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linux/arch/powerpc/kernel/traps.c
Matt Evans 0e524e761f powerpc: Clear branch trap (MSR.BE) before delivering SIGTRAP 
When using SIG_DBG_BRANCH_TRACING, MSR.BE is left enabled in the
user context when single_step_exception() prepares the SIGTRAP
delivery.  The resulting branch-trap-within-the-SIGTRAP-handler
isn't healthy.

Commit 2538c2d08f broke this, by
replacing an MSR mask operation of ~(MSR_SE | MSR_BE) with a call
to clear_single_step() which only clears MSR_SE.

This patch adds a new helper, clear_br_trace(), which clears the
debug trap before invoking the signal handler.  This helper is a
NOP for BookE as SIG_DBG_BRANCH_TRACING isn't supported on BookE.

Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-04-01 22:15:33 +10:00

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/*
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
* Copyright 2007-2010 Freescale Semiconductor, Inc.
*
* 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; either version
* 2 of the License, or (at your option) any later version.
*
* Modified by Cort Dougan (cort@cs.nmt.edu)
* and Paul Mackerras (paulus@samba.org)
*/
/*
* This file handles the architecture-dependent parts of hardware exceptions
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/pkeys.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/extable.h>
#include <linux/module.h> /* print_modules */
#include <linux/prctl.h>
#include <linux/delay.h>
#include <linux/kprobes.h>
#include <linux/kexec.h>
#include <linux/backlight.h>
#include <linux/bug.h>
#include <linux/kdebug.h>
#include <linux/ratelimit.h>
#include <linux/context_tracking.h>
#include <linux/smp.h>
#include <linux/console.h>
#include <linux/kmsg_dump.h>
#include <asm/emulated_ops.h>
#include <asm/pgtable.h>
#include <linux/uaccess.h>
#include <asm/debugfs.h>
#include <asm/io.h>
#include <asm/machdep.h>
#include <asm/rtas.h>
#include <asm/pmc.h>
#include <asm/reg.h>
#ifdef CONFIG_PMAC_BACKLIGHT
#include <asm/backlight.h>
#endif
#ifdef CONFIG_PPC64
#include <asm/firmware.h>
#include <asm/processor.h>
#include <asm/tm.h>
#endif
#include <asm/kexec.h>
#include <asm/ppc-opcode.h>
#include <asm/rio.h>
#include <asm/fadump.h>
#include <asm/switch_to.h>
#include <asm/tm.h>
#include <asm/debug.h>
#include <asm/asm-prototypes.h>
#include <asm/hmi.h>
#include <sysdev/fsl_pci.h>
#include <asm/kprobes.h>
#if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC_CORE)
int (*__debugger)(struct pt_regs *regs) __read_mostly;
int (*__debugger_ipi)(struct pt_regs *regs) __read_mostly;
int (*__debugger_bpt)(struct pt_regs *regs) __read_mostly;
int (*__debugger_sstep)(struct pt_regs *regs) __read_mostly;
int (*__debugger_iabr_match)(struct pt_regs *regs) __read_mostly;
int (*__debugger_break_match)(struct pt_regs *regs) __read_mostly;
int (*__debugger_fault_handler)(struct pt_regs *regs) __read_mostly;
EXPORT_SYMBOL(__debugger);
EXPORT_SYMBOL(__debugger_ipi);
EXPORT_SYMBOL(__debugger_bpt);
EXPORT_SYMBOL(__debugger_sstep);
EXPORT_SYMBOL(__debugger_iabr_match);
EXPORT_SYMBOL(__debugger_break_match);
EXPORT_SYMBOL(__debugger_fault_handler);
#endif
/* Transactional Memory trap debug */
#ifdef TM_DEBUG_SW
#define TM_DEBUG(x...) printk(KERN_INFO x)
#else
#define TM_DEBUG(x...) do { } while(0)
#endif
/*
* Trap & Exception support
*/
#ifdef CONFIG_PMAC_BACKLIGHT
static void pmac_backlight_unblank(void)
{
mutex_lock(&pmac_backlight_mutex);
if (pmac_backlight) {
struct backlight_properties *props;
props = &pmac_backlight->props;
props->brightness = props->max_brightness;
props->power = FB_BLANK_UNBLANK;
backlight_update_status(pmac_backlight);
}
mutex_unlock(&pmac_backlight_mutex);
}
#else
static inline void pmac_backlight_unblank(void) { }
#endif
/*
* If oops/die is expected to crash the machine, return true here.
*
* This should not be expected to be 100% accurate, there may be
* notifiers registered or other unexpected conditions that may bring
* down the kernel. Or if the current process in the kernel is holding
* locks or has other critical state, the kernel may become effectively
* unusable anyway.
*/
bool die_will_crash(void)
{
if (should_fadump_crash())
return true;
if (kexec_should_crash(current))
return true;
if (in_interrupt() || panic_on_oops ||
!current->pid || is_global_init(current))
return true;
return false;
}
static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
static int die_owner = -1;
static unsigned int die_nest_count;
static int die_counter;
extern void panic_flush_kmsg_start(void)
{
/*
* These are mostly taken from kernel/panic.c, but tries to do
* relatively minimal work. Don't use delay functions (TB may
* be broken), don't crash dump (need to set a firmware log),
* don't run notifiers. We do want to get some information to
* Linux console.
*/
console_verbose();
bust_spinlocks(1);
}
extern void panic_flush_kmsg_end(void)
{
printk_safe_flush_on_panic();
kmsg_dump(KMSG_DUMP_PANIC);
bust_spinlocks(0);
debug_locks_off();
console_flush_on_panic();
}
static unsigned long oops_begin(struct pt_regs *regs)
{
int cpu;
unsigned long flags;
oops_enter();
/* racy, but better than risking deadlock. */
raw_local_irq_save(flags);
cpu = smp_processor_id();
if (!arch_spin_trylock(&die_lock)) {
if (cpu == die_owner)
/* nested oops. should stop eventually */;
else
arch_spin_lock(&die_lock);
}
die_nest_count++;
die_owner = cpu;
console_verbose();
bust_spinlocks(1);
if (machine_is(powermac))
pmac_backlight_unblank();
return flags;
}
NOKPROBE_SYMBOL(oops_begin);
static void oops_end(unsigned long flags, struct pt_regs *regs,
int signr)
{
bust_spinlocks(0);
add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
die_nest_count--;
oops_exit();
printk("\n");
if (!die_nest_count) {
/* Nest count reaches zero, release the lock. */
die_owner = -1;
arch_spin_unlock(&die_lock);
}
raw_local_irq_restore(flags);
/*
* system_reset_excption handles debugger, crash dump, panic, for 0x100
*/
if (TRAP(regs) == 0x100)
return;
crash_fadump(regs, "die oops");
if (kexec_should_crash(current))
crash_kexec(regs);
if (!signr)
return;
/*
* While our oops output is serialised by a spinlock, output
* from panic() called below can race and corrupt it. If we
* know we are going to panic, delay for 1 second so we have a
* chance to get clean backtraces from all CPUs that are oopsing.
