diff options
Diffstat (limited to 'target/linux/ubicom32/files/arch/ubicom32/kernel/traps.c')
| -rw-r--r-- | target/linux/ubicom32/files/arch/ubicom32/kernel/traps.c | 514 |
1 files changed, 514 insertions, 0 deletions
diff --git a/target/linux/ubicom32/files/arch/ubicom32/kernel/traps.c b/target/linux/ubicom32/files/arch/ubicom32/kernel/traps.c new file mode 100644 index 000000000..8cb22e25e --- /dev/null +++ b/target/linux/ubicom32/files/arch/ubicom32/kernel/traps.c @@ -0,0 +1,514 @@ +/* + * arch/ubicom32/kernel/traps.c + * Ubicom32 architecture trap handling support. + * + * (C) Copyright 2009, Ubicom, Inc. + * + * This file is part of the Ubicom32 Linux Kernel Port. + * + * The Ubicom32 Linux Kernel Port 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. + * + * The Ubicom32 Linux Kernel Port is distributed in the hope that it + * will be useful, but WITHOUT ANY WARRANTY; without even the implied + * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See + * the GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with the Ubicom32 Linux Kernel Port. If not, + * see <http://www.gnu.org/licenses/>. + * + * Ubicom32 implementation derived from (with many thanks): + * arch/m68knommu + * arch/blackfin + * arch/parisc + */ + +/* + * Sets up all exception vectors + */ +#include <linux/sched.h> +#include <linux/signal.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/types.h> +#include <linux/a.out.h> +#include <linux/user.h> +#include <linux/string.h> +#include <linux/linkage.h> +#include <linux/init.h> +#include <linux/ptrace.h> +#include <linux/kallsyms.h> +#include <linux/compiler.h> +#include <linux/stacktrace.h> +#include <linux/personality.h> + +#include <asm/uaccess.h> +#include <asm/stacktrace.h> +#include <asm/devtree.h> +#include <asm/setup.h> +#include <asm/fpu.h> +#include <asm/system.h> +#include <asm/traps.h> +#include <asm/pgtable.h> +#include <asm/processor.h> +#include <asm/machdep.h> +#include <asm/siginfo.h> +#include <asm/ip5000.h> +#include <asm/thread.h> + +#define TRAP_MAX_STACK_DEPTH 20 + +/* + * These symbols are filled in by the linker. + */ +extern unsigned long _stext; +extern unsigned long _etext; + +extern unsigned long __ocm_text_run_begin; +extern unsigned long __data_begin; + +extern void show_vmas(struct task_struct *task); + +const char *trap_cause_strings[] = { + /*0*/ "inst address decode error", + /*1*/ "inst sync error", + /*2*/ "inst illegal", + /*3*/ "src1 address decode error", + /*4*/ "dst address decode error", + /*5*/ "src1 alignment error", + /*6*/ "dst alignment error", + /*7*/ "src1 sync error", + /*8*/ "dst sync error", + /*9*/ "DCAPT error", + /*10*/ "inst range error", + /*11*/ "src1 range error", + /*12*/ "dst range error", +}; + +/* + * The device tree trap node definition. + */ +struct trapnode { + struct devtree_node dn; + unsigned int intthread; +}; + +static struct trapnode *tn;; + +/* + * trap_interrupt_handler() + * Software Interrupt to ensure that a trap is serviced. + */ +static irqreturn_t trap_interrupt_handler(int irq, void *dummy) +{ + /* Do Nothing */ + return IRQ_HANDLED; +} + +/* + * Data used by setup_irq for the timer. + */ +static struct irqaction trap_irq = { + .name = "trap", + .flags = IRQF_DISABLED, + .handler = trap_interrupt_handler, +}; + +/* + * trap_cause_to_str() + * Convert a trap_cause into a series of printk + */ +static void trap_cause_to_str(long status) +{ + int bit; + + if ((status & ((1 << TRAP_CAUSE_TOTAL) - 1)) == 0) { + printk(KERN_NOTICE "decode: UNKNOWN CAUSES\n"); + return; + } + + for (bit = 0; bit < TRAP_CAUSE_TOTAL; bit++) { + if (status & (1 << bit)) { + printk(KERN_NOTICE "\tdecode: %08x %s\n", + 1 << bit, trap_cause_strings[bit]); + } + } +} + +/* + * trap_print_information() + * Print the cause of the trap and additional info. + */ +static void trap_print_information(const char *str, struct pt_regs *regs) +{ + printk(KERN_WARNING "\n"); + + if (current) { + printk(KERN_WARNING "Process %s (pid: %d)\n", + current->comm, current->pid); + } + + if (current && current->mm) { + printk(KERN_NOTICE "text = 0x%p-0x%p data = 0x%p-0x%p\n" + KERN_NOTICE "bss = 0x%p-0x%p user-stack = 0x%p\n" + KERN_NOTICE "\n", + (void *)current->mm->start_code, + (void *)current->mm->end_code, + (void *)current->mm->start_data, + (void *)current->mm->end_data, + (void *)current->mm->end_data, + (void *)current->mm->brk, + (void *)current->mm->start_stack); + } + + printk(KERN_WARNING "%s: Causes: 0x%08x\n", str, + (unsigned int)regs->trap_cause); + trap_cause_to_str(regs->trap_cause); + show_regs(regs); + show_stack(NULL, (unsigned long *)regs->an[7]); + printk(KERN_NOTICE "--- End Trap --- \n"); +} + +/* + * dump_stack() + * Dump the stack of the current task. + */ +void dump_stack(void) +{ + show_stack(NULL, NULL); +} +EXPORT_SYMBOL(dump_stack); + +/* + * show_stack() + * Print out information from the current stack. + */ +void show_stack(struct task_struct *task, unsigned long *sp) +{ + /* + * Allocate just enough entries on the stack. + */ + unsigned int calls[TRAP_MAX_STACK_DEPTH]; + unsigned long code_start; + unsigned long code_end; + unsigned long ocm_code_start = (unsigned long)&__ocm_text_run_begin; + unsigned long ocm_code_end = (unsigned long)&__data_begin; + unsigned long stack_end = (unsigned long)(current->stack + THREAD_SIZE - 8); + unsigned long stack = (unsigned long)sp; + int kernel_stack = 1; + + processor_dram(&code_start, &code_end); + + /* + * Which task are we talking about. + */ + if (!task) { + task = current; + } + + /* + * Find the stack for the task if one was not specified. Otherwise + * use the specified stack. + */ + if (!stack) { + if (task != current) { + stack = task->thread.sp; + stack_end = (unsigned long)task->stack + THREAD_SIZE - 8; + } else { + asm volatile ( + "move.4 %0, SP \n\t" + : "=r" (stack) + ); + } + } + + printk(KERN_NOTICE "Starting backtrace: PID %d '%s'\n", + task->pid, task->comm); + + /* + * We do 2 passes the first pass is Kernel stack is the second + * User stack. + */ + while (kernel_stack) { + unsigned long *handle; + unsigned int i, idx = 0; + struct pt_regs *pt = task_pt_regs(task); + + /* + * If the task is in user mode, reset the start + * and end values for text. + */ + if (__user_mode(stack)) { + if (!(task->personality & FDPIC_FUNCPTRS)) { + printk(KERN_NOTICE " User Stack:\n"); + code_start = task->mm->start_code; + code_end = task->mm->end_code; + } else { + printk(KERN_NOTICE " User Stack (fdpic):\n"); + show_vmas(task); + } + stack_end = task->mm->start_stack; + ocm_code_end = ocm_code_start = 0; + kernel_stack = 0; + } else { + printk(KERN_NOTICE " Kernel Stack:\n"); + } + + /* + * Collect the stack back trace information. + */ + printk(" code[0x%lx-0x%lx]", code_start, code_end); + if (ocm_code_start) { + printk(" ocm_code[0x%lx-0x%lx]", + ocm_code_start, ocm_code_end); + } + printk("\n stack[0x%lx-0x%lx]\n", stack, stack_end); + + handle = (unsigned long*)stack; + while (idx < TRAP_MAX_STACK_DEPTH) { + calls[idx] = stacktrace_iterate(&handle, + code_start, code_end, + ocm_code_start, ocm_code_end, + (unsigned long)stack, stack_end); + if (calls[idx] == 0) { + break; + } + idx++; + } + + /* + * Now print out the data. + */ + printk(KERN_NOTICE " CALL && CALLI on stack:"); + for (i = 0; i < idx; i++) { + printk("%s0x%x, ", (i & 0x3) == 0 ? "\n " : "", + calls[i]); + } + printk(idx == TRAP_MAX_STACK_DEPTH ? "...\n" : "\n"); + + /* + * If we are doing user stack we are done + */ + if (!kernel_stack) { + break; + } + + /* + * Does this kernel stack have a mm (i.e. is it user) + */ + if (!task->mm) { + printk("No mm for userspace stack.\n"); + break; + } + /* + * Get the user-mode stack (if any) + */ + stack = pt->an[7]; + printk(KERN_NOTICE "Userspace stack at 0x%lx frame type %d\n", + stack, (int)pt->frame_type); + if (!__user_mode(stack)) { + break; + } + } +} + +/* + * die_if_kernel() + * Determine if we are in kernel mode and if so print stuff out and die. + */ +void die_if_kernel(char *str, struct pt_regs *regs, long trap_cause) +{ + unsigned int s3value; + + if (user_mode(regs)) { + return; + } + + console_verbose(); + trap_print_information(str, regs); + + /* + * If the debugger is attached via the hardware mailbox protocol, + * go into an infinite loop and the debugger will figure things out. + */ + asm volatile ( + "move.4 %0, scratchpad3" + : "=r" (s3value) + ); + if (s3value) { + asm volatile("1: jmpt.t 1b"); + } + + /* + * Set the debug