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59dc5bfca0
When an interrupt is taken, the SRR registers are set to return to where it left off. Unless they are modified in the meantime, or the return address or MSR are modified, there is no need to reload these registers when returning from interrupt. Introduce per-CPU flags that track the validity of SRR and HSRR registers. These are cleared when returning from interrupt, when using the registers for something else (e.g., OPAL calls), when adjusting the return address or MSR of a context, and when context switching (which changes the return address and MSR). This improves the performance of interrupt returns. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Fold in fixup patch from Nick] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210617155116.2167984-5-npiggin@gmail.com
137 lines
3.5 KiB
ArmAsm
137 lines
3.5 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* FPU support code, moved here from head.S so that it can be used
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* by chips which use other head-whatever.S files.
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*
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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* Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
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* Copyright (C) 1996 Paul Mackerras.
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* Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
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*/
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#include <asm/reg.h>
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#include <asm/page.h>
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#include <asm/mmu.h>
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#include <asm/cputable.h>
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#include <asm/cache.h>
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#include <asm/thread_info.h>
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#include <asm/ppc_asm.h>
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#include <asm/asm-offsets.h>
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#include <asm/ptrace.h>
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#include <asm/export.h>
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#include <asm/asm-compat.h>
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#include <asm/feature-fixups.h>
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#ifdef CONFIG_VSX
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#define __REST_32FPVSRS(n,c,base) \
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BEGIN_FTR_SECTION \
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b 2f; \
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END_FTR_SECTION_IFSET(CPU_FTR_VSX); \
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REST_32FPRS(n,base); \
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b 3f; \
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2: REST_32VSRS(n,c,base); \
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3:
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#define __SAVE_32FPVSRS(n,c,base) \
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BEGIN_FTR_SECTION \
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b 2f; \
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END_FTR_SECTION_IFSET(CPU_FTR_VSX); \
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SAVE_32FPRS(n,base); \
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b 3f; \
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2: SAVE_32VSRS(n,c,base); \
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3:
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#else
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#define __REST_32FPVSRS(n,b,base) REST_32FPRS(n, base)
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#define __SAVE_32FPVSRS(n,b,base) SAVE_32FPRS(n, base)
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#endif
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#define REST_32FPVSRS(n,c,base) __REST_32FPVSRS(n,__REG_##c,__REG_##base)
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#define SAVE_32FPVSRS(n,c,base) __SAVE_32FPVSRS(n,__REG_##c,__REG_##base)
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/*
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* Load state from memory into FP registers including FPSCR.
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* Assumes the caller has enabled FP in the MSR.
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*/
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_GLOBAL(load_fp_state)
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lfd fr0,FPSTATE_FPSCR(r3)
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MTFSF_L(fr0)
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REST_32FPVSRS(0, R4, R3)
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blr
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EXPORT_SYMBOL(load_fp_state)
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_ASM_NOKPROBE_SYMBOL(load_fp_state); /* used by restore_math */
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/*
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* Store FP state into memory, including FPSCR
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* Assumes the caller has enabled FP in the MSR.
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*/
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_GLOBAL(store_fp_state)
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SAVE_32FPVSRS(0, R4, R3)
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mffs fr0
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stfd fr0,FPSTATE_FPSCR(r3)
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blr
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EXPORT_SYMBOL(store_fp_state)
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/*
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* This task wants to use the FPU now.
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* On UP, disable FP for the task which had the FPU previously,
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* and save its floating-point registers in its thread_struct.
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* Load up this task's FP registers from its thread_struct,
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* enable the FPU for the current task and return to the task.
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* Note that on 32-bit this can only use registers that will be
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* restored by fast_exception_return, i.e. r3 - r6, r10 and r11.
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*/
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_GLOBAL(load_up_fpu)
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mfmsr r5
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ori r5,r5,MSR_FP
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#ifdef CONFIG_VSX
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BEGIN_FTR_SECTION
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oris r5,r5,MSR_VSX@h
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END_FTR_SECTION_IFSET(CPU_FTR_VSX)
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#endif
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MTMSRD(r5) /* enable use of fpu now */
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isync
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/* enable use of FP after return */
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#ifdef CONFIG_PPC32
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mfspr r5,SPRN_SPRG_THREAD /* current task's THREAD (phys) */
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tovirt(r5, r5)
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lwz r4,THREAD_FPEXC_MODE(r5)
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ori r9,r9,MSR_FP /* enable FP for current */
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or r9,r9,r4
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#else
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ld r4,PACACURRENT(r13)
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addi r5,r4,THREAD /* Get THREAD */
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lwz r4,THREAD_FPEXC_MODE(r5)
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ori r12,r12,MSR_FP
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or r12,r12,r4
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std r12,_MSR(r1)
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#ifdef CONFIG_PPC_BOOK3S_64
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li r4,0
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stb r4,PACASRR_VALID(r13)
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#endif
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#endif
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li r4,1
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stb r4,THREAD_LOAD_FP(r5)
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addi r10,r5,THREAD_FPSTATE
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lfd fr0,FPSTATE_FPSCR(r10)
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MTFSF_L(fr0)
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REST_32FPVSRS(0, R4, R10)
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/* restore registers and return */
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/* we haven't used ctr or xer or lr */
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blr
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_ASM_NOKPROBE_SYMBOL(load_up_fpu)
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/*
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* save_fpu(tsk)
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* Save the floating-point registers in its thread_struct.
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* Enables the FPU for use in the kernel on return.
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*/
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_GLOBAL(save_fpu)
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addi r3,r3,THREAD /* want THREAD of task */
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PPC_LL r6,THREAD_FPSAVEAREA(r3)
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PPC_LL r5,PT_REGS(r3)
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PPC_LCMPI 0,r6,0
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bne 2f
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addi r6,r3,THREAD_FPSTATE
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2: SAVE_32FPVSRS(0, R4, R6)
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mffs fr0
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stfd fr0,FPSTATE_FPSCR(r6)
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blr
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