*/
if (in_interrupt() || panic_on_oops || !current->pid ||
is_global_init(current)) {
mdelay(MSEC_PER_SEC);
}
if (in_interrupt())
panic("Fatal exception in interrupt");
if (panic_on_oops)
panic("Fatal exception");
do_exit(signr);
}
NOKPROBE_SYMBOL(oops_end);
static int __die(const char *str, struct pt_regs *regs, long err)
{
printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
if (IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN))
printk("LE ");
else
printk("BE ");
if (IS_ENABLED(CONFIG_PREEMPT))
pr_cont("PREEMPT ");
if (IS_ENABLED(CONFIG_SMP))
pr_cont("SMP NR_CPUS=%d ", NR_CPUS);
if (debug_pagealloc_enabled())
pr_cont("DEBUG_PAGEALLOC ");
if (IS_ENABLED(CONFIG_NUMA))
pr_cont("NUMA ");
pr_cont("%s\n", ppc_md.name ? ppc_md.name : "");
if (notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV) == NOTIFY_STOP)
return 1;
print_modules();
show_regs(regs);
return 0;
}
NOKPROBE_SYMBOL(__die);
void die(const char *str, struct pt_regs *regs, long err)
{
unsigned long flags;
/*
* system_reset_excption handles debugger, crash dump, panic, for 0x100
*/
if (TRAP(regs) != 0x100) {
if (debugger(regs))
return;
}
flags = oops_begin(regs);
if (__die(str, regs, err))
err = 0;
oops_end(flags, regs, err);
}
NOKPROBE_SYMBOL(die);
void user_single_step_siginfo(struct task_struct *tsk,
struct pt_regs *regs, siginfo_t *info)
{
memset(info, 0, sizeof(*info));
info->si_signo = SIGTRAP;
info->si_code = TRAP_TRACE;
info->si_addr = (void __user *)regs->nip;
}
void _exception_pkey(int signr, struct pt_regs *regs, int code,
unsigned long addr, int key)
{
siginfo_t info;
const char fmt32[] = KERN_INFO "%s[%d]: unhandled signal %d " \
"at %08lx nip %08lx lr %08lx code %x\n";
const char fmt64[] = KERN_INFO "%s[%d]: unhandled signal %d " \
"at %016lx nip %016lx lr %016lx code %x\n";
if (!user_mode(regs)) {
die("Exception in kernel mode", regs, signr);
return;
}
if (show_unhandled_signals && unhandled_signal(current, signr)) {
printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
current->comm, current->pid, signr,
addr, regs->nip, regs->link, code);
}
if (arch_irqs_disabled() && !arch_irq_disabled_regs(regs))
local_irq_enable();
current->thread.trap_nr = code;
/*
* Save all the pkey registers AMR/IAMR/UAMOR. Eg: Core dumps need
* to capture the content, if the task gets killed.
*/
thread_pkey_regs_save(&current->thread);
memset(&info, 0, sizeof(info));
info.si_signo = signr;
info.si_code = code;
info.si_addr = (void __user *) addr;
info.si_pkey = key;
force_sig_info(signr, &info, current);
}
void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
{
_exception_pkey(signr, regs, code, addr, 0);
}
void system_reset_exception(struct pt_regs *regs)
{
/*
* Avoid crashes in case of nested NMI exceptions. Recoverability
* is determined by RI and in_nmi
*/
bool nested = in_nmi();
if (!nested)
nmi_enter();
__this_cpu_inc(irq_stat.sreset_irqs);
/* See if any machine dependent calls */
if (ppc_md.system_reset_exception) {
if (ppc_md.system_reset_exception(regs))
goto out;
}
if (debugger(regs))
goto out;
/*
* A system reset is a request to dump, so we always send
* it through the crashdump code (if fadump or kdump are
* registered).
*/
crash_fadump(regs, "System Reset");
crash_kexec(regs);
/*
* We aren't the primary crash CPU. We need to send it
* to a holding pattern to avoid it ending up in the panic
* code.
*/
crash_kexec_secondary(regs);
/*
* No debugger or crash dump registered, print logs then
* panic.
*/
die("System Reset", regs, SIGABRT);
mdelay(2*MSEC_PER_SEC); /* Wait a little while for others to print */
add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
nmi_panic(regs, "System Reset");
out:
#ifdef CONFIG_PPC_BOOK3S_64
BUG_ON(get_paca()->in_nmi == 0);
if (get_paca()->in_nmi > 1)
nmi_panic(regs, "Unrecoverable nested System Reset");
#endif
/* Must die if the interrupt is not recoverable */
if (!(regs->msr & MSR_RI))
nmi_panic(regs, "Unrecoverable System Reset");
if (!nested)
nmi_exit();
/* What should we do here? We could issue a shutdown or hard reset. */
}
/*
* I/O accesses can cause machine checks on powermacs.
* Check if the NIP corresponds to the address of a sync
* instruction for which there is an entry in the exception
* table.
* Note that the 601 only takes a machine check on TEA
* (transfer error ack) signal assertion, and does not
* set any of the top 16 bits of SRR1.
* -- paulus.
*/
static inline int check_io_access(struct pt_regs *regs)
{
#ifdef CONFIG_PPC32
unsigned long msr = regs->msr;
const struct exception_table_entry *entry;
unsigned int *nip = (unsigned int *)regs->nip;
if (((msr & 0xffff0000) == 0 || (msr & (0x80000 | 0x40000)))
&& (entry = search_exception_tables(regs->nip)) != NULL) {
/*
* Check that it's a sync instruction, or somewhere
* in the twi; isync; nop sequence that inb/inw/inl uses.
* As the address is in the exception table
* we should be able to read the instr there.
* For the debug message, we look at the preceding
* load or store.
*/
if (*nip == PPC_INST_NOP)
nip -= 2;
else if (*nip == PPC_INST_ISYNC)
--nip;
if (*nip == PPC_INST_SYNC || (*nip >> 26) == OP_TRAP) {
unsigned int rb;
--nip;
rb = (*nip >> 11) & 0x1f;
printk(KERN_DEBUG "%s bad port %lx at %p\n",
(*nip & 0x100)? "OUT to": "IN from",
regs->gpr[rb] - _IO_BASE, nip);
regs->msr |= MSR_RI;
regs->nip = extable_fixup(entry);
return 1;
}
}
#endif /* CONFIG_PPC32 */
return 0;
}
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
/* On 4xx, the reason for the machine check or program exception
is in the ESR. */
#define get_reason(regs) ((regs)->dsisr)
#define REASON_FP ESR_FP
#define REASON_ILLEGAL (ESR_PIL | ESR_PUO)
#define REASON_PRIVILEGED ESR_PPR
#define REASON_TRAP ESR_PTR
/* single-step stuff */
#define single_stepping(regs) (current->thread.debug.dbcr0 & DBCR0_IC)
#define clear_single_step(regs) (current->thread.debug.dbcr0 &= ~DBCR0_IC)
#define clear_br_trace(regs) do {} while(0)
#else
/* On non-4xx, the reason for the machine check or program
exception is in the MSR. */
#define get_reason(regs) ((regs)->msr)
#define REASON_TM SRR1_PROGTM
#define REASON_FP SRR1_PROGFPE
#define REASON_ILLEGAL SRR1_PROGILL
#define REASON_PRIVILEGED SRR1_PROGPRIV
#define REASON_TRAP SRR1_PROGTRAP
#define single_stepping(regs) ((regs)->msr & MSR_SE)
#define clear_single_step(regs) ((regs)->msr &= ~MSR_SE)
#define clear_br_trace(regs) ((regs)->msr &= ~MSR_BE)
#endif
#if defined(CONFIG_E500)
int machine_check_e500mc(struct pt_regs *regs)
{
unsigned long mcsr = mfspr(SPRN_MCSR);
unsigned long pvr = mfspr(SPRN_PVR);
unsigned long reason = mcsr;
int recoverable = 1;
if (reason & MCSR_LD) {
recoverable = fsl_rio_mcheck_exception(regs);
if (recoverable == 1)
goto silent_out;
}
printk("Machine check in kernel mode.\n");
printk("Caused by (from MCSR=%lx): ", reason);
if (reason & MCSR_MCP)
printk("Machine Check Signal\n");
if (reason & MCSR_ICPERR) {
printk("Instruction Cache Parity Error\n");
/*
* This is recoverable by invalidating the i-cache.
*/
mtspr(SPRN_L1CSR1, mfspr(SPRN_L1CSR1) | L1CSR1_ICFI);
while (mfspr(SPRN_L1CSR1) & L1CSR1_ICFI)
;
/*
* This will generally be accompanied by an instruction
* fetch error report -- only treat MCSR_IF as fatal
* if it wasn't due to an L1 parity error.
*/
reason &= ~MCSR_IF;
}
if (reason & MCSR_DCPERR_MC) {
printk("Data Cache Parity Error\n");
/*
* In write shadow mode we auto-recover from the error, but it
* may still get logged and cause a machine check. We should
* only treat the non-write shadow case as non-recoverable.
*/
/* On e6500 core, L1 DCWS (Data cache write shadow mode) bit
* is not implemented but L1 data cache always runs in write
* shadow mode. Hence on data cache parity errors HW will
* automatically invalidate the L1 Data Cache.
