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077e30e61d
Multiple issues existed within the powerpc FP/VSX save/restore functionality, leading to register corruption and loss of register contents in specific scenarios involving high signal load and use of both floating point and VSX instructions. Issue #1 On little endian systems the PCB used the wrong location for the shadowed FP register within the larger VSX register. This appears to have been an attempt to correct issue #2 without understanding how the vector load/store instructions actually operate. Issue #2 On little endian systems, the VSX state save/restore routines swapped 32-bit words within the 64-bit aliased double word for the associated floating point register. This was due to the use of a word-oriented load/store vs. doubleword oriented load/store. Issue #3 The FPU was turned off in the PCB but not in hardware, leading to a potential race condition if the same thread was scheduled immediately after sigreturn. The triggering codebase for this is Go, which makes heavy use of signals and and generates an unusual mix of floating point and VSX assembler. As a result, when combined with th powerpc lazy FPU restore, a condition was repeatedly hit whereby the thread was interrupted in FP+VSX mode, then restored in FP only mode, thus reliably triggering the issues above. Also clean up the associated asm() style issue flagged by GitHub Actions. Signed-off-by: Timothy Pearson <tpearson@raptorengineering.com> MFC after: 1 week Pull Request: https://github.com/freebsd/freebsd-src/pull/1756
129 lines
4.1 KiB
C
129 lines
4.1 KiB
C
/*-
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* SPDX-License-Identifier: BSD-4-Clause
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*
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* Copyright (C) 1995, 1996 Wolfgang Solfrank.
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* Copyright (C) 1995, 1996 TooLs GmbH.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by TooLs GmbH.
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* 4. The name of TooLs GmbH may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $NetBSD: pcb.h,v 1.4 2000/06/04 11:57:17 tsubai Exp $
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*/
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#ifndef _MACHINE_PCB_H_
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#define _MACHINE_PCB_H_
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#include <sys/endian.h>
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#include <machine/setjmp.h>
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#ifndef _STANDALONE
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struct pcb {
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register_t pcb_context[20]; /* non-volatile r12-r31 */
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register_t pcb_cr; /* Condition register */
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register_t pcb_sp; /* stack pointer */
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register_t pcb_toc; /* toc pointer */
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register_t pcb_lr; /* link register */
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register_t pcb_dscr; /* dscr value */
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register_t pcb_fscr;
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register_t pcb_tar;
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struct pmap *pcb_pm; /* pmap of our vmspace */
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jmp_buf *pcb_onfault; /* For use during
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copyin/copyout */
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int pcb_flags;
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#define PCB_FPU 0x1 /* Process uses FPU */
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#define PCB_FPREGS 0x2 /* Process had FPU registers initialized */
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#define PCB_VEC 0x4 /* Process uses Altivec */
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#define PCB_VSX 0x8 /* Process had VSX initialized */
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#define PCB_CDSCR 0x10 /* Process had Custom DSCR initialized */
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#define PCB_HTM 0x20 /* Process had HTM initialized */
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#define PCB_CFSCR 0x40 /* Process had FSCR updated */
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#define PCB_KERN_FPU 0x80 /* Kernel is using FPU/Vector unit */
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#define PCB_KERN_FPU_NOSAVE 0x100 /* FPU/Vec state not saved for kernel use */
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#define PCB_VECREGS 0x200 /* Process had Altivec registers initialized */
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struct fpu {
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union {
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uint32_t vsr[4];
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double fpr;
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} fpr[32];
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double fpscr; /* FPSCR stored as double for easier access */
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} pcb_fpu; /* Floating point processor */
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unsigned int pcb_fpcpu; /* which CPU had our FPU
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stuff. */
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struct vec {
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uint32_t vr[32][4];
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uint32_t spare[2];
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uint32_t vrsave;
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uint32_t vscr; /* aligned at vector element 3 */
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} pcb_vec __aligned(16); /* Vector processor */
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unsigned int pcb_veccpu; /* which CPU had our vector
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stuff. */
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struct htm {
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uint64_t tfhar;
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uint64_t texasr;
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uint64_t tfiar;
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} pcb_htm;
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struct ebb {
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uint64_t ebbhr;
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uint64_t ebbrr;
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uint64_t bescr;
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} pcb_ebb;
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struct lmon {
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uint64_t lmrr;
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uint64_t lmser;
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} pcb_lm;
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union {
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struct {
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vm_offset_t usr_segm; /* Base address */
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register_t usr_vsid; /* USER_SR segment */
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} aim;
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struct {
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register_t dbcr0;
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} booke;
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} pcb_cpu;
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vm_offset_t pcb_lastill; /* Last illegal instruction */
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};
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#endif
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#ifdef _KERNEL
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struct trapframe;
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#ifndef curpcb
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extern struct pcb *curpcb;
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#endif
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extern struct pmap *curpm;
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extern struct proc *fpuproc;
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void makectx(struct trapframe *, struct pcb *);
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void savectx(struct pcb *) __returns_twice;
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#endif
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#endif /* _MACHINE_PCB_H_ */
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