/thread_info.h> +#include <asm/ppc_asm.h> +#include <asm/asm-offsets.h> +#include <asm/ptrace.h> +#include <asm/asm-compat.h> +#include <asm/feature-fixups.h> + +#ifdef CONFIG_VSX +#define __REST_1FPVSR(n,c,base) \ +BEGIN_FTR_SECTION \ + b 2f; \ +END_FTR_SECTION_IFSET(CPU_FTR_VSX); \ + REST_FPR(n,base); \ + b 3f; \ +2: REST_VSR(n,c,base); \ +3: + +#define __REST_32FPVSRS(n,c,base) \ +BEGIN_FTR_SECTION \ + b 2f; \ +END_FTR_SECTION_IFSET(CPU_FTR_VSX); \ + REST_32FPRS(n,base); \ + b 3f; \ +2: REST_32VSRS(n,c,base); \ +3: + +#define __SAVE_32FPVSRS(n,c,base) \ +BEGIN_FTR_SECTION \ + b 2f; \ +END_FTR_SECTION_IFSET(CPU_FTR_VSX); \ + SAVE_32FPRS(n,base); \ + b 3f; \ +2: SAVE_32VSRS(n,c,base); \ +3: +#else +#define __REST_1FPVSR(n,b,base) REST_FPR(n, base) +#define __REST_32FPVSRS(n,b,base) REST_32FPRS(n, base) +#define __SAVE_32FPVSRS(n,b,base) SAVE_32FPRS(n, base) +#endif +#define REST_1FPVSR(n,c,base) __REST_1FPVSR(n,__REG_##c,__REG_##base) +#define REST_32FPVSRS(n,c,base) __REST_32FPVSRS(n,__REG_##c,__REG_##base) +#define SAVE_32FPVSRS(n,c,base) __SAVE_32FPVSRS(n,__REG_##c,__REG_##base) + +/* + * Load state from memory into FP registers including FPSCR. + * Assumes the caller has enabled FP in the MSR. + */ +_GLOBAL(load_fp_state) + lfd fr0,FPSTATE_FPSCR(r3) + MTFSF_L(fr0) + REST_32FPVSRS(0, R4, R3) + blr +EXPORT_SYMBOL(load_fp_state) +_ASM_NOKPROBE_SYMBOL(load_fp_state); /* used by restore_math */ + +/* + * Store FP state into memory, including FPSCR + * Assumes the caller has enabled FP in the MSR. + */ +_GLOBAL(store_fp_state) + SAVE_32FPVSRS(0, R4, R3) + mffs fr0 + stfd fr0,FPSTATE_FPSCR(r3) + REST_1FPVSR(0, R4, R3) + blr +EXPORT_SYMBOL(store_fp_state) + +/* + * This task wants to use the FPU now. + * On UP, disable FP for the task which had the FPU previously, + * and save its floating-point registers in its thread_struct. + * Load up this task's FP registers from its thread_struct, + * enable the FPU for the current task and return to the task. + * 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_fpu) + mfmsr r5 +#ifdef CONFIG_PPC_BOOK3S_64 + /* interrupt doesn't set MSR[RI] and HPT can fault on current access */ + ori r5,r5,MSR_FP|MSR_RI +#else + ori r5,r5,MSR_FP +#endif +#ifdef CONFIG_VSX +BEGIN_FTR_SECTION + oris r5,r5,MSR_VSX@h +END_FTR_SECTION_IFSET(CPU_FTR_VSX) +#endif + MTMSRD(r5) /* enable use of fpu now */ + isync + /* enable use of FP after return */ +#ifdef CONFIG_PPC32 + addi r5,r2,THREAD + lwz r4,THREAD_FPEXC_MODE(r5) + ori r9,r9,MSR_FP /* enable FP for current */ + or r9,r9,r4 +#else + ld r4,PACACURRENT(r13) + addi r5,r4,THREAD /* Get THREAD */ + lwz r4,THREAD_FPEXC_MODE(r5) + ori r12,r12,MSR_FP + or r12,r12,r4 + 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_FP(r5) + addi r10,r5,THREAD_FPSTATE + lfd fr0,FPSTATE_FPSCR(r10) + MTFSF_L(fr0) + REST_32FPVSRS(0, R4, R10) + /* restore registers and return */ + /* we haven't used ctr or xer or lr */ + blr +_ASM_NOKPROBE_SYMBOL(load_up_fpu) + +/* + * save_fpu(tsk) + * Save the floating-point registers in its thread_struct. + * Enables the FPU for use in the kernel on return. + */ +_GLOBAL(save_fpu) + addi r3,r3,THREAD /* want THREAD of task */ + PPC_LL r6,THREAD_FPSAVEAREA(r3) + PPC_LL r5,PT_REGS(r3) + PPC_LCMPI 0,r6,0 + bne 2f + addi r6,r3,THREAD_FPSTATE +2: SAVE_32FPVSRS(0, R4, R6) + mffs fr0 + stfd fr0,FPSTATE_FPSCR(r6) + REST_1FPVSR(0, R4, R6) + blr |