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linux/arch/powerpc/kernel/traps.c
Mahesh Salgaonkar d93b0ac01a powerpc/book3s/mce: Move add_taint() later in virtual mode 
machine_check_early() gets called in real mode. The very first time when
add_taint() is called, it prints a warning which ends up calling opal
call (that uses OPAL_CALL wrapper) for writing it to console. If we get a
very first machine check while we are in opal we are doomed. OPAL_CALL
overwrites the PACASAVEDMSR in r13 and in this case when we are done with
MCE handling the original opal call will use this new MSR on it's way
back to opal_return. This usually leads to unexpected behaviour or the
kernel to panic. Instead move the add_taint() call later in the virtual
mode where it is safe to call.

This is broken with current FW level. We got lucky so far for not getting
very first MCE hit while in OPAL. But easily reproducible on Mambo.

Fixes: 27ea2c420c ("powerpc: Set the correct kernel taint on machine check errors.")
Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-05-03 14:45:39 +10:00

2084 lines
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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/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 <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
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;
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);
crash_fadump(regs, "die oops");
/*
* A system reset (0x100) is a request to dump, so we always send
* it through the crashdump code.
*/
if (kexec_should_crash(current) || (TRAP(regs) == 0x100)) {
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);
}
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);
#ifdef CONFIG_PREEMPT
printk("PREEMPT ");
#endif
#ifdef CONFIG_SMP
printk("SMP NR_CPUS=%d ", NR_CPUS);
#endif
if (debug_pagealloc_enabled())
printk("DEBUG_PAGEALLOC ");
#ifdef CONFIG_NUMA
printk("NUMA ");
#endif
printk("%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;
if (debugger(regs))
return;
flags = oops_begin(regs);
if (__die(str, regs, err))
err = 0;
oops_end(flags, regs, err);
}
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(int signr, struct pt_regs *regs, int code, unsigned long addr)
{
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;
memset(&info, 0, sizeof(info));
info.si_signo = signr;
info.si_code = code;
info.si_addr = (void __user *) addr;
force_sig_info(signr, &info, current);
}
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();
/* See if any machine dependent calls */
if (ppc_md.system_reset_exception) {
if (ppc_md.system_reset_exception(regs))
goto out;
}
die("System Reset", regs, SIGABRT);
out:
#ifdef CONFIG_PPC_BOOK3S_64
BUG_ON(get_paca()->in_nmi == 0);
if (get_paca()->in_nmi > 1)
panic("Unrecoverable nested System Reset");
#endif
/* Must die if the interrupt is not recoverable */
if (!(regs->msr & MSR_RI))
panic("Unrecoverable System Reset");
if (!nested)
nmi_exit();
/* What should we do here? We could issue a shutdown or hard reset. */
}
#ifdef CONFIG_PPC64
/*
* This function is called in real mode. Strictly no printk's please.
*
* regs->nip and regs->msr contains srr0 and ssr1.
*/
long machine_check_early(struct pt_regs *regs)
{
long handled = 0;
__this_cpu_inc(irq_stat.mce_exceptions);
if (cur_cpu_spec && cur_cpu_spec->machine_check_early)
handled = cur_cpu_spec->machine_check_early(regs);
return handled;
}
long hmi_exception_realmode(struct pt_regs *regs)
{
__this_cpu_inc(irq_stat.hmi_exceptions);
wait_for_subcore_guest_exit();
if (ppc_md.hmi_exception_early)
ppc_md.hmi_exception_early(regs);
wait_for_tb_resync();
return 0;
}
#endif
/*
* 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)
