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linux/arch/blackfin/kernel/traps.c

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/*
* Main exception handling logic.
*
* Copyright 2004-2010 Analog Devices Inc.
*
* Licensed under the GPL-2 or later
*/
#include <linux/bug.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/sched/signal.h>
#include <linux/sched/debug.h>
#include <asm/traps.h>
#include <asm/cplb.h>
#include <asm/blackfin.h>
#include <asm/irq_handler.h>
#include <linux/irq.h>
#include <asm/trace.h>
#include <asm/fixed_code.h>
#include <asm/pseudo_instructions.h>
#include <asm/pda.h>
#include <asm/asm-offsets.h>
#ifdef CONFIG_KGDB
# include <linux/kgdb.h>
# define CHK_DEBUGGER_TRAP() \
do { \
kgdb_handle_exception(trapnr, sig, info.si_code, fp); \
} while (0)
# define CHK_DEBUGGER_TRAP_MAYBE() \
do { \
if (kgdb_connected) \
CHK_DEBUGGER_TRAP(); \
} while (0)
#else
# define CHK_DEBUGGER_TRAP() do { } while (0)
# define CHK_DEBUGGER_TRAP_MAYBE() do { } while (0)
#endif
#ifdef CONFIG_DEBUG_VERBOSE
#define verbose_printk(fmt, arg...) \
printk(fmt, ##arg)
#else
#define verbose_printk(fmt, arg...) \
({ if (0) printk(fmt, ##arg); 0; })
#endif
#if defined(CONFIG_DEBUG_MMRS) || defined(CONFIG_DEBUG_MMRS_MODULE)
u32 last_seqstat;
#ifdef CONFIG_DEBUG_MMRS_MODULE
EXPORT_SYMBOL(last_seqstat);
#endif
#endif
/* Initiate the event table handler */
void __init trap_init(void)
{
CSYNC();
bfin_write_EVT3(trap);
CSYNC();
}
static int kernel_mode_regs(struct pt_regs *regs)
{
return regs->ipend & 0xffc0;
}
asmlinkage notrace void trap_c(struct pt_regs *fp)
{
#ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
int j;
#endif
#ifdef CONFIG_BFIN_PSEUDODBG_INSNS
int opcode;
#endif
unsigned int cpu = raw_smp_processor_id();
const char *strerror = NULL;
int sig = 0;
siginfo_t info;
unsigned long trapnr = fp->seqstat & SEQSTAT_EXCAUSE;
trace_buffer_save(j);
#if defined(CONFIG_DEBUG_MMRS) || defined(CONFIG_DEBUG_MMRS_MODULE)
last_seqstat = (u32)fp->seqstat;
#endif
/* Important - be very careful dereferncing pointers - will lead to
* double faults if the stack has become corrupt
*/
/* trap_c() will be called for exceptions. During exceptions
* processing, the pc value should be set with retx value.
* With this change we can cleanup some code in signal.c- TODO
*/
fp->orig_pc = fp->retx;
/* printk("exception: 0x%x, ipend=%x, reti=%x, retx=%x\n",
trapnr, fp->ipend, fp->pc, fp->retx); */
/* send the appropriate signal to the user program */
switch (trapnr) {
/* This table works in conjunction with the one in ./mach-common/entry.S
* Some exceptions are handled there (in assembly, in exception space)
* Some are handled here, (in C, in interrupt space)
* Some, like CPLB, are handled in both, where the normal path is
* handled in assembly/exception space, and the error path is handled
* here
*/
/* 0x00 - Linux Syscall, getting here is an error */
