diff options
Diffstat (limited to 'arch/sh/kernel/traps_32.c')
-rw-r--r-- | arch/sh/kernel/traps_32.c | 795 |
1 files changed, 795 insertions, 0 deletions
diff --git a/arch/sh/kernel/traps_32.c b/arch/sh/kernel/traps_32.c new file mode 100644 index 000000000..6cdda3a62 --- /dev/null +++ b/arch/sh/kernel/traps_32.c @@ -0,0 +1,795 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 'traps.c' handles hardware traps and faults after we have saved some + * state in 'entry.S'. + * + * SuperH version: Copyright (C) 1999 Niibe Yutaka + * Copyright (C) 2000 Philipp Rumpf + * Copyright (C) 2000 David Howells + * Copyright (C) 2002 - 2010 Paul Mundt + */ +#include <linux/kernel.h> +#include <linux/ptrace.h> +#include <linux/hardirq.h> +#include <linux/init.h> +#include <linux/spinlock.h> +#include <linux/kallsyms.h> +#include <linux/io.h> +#include <linux/bug.h> +#include <linux/debug_locks.h> +#include <linux/kdebug.h> +#include <linux/limits.h> +#include <linux/sysfs.h> +#include <linux/uaccess.h> +#include <linux/perf_event.h> +#include <linux/sched/task_stack.h> + +#include <asm/alignment.h> +#include <asm/fpu.h> +#include <asm/kprobes.h> +#include <asm/traps.h> +#include <asm/bl_bit.h> + +#ifdef CONFIG_CPU_SH2 +# define TRAP_RESERVED_INST 4 +# define TRAP_ILLEGAL_SLOT_INST 6 +# define TRAP_ADDRESS_ERROR 9 +# ifdef CONFIG_CPU_SH2A +# define TRAP_UBC 12 +# define TRAP_FPU_ERROR 13 +# define TRAP_DIVZERO_ERROR 17 +# define TRAP_DIVOVF_ERROR 18 +# endif +#else +#define TRAP_RESERVED_INST 12 +#define TRAP_ILLEGAL_SLOT_INST 13 +#endif + +static inline void sign_extend(unsigned int count, unsigned char *dst) +{ +#ifdef __LITTLE_ENDIAN__ + if ((count == 1) && dst[0] & 0x80) { + dst[1] = 0xff; + dst[2] = 0xff; + dst[3] = 0xff; + } + if ((count == 2) && dst[1] & 0x80) { + dst[2] = 0xff; + dst[3] = 0xff; + } +#else + if ((count == 1) && dst[3] & 0x80) { + dst[2] = 0xff; + dst[1] = 0xff; + dst[0] = 0xff; + } + if ((count == 2) && dst[2] & 0x80) { + dst[1] = 0xff; + dst[0] = 0xff; + } +#endif +} + +static struct mem_access user_mem_access = { + copy_from_user, + copy_to_user, +}; + +static unsigned long copy_from_kernel_wrapper(void *dst, const void __user *src, + unsigned long cnt) +{ + return copy_from_kernel_nofault(dst, (const void __force *)src, cnt); +} + +static unsigned long copy_to_kernel_wrapper(void __user *dst, const void *src, + unsigned long cnt) +{ + return copy_to_kernel_nofault((void __force *)dst, src, cnt); +} + +static struct mem_access kernel_mem_access = { + copy_from_kernel_wrapper, + copy_to_kernel_wrapper, +}; + +/* + * 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(insn_size_t instruction, struct pt_regs *regs, + struct mem_access *ma) +{ + int ret, index, count; + unsigned long *rm, *rn; + unsigned char *src, *dst; + unsigned char __user *srcu, *dstu; + + index = (instruction>>8)&15; /* 0x0F00 */ + rn = ®s->regs[index]; + + index = (instruction>>4)&15; /* 0x00F0 */ + rm = ®s->regs[index]; + + count = 1<<(instruction&3); + + switch (count) { + case 1: inc_unaligned_byte_access(); break; + case 2: inc_unaligned_word_access(); break; + case 4: inc_unaligned_dword_access(); break; + case 8: inc_unaligned_multi_access(); break; + } + + ret = -EFAULT; + switch (instruction>>12) { + case 0: /* mov.