#ifndef CONFIG_FSL_BOOKE
#define get_mc_reason(regs) ((regs)->dsisr)
#else
#define get_mc_reason(regs) (mfspr(SPRN_MCSR))
#endif
#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)
#else
/* On non-4xx, the reason for the machine check or program
exception is in the MSR. */
#define get_reason(regs) ((regs)->msr)
#define get_mc_reason(regs) ((regs)->msr)
#define REASON_TM 0x200000
#define REASON_FP 0x100000
#define REASON_ILLEGAL 0x80000
#define REASON_PRIVILEGED 0x40000
#define REASON_TRAP 0x20000
#define single_stepping(regs) ((regs)->msr & MSR_SE)
#define clear_single_step(regs) ((regs)->msr &= ~MSR_SE)
#endif
#if defined(CONFIG_4xx)
int machine_check_4xx(struct pt_regs *regs)
{
unsigned long reason = get_mc_reason(regs);
if (reason & ESR_IMCP) {
printk("Instruction");
mtspr(SPRN_ESR, reason & ~ESR_IMCP);
} else
printk("Data");
printk(" machine check in kernel mode.\n");
return 0;
}
int machine_check_440A(struct pt_regs *regs)
{
unsigned long reason = get_mc_reason(regs);
printk("Machine check in kernel mode.\n");
if (reason & ESR_IMCP){
printk("Instruction Synchronous Machine Check exception\n");
mtspr(SPRN_ESR, reason & ~ESR_IMCP);
}
else {
u32 mcsr = mfspr(SPRN_MCSR);
if (mcsr & MCSR_IB)
printk("Instruction Read PLB Error\n");
if (mcsr & MCSR_DRB)
printk("Data Read PLB Error\n");
if (mcsr & MCSR_DWB)
printk("Data Write PLB Error\n");
if (mcsr & MCSR_TLBP)
printk("TLB Parity Error\n");
if (mcsr & MCSR_ICP){
flush_instruction_cache();
printk("I-Cache Parity Error\n");
}
if (mcsr & MCSR_DCSP)
printk("D-Cache Search Parity Error\n");
if (mcsr & MCSR_DCFP)
printk("D-Cache Flush Parity Error\n");
if (mcsr & MCSR_IMPE)
printk("Machine Check exception is imprecise\n");
/* Clear MCSR */
mtspr(SPRN_MCSR, mcsr);
}
return 0;
}
int machine_check_47x(struct pt_regs *regs)
{
unsigned long reason = get_mc_reason(regs);
u32 mcsr;
printk(KERN_ERR "Machine check in kernel mode.\n");
if (reason & ESR_IMCP) {
printk(KERN_ERR
"Instruction Synchronous Machine Check exception\n");
mtspr(SPRN_ESR, reason & ~ESR_IMCP);
return 0;
}
mcsr = mfspr(SPRN_MCSR);
if (mcsr & MCSR_IB)
printk(KERN_ERR "Instruction Read PLB Error\n");
if (mcsr & MCSR_DRB)
printk(KERN_ERR "Data Read PLB Error\n");
if (mcsr & MCSR_DWB)
printk(KERN_ERR "Data Write PLB Error\n");
if (mcsr & MCSR_TLBP)
printk(KERN_ERR "TLB Parity Error\n");
if (mcsr & MCSR_ICP) {
flush_instruction_cache();
printk(KERN_ERR "I-Cache Parity Error\n");
}
if (mcsr & MCSR_DCSP)
printk(KERN_ERR "D-Cache Search Parity Error\n");
if (mcsr & PPC47x_MCSR_GPR)
printk(KERN_ERR "GPR Parity Error\n");
if (mcsr & PPC47x_MCSR_FPR)
printk(KERN_ERR "FPR Parity Error\n");
if (mcsr & PPC47x_MCSR_IPR)
printk(KERN_ERR "Machine Check exception is imprecise\n");
/* Clear MCSR */
mtspr(SPRN_MCSR, mcsr);
return 0;
}
#elif defined(CONFIG_E500)
int machine_check_e500mc(struct pt_regs *regs)
{
unsigned long mcsr = mfspr(SPRN_MCSR);
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.
*/
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 = get_mc_reason(regs);
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 = get_mc_reason(regs);
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_PPC_8xx)
int machine_check_8xx(struct pt_regs *regs)
{
unsigned long reason = get_mc_reason(regs);
pr_err("Machine check in kernel mode.\n");
pr_err("Caused by (from SRR1=%lx): ", reason);
if (reason & 0x40000000)
pr_err("Fetch error at address %lx\n", regs->nip);
else
pr_err("Data access error at address %lx\n", regs->dar);
#ifdef CONFIG_PCI
/* the qspan pci read routines can cause machine checks -- Cort
*
* yuck !!! that totally needs to go away ! There are better ways
* to deal with that than having a wart in the mcheck handler.