/* 0x01 - userspace gdb breakpoint, handled here */
case VEC_EXCPT01:
info.si_code = TRAP_ILLTRAP;
sig = SIGTRAP;
CHK_DEBUGGER_TRAP_MAYBE();
/* Check if this is a breakpoint in kernel space */
if (kernel_mode_regs(fp))
goto traps_done;
else
break;
/* 0x03 - User Defined, userspace stack overflow */
case VEC_EXCPT03:
info.si_code = SEGV_STACKFLOW;
sig = SIGSEGV;
strerror = KERN_NOTICE EXC_0x03(KERN_NOTICE);
CHK_DEBUGGER_TRAP_MAYBE();
break;
/* 0x02 - KGDB initial connection and break signal trap */
case VEC_EXCPT02:
#ifdef CONFIG_KGDB
info.si_code = TRAP_ILLTRAP;
sig = SIGTRAP;
CHK_DEBUGGER_TRAP();
goto traps_done;
#endif
/* 0x04 - User Defined */
/* 0x05 - User Defined */
/* 0x06 - User Defined */
/* 0x07 - User Defined */
/* 0x08 - User Defined */
/* 0x09 - User Defined */
/* 0x0A - User Defined */
/* 0x0B - User Defined */
/* 0x0C - User Defined */
/* 0x0D - User Defined */
/* 0x0E - User Defined */
/* 0x0F - User Defined */
/* If we got here, it is most likely that someone was trying to use a
* custom exception handler, and it is not actually installed properly
*/
case VEC_EXCPT04 ... VEC_EXCPT15:
info.si_code = ILL_ILLPARAOP;
sig = SIGILL;
strerror = KERN_NOTICE EXC_0x04(KERN_NOTICE);
CHK_DEBUGGER_TRAP_MAYBE();
break;
/* 0x10 HW Single step, handled here */
case VEC_STEP:
info.si_code = TRAP_STEP;
sig = SIGTRAP;
CHK_DEBUGGER_TRAP_MAYBE();
/* Check if this is a single step in kernel space */
if (kernel_mode_regs(fp))
goto traps_done;
else
break;
/* 0x11 - Trace Buffer Full, handled here */
case VEC_OVFLOW:
info.si_code = TRAP_TRACEFLOW;
sig = SIGTRAP;
strerror = KERN_NOTICE EXC_0x11(KERN_NOTICE);
CHK_DEBUGGER_TRAP_MAYBE();
break;
/* 0x12 - Reserved, Caught by default */
/* 0x13 - Reserved, Caught by default */
/* 0x14 - Reserved, Caught by default */
/* 0x15 - Reserved, Caught by default */
/* 0x16 - Reserved, Caught by default */
/* 0x17 - Reserved, Caught by default */
/* 0x18 - Reserved, Caught by default */
/* 0x19 - Reserved, Caught by default */
/* 0x1A - Reserved, Caught by default */
/* 0x1B - Reserved, Caught by default */
/* 0x1C - Reserved, Caught by default */
/* 0x1D - Reserved, Caught by default */
/* 0x1E - Reserved, Caught by default */
/* 0x1F - Reserved, Caught by default */
/* 0x20 - Reserved, Caught by default */
/* 0x21 - Undefined Instruction, handled here */
case VEC_UNDEF_I:
#ifdef CONFIG_BUG
if (kernel_mode_regs(fp)) {
switch (report_bug(fp->pc, fp)) {
case BUG_TRAP_TYPE_NONE:
break;
case BUG_TRAP_TYPE_WARN:
dump_bfin_trace_buffer();
fp->pc += 2;
goto traps_done;
case BUG_TRAP_TYPE_BUG:
/* call to panic() will dump trace, and it is
* off at this point, so it won't be clobbered
*/
panic("BUG()");
}
}
#endif
#ifdef CONFIG_BFIN_PSEUDODBG_INSNS
/*
* Support for the fake instructions, if the instruction fails,
* then just execute a illegal opcode failure (like normal).