*/
if (PVR_VER(pvr) != PVR_VER_E6500) {
if (!(mfspr(SPRN_L1CSR2) & L1CSR2_DCWS))
recoverable = 0;
}
}
if (reason & MCSR_L2MMU_MHIT) {
printk("Hit on multiple TLB entries\n");
recoverable = 0;
}
if (reason & MCSR_NMI)
printk("Non-maskable interrupt\n");
if (reason & MCSR_IF) {
printk("Instruction Fetch Error Report\n");
recoverable = 0;
}
if (reason & MCSR_LD) {
printk("Load Error Report\n");
recoverable = 0;
}
if (reason & MCSR_ST) {
printk("Store Error Report\n");
recoverable = 0;
}
if (reason & MCSR_LDG) {
printk("Guarded Load Error Report\n");
recoverable = 0;
}
if (reason & MCSR_TLBSYNC)
printk("Simultaneous tlbsync operations\n");
if (reason & MCSR_BSL2_ERR) {
printk("Level 2 Cache Error\n");
recoverable = 0;
}
if (reason & MCSR_MAV) {
u64 addr;
addr = mfspr(SPRN_MCAR);
addr |= (u64)mfspr(SPRN_MCARU) << 32;
printk("Machine Check %s Address: %#llx\n",
reason & MCSR_MEA ? "Effective" : "Physical", addr);
}
silent_out:
mtspr(SPRN_MCSR, mcsr);
return mfspr(SPRN_MCSR) == 0 && recoverable;
}
int machine_check_e500(struct pt_regs *regs)
{
unsigned long reason = mfspr(SPRN_MCSR);
if (reason & MCSR_BUS_RBERR) {
if (fsl_rio_mcheck_exception(regs))
return 1;
if (fsl_pci_mcheck_exception(regs))
return 1;
}
printk("Machine check in kernel mode.\n");
printk("Caused by (from MCSR=%lx): ", reason);
if (reason & MCSR_MCP)
printk("Machine Check Signal\n");
if (reason & MCSR_ICPERR)
printk("Instruction Cache Parity Error\n");
if (reason & MCSR_DCP_PERR)
printk("Data Cache Push Parity Error\n");
if (reason & MCSR_DCPERR)
printk("Data Cache Parity Error\n");
if (reason & MCSR_BUS_IAERR)
printk("Bus - Instruction Address Error\n");
if (reason & MCSR_BUS_RAERR)
printk("Bus - Read Address Error\n");
if (reason & MCSR_BUS_WAERR)
printk("Bus - Write Address Error\n");
if (reason & MCSR_BUS_IBERR)
printk("Bus - Instruction Data Error\n");
if (reason & MCSR_BUS_RBERR)
printk("Bus - Read Data Bus Error\n");
if (reason & MCSR_BUS_WBERR)
printk("Bus - Write Data Bus Error\n");
if (reason & MCSR_BUS_IPERR)
printk("Bus - Instruction Parity Error\n");
if (reason & MCSR_BUS_RPERR)
printk("Bus - Read Parity Error\n");
return 0;
}
int machine_check_generic(struct pt_regs *regs)
{
return 0;
}
#elif defined(CONFIG_E200)
int machine_check_e200(struct pt_regs *regs)
{
unsigned long reason = mfspr(SPRN_MCSR);
printk("Machine check in kernel mode.\n");
printk("Caused by (from MCSR=%lx): ", reason);
if (reason & MCSR_MCP)
printk("Machine Check Signal\n");
if (reason & MCSR_CP_PERR)
printk("Cache Push Parity Error\n");
if (reason & MCSR_CPERR)
printk("Cache Parity Error\n");
if (reason & MCSR_EXCP_ERR)
printk("ISI, ITLB, or Bus Error on first instruction fetch for an exception handler\n");
if (reason & MCSR_BUS_IRERR)
printk("Bus - Read Bus Error on instruction fetch\n");
if (reason & MCSR_BUS_DRERR)
printk("Bus - Read Bus Error on data load\n");
if (reason & MCSR_BUS_WRERR)
printk("Bus - Write Bus Error on buffered store or cache line push\n");
return 0;
}
#elif defined(CONFIG_PPC32)
int machine_check_generic(struct pt_regs *regs)
{
unsigned long reason = regs->msr;
printk("Machine check in kernel mode.\n");
printk("Caused by (from SRR1=%lx): ", reason);
switch (reason & 0x601F0000) {
case 0x80000:
printk("Machine check signal\n");
break;
case 0: /* for 601 */
case 0x40000:
case 0x140000: /* 7450 MSS error and TEA */
printk("Transfer error ack signal\n");
break;
case 0x20000:
printk("Data parity error signal\n");
break;
case 0x10000:
printk("Address parity error signal\n");
break;
case 0x20000000:
printk("L1 Data Cache error\n");
break;
case 0x40000000:
printk("L1 Instruction Cache error\n");
break;
case 0x00100000:
printk("L2 data cache parity error\n");
break;
default:
printk("Unknown values in msr\n");
}
return 0;
}
#endif /* everything else */
void machine_check_exception(struct pt_regs *regs)
{
int recover = 0;
bool nested = in_nmi();
if (!nested)
nmi_enter();
/* 64s accounts the mce in machine_check_early when in HVMODE */
if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64) || !cpu_has_feature(CPU_FTR_HVMODE))
__this_cpu_inc(irq_stat.mce_exceptions);
add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
/* See if any machine dependent calls. In theory, we would want
* to call the CPU first, and call the ppc_md. one if the CPU
* one returns a positive number. However there is existing code
* that assumes the board gets a first chance, so let's keep it
* that way for now and fix things later. --BenH.
*/
if (ppc_md.machine_check_exception)
recover = ppc_md.machine_check_exception(regs);
else if (cur_cpu_spec->machine_check)
recover = cur_cpu_spec->machine_check(regs);
if (recover > 0)
goto bail;
if (debugger_fault_handler(regs))
goto bail;
if (check_io_access(regs))
goto bail;
die("Machine check", regs, SIGBUS);
/* Must die if the interrupt is not recoverable */
if (!(regs->msr & MSR_RI))
nmi_panic(regs, "Unrecoverable Machine check");
bail:
if (!nested)
nmi_exit();
}
void SMIException(struct pt_regs *regs)
{
die("System Management Interrupt", regs, SIGABRT);
}
#ifdef CONFIG_VSX
static void p9_hmi_special_emu(struct pt_regs *regs)
{
unsigned int ra, rb, t, i, sel, instr, rc;
const void __user *addr;
u8 vbuf[16], *vdst;
unsigned long ea, msr, msr_mask;
bool swap;
if (__get_user_inatomic(instr, (unsigned int __user *)regs->nip))
return;
/*
* lxvb16x opcode: 0x7c0006d8
* lxvd2x opcode: 0x7c000698
* lxvh8x opcode: 0x7c000658
* lxvw4x opcode: 0x7c000618
*/
if ((instr & 0xfc00073e) != 0x7c000618) {
pr_devel("HMI vec emu: not vector CI %i:%s[%d] nip=%016lx"
" instr=%08x\n",
smp_processor_id(), current->comm, current->pid,
regs->nip, instr);
return;
}
/* Grab vector registers into the task struct */
msr = regs->msr; /* Grab msr before we flush the bits */
flush_vsx_to_thread(current);
enable_kernel_altivec();
/*
* Is userspace running with a different endian (this is rare but
* not impossible)
*/
swap = (msr & MSR_LE) != (MSR_KERNEL & MSR_LE);
/* Decode the instruction */
ra = (instr >> 16) & 0x1f;
rb = (instr >> 11) & 0x1f;
t = (instr >> 21) & 0x1f;
if (instr & 1)
vdst = (u8 *)&current->thread.vr_state.vr[t];
else
vdst = (u8 *)&current->thread.fp_state.fpr[t][0];
/* Grab the vector address */
ea = regs->gpr[rb] + (ra ? regs->gpr[ra] : 0);
if (is_32bit_task())
ea &= 0xfffffffful;
addr = (__force const void __user *)ea;
/* Check it */
if (!access_ok(VERIFY_READ, addr, 16)) {
pr_devel("HMI vec emu: bad access %i:%s[%d] nip=%016lx"
" instr=%08x addr=%016lx\n",
smp_processor_id(), current->comm, current->pid,
regs->nip, instr, (unsigned long)addr);
return;
}
/* Read the vector */
rc = 0;
if ((unsigned long)addr & 0xfUL)
/* unaligned case */
rc = __copy_from_user_inatomic(vbuf, addr, 16);
else
__get_user_atomic_128_aligned(vbuf, addr, rc);
if (rc) {
pr_devel("HMI vec emu: page fault %i:%s[%d] nip=%016lx"
" instr=%08x addr=%016lx\n",
smp_processor_id(), current->comm, current->pid,
regs->nip, instr, (unsigned long)addr);
return;
}
pr_devel("HMI vec emu: emulated vector CI %i:%s[%d] nip=%016lx"
" instr=%08x addr=%016lx\n",
smp_processor_id(), current->comm, current->pid, regs->nip,
instr, (unsigned long) addr);
/* Grab instruction "selector" */
sel = (instr >> 6) & 3;
/*
* Check to make sure the facility is actually enabled. This
* could happen if we get a false positive hit.
