cregit-Linux how code gets into the kernel

Release 4.14 arch/blackfin/kernel/traps.c

/*
 * 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(); }

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Bryan Wu19100.00%1100.00%
Total19100.00%1100.00%


static int kernel_mode_regs(struct pt_regs *regs) { return regs->ipend & 0xffc0; }

Contributors

PersonTokensPropCommitsCommitProp
Robin Getz1794.44%150.00%
Bryan Wu15.56%150.00%
Total18100.00%2100.00%


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); }

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PersonTokensPropCommitsCommitProp
Robin Getz130892.57%1571.43%
Bryan Wu916.44%14.76%
Mike Frysinger120.85%314.29%
Lucas De Marchi10.07%14.76%
Graf Yang10.07%14.76%
Total1413100.00%21100.00%


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"); }

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PersonTokensPropCommitsCommitProp
Robin Getz15379.27%125.00%
Bryan Wu189.33%125.00%
Graf Yang115.70%125.00%
Mike Frysinger115.70%125.00%
Total193100.00%4100.00%


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"); }

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PersonTokensPropCommitsCommitProp
Bryan Wu5979.73%125.00%
Mike Frysinger1114.86%250.00%
Robin Getz45.41%125.00%
Total74100.00%4100.00%

#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; }

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Robin Getz37100.00%2100.00%
Total37100.00%2100.00%

#endif /* stub this out */ #ifndef CONFIG_DEBUG_VERBOSE
void show_regs(struct pt_regs *fp) { }

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Robin Getz9100.00%1100.00%
Total9100.00%1100.00%

#endif

Overall Contributors

PersonTokensPropCommitsCommitProp
Robin Getz162785.27%1954.29%
Bryan Wu20910.95%12.86%
Mike Frysinger462.41%822.86%
Graf Yang120.63%12.86%
Ingo Molnar60.31%25.71%
David Howells30.16%12.86%
Richard Weinberger30.16%12.86%
Lucas De Marchi10.05%12.86%
Sonic Zhang10.05%12.86%
Total1908100.00%35100.00%
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