diff options
Diffstat (limited to 'arch/hexagon/kernel/traps.c')
| -rw-r--r-- | arch/hexagon/kernel/traps.c | 456 |
1 files changed, 456 insertions, 0 deletions
diff --git a/arch/hexagon/kernel/traps.c b/arch/hexagon/kernel/traps.c new file mode 100644 index 000000000..110dab152 --- /dev/null +++ b/arch/hexagon/kernel/traps.c @@ -0,0 +1,456 @@ +/* + * Kernel traps/events for Hexagon processor + * + * Copyright (c) 2010-2014, The Linux Foundation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program 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 this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/module.h> +#include <linux/kallsyms.h> +#include <linux/kdebug.h> +#include <linux/syscalls.h> +#include <linux/signal.h> +#include <linux/tracehook.h> +#include <asm/traps.h> +#include <asm/vm_fault.h> +#include <asm/syscall.h> +#include <asm/registers.h> +#include <asm/unistd.h> +#include <asm/sections.h> +#ifdef CONFIG_KGDB +# include <linux/kgdb.h> +#endif + +#define TRAP_SYSCALL 1 +#define TRAP_DEBUG 0xdb + +void __init trap_init(void) +{ +} + +#ifdef CONFIG_GENERIC_BUG +/* Maybe should resemble arch/sh/kernel/traps.c ?? */ +int is_valid_bugaddr(unsigned long addr) +{ + return 1; +} +#endif /* CONFIG_GENERIC_BUG */ + +static const char *ex_name(int ex) +{ + switch (ex) { + case HVM_GE_C_XPROT: + case HVM_GE_C_XUSER: + return "Execute protection fault"; + case HVM_GE_C_RPROT: + case HVM_GE_C_RUSER: + return "Read protection fault"; + case HVM_GE_C_WPROT: + case HVM_GE_C_WUSER: + return "Write protection fault"; + case HVM_GE_C_XMAL: + return "Misaligned instruction"; + case HVM_GE_C_WREG: + return "Multiple writes to same register in packet"; + case HVM_GE_C_PCAL: + return "Program counter values that are not properly aligned"; + case HVM_GE_C_RMAL: + return "Misaligned data load"; + case HVM_GE_C_WMAL: + return "Misaligned data store"; + case HVM_GE_C_INVI: + case HVM_GE_C_PRIVI: + return "Illegal instruction"; + case HVM_GE_C_BUS: + return "Precise bus error"; + case HVM_GE_C_CACHE: + return "Cache error"; + + case 0xdb: + return "Debugger trap"; + + default: + return "Unrecognized exception"; + } +} + +static void do_show_stack(struct task_struct *task, unsigned long *fp, + unsigned long ip) +{ + int kstack_depth_to_print = 24; + unsigned long offset, size; + const char *name = NULL; + unsigned long *newfp; + unsigned long low, high; + char tmpstr[128]; + char *modname; + int i; + + if (task == NULL) + task = current; + + printk(KERN_INFO "CPU#%d, %s/%d, Call Trace:\n", + raw_smp_processor_id(), task->comm, + task_pid_nr(task)); + + if (fp == NULL) { + if (task == current) { + asm("%0 = r30" : "=r" (fp)); + } else { + fp = (unsigned long *) + ((struct hexagon_switch_stack *) + task->thread.switch_sp)->fp; + } + } + + if ((((unsigned long) fp) & 0x3) || ((unsigned long) fp < 0x1000)) { + printk(KERN_INFO "-- Corrupt frame pointer %p\n", fp); + return; + } + + /* Saved link reg is one word above FP */ + if (!ip) + ip = *(fp+1); + + /* Expect kernel stack to be in-bounds */ + low = (unsigned long)task_stack_page(task); + high = low + THREAD_SIZE - 8; + low += sizeof(struct thread_info); + + for (i = 0; i < kstack_depth_to_print; i++) { + + name = kallsyms_lookup(ip, &size, &offset, &modname, tmpstr); + + printk(KERN_INFO "[%p] 0x%lx: %s + 0x%lx", fp, ip, name, + offset); + if (((unsigned long) fp < low) || (high < (unsigned long) fp)) + printk(KERN_CONT " (FP out of bounds!)"); + if (modname) + printk(KERN_CONT " [%s] ", modname); + printk(KERN_CONT "\n"); + + newfp = (unsigned