*
* lxvd2x/lxvw4x always check MSR VSX sel = 0,2
* lxvh8x/lxvb16x check MSR VSX or VEC depending on VSR used sel = 1,3
*/
msr_mask = MSR_VSX;
if ((sel & 1) && (instr & 1)) /* lxvh8x & lxvb16x + VSR >= 32 */
msr_mask = MSR_VEC;
if (!(msr & msr_mask)) {
pr_devel("HMI vec emu: MSR fac clear %i:%s[%d] nip=%016lx"
" instr=%08x msr:%016lx\n",
smp_processor_id(), current->comm, current->pid,
regs->nip, instr, msr);
return;
}
/* Do logging here before we modify sel based on endian */
switch (sel) {
case 0: /* lxvw4x */
PPC_WARN_EMULATED(lxvw4x, regs);
break;
case 1: /* lxvh8x */
PPC_WARN_EMULATED(lxvh8x, regs);
break;
case 2: /* lxvd2x */
PPC_WARN_EMULATED(lxvd2x, regs);
break;
case 3: /* lxvb16x */
PPC_WARN_EMULATED(lxvb16x, regs);
break;
}
#ifdef __LITTLE_ENDIAN__
/*
* An LE kernel stores the vector in the task struct as an LE
* byte array (effectively swapping both the components and
* the content of the components). Those instructions expect
* the components to remain in ascending address order, so we
* swap them back.
*
* If we are running a BE user space, the expectation is that
* of a simple memcpy, so forcing the emulation to look like
* a lxvb16x should do the trick.
*/
if (swap)
sel = 3;
switch (sel) {
case 0: /* lxvw4x */
for (i = 0; i < 4; i++)
((u32 *)vdst)[i] = ((u32 *)vbuf)[3-i];
break;
case 1: /* lxvh8x */
for (i = 0; i < 8; i++)
((u16 *)vdst)[i] = ((u16 *)vbuf)[7-i];
break;
case 2: /* lxvd2x */
for (i = 0; i < 2; i++)
((u64 *)vdst)[i] = ((u64 *)vbuf)[1-i];
break;
case 3: /* lxvb16x */
for (i = 0; i < 16; i++)
vdst[i] = vbuf[15-i];
break;
}
#else /* __LITTLE_ENDIAN__ */
/* On a big endian kernel, a BE userspace only needs a memcpy */
if (!swap)
sel = 3;
/* Otherwise, we need to swap the content of the components */
switch (sel) {
case 0: /* lxvw4x */
for (i = 0; i < 4; i++)
((u32 *)vdst)[i] = cpu_to_le32(((u32 *)vbuf)[i]);
break;
case 1: /* lxvh8x */
for (i = 0; i < 8; i++)
((u16 *)vdst)[i] = cpu_to_le16(((u16 *)vbuf)[i]);
break;
case 2: /* lxvd2x */
for (i = 0; i < 2; i++)
((u64 *)vdst)[i] = cpu_to_le64(((u64 *)vbuf)[i]);
break;
case 3: /* lxvb16x */
memcpy(vdst, vbuf, 16);
break;
}
#endif /* !__LITTLE_ENDIAN__ */
/* Go to next instruction */
regs->nip += 4;
}
#endif /* CONFIG_VSX */
void handle_hmi_exception(struct pt_regs *regs)
{
struct pt_regs *old_regs;
old_regs = set_irq_regs(regs);
irq_enter();
#ifdef CONFIG_VSX
/* Real mode flagged P9 special emu is needed */
if (local_paca->hmi_p9_special_emu) {
local_paca->hmi_p9_special_emu = 0;
/*
* We don't want to take page faults while doing the
* emulation, we just replay the instruction if necessary.
*/
pagefault_disable();
p9_hmi_special_emu(regs);
pagefault_enable();
}
#endif /* CONFIG_VSX */
if (ppc_md.handle_hmi_exception)
ppc_md.handle_hmi_exception(regs);
irq_exit();
set_irq_regs(old_regs);
}
void unknown_exception(struct pt_regs *regs)
{
enum ctx_state prev_state = exception_enter();
printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
regs->nip, regs->msr, regs->trap);
_exception(SIGTRAP, regs, TRAP_FIXME, 0);
exception_exit(prev_state);
}
void instruction_breakpoint_exception(struct pt_regs *regs)
{
enum ctx_state prev_state = exception_enter();
if (notify_die(DIE_IABR_MATCH, "iabr_match", regs, 5,
5, SIGTRAP) == NOTIFY_STOP)
goto bail;
if (debugger_iabr_match(regs))
goto bail;
_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
bail:
exception_exit(prev_state);
}
void RunModeException(struct pt_regs *regs)
{
_exception(SIGTRAP, regs, TRAP_FIXME, 0);
}
void single_step_exception(struct pt_regs *regs)
{
enum ctx_state prev_state = exception_enter();
clear_single_step(regs);
clear_br_trace(regs);
if (kprobe_post_handler(regs))
return;
if (notify_die(DIE_SSTEP, "single_step", regs, 5,
5, SIGTRAP) == NOTIFY_STOP)
goto bail;
if (debugger_sstep(regs))
goto bail;
_exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
bail:
exception_exit(prev_state);
}
NOKPROBE_SYMBOL(single_step_exception);
/*
* After we have successfully emulated an instruction, we have to
* check if the instruction was being single-stepped, and if so,
* pretend we got a single-step exception. This was pointed out
* by Kumar Gala. -- paulus
*/
static void emulate_single_step(struct pt_regs *regs)
{
if (single_stepping(regs))
single_step_exception(regs);
}
static inline int __parse_fpscr(unsigned long fpscr)
{
int ret = FPE_FIXME;
/* Invalid operation */
if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
ret = FPE_FLTINV;
/* Overflow */
else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
ret = FPE_FLTOVF;
/* Underflow */
else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
ret = FPE_FLTUND;
/* Divide by zero */
else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
ret = FPE_FLTDIV;
/* Inexact result */
else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
ret = FPE_FLTRES;
return ret;
}
static void parse_fpe(struct pt_regs *regs)
{
int code = 0;
flush_fp_to_thread(current);
code = __parse_fpscr(current->thread.fp_state.fpscr);
_exception(SIGFPE, regs, code, regs->nip);
}
/*
* Illegal instruction emulation support. Originally written to
* provide the PVR to user applications using the mfspr rd, PVR.
* Return non-zero if we can't emulate, or -EFAULT if the associated
* memory access caused an access fault. Return zero on success.
*
* There are a couple of ways to do this, either "decode" the instruction
* or directly match lots of bits. In this case, matching lots of
* bits is faster and easier.
