freebsd-dev/sys/arm/include/pcb.h
Ian Lepore f00519b613 Remove all dregs of a per-thread undefined-exception-mode stack. This is
a leftover from the days when a low-level debugger had hooks in the
undefined exception vector and needed stack space to function.  These days
it effectively isn't used because we switch immediately to the svc32 mode
stack on exception entry.  For that, the single undef mode stack per core
that gets set up at init time works fine.

The stack wasn't necessary but it was harmful, because the space for it
was carved out of the normal per-thread svc32 stack, in effect cutting
that 8K stack in half.  If svc32 mode used more than 4k of stack space it
wandered down into the undef mode stack, and then an undef exception would
overwrite a couple words on the stack while switching to svc32 mode,
corrupting the scv32 stack.  Having another stack abut the bottom of the
svc32 stack also effectively mooted the guard page below the stack.

This work is based on analysis and patches submitted by Juergen Weiss.
2014-03-09 03:49:06 +00:00

104 lines
3.4 KiB
C

/* $NetBSD: pcb.h,v 1.10 2003/10/13 21:46:39 scw Exp $ */
/*-
* Copyright (c) 2001 Matt Thomas <matt@3am-software.com>.
* Copyright (c) 1994 Mark Brinicombe.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the RiscBSD team.
* 4. The name "RiscBSD" nor the name of the author may be used to
* endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY RISCBSD ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL RISCBSD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _MACHINE_PCB_H_
#define _MACHINE_PCB_H_
#include <machine/fp.h>
struct trapframe;
struct pcb_arm32 {
vm_offset_t pcb32_pagedir; /* PT hooks */
uint32_t *pcb32_pl1vec; /* PTR to vector_base L1 entry*/
uint32_t pcb32_l1vec; /* Value to stuff on ctx sw */
u_int pcb32_dacr; /* Domain Access Control Reg */
/*
* WARNING!
* cpuswitch.S relies on pcb32_r8 being quad-aligned in struct pcb
* (due to the use of "strd" when compiled for XSCALE)
*/
u_int pcb32_r8; /* used */
u_int pcb32_r9; /* used */
u_int pcb32_r10; /* used */
u_int pcb32_r11; /* used */
u_int pcb32_r12; /* used */
u_int pcb32_sp; /* used */
u_int pcb32_lr;
u_int pcb32_pc;
};
#define pcb_pagedir un_32.pcb32_pagedir
#define pcb_pl1vec un_32.pcb32_pl1vec
#define pcb_l1vec un_32.pcb32_l1vec
#define pcb_dacr un_32.pcb32_dacr
#define pcb_cstate un_32.pcb32_cstate
/*
* WARNING!
* See warning for struct pcb_arm32, above, before changing struct pcb!
*/
struct pcb {
u_int pcb_flags;
#define PCB_OWNFPU 0x00000001
#define PCB_NOALIGNFLT 0x00000002
caddr_t pcb_onfault; /* On fault handler */
struct pcb_arm32 un_32;
struct vfp_state pcb_vfpstate; /* VP/NEON state */
u_int pcb_vfpcpu; /* VP/NEON last cpu */
} __aligned(8); /*
* We need the PCB to be aligned on 8 bytes, as we may
* access it using ldrd/strd, and some CPUs require it
* to by aligned on 8 bytes.
*/
/*
* No additional data for core dumps.
*/
struct md_coredump {
int md_empty;
};
void makectx(struct trapframe *tf, struct pcb *pcb);
#ifdef _KERNEL
void savectx(struct pcb *) __returns_twice;
#endif /* _KERNEL */
#endif /* !_MACHINE_PCB_H_ */