diff options
Diffstat (limited to 'arch/mips/kernel/unaligned.c')
| -rw-r--r-- | arch/mips/kernel/unaligned.c | 1572 |
1 files changed, 1572 insertions, 0 deletions
diff --git a/arch/mips/kernel/unaligned.c b/arch/mips/kernel/unaligned.c new file mode 100644 index 000000000..7b5aba5df --- /dev/null +++ b/arch/mips/kernel/unaligned.c @@ -0,0 +1,1572 @@ +/* + * Handle unaligned accesses by emulation. + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 1996, 1998, 1999, 2002 by Ralf Baechle + * Copyright (C) 1999 Silicon Graphics, Inc. + * Copyright (C) 2014 Imagination Technologies Ltd. + * + * This file contains exception handler for address error exception with the + * special capability to execute faulting instructions in software. The + * handler does not try to handle the case when the program counter points + * to an address not aligned to a word boundary. + * + * Putting data to unaligned addresses is a bad practice even on Intel where + * only the performance is affected. Much worse is that such code is non- + * portable. Due to several programs that die on MIPS due to alignment + * problems I decided to implement this handler anyway though I originally + * didn't intend to do this at all for user code. + * + * For now I enable fixing of address errors by default to make life easier. + * I however intend to disable this somewhen in the future when the alignment + * problems with user programs have been fixed. For programmers this is the + * right way to go. + * + * Fixing address errors is a per process option. The option is inherited + * across fork(2) and execve(2) calls. If you really want to use the + * option in your user programs - I discourage the use of the software + * emulation strongly - use the following code in your userland stuff: + * + * #include <sys/sysmips.h> + * + * ... + * sysmips(MIPS_FIXADE, x); + * ... + * + * The argument x is 0 for disabling software emulation, enabled otherwise. + * + * Below a little program to play around with this feature. + * + * #include <stdio.h> + * #include <sys/sysmips.h> + * + * struct foo { + * unsigned char bar[8]; + * }; + * + * main(int argc, char *argv[]) + * { + * struct foo x = {0, 1, 2, 3, 4, 5, 6, 7}; + * unsigned int *p = (unsigned int *) (x.bar + 3); + * int i; + * + * if (argc > 1) + * sysmips(MIPS_FIXADE, atoi(argv[1])); + * + * printf("*p = %08lx\n", *p); + * + * *p = 0xdeadface; + * + * for(i = 0; i <= 7; i++) + * printf("%02x ", x.bar[i]); + * printf("\n"); + * } + * + * Coprocessor loads are not supported; I think this case is unimportant + * in the practice. + * + * TODO: Handle ndc (attempted store to doubleword in uncached memory) + * exception for the R6000. + * A store crossing a page boundary might be executed only partially. + * Undo the partial store in this case. + */ +#include <linux/context_tracking.h> +#include <linux/mm.h> +#include <linux/signal.h> +#include <linux/smp.h> +#include <linux/sched.h> +#include <linux/debugfs.h> +#include <linux/perf_event.h> + +#include <asm/asm.h> +#include <asm/branch.h> +#include <asm/byteorder.h> +#include <asm/cop2.h> +#include <asm/debug.h> +#include <asm/fpu.h> +#include <asm/fpu_emulator.h> +#include <asm/inst.h> +#include <asm/unaligned-emul.h> +#include <asm/mmu_context.h> +#include <linux/uaccess.h> + +#include "access-helper.h" + +enum { + UNALIGNED_ACTION_QUIET, + UNALIGNED_ACTION_SIGNAL, + UNALIGNED_ACTION_SHOW, +}; +#ifdef CONFIG_DEBUG_FS +static u32 unaligned_instructions; +static u32 unaligned_action; +#else +#define unaligned_action UNALIGNED_ACTION_QUIET +#endif +extern void show_registers(struct pt_regs *regs); + +static void emulate_load_store_insn(struct pt_regs *regs, + void __user *addr, unsigned int *pc) +{ + unsigned long origpc, orig31, value; + union