*
*/
static int emulate_string_inst(struct pt_regs *regs, u32 instword)
{
u8 rT = (instword >> 21) & 0x1f;
u8 rA = (instword >> 16) & 0x1f;
u8 NB_RB = (instword >> 11) & 0x1f;
u32 num_bytes;
unsigned long EA;
int pos = 0;
/* Early out if we are an invalid form of lswx */
if ((instword & PPC_INST_STRING_MASK) == PPC_INST_LSWX)
if ((rT == rA) || (rT == NB_RB))
return -EINVAL;
EA = (rA == 0) ? 0 : regs->gpr[rA];
switch (instword & PPC_INST_STRING_MASK) {
case PPC_INST_LSWX:
case PPC_INST_STSWX:
EA += NB_RB;
num_bytes = regs->xer & 0x7f;
break;
case PPC_INST_LSWI:
case PPC_INST_STSWI:
num_bytes = (NB_RB == 0) ? 32 : NB_RB;
break;
default:
return -EINVAL;
}
while (num_bytes != 0)
{
u8 val;
u32 shift = 8 * (3 - (pos & 0x3));
/* if process is 32-bit, clear upper 32 bits of EA */
if ((regs->msr & MSR_64BIT) == 0)
EA &= 0xFFFFFFFF;
switch ((instword & PPC_INST_STRING_MASK)) {
case PPC_INST_LSWX:
case PPC_INST_LSWI:
if (get_user(val, (u8 __user *)EA))
return -EFAULT;
/* first time updating this reg,
* zero it out */
if (pos == 0)
regs->gpr[rT] = 0;
regs->gpr[rT] |= val << shift;
break;
case PPC_INST_STSWI:
case PPC_INST_STSWX:
val = regs->gpr[rT] >> shift;
if (put_user(val, (u8 __user *)EA))
return -EFAULT;
break;
}
/* move EA to next address */
EA += 1;
num_bytes--;
/* manage our position within the register */
if (++pos == 4) {
pos = 0;
if (++rT == 32)
rT = 0;
}
}
return 0;
}
static int emulate_popcntb_inst(struct pt_regs *regs, u32 instword)
{
u32 ra,rs;
unsigned long tmp;
ra = (instword >> 16) & 0x1f;
rs = (instword >> 21) & 0x1f;
tmp = regs->gpr[rs];
tmp = tmp - ((tmp >> 1) & 0x5555555555555555ULL);
tmp = (tmp & 0x3333333333333333ULL) + ((tmp >> 2) & 0x3333333333333333ULL);
tmp = (tmp + (tmp >> 4)) & 0x0f0f0f0f0f0f0f0fULL;
regs->gpr[ra] = tmp;
return 0;
}
static int emulate_isel(struct pt_regs *regs, u32 instword)
{
u8 rT = (instword >> 21) & 0x1f;
u8 rA = (instword >> 16) & 0x1f;
u8 rB = (instword >> 11) & 0x1f;
u8 BC = (instword >> 6) & 0x1f;
u8 bit;
unsigned long tmp;
tmp = (rA == 0) ? 0 : regs->gpr[rA];
bit = (regs->ccr >> (31 - BC)) & 0x1;
regs->gpr[rT] = bit ? tmp : regs->gpr[rB];
return 0;
}
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
static inline bool tm_abort_check(struct pt_regs *regs, int cause)
{
/* If we're emulating a load/store in an active transaction, we cannot
* emulate it as the kernel operates in transaction suspended context.
* We need to abort the transaction. This creates a persistent TM
* abort so tell the user what caused it with a new code.
*/
if (MSR_TM_TRANSACTIONAL(regs->msr)) {
tm_enable();
tm_abort(cause);
return true;
}
return false;
}
#else
static inline bool tm_abort_check(struct pt_regs *regs, int reason)
{
return false;
}
#endif
static int emulate_instruction(struct pt_regs *regs)
{
u32 instword;
u32 rd;
if (!user_mode(regs))
return -EINVAL;
CHECK_FULL_REGS(regs);
if (get_user(instword, (u32 __user *)(regs->nip)))
return -EFAULT;
/* Emulate the mfspr rD, PVR. */
if ((instword & PPC_INST_MFSPR_PVR_MASK) == PPC_INST_MFSPR_PVR) {
PPC_WARN_EMULATED(mfpvr, regs);
rd = (instword >> 21) & 0x1f;
regs->gpr[rd] = mfspr(SPRN_PVR);
return 0;
}
/* Emulating the dcba insn is just a no-op. */
if ((instword & PPC_INST_DCBA_MASK) == PPC_INST_DCBA) {
PPC_WARN_EMULATED(dcba, regs);
return 0;
}
/* Emulate the mcrxr insn. */
if ((instword & PPC_INST_MCRXR_MASK) == PPC_INST_MCRXR) {
int shift = (instword >> 21) & 0x1c;
unsigned long msk = 0xf0000000UL >> shift;
PPC_WARN_EMULATED(mcrxr, regs);
regs->ccr = (regs->ccr & ~msk) | ((regs->xer >> shift) & msk);
regs->xer &= ~0xf0000000UL;
return 0;
}
/* Emulate load/store string insn. */
if ((instword & PPC_INST_STRING_GEN_MASK) == PPC_INST_STRING) {
if (tm_abort_check(regs,
TM_CAUSE_EMULATE | TM_CAUSE_PERSISTENT))
return -EINVAL;
PPC_WARN_EMULATED(string, regs);
return emulate_string_inst(regs, instword);
}
/* Emulate the popcntb (Population Count Bytes) instruction. */
if ((instword & PPC_INST_POPCNTB_MASK) == PPC_INST_POPCNTB) {
PPC_WARN_EMULATED(popcntb, regs);
return emulate_popcntb_inst(regs, instword);
}
/* Emulate isel (Integer Select) instruction */
if ((instword & PPC_INST_ISEL_MASK) == PPC_INST_ISEL) {
PPC_WARN_EMULATED(isel, regs);
return emulate_isel(regs, instword);
}
/* Emulate sync instruction variants */
if ((instword & PPC_INST_SYNC_MASK) == PPC_INST_SYNC) {
PPC_WARN_EMULATED(sync, regs);
asm volatile("sync");
return 0;
}
#ifdef CONFIG_PPC64
/* Emulate the mfspr rD, DSCR. */
if ((((instword & PPC_INST_MFSPR_DSCR_USER_MASK) ==
PPC_INST_MFSPR_DSCR_USER) ||
((instword & PPC_INST_MFSPR_DSCR_MASK) ==
PPC_INST_MFSPR_DSCR)) &&
cpu_has_feature(CPU_FTR_DSCR)) {
PPC_WARN_EMULATED(mfdscr, regs);
rd = (instword >> 21) & 0x1f;
regs->gpr[rd] = mfspr(SPRN_DSCR);
return 0;
}
/* Emulate the mtspr DSCR, rD. */
if ((((instword & PPC_INST_MTSPR_DSCR_USER_MASK) ==
PPC_INST_MTSPR_DSCR_USER) ||
((instword & PPC_INST_MTSPR_DSCR_MASK) ==
PPC_INST_MTSPR_DSCR)) &&
cpu_has_feature(CPU_FTR_DSCR)) {
PPC_WARN_EMULATED(mtdscr, regs);
rd = (instword >> 21) & 0x1f;
current->thread.dscr = regs->gpr[rd];
current->thread.dscr_inherit = 1;
mtspr(SPRN_DSCR, current->thread.dscr);
return 0;
}
#endif
return -EINVAL;
}
int is_valid_bugaddr(unsigned long addr)
{
return is_kernel_addr(addr);
}
#ifdef CONFIG_MATH_EMULATION
static int emulate_math(struct pt_regs *regs)
{
int ret;
extern int do_mathemu(struct pt_regs *regs);
ret = do_mathemu(regs);
if (ret >= 0)
PPC_WARN_EMULATED(math, regs);
switch (ret) {
case 0:
emulate_single_step(regs);
return 0;
case 1: {
int code = 0;
code = __parse_fpscr(current->thread.fp_state.fpscr);
_exception(SIGFPE, regs, code, regs->nip);
return 0;
}
case -EFAULT:
_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
return 0;
}
return -1;
}
#else
static inline int emulate_math(struct pt_regs *regs) { return -1; }
#endif
void program_check_exception(struct pt_regs *regs)
{
enum ctx_state prev_state = exception_enter();
unsigned int reason = get_reason(regs);
/* We can now get here via a FP Unavailable exception if the core
* has no FPU, in that case the reason flags will be 0 */
if (reason & REASON_FP) {
/* IEEE FP exception */
parse_fpe(regs);
goto bail;
}
if (reason & REASON_TRAP) {
unsigned long bugaddr;
/* Debugger is first in line to stop recursive faults in
* rcu_lock, notify_die, or atomic_notifier_call_chain */
if (debugger_bpt(regs))
goto bail;
if (kprobe_handler(regs))
goto bail;
/* trap exception */
if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP)
== NOTIFY_STOP)
goto bail;
bugaddr = regs->nip;
/*
* Fixup bugaddr for BUG_ON() in real mode
*/
if (!is_kernel_addr(bugaddr) && !(regs->msr & MSR_IR))
bugaddr += PAGE_OFFSET;
if (!(regs->msr & MSR_PR) && /* not user-mode */
report_bug(bugaddr, regs) == BUG_TRAP_TYPE_WARN) {
regs->nip += 4;
goto bail;
}
_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
goto bail;
}
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
if (reason & REASON_TM) {
/* This is a TM "Bad Thing Exception" program check.
* This occurs when:
* - An rfid/hrfid/mtmsrd attempts to cause an illegal
* transition in TM states.
* - A trechkpt is attempted when transactional.
