mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-03 17:40:04 +00:00
![Chris Metcalf](/assets/img/avatar_default.png)
If the kernel unexpectedly takes a bad trap, it's convenient to have it report the type of trap as part of the error. This gives customers a bit more context before they call up customer support. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
355 lines
8.7 KiB
C
355 lines
8.7 KiB
C
/*
|
|
* Copyright 2010 Tilera Corporation. All Rights Reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation, version 2.
|
|
*
|
|
* This program is distributed in the hope that it will be useful, but
|
|
* WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
|
|
* NON INFRINGEMENT. See the GNU General Public License for
|
|
* more details.
|
|
*/
|
|
|
|
#include <linux/sched.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/kprobes.h>
|
|
#include <linux/module.h>
|
|
#include <linux/reboot.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/ptrace.h>
|
|
#include <asm/stack.h>
|
|
#include <asm/traps.h>
|
|
#include <asm/setup.h>
|
|
|
|
#include <arch/interrupts.h>
|
|
#include <arch/spr_def.h>
|
|
#include <arch/opcode.h>
|
|
|
|
void __init trap_init(void)
|
|
{
|
|
/* Nothing needed here since we link code at .intrpt1 */
|
|
}
|
|
|
|
int unaligned_fixup = 1;
|
|
|
|
static int __init setup_unaligned_fixup(char *str)
|
|
{
|
|
/*
|
|
* Say "=-1" to completely disable it. If you just do "=0", we
|
|
* will still parse the instruction, then fire a SIGBUS with
|
|
* the correct address from inside the single_step code.
|
|
*/
|
|
long val;
|
|
if (strict_strtol(str, 0, &val) != 0)
|
|
return 0;
|
|
unaligned_fixup = val;
|
|
pr_info("Fixups for unaligned data accesses are %s\n",
|
|
unaligned_fixup >= 0 ?
|
|
(unaligned_fixup ? "enabled" : "disabled") :
|
|
"completely disabled");
|
|
return 1;
|
|
}
|
|
__setup("unaligned_fixup=", setup_unaligned_fixup);
|
|
|
|
#if CHIP_HAS_TILE_DMA()
|
|
|
|
static int dma_disabled;
|
|
|
|
static int __init nodma(char *str)
|
|
{
|
|
pr_info("User-space DMA is disabled\n");
|
|
dma_disabled = 1;
|
|
return 1;
|
|
}
|
|
__setup("nodma", nodma);
|
|
|
|
/* How to decode SPR_GPV_REASON */
|
|
#define IRET_ERROR (1U << 31)
|
|
#define MT_ERROR (1U << 30)
|
|
#define MF_ERROR (1U << 29)
|
|
#define SPR_INDEX ((1U << 15) - 1)
|
|
#define SPR_MPL_SHIFT 9 /* starting bit position for MPL encoded in SPR */
|
|
|
|
/*
|
|
* See if this GPV is just to notify the kernel of SPR use and we can
|
|
* retry the user instruction after adjusting some MPLs suitably.
|
|
*/
|
|
static int retry_gpv(unsigned int gpv_reason)
|
|
{
|
|
int mpl;
|
|
|
|
if (gpv_reason & IRET_ERROR)
|
|
return 0;
|
|
|
|
BUG_ON((gpv_reason & (MT_ERROR|MF_ERROR)) == 0);
|
|
mpl = (gpv_reason & SPR_INDEX) >> SPR_MPL_SHIFT;
|
|
if (mpl == INT_DMA_NOTIFY && !dma_disabled) {
|
|
/* User is turning on DMA. Allow it and retry. */
|
|
printk(KERN_DEBUG "Process %d/%s is now enabled for DMA\n",
|
|
current->pid, current->comm);
|
|
BUG_ON(current->thread.tile_dma_state.enabled);
|
|
current->thread.tile_dma_state.enabled = 1;
|
|
grant_dma_mpls();
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
#endif /* CHIP_HAS_TILE_DMA() */
|
|
|
|
#ifdef __tilegx__
|
|
#define bundle_bits tilegx_bundle_bits
|
|
#else
|
|
#define bundle_bits tile_bundle_bits
|
|
#endif
|
|
|
|
extern bundle_bits bpt_code;