long *) *fp; + + if (((unsigned long) newfp) & 0x3) { + printk(KERN_INFO "-- Corrupt frame pointer %p\n", + newfp); + break; + } + + /* Attempt to continue past exception. */ + if (0 == newfp) { + struct pt_regs *regs = (struct pt_regs *) (((void *)fp) + + 8); + + if (regs->syscall_nr != -1) { + printk(KERN_INFO "-- trap0 -- syscall_nr: %ld", + regs->syscall_nr); + printk(KERN_CONT " psp: %lx elr: %lx\n", + pt_psp(regs), pt_elr(regs)); + break; + } else { + /* really want to see more ... */ + kstack_depth_to_print += 6; + printk(KERN_INFO "-- %s (0x%lx) badva: %lx\n", + ex_name(pt_cause(regs)), pt_cause(regs), + pt_badva(regs)); + } + + newfp = (unsigned long *) regs->r30; + ip = pt_elr(regs); + } else { + ip = *(newfp + 1); + } + + /* If link reg is null, we are done. */ + if (ip == 0x0) + break; + + /* If newfp isn't larger, we're tracing garbage. */ + if (newfp > fp) + fp = newfp; + else + break; + } +} + +void show_stack(struct task_struct *task, unsigned long *fp) +{ + /* Saved link reg is one word above FP */ + do_show_stack(task, fp, 0); +} + +int die(const char *str, struct pt_regs *regs, long err) +{ + static struct { + spinlock_t lock; + int counter; + } die = { + .lock = __SPIN_LOCK_UNLOCKED(die.lock), + .counter = 0 + }; + + console_verbose(); + oops_enter(); + + spin_lock_irq(&die.lock); + bust_spinlocks(1); + printk(KERN_EMERG "Oops: %s[#%d]:\n", str, ++die.counter); + + if (notify_die(DIE_OOPS, str, regs, err, pt_cause(regs), SIGSEGV) == + NOTIFY_STOP) + return 1; + + print_modules(); + show_regs(regs); + do_show_stack(current, ®s->r30, pt_elr(regs)); + + bust_spinlocks(0); + add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); + + spin_unlock_irq(&die.lock); + + if (in_interrupt()) + panic("Fatal exception in interrupt"); + + if (panic_on_oops) + panic("Fatal exception"); + + oops_exit(); + do_exit(err); + return 0; +} + +int die_if_kernel(char *str, struct pt_regs *regs, long err) +{ + if (!user_mode(regs)) + return die(str, regs, err); + else + return 0; +} + +/* + * It's not clear that misaligned fetches are ever recoverable. + */ +static void misaligned_instruction(struct pt_regs *regs) +{ + die_if_kernel("Misaligned Instruction", regs, 0); + force_sig(SIGBUS, current); +} + +/* + * Misaligned loads and stores, on the other hand, can be + * emulated, and probably should be, some day. But for now + * they will be considered fatal. + */ +static void misaligned_data_load(struct pt_regs *regs) +{ + die_if_kernel("Misaligned Data Load", regs, 0); + force_sig(SIGBUS, current); +} + +static void misaligned_data_store(struct pt_regs *regs) +{ + die_if_kernel("Misaligned Data Store", regs, 0); + force_sig(SIGBUS, current); +} + +static void illegal_instruction(struct pt_regs *regs) +{ + die_if_kernel("Illegal Instruction", regs, 0); + force_sig(SIGILL, current); +} + +/* + * Precise bus errors may be recoverable with a a retry, + * but for now, treat them as irrecoverable. + */ +static void precise_bus_error(struct pt_regs *regs) +{ + die_if_kernel("Precise Bus Error", regs, 0); + force_sig(SIGBUS, current); +} + +/* + * If anything is to be done here other than panic, + * it will probably be complex and migrate to another + * source module. For now, just die. + */ +static void cache_error(struct pt_regs *regs) +{ + die("Cache Error", regs, 0); +} + +/* + * General exception handler + */ +void do_genex(struct pt_regs *regs) +{ + /* + * Decode Cause and Dispatch + */ + switch (pt_cause(regs)) { + case HVM_GE_C_XPROT: + case HVM_GE_C_XUSER: + execute_protection_fault(regs); + break; + case