[bwl] to/from memory via r0+rn */ + if (instruction & 8) { + /* from memory */ + srcu = (unsigned char __user *)*rm; + srcu += regs->regs[0]; + dst = (unsigned char *)rn; + *(unsigned long *)dst = 0; + +#if !defined(__LITTLE_ENDIAN__) + dst += 4-count; +#endif + if (ma->from(dst, srcu, count)) + goto fetch_fault; + + sign_extend(count, dst); + } else { + /* to memory */ + src = (unsigned char *)rm; +#if !defined(__LITTLE_ENDIAN__) + src += 4-count; +#endif + dstu = (unsigned char __user *)*rn; + dstu += regs->regs[0]; + + if (ma->to(dstu, src, count)) + goto fetch_fault; + } + ret = 0; + break; + + case 1: /* mov.l Rm,@(disp,Rn) */ + src = (unsigned char*) rm; + dstu = (unsigned char __user *)*rn; + dstu += (instruction&0x000F)<<2; + + if (ma->to(dstu, 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; + dstu = (unsigned char __user *)*rn; +#if !defined(__LITTLE_ENDIAN__) + src += 4-count; +#endif + if (ma->to(dstu, src, count)) + goto fetch_fault; + ret = 0; + break; + + case 5: /* mov.l @(disp,Rm),Rn */ + srcu = (unsigned char __user *)*rm; + srcu += (instruction & 0x000F) << 2; + dst = (unsigned char *)rn; + *(unsigned long *)dst = 0; + + if (ma->from(dst, srcu, 4)) + goto fetch_fault; + ret = 0; + break; + + case 6: /* mov.[bwl] from memory, possibly with post-increment */ + srcu = (unsigned char __user *)*rm; + if (instruction & 4) + *rm += count; + dst = (unsigned char*) rn; + *(unsigned long*)dst = 0; + +#if !defined(__LITTLE_ENDIAN__) + dst += 4-count; +#endif + if (ma->from(dst, srcu, count)) + goto fetch_fault; + sign_extend(count, dst); + ret = 0; + break; + + case 8: + switch ((instruction&0xFF00)>>8) { + case 0x81: /* mov.w R0,@(disp,Rn) */ + src = (unsigned char *) ®s->regs[0]; +#if !defined(__LITTLE_ENDIAN__) + src += 2; +#endif + dstu = (unsigned char __user *)*rm; /* called Rn in the spec */ + dstu += (instruction & 0x000F) << 1; + + if (ma->to(dstu, src, 2)) + goto fetch_fault; + ret = 0; + break; + + case 0x85: /* mov.w @(disp,Rm),R0 */ + srcu = (unsigned char __user *)*rm; + srcu += (instruction & 0x000F) << 1; + dst = (unsigned char *) ®s->regs[0]; + *(unsigned long *)dst = 0; + +#if !defined(__LITTLE_ENDIAN__) + dst += 2; +#endif + if (ma->from(dst, srcu, 2)) + goto fetch_fault; + sign_extend(2, dst); + ret = 0; + break; + } + break; + + case 9: /* mov.w @(disp,PC),Rn */ + srcu = (unsigned char __user *)regs->pc; + srcu += 4; + srcu += (instruction & 0x00FF) << 1; + dst = (unsigned char *)rn; + *(unsigned long *)dst = 0; + +#if !defined(__LITTLE_ENDIAN__) + dst += 2; +#endif + + if (ma->from(dst, srcu, 2)) + goto fetch_fault; + sign_extend(2, dst); + ret = 0; + break; + + case 0xd: /* mov.l @(disp,PC),Rn */ + srcu = (unsigned char __user *)(regs->pc & ~0x3); + srcu += 4; + srcu += (instruction & 0x00FF) << 2; + dst = (unsigned char *)rn; + *(unsigned long *)dst = 0; + + if (ma->from(dst, srcu, 4)) + goto fetch_fault; + ret = 0; + break; + } + return ret; + + fetch_fault: + /* Argh. Address not only misaligned but also non-existent. + * Raise an EFAULT and see if it's trapped + */ + die_if_no_fixup("Fault in unaligned fixup", regs, 0); + return -EFAULT; +} + +/* + * emulate the instruction in the delay slot + * - fetches the instruction from PC+2 + */ +static inline int handle_delayslot(struct pt_regs *regs, + insn_size_t old_instruction, + struct mem_access *ma) +{ + insn_size_t instruction; + void __user *addr = (void __user *)(regs->pc + + instruction_size(old_instruction)); + + if (copy_from_user(&instruction, addr, sizeof(instruction))) { + /* 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, ma); +} + +/* + * 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) + +int handle_unaligned_access(insn_size_t instruction, struct pt_regs *regs, + struct mem_access *ma, int expected, + unsigned long address) +{ + u_int rm; + int ret, index; + + /* + * XXX: We can't handle mixed 16/32-bit instructions yet + */ + if (instruction_size(instruction) != 2) + return -EINVAL; + + index = (instruction>>8)&15; /* 0x0F00 */ + rm = regs->regs[index]; + + /* + * Log the unexpected fixups, and then pass them on to perf. + * + * We intentionally don't report the expected cases to perf as + * otherwise the trapped I/O case will skew the results too much + * to be useful. + */ + if (!expected) { + unaligned_fixups_notify(current, instruction, regs); + perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, + regs, address); + } + + ret = -EFAULT; + switch (instruction&0xF000) { + case 0x0000: + if (instruction==0x000B) { + /* rts */ + ret = handle_delayslot(regs, instruction, ma); + if (ret==0) + regs->pc = regs->pr; + } + else if ((instruction&0x00FF)==0x0023) { + /* braf @Rm */ + ret = handle_delayslot(regs, instruction, ma); + if (ret==0) + regs->pc += rm + 4; + } + else if ((instruction&0x00FF)==0x0003) { + /* bsrf @Rm */ + ret = handle_delayslot(regs, instruction, ma); + 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_delayslot(regs, instruction, ma); + if (ret==0) + regs->pc = rm; + } + else if ((instruction&0x00FF)==0x000B) { + /* jsr @Rm */ + ret = handle_delayslot(regs, instruction, ma); + 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*/ + ret = 0; + break; + case 0x0F00: /* bf/s lab */ + ret = handle_delayslot(regs, instruction, ma); + 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 */ + ret = 0; + break; + case 0x0D00: /* bt/s lab */ + ret = handle_delayslot(regs, instruction, ma); + 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 0x9000: /* mov.w @(disp,Rm),Rn */ + goto simple; + + case 0xA000: /* bra label */ + ret = handle_delayslot(regs, instruction, ma); + if (ret==0) + regs->pc += SH_PC_12BIT_OFFSET(instruction); + break; + + case 0xB000: /* bsr label */ + ret = handle_delayslot(regs, instruction, ma); + if (ret==0) { + regs->pr = regs->pc + 4; + regs->pc += SH_PC_12BIT_OFFSET(instruction); + } + break; + + case 0xD000: /* mov.l @(disp,Rm),Rn */ + goto simple; + } + return ret; + + /* handle non-delay-slot instruction */ + simple: + ret = handle_unaligned_ins(instruction, regs, ma); + if (ret==0) + regs->pc += instruction_size(instruction); + return ret; +} + +/* + * Handle various address error exceptions: + * - instruction address error: + * misaligned PC + * PC >= 0x80000000 in user mode + * - data address error (read and write) + * misaligned data access + * access to >= 0x80000000 is user mode + * Unfortuntaly we can't distinguish between instruction address error + * and data address errors caused by read accesses. + */ +asmlinkage void do_address_error(struct pt_regs *regs, + unsigned long writeaccess, + unsigned long address) +{ + unsigned long error_code = 0; + insn_size_t