* Don't support these instructions inside the kernel
*/
if (!kernel_mode_regs(fp) && get_instruction(&opcode, (unsigned short *)fp->pc)) {
if (execute_pseudodbg_assert(fp, opcode))
goto traps_done;
if (execute_pseudodbg(fp, opcode))
goto traps_done;
}
#endif
info.si_code = ILL_ILLOPC;
sig = SIGILL;
strerror = KERN_NOTICE EXC_0x21(KERN_NOTICE);
CHK_DEBUGGER_TRAP_MAYBE();
break;
/* 0x22 - Illegal Instruction Combination, handled here */
case VEC_ILGAL_I:
info.si_code = ILL_ILLPARAOP;
sig = SIGILL;
strerror = KERN_NOTICE EXC_0x22(KERN_NOTICE);
CHK_DEBUGGER_TRAP_MAYBE();
break;
/* 0x23 - Data CPLB protection violation, handled here */
case VEC_CPLB_VL:
info.si_code = ILL_CPLB_VI;
sig = SIGSEGV;
strerror = KERN_NOTICE EXC_0x23(KERN_NOTICE);
CHK_DEBUGGER_TRAP_MAYBE();
break;
/* 0x24 - Data access misaligned, handled here */
case VEC_MISALI_D:
info.si_code = BUS_ADRALN;
sig = SIGBUS;
strerror = KERN_NOTICE EXC_0x24(KERN_NOTICE);
CHK_DEBUGGER_TRAP_MAYBE();
break;
/* 0x25 - Unrecoverable Event, handled here */
case VEC_UNCOV:
info.si_code = ILL_ILLEXCPT;
sig = SIGILL;
strerror = KERN_NOTICE EXC_0x25(KERN_NOTICE);
CHK_DEBUGGER_TRAP_MAYBE();
break;
/* 0x26 - Data CPLB Miss, normal case is handled in _cplb_hdr,
error case is handled here */
case VEC_CPLB_M:
info.si_code = BUS_ADRALN;
sig = SIGBUS;
strerror = KERN_NOTICE EXC_0x26(KERN_NOTICE);
break;
/* 0x27 - Data CPLB Multiple Hits - Linux Trap Zero, handled here */
case VEC_CPLB_MHIT:
info.si_code = ILL_CPLB_MULHIT;
sig = SIGSEGV;
#ifdef CONFIG_DEBUG_HUNT_FOR_ZERO
if (cpu_pda[cpu].dcplb_fault_addr < FIXED_CODE_START)
strerror = KERN_NOTICE "NULL pointer access\n";
else
#endif
strerror = KERN_NOTICE EXC_0x27(KERN_NOTICE);
CHK_DEBUGGER_TRAP_MAYBE();
break;
/* 0x28 - Emulation Watchpoint, handled here */
case VEC_WATCH:
info.si_code = TRAP_WATCHPT;
sig = SIGTRAP;
pr_debug(EXC_0x28(KERN_DEBUG));
CHK_DEBUGGER_TRAP_MAYBE();
/* Check if this is a watchpoint in kernel space */
if (kernel_mode_regs(fp))
goto traps_done;
else
break;
#ifdef CONFIG_BF535
/* 0x29 - Instruction fetch access error (535 only) */
case VEC_ISTRU_VL: /* ADSP-BF535 only (MH) */
info.si_code = BUS_OPFETCH;
sig = SIGBUS;
strerror = KERN_NOTICE "BF535: VEC_ISTRU_VL\n";
CHK_DEBUGGER_TRAP_MAYBE();
break;
#else
/* 0x29 - Reserved, Caught by default */
#endif
/* 0x2A - Instruction fetch misaligned, handled here */
case VEC_MISALI_I:
info.si_code = BUS_ADRALN;
sig = SIGBUS;
strerror = KERN_NOTICE EXC_0x2A(KERN_NOTICE);
CHK_DEBUGGER_TRAP_MAYBE();
break;
/* 0x2B - Instruction CPLB protection violation, handled here */
case VEC_CPLB_I_VL:
info.si_code = ILL_CPLB_VI;
sig = SIGBUS;
strerror = KERN_NOTICE EXC_0x2B(KERN_NOTICE);
CHK_DEBUGGER_TRAP_MAYBE();
break;
/* 0x2C - Instruction CPLB miss, handled in _cplb_hdr */
case VEC_CPLB_I_M:
info.si_code = ILL_CPLB_MISS;
sig = SIGBUS;
strerror = KERN_NOTICE EXC_0x2C(KERN_NOTICE);
break;
/* 0x2D - Instruction CPLB Multiple Hits, handled here */
case VEC_CPLB_I_MHIT:
info.si_code = ILL_CPLB_MULHIT;
sig = SIGSEGV;
#ifdef CONFIG_DEBUG_HUNT_FOR_ZERO
if (cpu_pda[cpu].icplb_fault_addr < FIXED_CODE_START)