* - A treclaim is attempted when non transactional.
* - A tend is illegally attempted.
* - writing a TM SPR when transactional.
*
* If usermode caused this, it's done something illegal and
* gets a SIGILL slap on the wrist. We call it an illegal
* operand to distinguish from the instruction just being bad
* (e.g. executing a 'tend' on a CPU without TM!); it's an
* illegal /placement/ of a valid instruction.
*/
if (user_mode(regs)) {
_exception(SIGILL, regs, ILL_ILLOPN, regs->nip);
goto bail;
} else {
printk(KERN_EMERG "Unexpected TM Bad Thing exception "
"at %lx (msr 0x%x)\n", regs->nip, reason);
die("Unrecoverable exception", regs, SIGABRT);
}
}
#endif
/*
* If we took the program check in the kernel skip down to sending a
* SIGILL. The subsequent cases all relate to emulating instructions
* which we should only do for userspace. We also do not want to enable
* interrupts for kernel faults because that might lead to further
* faults, and loose the context of the original exception.
*/
if (!user_mode(regs))
goto sigill;
/* We restore the interrupt state now */
if (!arch_irq_disabled_regs(regs))
local_irq_enable();
/* (reason & REASON_ILLEGAL) would be the obvious thing here,
* but there seems to be a hardware bug on the 405GP (RevD)
* that means ESR is sometimes set incorrectly - either to
* ESR_DST (!?) or 0. In the process of chasing this with the
* hardware people - not sure if it can happen on any illegal
* instruction or only on FP instructions, whether there is a
* pattern to occurrences etc. -dgibson 31/Mar/2003
*/
if (!emulate_math(regs))
goto bail;
/* Try to emulate it if we should. */
if (reason & (REASON_ILLEGAL | REASON_PRIVILEGED)) {
switch (emulate_instruction(regs)) {
case 0:
regs->nip += 4;
emulate_single_step(regs);
goto bail;
case -EFAULT:
_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
goto bail;
}
}
sigill:
if (reason & REASON_PRIVILEGED)
_exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
else
_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
bail:
exception_exit(prev_state);
}
NOKPROBE_SYMBOL(program_check_exception);
/*
* This occurs when running in hypervisor mode on POWER6 or later
* and an illegal instruction is encountered.
*/
void emulation_assist_interrupt(struct pt_regs *regs)
{
regs->msr |= REASON_ILLEGAL;
program_check_exception(regs);
}
NOKPROBE_SYMBOL(emulation_assist_interrupt);
void alignment_exception(struct pt_regs *regs)
{
enum ctx_state prev_state = exception_enter();
int sig, code, fixed = 0;
/* We restore the interrupt state now */
if (!arch_irq_disabled_regs(regs))
local_irq_enable();
if (tm_abort_check(regs, TM_CAUSE_ALIGNMENT | TM_CAUSE_PERSISTENT))
goto bail;
/* we don't implement logging of alignment exceptions */
if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))
fixed = fix_alignment(regs);
if (fixed == 1) {
regs->nip += 4; /* skip over emulated instruction */
emulate_single_step(regs);
goto bail;
}
/* Operand address was bad */
if (fixed == -EFAULT) {
sig = SIGSEGV;
code = SEGV_ACCERR;
} else {
sig = SIGBUS;
code = BUS_ADRALN;
}
if (user_mode(regs))
_exception(sig, regs, code, regs->dar);
else
bad_page_fault(regs, regs->dar, sig);
bail:
exception_exit(prev_state);
}
void StackOverflow(struct pt_regs *regs)
{
printk(KERN_CRIT "Kernel stack overflow in process %p, r1=%lx\n",
current, regs->gpr[1]);
debugger(regs);
show_regs(regs);
panic("kernel stack overflow");
}
void nonrecoverable_exception(struct pt_regs *regs)
{
printk(KERN_ERR "Non-recoverable exception at PC=%lx MSR=%lx\n",
regs->nip, regs->msr);
debugger(regs);
die("nonrecoverable exception", regs, SIGKILL);
}
void kernel_fp_unavailable_exception(struct pt_regs *regs)
{
enum ctx_state prev_state = exception_enter();
printk(KERN_EMERG "Unrecoverable FP Unavailable Exception "
"%lx at %lx\n", regs->trap, regs->nip);
die("Unrecoverable FP Unavailable Exception", regs, SIGABRT);
exception_exit(prev_state);
}
void altivec_unavailable_exception(struct pt_regs *regs)
{
enum ctx_state prev_state = exception_enter();
if (user_mode(regs)) {
/* A user program has executed an altivec instruction,
but this kernel doesn't support altivec. */
_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
goto bail;
}
printk(KERN_EMERG "Unrecoverable VMX/Altivec Unavailable Exception "
"%lx at %lx\n", regs->trap, regs->nip);
die("Unrecoverable VMX/Altivec Unavailable Exception", regs, SIGABRT);
bail:
exception_exit(prev_state);
}
void vsx_unavailable_exception(struct pt_regs *regs)
{
if (user_mode(regs)) {
/* A user program has executed an vsx instruction,
but this kernel doesn't support vsx. */
_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
return;
}
printk(KERN_EMERG "Unrecoverable VSX Unavailable Exception "
"%lx at %lx\n", regs->trap, regs->nip);
die("Unrecoverable VSX Unavailable Exception", regs, SIGABRT);
}
#ifdef CONFIG_PPC64
static void tm_unavailable(struct pt_regs *regs)
{
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
if (user_mode(regs)) {
current->thread.load_tm++;
regs->msr |= MSR_TM;
tm_enable();
tm_restore_sprs(&current->thread);
return;
}
#endif
pr_emerg("Unrecoverable TM Unavailable Exception "
"%lx at %lx\n", regs->trap, regs->nip);
die("Unrecoverable TM Unavailable Exception", regs, SIGABRT);
}
void facility_unavailable_exception(struct pt_regs *regs)
{
static char *facility_strings[] = {
[FSCR_FP_LG] = "FPU",
[FSCR_VECVSX_LG] = "VMX/VSX",
[FSCR_DSCR_LG] = "DSCR",
[FSCR_PM_LG] = "PMU SPRs",
[FSCR_BHRB_LG] = "BHRB",
[FSCR_TM_LG] = "TM",
[FSCR_EBB_LG] = "EBB",
[FSCR_TAR_LG] = "TAR",
[FSCR_MSGP_LG] = "MSGP",
[FSCR_SCV_LG] = "SCV",
};
char *facility = "unknown";
u64 value;
u32 instword, rd;
u8 status;
bool hv;
hv = (TRAP(regs) == 0xf80);
if (hv)
value = mfspr(SPRN_HFSCR);
else
value = mfspr(SPRN_FSCR);
status = value >> 56;
if (status == FSCR_DSCR_LG) {
/*
* User is accessing the DSCR register using the problem
* state only SPR number (0x03) either through a mfspr or
* a mtspr instruction. If it is a write attempt through
* a mtspr, then we set the inherit bit. This also allows
* the user to write or read the register directly in the
* future by setting via the FSCR DSCR bit. But in case it
* is a read DSCR attempt through a mfspr instruction, we
* just emulate the instruction instead. This code path will
* always emulate all the mfspr instructions till the user
* has attempted at least one mtspr instruction. This way it
* preserves the same behaviour when the user is accessing
* the DSCR through privilege level only SPR number (0x11)
* which is emulated through illegal instruction exception.
* We always leave HFSCR DSCR set.
*/
if (get_user(instword, (u32 __user *)(regs->nip))) {
pr_err("Failed to fetch the user instruction\n");
return;
}
/* Write into DSCR (mtspr 0x03, RS) */
if ((instword & PPC_INST_MTSPR_DSCR_USER_MASK)
== PPC_INST_MTSPR_DSCR_USER) {
rd = (instword >> 21) & 0x1f;
current->thread.dscr = regs->gpr[rd];
current->thread.dscr_inherit = 1;
current->thread.fscr |= FSCR_DSCR;
mtspr(SPRN_FSCR, current->thread.fscr);
}
/* Read from DSCR (mfspr RT, 0x03) */
if ((instword & PPC_INST_MFSPR_DSCR_USER_MASK)
== PPC_INST_MFSPR_DSCR_USER) {
if (emulate_instruction(regs)) {
pr_err("DSCR based mfspr emulation failed\n");
return;
}
regs->nip += 4;
emulate_single_step(regs);
}
return;
}
if (status == FSCR_TM_LG) {
/*
* If we're here then the hardware is TM aware because it
* generated an exception with FSRM_TM set.