|
|
|
|
asm(".pushsection .rodata.bpt_code,\"a\";"
|
|
".align 8;"
|
|
"bpt_code: bpt;"
|
|
".size bpt_code,.-bpt_code;"
|
|
".popsection");
|
|
|
|
static int special_ill(bundle_bits bundle, int *sigp, int *codep)
|
|
{
|
|
int sig, code, maxcode;
|
|
|
|
if (bundle == bpt_code) {
|
|
*sigp = SIGTRAP;
|
|
*codep = TRAP_BRKPT;
|
|
return 1;
|
|
}
|
|
|
|
/* If it's a "raise" bundle, then "ill" must be in pipe X1. */
|
|
#ifdef __tilegx__
|
|
if ((bundle & TILEGX_BUNDLE_MODE_MASK) != 0)
|
|
return 0;
|
|
if (get_Opcode_X1(bundle) != RRR_0_OPCODE_X1)
|
|
return 0;
|
|
if (get_RRROpcodeExtension_X1(bundle) != UNARY_RRR_0_OPCODE_X1)
|
|
return 0;
|
|
if (get_UnaryOpcodeExtension_X1(bundle) != ILL_UNARY_OPCODE_X1)
|
|
return 0;
|
|
#else
|
|
if (bundle & TILEPRO_BUNDLE_Y_ENCODING_MASK)
|
|
return 0;
|
|
if (get_Opcode_X1(bundle) != SHUN_0_OPCODE_X1)
|
|
return 0;
|
|
if (get_UnShOpcodeExtension_X1(bundle) != UN_0_SHUN_0_OPCODE_X1)
|
|
return 0;
|
|
if (get_UnOpcodeExtension_X1(bundle) != ILL_UN_0_SHUN_0_OPCODE_X1)
|
|
return 0;
|
|
#endif
|
|
|
|
/* Check that the magic distinguishers are set to mean "raise". */
|
|
if (get_Dest_X1(bundle) != 29 || get_SrcA_X1(bundle) != 37)
|
|
return 0;
|
|
|
|
/* There must be an "addli zero, zero, VAL" in X0. */
|
|
if (get_Opcode_X0(bundle) != ADDLI_OPCODE_X0)
|
|
return 0;
|
|
if (get_Dest_X0(bundle) != TREG_ZERO)
|
|
return 0;
|
|
if (get_SrcA_X0(bundle) != TREG_ZERO)
|
|
return 0;
|
|
|
|
/*
|
|
* Validate the proposed signal number and si_code value.
|
|
* Note that we embed these in the static instruction itself
|
|
* so that we perturb the register state as little as possible
|
|
* at the time of the actual fault; it's unlikely you'd ever
|
|
* need to dynamically choose which kind of fault to raise
|
|
* from user space.
|
|
*/
|
|
sig = get_Imm16_X0(bundle) & 0x3f;
|
|
switch (sig) {
|
|
case SIGILL:
|
|
maxcode = NSIGILL;
|
|
break;
|
|
case SIGFPE:
|
|
maxcode = NSIGFPE;
|
|
break;
|
|
case SIGSEGV:
|
|
maxcode = NSIGSEGV;
|
|
break;
|
|
case SIGBUS:
|
|
maxcode = NSIGBUS;
|
|
break;
|
|
case SIGTRAP:
|
|
maxcode = NSIGTRAP;
|
|
break;
|
|
default:
|
|
return 0;
|
|
}
|
|
code = (get_Imm16_X0(bundle) >> 6) & 0xf;
|
|
if (code <= 0 || code > maxcode)
|
|
return 0;
|
|
|
|
/* Make it the requested signal. */
|
|
*sigp = sig;
|
|
*codep = code | __SI_FAULT;
|
|
return 1;
|
|
}
|
|
|
|
static const char *const int_name[] = {
|
|
[INT_MEM_ERROR] = "Memory error",
|
|
[INT_ILL] = "Illegal instruction",
|
|
[INT_GPV] = "General protection violation",
|
|
[INT_UDN_ACCESS] = "UDN access",
|
|
[INT_IDN_ACCESS] = "IDN access",
|
|
#if CHIP_HAS_SN()
|
|
[INT_SN_ACCESS] = "SN access",
|
|
#endif
|
|
[INT_SWINT_3] = "Software interrupt 3",
|
|
[INT_SWINT_2] = "Software interrupt 2",
|
|
[INT_SWINT_0] = "Software interrupt 0",
|
|
[INT_UNALIGN_DATA] = "Unaligned data",
|
|
[INT_DOUBLE_FAULT] = "Double fault",
|
|
#ifdef __tilegx__
|
|
[INT_ILL_TRANS] = "Illegal virtual address",
|
|
#endif
|
|
};
|
|
|
|
void __kprobes do_trap(struct pt_regs *regs, int fault_num,
|
|
unsigned long reason)
|
|
{
|
|
siginfo_t info = { 0 };
|
|
int signo, code;
|
|
unsigned long address = 0;
|
|
bundle_bits instr;
|
|
|
|
/* Re-enable interrupts. */
|
|
local_irq_enable();
|
|
|
|
/*
|
|
* If it hits in kernel mode and we can't fix it up, just exit the
|
|
* current process and hope for the best.
