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-rw-r--r--arch/sh/kernel/traps.c712
1 files changed, 712 insertions, 0 deletions
diff --git a/arch/sh/kernel/traps.c b/arch/sh/kernel/traps.c
new file mode 100644
index 000000000000..7eb06719d844
--- /dev/null
+++ b/arch/sh/kernel/traps.c
@@ -0,0 +1,712 @@
+/* $Id: traps.c,v 1.17 2004/05/02 01:46:30 sugioka Exp $
+ *
+ * linux/arch/sh/traps.c
+ *
+ * SuperH version: Copyright (C) 1999 Niibe Yutaka
+ * Copyright (C) 2000 Philipp Rumpf
+ * Copyright (C) 2000 David Howells
+ * Copyright (C) 2002, 2003 Paul Mundt
+ */
+
+/*
+ * 'Traps.c' handles hardware traps and faults after we have saved some
+ * state in 'entry.S'.
+ */
+#include <linux/config.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/timer.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/atomic.h>
+#include <asm/processor.h>
+#include <asm/sections.h>
+
+#ifdef CONFIG_SH_KGDB
+#include <asm/kgdb.h>
+#define CHK_REMOTE_DEBUG(regs) \
+{ \
+ if ((kgdb_debug_hook != (kgdb_debug_hook_t *) NULL) && (!user_mode(regs))) \
+ { \
+ (*kgdb_debug_hook)(regs); \
+ } \
+}
+#else
+#define CHK_REMOTE_DEBUG(regs)
+#endif
+
+#define DO_ERROR(trapnr, signr, str, name, tsk) \
+asmlinkage void do_##name(unsigned long r4, unsigned long r5, \
+ unsigned long r6, unsigned long r7, \
+ struct pt_regs regs) \
+{ \
+ unsigned long error_code; \
+ \
+ /* Check if it's a DSP instruction */ \
+ if (is_dsp_inst(&regs)) { \
+ /* Enable DSP mode, and restart instruction. */ \
+ regs.sr |= SR_DSP; \
+ return; \
+ } \
+ \
+ asm volatile("stc r2_bank, %0": "=r" (error_code)); \
+ local_irq_enable(); \
+ tsk->thread.error_code = error_code; \
+ tsk->thread.trap_no = trapnr; \
+ CHK_REMOTE_DEBUG(&regs); \
+ force_sig(signr, tsk); \
+ die_if_no_fixup(str,&regs,error_code); \
+}
+
+#ifdef CONFIG_CPU_SH2
+#define TRAP_RESERVED_INST 4
+#define TRAP_ILLEGAL_SLOT_INST 6
+#else
+#define TRAP_RESERVED_INST 12
+#define TRAP_ILLEGAL_SLOT_INST 13
+#endif
+
+/*
+ * These constants are for searching for possible module text
+ * segments. VMALLOC_OFFSET comes from mm/vmalloc.c; MODULE_RANGE is
+ * a guess of how much space is likely to be vmalloced.
+ */
+#define VMALLOC_OFFSET (8*1024*1024)
+#define MODULE_RANGE (8*1024*1024)
+
+spinlock_t die_lock;
+
+void die(const char * str, struct pt_regs * regs, long err)
+{
+ static int die_counter;
+
+ console_verbose();
+ spin_lock_irq(&die_lock);
+ printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
+ CHK_REMOTE_DEBUG(regs);
+ show_regs(regs);
+ spin_unlock_irq(&die_lock);
+ do_exit(SIGSEGV);
+}
+
+static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err)
+{
+ if (!user_mode(regs))
+ die(str, regs, err);
+}
+
+static int handle_unaligned_notify_count = 10;
+
+/*
+ * try and fix up kernelspace address errors
+ * - userspace errors just cause EFAULT to be returned, resulting in SEGV
+ * - kernel/userspace interfaces cause a jump to an appropriate handler
+ * - other kernel errors are bad
+ * - return 0 if fixed-up, -EFAULT if non-fatal (to the kernel) fault
+ */
+static int die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
+{
+ if (!user_mode(regs))
+ {
+ const struct exception_table_entry *fixup;
+ fixup = search_exception_tables(regs->pc);
+ if (fixup) {
+ regs->pc = fixup->fixup;
+ return 0;
+ }
+ die(str, regs, err);
+ }
+ return -EFAULT;
+}
+
+/*
+ * handle an instruction that does an unaligned memory access by emulating the
+ * desired behaviour
+ * - note that PC _may not_ point to the faulting instruction