*
* If cpu_has_feature(CPU_FTR_TM) is false, then either firmware
* told us not to do TM, or the kernel is not built with TM
* support.
*
* If both of those things are true, then userspace can spam the
* console by triggering the printk() below just by continually
* doing tbegin (or any TM instruction). So in that case just
* send the process a SIGILL immediately.
*/
if (!cpu_has_feature(CPU_FTR_TM))
goto out;
tm_unavailable(regs);
return;
}
if ((hv || status >= 2) &&
(status < ARRAY_SIZE(facility_strings)) &&
facility_strings[status])
facility = facility_strings[status];
/* We restore the interrupt state now */
if (!arch_irq_disabled_regs(regs))
local_irq_enable();
pr_err_ratelimited("%sFacility '%s' unavailable (%d), exception at 0x%lx, MSR=%lx\n",
hv ? "Hypervisor " : "", facility, status, regs->nip, regs->msr);
out:
if (user_mode(regs)) {
_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
return;
}
die("Unexpected facility unavailable exception", regs, SIGABRT);
}
#endif
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
void fp_unavailable_tm(struct pt_regs *regs)
{
/* Note: This does not handle any kind of FP laziness. */
TM_DEBUG("FP Unavailable trap whilst transactional at 0x%lx, MSR=%lx\n",
regs->nip, regs->msr);
/* We can only have got here if the task started using FP after
* beginning the transaction. So, the transactional regs are just a
* copy of the checkpointed ones. But, we still need to recheckpoint
* as we're enabling FP for the process; it will return, abort the
* transaction, and probably retry but now with FP enabled. So the
* checkpointed FP registers need to be loaded.
*/
tm_reclaim_current(TM_CAUSE_FAC_UNAV);
/* Reclaim didn't save out any FPRs to transact_fprs. */
/* Enable FP for the task: */
current->thread.load_fp = 1;
/* This loads and recheckpoints the FP registers from
* thread.fpr[]. They will remain in registers after the
* checkpoint so we don't need to reload them after.
* If VMX is in use, the VRs now hold checkpointed values,
* so we don't want to load the VRs from the thread_struct.
*/
tm_recheckpoint(&current->thread);
}
void altivec_unavailable_tm(struct pt_regs *regs)
{
/* See the comments in fp_unavailable_tm(). This function operates
* the same way.
*/
TM_DEBUG("Vector Unavailable trap whilst transactional at 0x%lx,"
"MSR=%lx\n",
regs->nip, regs->msr);
tm_reclaim_current(TM_CAUSE_FAC_UNAV);
current->thread.load_vec = 1;
tm_recheckpoint(&current->thread);
current->thread.used_vr = 1;
}
void vsx_unavailable_tm(struct pt_regs *regs)
{
/* See the comments in fp_unavailable_tm(). This works similarly,
* though we're loading both FP and VEC registers in here.
*
* If FP isn't in use, load FP regs. If VEC isn't in use, load VEC
* regs. Either way, set MSR_VSX.
*/
TM_DEBUG("VSX Unavailable trap whilst transactional at 0x%lx,"
"MSR=%lx\n",
regs->nip, regs->msr);
current->thread.used_vsr = 1;
/* This reclaims FP and/or VR regs if they're already enabled */
tm_reclaim_current(TM_CAUSE_FAC_UNAV);
current->thread.load_vec = 1;
current->thread.load_fp = 1;
tm_recheckpoint(&current->thread);
}
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
void performance_monitor_exception(struct pt_regs *regs)
{
__this_cpu_inc(irq_stat.pmu_irqs);
perf_irq(regs);
}
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
static void handle_debug(struct pt_regs *regs, unsigned long debug_status)
{
int changed = 0;
/*
* Determine the cause of the debug event, clear the
* event flags and send a trap to the handler. Torez
*/
if (debug_status & (DBSR_DAC1R | DBSR_DAC1W)) {
dbcr_dac(current) &= ~(DBCR_DAC1R | DBCR_DAC1W);
#ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
current->thread.debug.dbcr2 &= ~DBCR2_DAC12MODE;
#endif
do_send_trap(regs, mfspr(SPRN_DAC1), debug_status,
5);
changed |= 0x01;
} else if (debug_status & (DBSR_DAC2R | DBSR_DAC2W)) {
dbcr_dac(current) &= ~(DBCR_DAC2R | DBCR_DAC2W);
do_send_trap(regs, mfspr(SPRN_DAC2), debug_status,
6);
changed |= 0x01;
} else if (debug_status & DBSR_IAC1) {
current->thread.debug.dbcr0 &= ~DBCR0_IAC1;
dbcr_iac_range(current) &= ~DBCR_IAC12MODE;
do_send_trap(regs, mfspr(SPRN_IAC1), debug_status,
1);
changed |= 0x01;
} else if (debug_status & DBSR_IAC2) {
current->thread.debug.dbcr0 &= ~DBCR0_IAC2;
do_send_trap(regs, mfspr(SPRN_IAC2), debug_status,
2);
changed |= 0x01;
} else if (debug_status & DBSR_IAC3) {
current->thread.debug.dbcr0 &= ~DBCR0_IAC3;
dbcr_iac_range(current) &= ~DBCR_IAC34MODE;
do_send_trap(regs, mfspr(SPRN_IAC3), debug_status,
3);
changed |= 0x01;
} else if (debug_status & DBSR_IAC4) {
current->thread.debug.dbcr0 &= ~DBCR0_IAC4;
do_send_trap(regs, mfspr(SPRN_IAC4), debug_status,
4);
changed |= 0x01;
}
/*
* At the point this routine was called, the MSR(DE) was turned off.
* Check all other debug flags and see if that bit needs to be turned
* back on or not.
*/
if (DBCR_ACTIVE_EVENTS(current->thread.debug.dbcr0,
current->thread.debug.dbcr1))
regs->msr |= MSR_DE;
else
/* Make sure the IDM flag is off */
current->thread.debug.dbcr0 &= ~DBCR0_IDM;
if (changed & 0x01)
mtspr(SPRN_DBCR0, current->thread.debug.dbcr0);
}
void DebugException(struct pt_regs *regs, unsigned long debug_status)
{
current->thread.debug.dbsr = debug_status;
/* Hack alert: On BookE, Branch Taken stops on the branch itself, while
* on server, it stops on the target of the branch. In order to simulate
* the server behaviour, we thus restart right away with a single step
* instead of stopping here when hitting a BT
*/
if (debug_status & DBSR_BT) {
regs->msr &= ~MSR_DE;
/* Disable BT */
mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_BT);
/* Clear the BT event */
mtspr(SPRN_DBSR, DBSR_BT);
/* Do the single step trick only when coming from userspace */
if (user_mode(regs)) {
current->thread.debug.dbcr0 &= ~DBCR0_BT;
current->thread.debug.dbcr0 |= DBCR0_IDM | DBCR0_IC;
regs->msr |= MSR_DE;
return;
}
if (kprobe_post_handler(regs))
return;
if (notify_die(DIE_SSTEP, "block_step", regs, 5,
5, SIGTRAP) == NOTIFY_STOP) {
return;
}
if (debugger_sstep(regs))
return;
} else if (debug_status & DBSR_IC) { /* Instruction complete */
regs->msr &= ~MSR_DE;
/* Disable instruction completion */
mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC);
/* Clear the instruction completion event */
mtspr(SPRN_DBSR, DBSR_IC);
if (kprobe_post_handler(regs))
return;
if (notify_die(DIE_SSTEP, "single_step", regs, 5,
5, SIGTRAP) == NOTIFY_STOP) {
return;
}
if (debugger_sstep(regs))
return;
if (user_mode(regs)) {
current->thread.debug.dbcr0 &= ~DBCR0_IC;
if (DBCR_ACTIVE_EVENTS(current->thread.debug.dbcr0,
current->thread.debug.dbcr1))
regs->msr |= MSR_DE;
else
/* Make sure the IDM bit is off */
current->thread.debug.dbcr0 &= ~DBCR0_IDM;