|
|
*/
|
|
if (!user_mode(regs)) {
|
|
const char *name;
|
|
if (fixup_exception(regs)) /* only UNALIGN_DATA in practice */
|
|
return;
|
|
if (fault_num >= 0 &&
|
|
fault_num < sizeof(int_name)/sizeof(int_name[0]) &&
|
|
int_name[fault_num] != NULL)
|
|
name = int_name[fault_num];
|
|
else
|
|
name = "Unknown interrupt";
|
|
pr_alert("Kernel took bad trap %d (%s) at PC %#lx\n",
|
|
fault_num, name, regs->pc);
|
|
if (fault_num == INT_GPV)
|
|
pr_alert("GPV_REASON is %#lx\n", reason);
|
|
show_regs(regs);
|
|
do_exit(SIGKILL); /* FIXME: implement i386 die() */
|
|
return;
|
|
}
|
|
|
|
switch (fault_num) {
|
|
case INT_MEM_ERROR:
|
|
signo = SIGBUS;
|
|
code = BUS_OBJERR;
|
|
break;
|
|
case INT_ILL:
|
|
if (copy_from_user(&instr, (void __user *)regs->pc,
|
|
sizeof(instr))) {
|
|
pr_err("Unreadable instruction for INT_ILL:"
|
|
" %#lx\n", regs->pc);
|
|
do_exit(SIGKILL);
|
|
return;
|
|
}
|
|
if (!special_ill(instr, &signo, &code)) {
|
|
signo = SIGILL;
|
|
code = ILL_ILLOPC;
|
|
}
|
|
address = regs->pc;
|
|
break;
|
|
case INT_GPV:
|
|
#if CHIP_HAS_TILE_DMA()
|
|
if (retry_gpv(reason))
|
|
return;
|
|
#endif
|
|
/*FALLTHROUGH*/
|
|
case INT_UDN_ACCESS:
|
|
case INT_IDN_ACCESS:
|
|
#if CHIP_HAS_SN()
|
|
case INT_SN_ACCESS:
|
|
#endif
|
|
signo = SIGILL;
|
|
code = ILL_PRVREG;
|
|
address = regs->pc;
|
|
break;
|
|
case INT_SWINT_3:
|
|
case INT_SWINT_2:
|
|
case INT_SWINT_0:
|
|
signo = SIGILL;
|
|
code = ILL_ILLTRP;
|
|
address = regs->pc;
|
|
break;
|
|
case INT_UNALIGN_DATA:
|
|
#ifndef __tilegx__ /* Emulated support for single step debugging */
|
|
if (unaligned_fixup >= 0) {
|
|
struct single_step_state *state =
|
|
current_thread_info()->step_state;
|
|
if (!state ||
|
|
(void __user *)(regs->pc) != state->buffer) {
|
|
single_step_once(regs);
|
|
return;
|
|
}
|
|
}
|
|
#endif
|
|
signo = SIGBUS;
|
|
code = BUS_ADRALN;
|
|
address = 0;
|
|
break;
|
|
case INT_DOUBLE_FAULT:
|
|
/*
|
|
* For double fault, "reason" is actually passed as
|
|
* SYSTEM_SAVE_K_2, the hypervisor's double-fault info, so
|
|
* we can provide the original fault number rather than
|
|
* the uninteresting "INT_DOUBLE_FAULT" so the user can
|
|
* learn what actually struck while PL0 ICS was set.
|
|
*/
|
|
fault_num = reason;
|
|
signo = SIGILL;
|
|
code = ILL_DBLFLT;
|
|
address = regs->pc;
|
|
break;
|
|
#ifdef __tilegx__
|
|
case INT_ILL_TRANS: {
|
|
/* Avoid a hardware erratum with the return address stack. */
|
|
fill_ra_stack();
|
|
|
|
signo = SIGSEGV;
|
|
code = SEGV_MAPERR;
|
|
if (reason & SPR_ILL_TRANS_REASON__I_STREAM_VA_RMASK)
|
|
address = regs->pc;
|
|
else
|
|
address = 0; /* FIXME: GX: single-step for address */
|
|
break;
|
|
}
|
|
#endif
|
|
default:
|
|
panic("Unexpected do_trap interrupt number %d", fault_num);
|
|
return;
|
|
}
|
|
|
|
info.si_signo = signo;
|
|
info.si_code = code;
|
|
info.si_addr = (void __user *)address;
|
|
if (signo == SIGILL)
|
|
info.si_trapno = fault_num;
|
|
if (signo != SIGTRAP)
|
|
trace_unhandled_signal("trap", regs, address, signo);
|
|
force_sig_info(signo, &info, current);
|
|
}
|
|
|
|
void kernel_double_fault(int dummy, ulong pc, ulong lr, ulong sp, ulong r52)
|
|
{
|
|
_dump_stack(dummy, pc, lr, sp, r52);
|
|
pr_emerg("Double fault: exiting\n");
|
|
machine_halt();
|
|
}
|