+ * (if that instruction is in a branch delay slot)
+ * - return 0 if emulation okay, -EFAULT on existential error
+ */
+static int handle_unaligned_ins(u16 instruction, struct pt_regs *regs)
+{
+ int ret, index, count;
+ unsigned long *rm, *rn;
+ unsigned char *src, *dst;
+
+ index = (instruction>>8)&15; /* 0x0F00 */
+ rn = &regs->regs[index];
+
+ index = (instruction>>4)&15; /* 0x00F0 */
+ rm = &regs->regs[index];
+
+ count = 1<<(instruction&3);
+
+ ret = -EFAULT;
+ switch (instruction>>12) {
+ case 0: /* mov.[bwl] to/from memory via r0+rn */
+ if (instruction & 8) {
+ /* from memory */
+ src = (unsigned char*) *rm;
+ src += regs->regs[0];
+ dst = (unsigned char*) rn;
+ *(unsigned long*)dst = 0;
+
+#ifdef __LITTLE_ENDIAN__
+ if (copy_from_user(dst, src, count))
+ goto fetch_fault;
+
+ if ((count == 2) && dst[1] & 0x80) {
+ dst[2] = 0xff;
+ dst[3] = 0xff;
+ }
+#else
+ dst += 4-count;
+
+ if (__copy_user(dst, src, count))
+ goto fetch_fault;
+
+ if ((count == 2) && dst[2] & 0x80) {
+ dst[0] = 0xff;
+ dst[1] = 0xff;
+ }
+#endif
+ } else {
+ /* to memory */
+ src = (unsigned char*) rm;
+#if !defined(__LITTLE_ENDIAN__)
+ src += 4-count;
+#endif
+ dst = (unsigned char*) *rn;
+ dst += regs->regs[0];
+
+ if (copy_to_user(dst, src, count))
+ goto fetch_fault;
+ }
+ ret = 0;
+ break;
+
+ case 1: /* mov.l Rm,@(disp,Rn) */
+ src = (unsigned char*) rm;
+ dst = (unsigned char*) *rn;
+ dst += (instruction&0x000F)<<2;
+
+ if (copy_to_user(dst,src,4))
+ goto fetch_fault;
+ ret = 0;
+ break;
+
+ case 2: /* mov.[bwl] to memory, possibly with pre-decrement */
+ if (instruction & 4)
+ *rn -= count;
+ src = (unsigned char*) rm;
+ dst = (unsigned char*) *rn;
+#if !defined(__LITTLE_ENDIAN__)
+ src += 4-count;
+#endif
+ if (copy_to_user(dst, src, count))
+ goto fetch_fault;
+ ret = 0;
+ break;
+
+ case 5: /* mov.l @(disp,Rm),Rn */
+ src = (unsigned char*) *rm;
+ src += (instruction&0x000F)<<2;
+ dst = (unsigned char*) rn;
+ *(unsigned long*)dst = 0;
+
+ if (copy_from_user(dst,src,4))
+ goto fetch_fault;
+ ret = 0;
+ break;
+
+ case 6: /* mov.[bwl] from memory, possibly with post-increment */
+ src = (unsigned char*) *rm;
+ if (instruction & 4)
+ *rm += count;
+ dst = (unsigned char*) rn;
+ *(unsigned long*)dst = 0;
+
+#ifdef __LITTLE_ENDIAN__
+ if (copy_from_user(dst, src, count))
+ goto fetch_fault;
+
+ if ((count == 2) && dst[1] & 0x80) {
+ dst[2] = 0xff;
+ dst[3] = 0xff;
+ }
+#else
+ dst += 4-count;
+
+ if (copy_from_user(dst, src, count))
+ goto fetch_fault;
+
+ if ((count == 2) && dst[2] & 0x80) {
+ dst[0] = 0xff;
+ dst[1] = 0xff;
+ }
+#endif
+ ret = 0;
+ break;
+
+ case 8:
+ switch ((instruction&0xFF00)>>8) {
+ case 0x81: /* mov.w R0,@(disp,Rn) */
+ src = (unsigned char*) &regs->regs[0];
+#if !defined(__LITTLE_ENDIAN__)
+ src += 2;
+#endif
+ dst = (unsigned char*) *rm; /* called Rn in the spec */
+ dst += (instruction&0x000F)<<1;
+
+ if (copy_to_user(dst, src, 2))
+ goto fetch_fault;
+ ret = 0;
+ break;
+
+ case 0x85: /* mov.w @(disp,Rm),R0 */
+ src = (unsigned char*) *rm;
+ src += (instruction&0x000F)<<1;
+ dst = (unsigned char*) &regs->regs[0];
+ *(unsigned long*)dst = 0;
+
+#if !defined(__LITTLE_ENDIAN__)
+ dst += 2;
+#endif
+
+ if (copy_from_user(dst, src, 2))
+ goto fetch_fault;
+
+#ifdef __LITTLE_ENDIAN__
+ if (dst[1] & 0x80) {
+ dst[2] = 0xff;
+ dst[3] = 0xff;
+ }
+#else
+ if (dst[2] & 0x80) {
+ dst[0] = 0xff;
+ dst[1] = 0xff;
+ }
+#endif
+ ret = 0;
+ break;
+ }
+ break;
+ }
+ return ret;
+
+ fetch_fault:
+ /* Argh. Address not only misaligned but also non-existent.