instruction; + int tmp; + + /* Intentional ifdef */ +#ifdef CONFIG_CPU_HAS_SR_RB + error_code = lookup_exception_vector(); +#endif + + if (user_mode(regs)) { + int si_code = BUS_ADRERR; + unsigned int user_action; + + local_irq_enable(); + inc_unaligned_user_access(); + + if (copy_from_user(&instruction, (insn_size_t __user *)(regs->pc & ~1), + sizeof(instruction))) { + goto uspace_segv; + } + + /* shout about userspace fixups */ + unaligned_fixups_notify(current, instruction, regs); + + user_action = unaligned_user_action(); + if (user_action & UM_FIXUP) + goto fixup; + if (user_action & UM_SIGNAL) + goto uspace_segv; + else { + /* ignore */ + regs->pc += instruction_size(instruction); + return; + } + +fixup: + /* bad PC is not something we can fix */ + if (regs->pc & 1) { + si_code = BUS_ADRALN; + goto uspace_segv; + } + + tmp = handle_unaligned_access(instruction, regs, + &user_mem_access, 0, + address); + + if (tmp == 0) + return; /* sorted */ +uspace_segv: + printk(KERN_NOTICE "Sending SIGBUS to \"%s\" due to unaligned " + "access (PC %lx PR %lx)\n", current->comm, regs->pc, + regs->pr); + + force_sig_fault(SIGBUS, si_code, (void __user *)address); + } else { + inc_unaligned_kernel_access(); + + if (regs->pc & 1) + die("unaligned program counter", regs, error_code); + + if (copy_from_kernel_nofault(&instruction, (void *)(regs->pc), + sizeof(instruction))) { + /* Argh. Fault on the instruction itself. + This should never happen non-SMP + */ + die("insn faulting in do_address_error", regs, 0); + } + + unaligned_fixups_notify(current, instruction, regs); + + handle_unaligned_access(instruction, regs, &kernel_mem_access, + 0, address); + } +} + +#ifdef CONFIG_SH_DSP +/* + * SH-DSP support gerg@snapgear.com. + */ +int is_dsp_inst(struct pt_regs *regs) +{ + unsigned short inst = 0; + + /* + * Safe guard if DSP mode is already enabled or we're lacking + * the DSP altogether. + */ + if (!(current_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 */ + +#ifdef CONFIG_CPU_SH2A +asmlinkage void do_divide_error(unsigned long r4) +{ + int code; + + switch (r4) { + case TRAP_DIVZERO_ERROR: + code = FPE_INTDIV; + break; + case TRAP_DIVOVF_ERROR: + code = FPE_INTOVF; + break; + default: + /* Let gcc know unhandled cases don't make it past here */ + return; + } + force_sig_fault(SIGFPE, code, NULL); +} +#endif + +asmlinkage void do_reserved_inst(void) +{ + struct pt_regs *regs = current_pt_regs(); + unsigned long error_code; + +#ifdef CONFIG_SH_FPU_EMU + unsigned short inst = 0; + int err; + + get_user(inst, (unsigned short __user *)regs->pc); + + err = do_fpu_inst(inst, regs); + if (!err) { + regs->pc += instruction_size(inst); + return; + } + /* not a FPU inst. */ +#endif + +#ifdef CONFIG_SH_DSP + /* Check if it's a DSP instruction */ + if (is_dsp_inst(regs)) { + /* Enable DSP mode, and restart instruction. */ + regs->sr |= SR_DSP; + /* Save DSP mode */ + current->thread.dsp_status.status |= SR_DSP; + return; + } +#endif + + error_code = lookup_exception_vector(); + + local_irq_enable(); + force_sig(SIGILL); + die_if_no_fixup("reserved instruction", regs, error_code); +} + +#ifdef CONFIG_SH_FPU_EMU +static int emulate_branch(unsigned short inst, struct pt_regs *regs) +{ + /* + * bfs: 8fxx: PC+=d*2+4; + * bts: 8dxx: PC+=d*2+4; + * bra: axxx: PC+=D*2+4; + * bsr: bxxx: PC+=D*2+4 after PR=PC+4; + * braf:0x23: PC+=Rn*2+4; + * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4; + * jmp: 4x2b: PC=Rn; + * jsr: 4x0b: PC=Rn after PR=PC+4; + * rts: 000b: PC=PR; + */ + if (((inst & 0xf000) == 0xb000) || /* bsr */ + ((inst & 0xf0ff) == 0x0003) || /* bsrf */ + ((inst & 0xf0ff) == 0x400b)) /* jsr */ + regs->pr = regs->pc + 4; + + if ((inst & 0xfd00) == 0x8d00) { /* bfs, bts */ + regs->pc += SH_PC_8BIT_OFFSET(inst); + return 0; + } + + if ((inst & 0xe000) == 0xa000) { /* bra, bsr */ + regs->pc += SH_PC_12BIT_OFFSET(inst); + return 0; + } + + if ((inst & 0xf0df) == 0x0003) { /* braf, bsrf */ + regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4; + return 0; + } + + if ((inst & 0xf0df) == 0x400b) { /* jmp, jsr */ + regs->pc = regs->regs[(inst & 0x0f00) >> 8]; + return 0; + } + + if ((inst & 0xffff) == 0x000b) { /* rts */ + regs->pc = regs->pr; + return 0; + } + + return 1; +} +#endif + +asmlinkage void do_illegal_slot_inst(void) +{ + struct pt_regs *regs = current_pt_regs(); + unsigned long inst; + + if (kprobe_handle_illslot(regs->pc) == 0) + return; + +#ifdef CONFIG_SH_FPU_EMU + get_user(inst, (unsigned short __user *)regs->pc + 1); + if (!do_fpu_inst(inst, regs)) { + get_user(inst, (unsigned short __user *)regs->pc); + if (!emulate_branch(inst, regs)) + return; + /* fault in branch.*/ + } + /* not a FPU inst. */ +#endif + + inst = lookup_exception_vector(); + + local_irq_enable(); + force_sig(SIGILL); + die_if_no_fixup("illegal slot instruction", regs, inst); +} + +asmlinkage void do_exception_error(void) +{ + long ex; + + ex = lookup_exception_vector(); + die_if_kernel("exception", current_pt_regs(), ex); +} + +void per_cpu_trap_init(void) +{ + extern void *vbr_base; + + /* 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"); + + /* disable exception blocking now when the vbr has been setup */ + clear_bl_bit(); +} + +void *set_exception_table_vec(unsigned int vec, void *handler) +{ + extern void *exception_handling_table[]; + void *old_handler; + + old_handler = exception_handling_table[vec]; + exception_handling_table[vec] = handler; + return old_handler; +} + +void __init trap_init(void) +{ + set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst); + set_exception_table_vec(TRAP_ILLEGAL_SLOT_INST, do_illegal_slot_inst); + +#if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \ + defined(CONFIG_SH_FPU_EMU) + /* + * For SH-4 lacking an FPU, treat floating point instructions as + * reserved. They'll be handled in the math-emu case, or faulted on + * otherwise. + */ + set_exception_table_evt(0x800, do_reserved_inst); + set_exception_table_evt(0x820, do_illegal_slot_inst); +#elif defined(CONFIG_SH_FPU) + set_exception_table_evt(0x800, fpu_state_restore_trap_handler); + set_exception_table_evt(0x820, fpu_state_restore_trap_handler); +#endif + +#ifdef CONFIG_CPU_SH2 + set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_trap_handler); +#endif +#ifdef CONFIG_CPU_SH2A + set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error); + set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error); +#ifdef CONFIG_SH_FPU + set_exception_table_vec(TRAP_FPU_ERROR, fpu_error_trap_handler); +#endif +#endif + +#ifdef TRAP_UBC + set_exception_table_vec(TRAP_UBC, breakpoint_trap_handler); +#endif +} |