strerror = KERN_NOTICE "Jump to NULL address\n";
else
#endif
strerror = KERN_NOTICE EXC_0x2D(KERN_NOTICE);
CHK_DEBUGGER_TRAP_MAYBE();
break;
/* 0x2E - Illegal use of Supervisor Resource, handled here */
case VEC_ILL_RES:
info.si_code = ILL_PRVOPC;
sig = SIGILL;
strerror = KERN_NOTICE EXC_0x2E(KERN_NOTICE);
CHK_DEBUGGER_TRAP_MAYBE();
break;
/* 0x2F - Reserved, Caught by default */
/* 0x30 - Reserved, Caught by default */
/* 0x31 - Reserved, Caught by default */
/* 0x32 - Reserved, Caught by default */
/* 0x33 - Reserved, Caught by default */
/* 0x34 - Reserved, Caught by default */
/* 0x35 - Reserved, Caught by default */
/* 0x36 - Reserved, Caught by default */
/* 0x37 - Reserved, Caught by default */
/* 0x38 - Reserved, Caught by default */
/* 0x39 - Reserved, Caught by default */
/* 0x3A - Reserved, Caught by default */
/* 0x3B - Reserved, Caught by default */
/* 0x3C - Reserved, Caught by default */
/* 0x3D - Reserved, Caught by default */
/* 0x3E - Reserved, Caught by default */
/* 0x3F - Reserved, Caught by default */
case VEC_HWERR:
info.si_code = BUS_ADRALN;
sig = SIGBUS;
switch (fp->seqstat & SEQSTAT_HWERRCAUSE) {
/* System MMR Error */
case (SEQSTAT_HWERRCAUSE_SYSTEM_MMR):
info.si_code = BUS_ADRALN;
sig = SIGBUS;
strerror = KERN_NOTICE HWC_x2(KERN_NOTICE);
break;
/* External Memory Addressing Error */
case (SEQSTAT_HWERRCAUSE_EXTERN_ADDR):
if (ANOMALY_05000310) {
static unsigned long anomaly_rets;
if ((fp->pc >= (L1_CODE_START + L1_CODE_LENGTH - 512)) &&
(fp->pc < (L1_CODE_START + L1_CODE_LENGTH))) {
/*
* A false hardware error will happen while fetching at
* the L1 instruction SRAM boundary. Ignore it.
*/
anomaly_rets = fp->rets;
goto traps_done;
} else if (fp->rets == anomaly_rets) {
/*
* While boundary code returns to a function, at the ret
* point, a new false hardware error might occur too based
* on tests. Ignore it too.
*/
goto traps_done;
} else if ((fp->rets >= (L1_CODE_START + L1_CODE_LENGTH - 512)) &&
(fp->rets < (L1_CODE_START + L1_CODE_LENGTH))) {
/*
* If boundary code calls a function, at the entry point,
* a new false hardware error maybe happen based on tests.
* Ignore it too.
*/
goto traps_done;
} else
anomaly_rets = 0;
}
info.si_code = BUS_ADRERR;
sig = SIGBUS;
strerror = KERN_NOTICE HWC_x3(KERN_NOTICE);
break;
/* Performance Monitor Overflow */
case (SEQSTAT_HWERRCAUSE_PERF_FLOW):
strerror = KERN_NOTICE HWC_x12(KERN_NOTICE);
break;
/* RAISE 5 instruction */
case (SEQSTAT_HWERRCAUSE_RAISE_5):
printk(KERN_NOTICE HWC_x18(KERN_NOTICE));
break;
default: /* Reserved */
printk(KERN_NOTICE HWC_default(KERN_NOTICE));
break;
}
CHK_DEBUGGER_TRAP_MAYBE();
break;
/*
* We should be handling all known exception types above,
* if we get here we hit a reserved one, so panic
*/
default:
info.si_code = ILL_ILLPARAOP;
sig = SIGILL;
verbose_printk(KERN_EMERG "Caught Unhandled Exception, code = %08lx\n",
(fp->seqstat & SEQSTAT_EXCAUSE));
CHK_DEBUGGER_TRAP_MAYBE();
break;
}
BUG_ON(sig == 0);
/* If the fault was caused by a kernel thread, or interrupt handler
* we will kernel panic, so the system reboots.