+ * Raise an EFAULT and see if it's trapped
+ */
+ return die_if_no_fixup("Fault in unaligned fixup", regs, 0);
+}
+
+/*
+ * emulate the instruction in the delay slot
+ * - fetches the instruction from PC+2
+ */
+static inline int handle_unaligned_delayslot(struct pt_regs *regs)
+{
+ u16 instruction;
+
+ if (copy_from_user(&instruction, (u16 *)(regs->pc+2), 2)) {
+ /* the instruction-fetch faulted */
+ if (user_mode(regs))
+ return -EFAULT;
+
+ /* kernel */
+ die("delay-slot-insn faulting in handle_unaligned_delayslot", regs, 0);
+ }
+
+ return handle_unaligned_ins(instruction,regs);
+}
+
+/*
+ * handle an instruction that does an unaligned memory access
+ * - have to be careful of branch delay-slot instructions that fault
+ * SH3:
+ * - if the branch would be taken PC points to the branch
+ * - if the branch would not be taken, PC points to delay-slot
+ * SH4:
+ * - PC always points to delayed branch
+ * - return 0 if handled, -EFAULT if failed (may not return if in kernel)
+ */
+
+/* Macros to determine offset from current PC for branch instructions */
+/* Explicit type coercion is used to force sign extension where needed */
+#define SH_PC_8BIT_OFFSET(instr) ((((signed char)(instr))*2) + 4)
+#define SH_PC_12BIT_OFFSET(instr) ((((signed short)(instr<<4))>>3) + 4)
+
+static int handle_unaligned_access(u16 instruction, struct pt_regs *regs)
+{
+ u_int rm;
+ int ret, index;
+
+ index = (instruction>>8)&15; /* 0x0F00 */
+ rm = regs->regs[index];
+
+ /* shout about the first ten userspace fixups */
+ if (user_mode(regs) && handle_unaligned_notify_count>0) {
+ handle_unaligned_notify_count--;
+
+ printk("Fixing up unaligned userspace access in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n",
+ current->comm,current->pid,(u16*)regs->pc,instruction);
+ }
+
+ ret = -EFAULT;
+ switch (instruction&0xF000) {
+ case 0x0000:
+ if (instruction==0x000B) {
+ /* rts */
+ ret = handle_unaligned_delayslot(regs);
+ if (ret==0)
+ regs->pc = regs->pr;
+ }
+ else if ((instruction&0x00FF)==0x0023) {
+ /* braf @Rm */
+ ret = handle_unaligned_delayslot(regs);
+ if (ret==0)
+ regs->pc += rm + 4;
+ }
+ else if ((instruction&0x00FF)==0x0003) {
+ /* bsrf @Rm */
+ ret = handle_unaligned_delayslot(regs);
+ if (ret==0) {
+ regs->pr = regs->pc + 4;
+ regs->pc += rm + 4;
+ }
+ }
+ else {
+ /* mov.[bwl] to/from memory via r0+rn */
+ goto simple;
+ }
+ break;
+
+ case 0x1000: /* mov.l Rm,@(disp,Rn) */
+ goto simple;
+
+ case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */
+ goto simple;
+
+ case 0x4000:
+ if ((instruction&0x00FF)==0x002B) {
+ /* jmp @Rm */
+ ret = handle_unaligned_delayslot(regs);
+ if (ret==0)
+ regs->pc = rm;
+ }
+ else if ((instruction&0x00FF)==0x000B) {
+ /* jsr @Rm */
+ ret = handle_unaligned_delayslot(regs);
+ if (ret==0) {
+ regs->pr = regs->pc + 4;
+ regs->pc = rm;
+ }
+ }
+ else {
+ /* mov.[bwl] to/from memory via r0+rn */
+ goto simple;
+ }
+ break;
+
+ case 0x5000: /* mov.l @(disp,Rm),Rn */
+ goto simple;
+
+ case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */
+ goto simple;