* -- BenH
*/
bad_page_fault(regs, regs->dar, SIGBUS);
return 1;
#else
return 0;
#endif
}
#else
int machine_check_generic(struct pt_regs *regs)
{
unsigned long reason = get_mc_reason(regs);
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)
{
enum ctx_state prev_state = exception_enter();
int recover = 0;
__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))
panic("Unrecoverable Machine check");
bail:
exception_exit(prev_state);
}
void SMIException(struct pt_regs *regs)
{
die("System Management Interrupt", regs, SIGABRT);
}
void handle_hmi_exception(struct pt_regs *regs)
{
struct pt_regs *old_regs;
old_regs = set_irq_regs(regs);
irq_enter();
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, 0, 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, 0, 0);
}
void single_step_exception(struct pt_regs *regs)
{
enum ctx_state prev_state = exception_enter();
clear_single_step(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 = 0;
/* 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 (!user_mode(regs) &&
report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
regs->nip += 4;
goto bail;
}
/* 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 slb_miss_bad_addr(struct pt_regs *regs)
{
enum ctx_state prev_state = exception_enter();
if (user_mode(regs))
_exception(SIGSEGV, regs, SEGV_BNDERR, regs->dar);
else
bad_page_fault(regs, regs->dar, SIGSEGV);
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 = (regs->trap == 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: */
regs->msr |= (MSR_FP | current->thread.fpexc_mode);
/* 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, MSR_FP);
/* If VMX is in use, get the transactional values back */
if (regs->msr & MSR_VEC) {
msr_check_and_set(MSR_VEC);
load_vr_state(&current->thread.vr_state);
/* At this point all the VSX state is loaded, so enable it */
regs->msr |= MSR_VSX;
}
}
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);
regs->msr |= MSR_VEC;
tm_recheckpoint(&current->thread, MSR_VEC);
current->thread.used_vr = 1;
if (regs->msr & MSR_FP) {
msr_check_and_set(MSR_FP);
load_fp_state(&current->thread.fp_state);
regs->msr |= MSR_VSX;
}
}
void vsx_unavailable_tm(struct pt_regs *regs)
{
unsigned long orig_msr = regs->msr;
/* 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;
/* If FP and VMX are already loaded, we have all the state we need */
if ((orig_msr & (MSR_FP | MSR_VEC)) == (MSR_FP | MSR_VEC)) {
regs->msr |= MSR_VSX;
return;
}
/* This reclaims FP and/or VR regs if they're already enabled */
tm_reclaim_current(TM_CAUSE_FAC_UNAV);
regs->msr |= MSR_VEC | MSR_FP | current->thread.fpexc_mode |
MSR_VSX;
/* This loads & recheckpoints FP and VRs; but we have
* to be sure not to overwrite previously-valid state.
*/
tm_recheckpoint(&current->thread, regs->msr & ~orig_msr);
msr_check_and_set(orig_msr & (MSR_FP | MSR_VEC));
if (orig_msr & MSR_FP)
load_fp_state(&current->thread.fp_state);
if (orig_msr & MSR_VEC)
load_vr_state(&current->thread.vr_state);
}
#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_8xx
void SoftwareEmulation(struct pt_regs *regs)
{
CHECK_FULL_REGS(regs);
if (!user_mode(regs)) {
debugger(regs);
die("Kernel Mode Unimplemented Instruction or SW FPU Emulation",
regs, SIGFPE);
}
if (!emulate_math(regs))
return;
_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
}
#endif /* CONFIG_8xx */
#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, TRAP_HWBKPT,
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, TRAP_HWBKPT,
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, TRAP_HWBKPT,
1);
changed |= 0x01;
} else if (debug_status & DBSR_IAC2) {
current->thread.debug.dbcr0 &= ~DBCR0_IAC2;
do_send_trap(regs, mfspr(SPRN_IAC2), debug_status, TRAP_HWBKPT,
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, TRAP_HWBKPT,
3);
changed |= 0x01;
} else if (debug_status & DBSR_IAC4) {
current->thread.debug.dbcr0 &= ~DBCR0_IAC4;
do_send_trap(regs, mfspr(SPRN_IAC4), debug_status, TRAP_HWBKPT,
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 = 0;
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, 0, 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);
}
#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);
}
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),
#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", S_IRUGO | S_IWUSR, 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, S_IRUGO | S_IWUSR, 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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