taint value. + */ + add_taint(TAINT_DIE); + do_exit(SIGSEGV); +} + +/* + * trap_handler() + * Handle traps. + * + * Traps are treated as interrupts and registered with the LDSR. When + * the LDSR takes the interrupt, it will determine if a trap has occurred + * and service the trap prior to servicing the interrupt. + * + * This function is directly called by the LDSR. + */ +void trap_handler(int irq, struct pt_regs *regs) +{ + int sig = SIGSEGV; + siginfo_t info; + unsigned int trap_cause = regs->trap_cause; + + BUG_ON(!irqs_disabled()); + + /* + * test if in kernel and die. + */ + die_if_kernel("Kernel Trap", regs, trap_cause); + + /* + * User process problem, setup a signal for this process + */ + if ((trap_cause & (1 << TRAP_CAUSE_DST_RANGE_ERR)) || + (trap_cause & (1 << TRAP_CAUSE_SRC1_RANGE_ERR)) || + (trap_cause & (1 << TRAP_CAUSE_I_RANGE_ERR))) { + sig = SIGSEGV; + info.si_code = SEGV_MAPERR; + } else if ((trap_cause & (1 << TRAP_CAUSE_DST_MISALIGNED)) || + (trap_cause & (1 << TRAP_CAUSE_SRC1_MISALIGNED))) { + sig = SIGBUS; + info.si_code = BUS_ADRALN; + } else if ((trap_cause & (1 << TRAP_CAUSE_DST_DECODE_ERR)) || + (trap_cause & (1 << TRAP_CAUSE_SRC1_DECODE_ERR))) { + sig = SIGILL; + info.si_code = ILL_ILLOPN; + } else if ((trap_cause & (1 << TRAP_CAUSE_ILLEGAL_INST))) { + /* + * Check for software break point and if found signal trap + * not illegal instruction. + */ + unsigned long instruction; + if (between(regs->pc, KERNELSTART, memory_end) && + (regs->pc & 3) == 0 && + get_user(instruction, (unsigned long *)regs->pc) == 0) { + + /* + * This used to be 0xaabbccdd but it turns out + * that is now valid in ubicom32v4 isa so we + * have switched to 0xfabbccdd + */ + if ((instruction == 0xfabbccdd) || + (instruction == 0xaabbccdd)) { + sig = SIGTRAP; + info.si_code = TRAP_BRKPT; + goto send_signal; + } + } + sig = SIGILL; + info.si_code = ILL_ILLOPC; + } else if ((trap_cause & (1 << TRAP_CAUSE_I_DECODE_ERR))) { + sig = SIGILL; + info.si_code = ILL_ILLOPC; + } else if ((trap_cause & (1 << TRAP_CAUSE_DCAPT))) { + sig = SIGTRAP; + info.si_code = TRAP_TRACE; + } + + /* + * Print a trap information block to the console, do not + * print this above the case because we don't want it + * printed for software break points. + */ + trap_print_information("User Trap", regs); + +send_signal: + + force_sig_info(sig, &info, current); + + /* + * Interrupts are disabled, re-enable them now. + */ + if (!irqs_disabled()) { + printk(KERN_EMERG "interrupts enabled on exit, irq=%d, regs=%p", + irq, regs); + BUG(); + } +} + +/* + * trap_init_interrupt() + * We need a 2nd trap handling init that will occur after init_IRQ(). + */ +void __init trap_init_interrupt(void) +{ + int err; + unsigned char tirq; + struct devtree_node *dn = (struct devtree_node *)tn; + + /* + * Now setup the Software IRQ so that if a trap occurs the LDSR + * is started. The irq is there just to "force" the LDSR to run. + */ + if (!tn) { + printk(KERN_WARNING "trap_init_interrupt skipped.\n"); + return; + } + + err = devtree_irq(dn, NULL, &tirq); + if (err) { + printk(KERN_WARNING "error obtaining trap irq value: %d\n", + err); + return; + } + + if (tirq == DEVTREE_IRQ_NONE) { + printk(KERN_WARNING "trap irq not available: %d\n", tirq); + return; + } + + err = setup_irq(tirq, &trap_irq); + if (err) { + printk(KERN_WARNING "trap irq setup failed: %d\n", err); + return; + } + + /* + * Let ultra know which thread is handling the traps and + * what the interrupt to use is. + */ + tn->intthread = ldsr_get_threadid(); + + /* + * Tell the LDSR about our IRQ so that it will unsuspend + * if one occurs while waiting for the per thread lock. + */ + ldsr_set_trap_irq(tirq); +} + +/* + * trap_init() + * init trap handling + * + * Trap handling is done through the ldsr. Every time an interrupt + * occurs, the LDSR looks for threads that are listed in the TRAP + * register and forces a call to the trap handler. + */ +void __init trap_init(void) +{ + /* + * If we do not have a trap node in the device tree, we leave the fault + * handling to the underlying hardware. + */ + tn = (struct trapnode *)devtree_find_node("traps"); + if (!tn) { + printk(KERN_WARNING "traps are not handled by linux\n"); + return; + } +} |