+
+ case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */
+ switch (instruction&0x0F00) {
+ case 0x0100: /* mov.w R0,@(disp,Rm) */
+ goto simple;
+ case 0x0500: /* mov.w @(disp,Rm),R0 */
+ goto simple;
+ case 0x0B00: /* bf lab - no delayslot*/
+ break;
+ case 0x0F00: /* bf/s lab */
+ ret = handle_unaligned_delayslot(regs);
+ if (ret==0) {
+#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
+ if ((regs->sr & 0x00000001) != 0)
+ regs->pc += 4; /* next after slot */
+ else
+#endif
+ regs->pc += SH_PC_8BIT_OFFSET(instruction);
+ }
+ break;
+ case 0x0900: /* bt lab - no delayslot */
+ break;
+ case 0x0D00: /* bt/s lab */
+ ret = handle_unaligned_delayslot(regs);
+ if (ret==0) {
+#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
+ if ((regs->sr & 0x00000001) == 0)
+ regs->pc += 4; /* next after slot */
+ else
+#endif
+ regs->pc += SH_PC_8BIT_OFFSET(instruction);
+ }
+ break;
+ }
+ break;
+
+ case 0xA000: /* bra label */
+ ret = handle_unaligned_delayslot(regs);
+ if (ret==0)
+ regs->pc += SH_PC_12BIT_OFFSET(instruction);
+ break;
+
+ case 0xB000: /* bsr label */
+ ret = handle_unaligned_delayslot(regs);
+ if (ret==0) {
+ regs->pr = regs->pc + 4;
+ regs->pc += SH_PC_12BIT_OFFSET(instruction);
+ }
+ break;
+ }
+ return ret;
+
+ /* handle non-delay-slot instruction */
+ simple:
+ ret = handle_unaligned_ins(instruction,regs);
+ if (ret==0)
+ regs->pc += 2;
+ return ret;
+}
+
+/*
+ * Handle various address error exceptions
+ */
+asmlinkage void do_address_error(struct pt_regs *regs,
+ unsigned long writeaccess,
+ unsigned long address)
+{
+ unsigned long error_code;
+ mm_segment_t oldfs;
+ u16 instruction;
+ int tmp;
+
+ asm volatile("stc r2_bank,%0": "=r" (error_code));
+
+ oldfs = get_fs();
+
+ if (user_mode(regs)) {
+ local_irq_enable();
+ current->thread.error_code = error_code;
+ current->thread.trap_no = (writeaccess) ? 8 : 7;
+
+ /* bad PC is not something we can fix */
+ if (regs->pc & 1)
+ goto uspace_segv;
+
+ set_fs(USER_DS);
+ if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) {
+ /* Argh. Fault on the instruction itself.
+ This should never happen non-SMP
+ */
+ set_fs(oldfs);
+ goto uspace_segv;
+ }
+
+ tmp = handle_unaligned_access(instruction, regs);
+ set_fs(oldfs);
+
+ if (tmp==0)
+ return; /* sorted */
+
+ uspace_segv:
+ printk(KERN_NOTICE "Killing process \"%s\" due to unaligned access\n", current->comm);
+ force_sig(SIGSEGV, current);
+ } else {
+ if (regs->pc & 1)
+ die("unaligned program counter", regs, error_code);
+
+ set_fs(KERNEL_DS);
+ if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) {
+ /* Argh. Fault on the instruction itself.
+ This should never happen non-SMP
+ */
+ set_fs(oldfs);
+ die("insn faulting in do_address_error", regs, 0);
+ }
+
+ handle_unaligned_access(instruction, regs);
+ set_fs(oldfs);
+ }
+}
+
+#ifdef CONFIG_SH_DSP
+/*
+ * SH-DSP support gerg@snapgear.com.
+ */
+int is_dsp_inst(struct pt_regs *regs)
+{
+ unsigned short inst;
+
+ /*
+ * Safe guard if DSP mode is already enabled or we're lacking
+ * the DSP altogether.