}
_exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
} else
handle_debug(regs, debug_status);
}
NOKPROBE_SYMBOL(DebugException);
#endif /* CONFIG_PPC_ADV_DEBUG_REGS */
#if !defined(CONFIG_TAU_INT)
void TAUException(struct pt_regs *regs)
{
printk("TAU trap at PC: %lx, MSR: %lx, vector=%lx %s\n",
regs->nip, regs->msr, regs->trap, print_tainted());
}
#endif /* CONFIG_INT_TAU */
#ifdef CONFIG_ALTIVEC
void altivec_assist_exception(struct pt_regs *regs)
{
int err;
if (!user_mode(regs)) {
printk(KERN_EMERG "VMX/Altivec assist exception in kernel mode"
" at %lx\n", regs->nip);
die("Kernel VMX/Altivec assist exception", regs, SIGILL);
}
flush_altivec_to_thread(current);
PPC_WARN_EMULATED(altivec, regs);
err = emulate_altivec(regs);
if (err == 0) {
regs->nip += 4; /* skip emulated instruction */
emulate_single_step(regs);
return;
}
if (err == -EFAULT) {
/* got an error reading the instruction */
_exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
} else {
/* didn't recognize the instruction */
/* XXX quick hack for now: set the non-Java bit in the VSCR */
printk_ratelimited(KERN_ERR "Unrecognized altivec instruction "
"in %s at %lx\n", current->comm, regs->nip);
current->thread.vr_state.vscr.u[3] |= 0x10000;
}
}
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_FSL_BOOKE
void CacheLockingException(struct pt_regs *regs, unsigned long address,
unsigned long error_code)
{
/* We treat cache locking instructions from the user
* as priv ops, in the future we could try to do
* something smarter
*/
if (error_code & (ESR_DLK|ESR_ILK))
_exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
return;
}
#endif /* CONFIG_FSL_BOOKE */
#ifdef CONFIG_SPE
void SPEFloatingPointException(struct pt_regs *regs)
{
extern int do_spe_mathemu(struct pt_regs *regs);
unsigned long spefscr;
int fpexc_mode;
int code = FPE_FIXME;
int err;
flush_spe_to_thread(current);
spefscr = current->thread.spefscr;
fpexc_mode = current->thread.fpexc_mode;
if ((spefscr & SPEFSCR_FOVF) && (fpexc_mode & PR_FP_EXC_OVF)) {
code = FPE_FLTOVF;
}
else if ((spefscr & SPEFSCR_FUNF) && (fpexc_mode & PR_FP_EXC_UND)) {
code = FPE_FLTUND;
}
else if ((spefscr & SPEFSCR_FDBZ) && (fpexc_mode & PR_FP_EXC_DIV))
code = FPE_FLTDIV;
else if ((spefscr & SPEFSCR_FINV) && (fpexc_mode & PR_FP_EXC_INV)) {
code = FPE_FLTINV;
}
else if ((spefscr & (SPEFSCR_FG | SPEFSCR_FX)) && (fpexc_mode & PR_FP_EXC_RES))
code = FPE_FLTRES;
err = do_spe_mathemu(regs);
if (err == 0) {
regs->nip += 4; /* skip emulated instruction */
emulate_single_step(regs);
return;
}
if (err == -EFAULT) {
/* got an error reading the instruction */
_exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
} else if (err == -EINVAL) {
/* didn't recognize the instruction */
printk(KERN_ERR "unrecognized spe instruction "
"in %s at %lx\n", current->comm, regs->nip);
} else {
_exception(SIGFPE, regs, code, regs->nip);
}
return;
}
void SPEFloatingPointRoundException(struct pt_regs *regs)
{
extern int speround_handler(struct pt_regs *regs);
int err;
preempt_disable();
if (regs->msr & MSR_SPE)
giveup_spe(current);
preempt_enable();
regs->nip -= 4;
err = speround_handler(regs);
if (err == 0) {
regs->nip += 4; /* skip emulated instruction */
emulate_single_step(regs);
return;
}
if (err == -EFAULT) {
/* got an error reading the instruction */
_exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
} else if (err == -EINVAL) {
/* didn't recognize the instruction */
printk(KERN_ERR "unrecognized spe instruction "
"in %s at %lx\n", current->comm, regs->nip);
} else {
_exception(SIGFPE, regs, FPE_FIXME, regs->nip);
return;
}
}
#endif
/*
* We enter here if we get an unrecoverable exception, that is, one
* that happened at a point where the RI (recoverable interrupt) bit
* in the MSR is 0. This indicates that SRR0/1 are live, and that
* we therefore lost state by taking this exception.
*/
void unrecoverable_exception(struct pt_regs *regs)
{
printk(KERN_EMERG "Unrecoverable exception %lx at %lx\n",
regs->trap, regs->nip);
die("Unrecoverable exception", regs, SIGABRT);
}
NOKPROBE_SYMBOL(unrecoverable_exception);
#if defined(CONFIG_BOOKE_WDT) || defined(CONFIG_40x)
/*
* Default handler for a Watchdog exception,
* spins until a reboot occurs
*/
void __attribute__ ((weak)) WatchdogHandler(struct pt_regs *regs)
{
/* Generic WatchdogHandler, implement your own */
mtspr(SPRN_TCR, mfspr(SPRN_TCR)&(~TCR_WIE));
return;
}
void WatchdogException(struct pt_regs *regs)
{
printk (KERN_EMERG "PowerPC Book-E Watchdog Exception\n");
WatchdogHandler(regs);
}
#endif
/*
* We enter here if we discover during exception entry that we are
* running in supervisor mode with a userspace value in the stack pointer.
*/
void kernel_bad_stack(struct pt_regs *regs)
{
printk(KERN_EMERG "Bad kernel stack pointer %lx at %lx\n",
regs->gpr[1], regs->nip);
die("Bad kernel stack pointer", regs, SIGABRT);
}
NOKPROBE_SYMBOL(kernel_bad_stack);
void __init trap_init(void)
{
}
#ifdef CONFIG_PPC_EMULATED_STATS
#define WARN_EMULATED_SETUP(type) .type = { .name = #type }
struct ppc_emulated ppc_emulated = {
#ifdef CONFIG_ALTIVEC
WARN_EMULATED_SETUP(altivec),
#endif
WARN_EMULATED_SETUP(dcba),
WARN_EMULATED_SETUP(dcbz),
WARN_EMULATED_SETUP(fp_pair),
WARN_EMULATED_SETUP(isel),
WARN_EMULATED_SETUP(mcrxr),
WARN_EMULATED_SETUP(mfpvr),
WARN_EMULATED_SETUP(multiple),
WARN_EMULATED_SETUP(popcntb),
WARN_EMULATED_SETUP(spe),
WARN_EMULATED_SETUP(string),
WARN_EMULATED_SETUP(sync),
WARN_EMULATED_SETUP(unaligned),
#ifdef CONFIG_MATH_EMULATION
WARN_EMULATED_SETUP(math),
#endif
#ifdef CONFIG_VSX
WARN_EMULATED_SETUP(vsx),
#endif
#ifdef CONFIG_PPC64
WARN_EMULATED_SETUP(mfdscr),
WARN_EMULATED_SETUP(mtdscr),
WARN_EMULATED_SETUP(lq_stq),
WARN_EMULATED_SETUP(lxvw4x),
WARN_EMULATED_SETUP(lxvh8x),
WARN_EMULATED_SETUP(lxvd2x),
WARN_EMULATED_SETUP(lxvb16x),
#endif
};
u32 ppc_warn_emulated;
void ppc_warn_emulated_print(const char *type)
{
pr_warn_ratelimited("%s used emulated %s instruction\n", current->comm,
type);
}
static int __init ppc_warn_emulated_init(void)
{
struct dentry *dir, *d;
unsigned int i;
struct ppc_emulated_entry *entries = (void *)&ppc_emulated;
if (!powerpc_debugfs_root)
return -ENODEV;
dir = debugfs_create_dir("emulated_instructions",
powerpc_debugfs_root);
if (!dir)
return -ENOMEM;
d = debugfs_create_u32("do_warn", 0644, dir,
&ppc_warn_emulated);
if (!d)
goto fail;
for (i = 0; i < sizeof(ppc_emulated)/sizeof(*entries); i++) {
d = debugfs_create_u32(entries[i].name, 0644, dir,
(u32 *)&entries[i].val.counter);
if (!d)
goto fail;
}
return 0;
fail:
debugfs_remove_recursive(dir);
return -ENOMEM;
}
device_initcall(ppc_warn_emulated_init);
#endif /* CONFIG_PPC_EMULATED_STATS */
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