HVM_GE_C_RPROT: + case HVM_GE_C_RUSER: + read_protection_fault(regs); + break; + case HVM_GE_C_WPROT: + case HVM_GE_C_WUSER: + write_protection_fault(regs); + break; + case HVM_GE_C_XMAL: + misaligned_instruction(regs); + break; + case HVM_GE_C_WREG: + illegal_instruction(regs); + break; + case HVM_GE_C_PCAL: + misaligned_instruction(regs); + break; + case HVM_GE_C_RMAL: + misaligned_data_load(regs); + break; + case HVM_GE_C_WMAL: + misaligned_data_store(regs); + break; + case HVM_GE_C_INVI: + case HVM_GE_C_PRIVI: + illegal_instruction(regs); + break; + case HVM_GE_C_BUS: + precise_bus_error(regs); + break; + case HVM_GE_C_CACHE: + cache_error(regs); + break; + default: + /* Halt and catch fire */ + panic("Unrecognized exception 0x%lx\n", pt_cause(regs)); + break; + } +} + +/* Indirect system call dispatch */ +long sys_syscall(void) +{ + printk(KERN_ERR "sys_syscall invoked!\n"); + return -ENOSYS; +} + +void do_trap0(struct pt_regs *regs) +{ + syscall_fn syscall; + + switch (pt_cause(regs)) { + case TRAP_SYSCALL: + /* System call is trap0 #1 */ + + /* allow strace to catch syscall args */ + if (unlikely(test_thread_flag(TIF_SYSCALL_TRACE) && + tracehook_report_syscall_entry(regs))) + return; /* return -ENOSYS somewhere? */ + + /* Interrupts should be re-enabled for syscall processing */ + __vmsetie(VM_INT_ENABLE); + + /* + * System call number is in r6, arguments in r0..r5. + * Fortunately, no Linux syscall has more than 6 arguments, + * and Hexagon ABI passes first 6 arguments in registers. + * 64-bit arguments are passed in odd/even register pairs. + * Fortunately, we have no system calls that take more + * than three arguments with more than one 64-bit value. + * Should that change, we'd need to redesign to copy + * between user and kernel stacks. + */ + regs->syscall_nr = regs->r06; + + /* + * GPR R0 carries the first parameter, and is also used + * to report the return value. We need a backup of + * the user's value in case we need to do a late restart + * of the system call. + */ + regs->restart_r0 = regs->r00; + + if ((unsigned long) regs->syscall_nr >= __NR_syscalls) { + regs->r00 = -1; + } else { + syscall = (syscall_fn) + (sys_call_table[regs->syscall_nr]); + regs->r00 = syscall(regs->r00, regs->r01, + regs->r02, regs->r03, + regs->r04, regs->r05); + } + + /* allow strace to get the syscall return state */ + if (unlikely(test_thread_flag(TIF_SYSCALL_TRACE))) + tracehook_report_syscall_exit(regs, 0); + + break; + case TRAP_DEBUG: + /* Trap0 0xdb is debug breakpoint */ + if (user_mode(regs)) { + struct siginfo info; + + info.si_signo = SIGTRAP; + info.si_errno = 0; + /* + * Some architecures add some per-thread state + * to distinguish between breakpoint traps and + * trace traps. We may want to do that, and + * set the si_code value appropriately, or we + * may want to use a different trap0 flavor. + */ + info.si_code = TRAP_BRKPT; + info.si_addr = (void __user *) pt_elr(regs); + force_sig_info(SIGTRAP, &info, current); + } else { +#ifdef CONFIG_KGDB + kgdb_handle_exception(pt_cause(regs), SIGTRAP, + TRAP_BRKPT, regs); +#endif + } + break; + } + /* Ignore other trap0 codes for now, especially 0 (Angel calls) */ +} + +/* + * Machine check exception handler + */ +void do_machcheck(struct pt_regs *regs) +{ + /* Halt and catch fire */ + __vmstop(); +} + +/* + * Treat this like the old 0xdb trap. + */ + +void do_debug_exception(struct pt_regs *regs) +{ + regs->hvmer.vmest &= ~HVM_VMEST_CAUSE_MSK; + regs->hvmer.vmest |= (TRAP_DEBUG << HVM_VMEST_CAUSE_SFT); + do_trap0(regs); +} |