+ */
+ if (!(cpu_data->flags & CPU_HAS_DSP) || (regs->sr & SR_DSP))
+ return 0;
+
+ get_user(inst, ((unsigned short *) regs->pc));
+
+ inst &= 0xf000;
+
+ /* Check for any type of DSP or support instruction */
+ if ((inst == 0xf000) || (inst == 0x4000))
+ return 1;
+
+ return 0;
+}
+#else
+#define is_dsp_inst(regs) (0)
+#endif /* CONFIG_SH_DSP */
+
+DO_ERROR(TRAP_RESERVED_INST, SIGILL, "reserved instruction", reserved_inst, current)
+DO_ERROR(TRAP_ILLEGAL_SLOT_INST, SIGILL, "illegal slot instruction", illegal_slot_inst, current)
+
+asmlinkage void do_exception_error(unsigned long r4, unsigned long r5,
+ unsigned long r6, unsigned long r7,
+ struct pt_regs regs)
+{
+ long ex;
+ asm volatile("stc r2_bank, %0" : "=r" (ex));
+ die_if_kernel("exception", &regs, ex);
+}
+
+#if defined(CONFIG_SH_STANDARD_BIOS)
+void *gdb_vbr_vector;
+
+static inline void __init gdb_vbr_init(void)
+{
+ register unsigned long vbr;
+
+ /*
+ * Read the old value of the VBR register to initialise
+ * the vector through which debug and BIOS traps are
+ * delegated by the Linux trap handler.
+ */
+ asm volatile("stc vbr, %0" : "=r" (vbr));
+
+ gdb_vbr_vector = (void *)(vbr + 0x100);
+ printk("Setting GDB trap vector to 0x%08lx\n",
+ (unsigned long)gdb_vbr_vector);
+}
+#endif
+
+void __init per_cpu_trap_init(void)
+{
+ extern void *vbr_base;
+
+#ifdef CONFIG_SH_STANDARD_BIOS
+ gdb_vbr_init();
+#endif
+
+ /* NOTE: The VBR value should be at P1
+ (or P2, virtural "fixed" address space).
+ It's definitely should not in physical address. */
+
+ asm volatile("ldc %0, vbr"
+ : /* no output */
+ : "r" (&vbr_base)
+ : "memory");
+}
+
+void __init trap_init(void)
+{
+ extern void *exception_handling_table[];
+
+ exception_handling_table[TRAP_RESERVED_INST]
+ = (void *)do_reserved_inst;
+ exception_handling_table[TRAP_ILLEGAL_SLOT_INST]
+ = (void *)do_illegal_slot_inst;
+
+#ifdef CONFIG_CPU_SH4
+ if (!(cpu_data->flags & CPU_HAS_FPU)) {
+ /* For SH-4 lacking an FPU, treat floating point instructions
+ as reserved. */
+ /* entry 64 corresponds to EXPEVT=0x800 */
+ exception_handling_table[64] = (void *)do_reserved_inst;
+ exception_handling_table[65] = (void *)do_illegal_slot_inst;
+ }
+#endif
+
+ /* Setup VBR for boot cpu */
+ per_cpu_trap_init();
+}
+
+void show_stack(struct task_struct *tsk, unsigned long *sp)
+{
+ unsigned long *stack, addr;
+ unsigned long module_start = VMALLOC_START;
+ unsigned long module_end = VMALLOC_END;
+ int i = 1;
+
+ if (tsk && !sp) {
+ sp = (unsigned long *)tsk->thread.sp;
+ }
+
+ if (!sp) {
+ __asm__ __volatile__ (
+ "mov r15, %0\n\t"
+ "stc r7_bank, %1\n\t"
+ : "=r" (module_start),
+ "=r" (module_end)
+ );
+
+ sp = (unsigned long *)module_start;
+ }
+
+ stack = sp;
+
+ printk("\nCall trace: ");
+#ifdef CONFIG_KALLSYMS
+ printk("\n");
+#endif
+
+ while (!kstack_end(stack)) {
+ addr = *stack++;
+ if (((addr >= (unsigned long)_text) &&
+ (addr <= (unsigned long)_etext)) ||
+ ((addr >= module_start) && (addr <= module_end))) {
+ /*
+ * For 80-columns display, 6 entry is maximum.
+ * NOTE: '[<8c00abcd>] ' consumes 13 columns .
+ */
+#ifndef CONFIG_KALLSYMS
+ if (i && ((i % 6) == 0))
+ printk("\n ");
+#endif
+ printk("[<%08lx>] ", addr);
+ print_symbol("%s\n", addr);
+ i++;
+ }
+ }
+
+ printk("\n");
+}
+
+void show_task(unsigned long *sp)
+{
+ show_stack(NULL, sp);
+}
+
+void dump_stack(void)
+{
+ show_stack(NULL, NULL);
+}
+EXPORT_SYMBOL(dump_stack);