*/
if (kernel_mode_regs(fp) || (current && !current->mm)) {
console_verbose();
oops_in_progress = 1;
}
if (sig != SIGTRAP) {
if (strerror)
verbose_printk(strerror);
dump_bfin_process(fp);
dump_bfin_mem(fp);
show_regs(fp);
/* Print out the trace buffer if it makes sense */
#ifndef CONFIG_DEBUG_BFIN_NO_KERN_HWTRACE
if (trapnr == VEC_CPLB_I_M || trapnr == VEC_CPLB_M)
verbose_printk(KERN_NOTICE "No trace since you do not have "
"CONFIG_DEBUG_BFIN_NO_KERN_HWTRACE enabled\n\n");
else
#endif
dump_bfin_trace_buffer();
if (oops_in_progress) {
/* Dump the current kernel stack */
verbose_printk(KERN_NOTICE "Kernel Stack\n");
show_stack(current, NULL);
print_modules();
#ifndef CONFIG_ACCESS_CHECK
verbose_printk(KERN_EMERG "Please turn on "
"CONFIG_ACCESS_CHECK\n");
#endif
panic("Kernel exception");
} else {
#ifdef CONFIG_DEBUG_VERBOSE
unsigned long *stack;
/* Dump the user space stack */
stack = (unsigned long *)rdusp();
verbose_printk(KERN_NOTICE "Userspace Stack\n");
show_stack(NULL, stack);
#endif
}
}
#ifdef CONFIG_IPIPE
if (!ipipe_trap_notify(fp->seqstat & 0x3f, fp))
#endif
{
info.si_signo = sig;
info.si_errno = 0;
switch (trapnr) {
case VEC_CPLB_VL:
case VEC_MISALI_D:
case VEC_CPLB_M:
case VEC_CPLB_MHIT:
info.si_addr = (void __user *)cpu_pda[cpu].dcplb_fault_addr;
break;
default:
info.si_addr = (void __user *)fp->pc;
break;
}
force_sig_info(sig, &info, current);
}
if ((ANOMALY_05000461 && trapnr == VEC_HWERR && !access_ok(VERIFY_READ, fp->pc, 8)) ||
(ANOMALY_05000281 && trapnr == VEC_HWERR) ||
(ANOMALY_05000189 && (trapnr == VEC_CPLB_I_VL || trapnr == VEC_CPLB_VL)))
fp->pc = SAFE_USER_INSTRUCTION;
traps_done:
trace_buffer_restore(j);
}
asmlinkage void double_fault_c(struct pt_regs *fp)
{
#ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
int j;
trace_buffer_save(j);
#endif
console_verbose();
oops_in_progress = 1;
#ifdef CONFIG_DEBUG_VERBOSE
printk(KERN_EMERG "Double Fault\n");
#ifdef CONFIG_DEBUG_DOUBLEFAULT_PRINT
if (((long)fp->seqstat & SEQSTAT_EXCAUSE) == VEC_UNCOV) {
unsigned int cpu = raw_smp_processor_id();
char buf[150];
decode_address(buf, cpu_pda[cpu].retx_doublefault);
printk(KERN_EMERG "While handling exception (EXCAUSE = 0x%x) at %s:\n",
(unsigned int)cpu_pda[cpu].seqstat_doublefault & SEQSTAT_EXCAUSE, buf);
decode_address(buf, cpu_pda[cpu].dcplb_doublefault_addr);
printk(KERN_NOTICE " DCPLB_FAULT_ADDR: %s\n", buf);
decode_address(buf, cpu_pda[cpu].icplb_doublefault_addr);
printk(KERN_NOTICE " ICPLB_FAULT_ADDR: %s\n", buf);
decode_address(buf, fp->retx);
printk(KERN_NOTICE "The instruction at %s caused a double exception\n", buf);
} else
#endif
{
dump_bfin_process(fp);
dump_bfin_mem(fp);
show_regs(fp);
dump_bfin_trace_buffer();
}
#endif
panic("Double Fault - unrecoverable event");
}
void panic_cplb_error(int cplb_panic, struct pt_regs *fp)
{
switch (cplb_panic) {
case CPLB_NO_UNLOCKED:
printk(KERN_EMERG "All CPLBs are locked\n");
break;
case CPLB_PROT_VIOL:
return;
case CPLB_NO_ADDR_MATCH:
return;
case CPLB_UNKNOWN_ERR:
printk(KERN_EMERG "Unknown CPLB Exception\n");
break;
}
oops_in_progress = 1;
dump_bfin_process(fp);
dump_bfin_mem(fp);
show_regs(fp);
dump_stack();
panic("Unrecoverable event");
}
#ifdef CONFIG_BUG
int is_valid_bugaddr(unsigned long addr)
{
unsigned int opcode;
if (!get_instruction(&opcode, (unsigned short *)addr))
return 0;
return opcode == BFIN_BUG_OPCODE;
}
#endif
/* stub this out */
#ifndef CONFIG_DEBUG_VERBOSE
void show_regs(struct pt_regs *fp)
{
}
#endif
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