mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
synced 2025-10-31 16:38:31 +00:00
9bbafce2ee
Presently with preempt enabled there's the possibility to be preempted after the TIF_USEDFPU test and the register save, leading to bogus state post-__switch_to(). Use an explicit preempt_disable()/enable() pair around unlazy_fpu()/clear_fpu() to avoid this. Follows the x86 change. Reported-by: Takuo Koguchi <takuo.koguchi.sw@hitachi.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
168 lines
4.7 KiB
C
168 lines
4.7 KiB
C
/*
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* arch/sh/kernel/cpu/sh5/fpu.c
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*
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* Copyright (C) 2001 Manuela Cirronis, Paolo Alberelli
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* Copyright (C) 2002 STMicroelectronics Limited
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* Author : Stuart Menefy
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*
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* Started from SH4 version:
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* Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/sched.h>
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#include <linux/signal.h>
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#include <asm/processor.h>
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#include <asm/user.h>
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#include <asm/io.h>
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#include <asm/fpu.h>
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/*
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* Initially load the FPU with signalling NANS. This bit pattern
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* has the property that no matter whether considered as single or as
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* double precision, it still represents a signalling NAN.
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*/
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#define sNAN64 0xFFFFFFFFFFFFFFFFULL
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#define sNAN32 0xFFFFFFFFUL
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static union sh_fpu_union init_fpuregs = {
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.hard = {
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.fp_regs = { [0 ... 63] = sNAN32 },
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.fpscr = FPSCR_INIT
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}
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};
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void save_fpu(struct task_struct *tsk, struct pt_regs *regs)
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{
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asm volatile("fst.p %0, (0*8), fp0\n\t"
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"fst.p %0, (1*8), fp2\n\t"
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"fst.p %0, (2*8), fp4\n\t"
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"fst.p %0, (3*8), fp6\n\t"
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"fst.p %0, (4*8), fp8\n\t"
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"fst.p %0, (5*8), fp10\n\t"
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"fst.p %0, (6*8), fp12\n\t"
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"fst.p %0, (7*8), fp14\n\t"
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"fst.p %0, (8*8), fp16\n\t"
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"fst.p %0, (9*8), fp18\n\t"
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"fst.p %0, (10*8), fp20\n\t"
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"fst.p %0, (11*8), fp22\n\t"
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"fst.p %0, (12*8), fp24\n\t"
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"fst.p %0, (13*8), fp26\n\t"
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"fst.p %0, (14*8), fp28\n\t"
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"fst.p %0, (15*8), fp30\n\t"
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"fst.p %0, (16*8), fp32\n\t"
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"fst.p %0, (17*8), fp34\n\t"
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"fst.p %0, (18*8), fp36\n\t"
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"fst.p %0, (19*8), fp38\n\t"
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"fst.p %0, (20*8), fp40\n\t"
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"fst.p %0, (21*8), fp42\n\t"
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"fst.p %0, (22*8), fp44\n\t"
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"fst.p %0, (23*8), fp46\n\t"
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"fst.p %0, (24*8), fp48\n\t"
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"fst.p %0, (25*8), fp50\n\t"
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"fst.p %0, (26*8), fp52\n\t"
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"fst.p %0, (27*8), fp54\n\t"
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"fst.p %0, (28*8), fp56\n\t"
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"fst.p %0, (29*8), fp58\n\t"
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"fst.p %0, (30*8), fp60\n\t"
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"fst.p %0, (31*8), fp62\n\t"
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"fgetscr fr63\n\t"
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"fst.s %0, (32*8), fr63\n\t"
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: /* no output */
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: "r" (&tsk->thread.fpu.hard)
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: "memory");
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}
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static inline void
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fpload(struct sh_fpu_hard_struct *fpregs)
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{
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asm volatile("fld.p %0, (0*8), fp0\n\t"
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"fld.p %0, (1*8), fp2\n\t"
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"fld.p %0, (2*8), fp4\n\t"
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"fld.p %0, (3*8), fp6\n\t"
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"fld.p %0, (4*8), fp8\n\t"
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"fld.p %0, (5*8), fp10\n\t"
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"fld.p %0, (6*8), fp12\n\t"
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"fld.p %0, (7*8), fp14\n\t"
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"fld.p %0, (8*8), fp16\n\t"
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"fld.p %0, (9*8), fp18\n\t"
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"fld.p %0, (10*8), fp20\n\t"
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"fld.p %0, (11*8), fp22\n\t"
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"fld.p %0, (12*8), fp24\n\t"
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"fld.p %0, (13*8), fp26\n\t"
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"fld.p %0, (14*8), fp28\n\t"
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"fld.p %0, (15*8), fp30\n\t"
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"fld.p %0, (16*8), fp32\n\t"
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"fld.p %0, (17*8), fp34\n\t"
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"fld.p %0, (18*8), fp36\n\t"
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"fld.p %0, (19*8), fp38\n\t"
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"fld.p %0, (20*8), fp40\n\t"
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"fld.p %0, (21*8), fp42\n\t"
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"fld.p %0, (22*8), fp44\n\t"
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"fld.p %0, (23*8), fp46\n\t"
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"fld.p %0, (24*8), fp48\n\t"
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"fld.p %0, (25*8), fp50\n\t"
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"fld.p %0, (26*8), fp52\n\t"
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"fld.p %0, (27*8), fp54\n\t"
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"fld.p %0, (28*8), fp56\n\t"
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"fld.p %0, (29*8), fp58\n\t"
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"fld.p %0, (30*8), fp60\n\t"
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"fld.s %0, (32*8), fr63\n\t"
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"fputscr fr63\n\t"
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"fld.p %0, (31*8), fp62\n\t"
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: /* no output */
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: "r" (fpregs) );
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}
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void fpinit(struct sh_fpu_hard_struct *fpregs)
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{
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*fpregs = init_fpuregs.hard;
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}
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asmlinkage void
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do_fpu_error(unsigned long ex, struct pt_regs *regs)
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{
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struct task_struct *tsk = current;
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regs->pc += 4;
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tsk->thread.trap_no = 11;
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tsk->thread.error_code = 0;
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force_sig(SIGFPE, tsk);
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}
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asmlinkage void
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do_fpu_state_restore(unsigned long ex, struct pt_regs *regs)
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{
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void die(const char *str, struct pt_regs *regs, long err);
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if (! user_mode(regs))
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die("FPU used in kernel", regs, ex);
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regs->sr &= ~SR_FD;
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if (last_task_used_math == current)
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return;
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enable_fpu();
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if (last_task_used_math != NULL)
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/* Other processes fpu state, save away */
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save_fpu(last_task_used_math, regs);
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last_task_used_math = current;
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if (used_math()) {
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fpload(¤t->thread.fpu.hard);
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} else {
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/* First time FPU user. */
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fpload(&init_fpuregs.hard);
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set_used_math();
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}
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disable_fpu();
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}
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