mips_instruction insn; + unsigned int res; + bool user = user_mode(regs); + + origpc = (unsigned long)pc; + orig31 = regs->regs[31]; + + perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0); + + /* + * This load never faults. + */ + __get_inst32(&insn.word, pc, user); + + switch (insn.i_format.opcode) { + /* + * These are instructions that a compiler doesn't generate. We + * can assume therefore that the code is MIPS-aware and + * really buggy. Emulating these instructions would break the + * semantics anyway. + */ + case ll_op: + case lld_op: + case sc_op: + case scd_op: + + /* + * For these instructions the only way to create an address + * error is an attempted access to kernel/supervisor address + * space. + */ + case ldl_op: + case ldr_op: + case lwl_op: + case lwr_op: + case sdl_op: + case sdr_op: + case swl_op: + case swr_op: + case lb_op: + case lbu_op: + case sb_op: + goto sigbus; + + /* + * The remaining opcodes are the ones that are really of + * interest. + */ + case spec3_op: + if (insn.dsp_format.func == lx_op) { + switch (insn.dsp_format.op) { + case lwx_op: + if (user && !access_ok(addr, 4)) + goto sigbus; + LoadW(addr, value, res); + if (res) + goto fault; + compute_return_epc(regs); + regs->regs[insn.dsp_format.rd] = value; + break; + case lhx_op: + if (user && !access_ok(addr, 2)) + goto sigbus; + LoadHW(addr, value, res); + if (res) + goto fault; + compute_return_epc(regs); + regs->regs[insn.dsp_format.rd] = value; + break; + default: + goto sigill; + } + } +#ifdef CONFIG_EVA + else { + /* + * we can land here only from kernel accessing user + * memory, so we need to "switch" the address limit to + * user space, so that address check can work properly. + */ + switch (insn.spec3_format.func) { + case lhe_op: + if (!access_ok(addr, 2)) + goto sigbus; + LoadHWE(addr, value, res); + if (res) + goto fault; + compute_return_epc(regs); + regs->regs[insn.spec3_format.rt] = value; + break; + case lwe_op: + if (!access_ok(addr, 4)) + goto sigbus; + LoadWE(addr, value, res); + if (res) + goto fault; + compute_return_epc(regs); + regs->regs[insn.spec3_format.rt] = value; + break; + case lhue_op: + if (!access_ok(addr, 2)) + goto sigbus; + LoadHWUE(addr, value, res); + if (res) + goto fault; + compute_return_epc(regs); + regs->regs[insn.spec3_format.rt] = value; + break; + case she_op: + if (!access_ok(addr, 2)) + goto sigbus; + compute_return_epc(regs); + value = regs->regs[insn.spec3_format.rt]; + StoreHWE(addr, value, res); + if (res) + goto fault; + break; + case swe_op: + if (!access_ok(addr, 4)) + goto sigbus; + compute_return_epc(regs); + value = regs->regs[insn.spec3_format.rt]; + StoreWE(addr, value, res); + if (res) + goto fault; + break; + default: + goto sigill; + } + } +#endif + break; + case lh_op: + if (user && !access_ok(addr, 2)) + goto sigbus; + + if (IS_ENABLED(CONFIG_EVA) && user) + LoadHWE(addr, value, res); + else + LoadHW(addr, value, res); + + if (res) + goto fault; + compute_return_epc(regs); + regs->regs[insn.i_format.rt] = value; + break; + + case lw_op: + if (user && !access_ok(addr, 4)) + goto sigbus; + + if (IS_ENABLED(CONFIG_EVA) && user) + LoadWE(addr, value, res); + else + LoadW(addr, value, res); + + if (res) + goto fault; + compute_return_epc(regs); + regs->regs[insn.i_format.rt] = value; + break; + + case lhu_op: + if (user && !access_ok(addr, 2)) + goto sigbus; + + if (IS_ENABLED(CONFIG_EVA) && user) + LoadHWUE(addr, value, res); + else + LoadHWU(addr, value, res); + + if (res) + goto fault; + compute_return_epc(regs); + regs->regs[insn.i_format.rt] = value; + break; + + case lwu_op: +#ifdef CONFIG_64BIT + /* + * A 32-bit kernel might be running on a 64-bit processor. But + * if we're on a 32-bit processor and an i-cache incoherency + * or race makes us see a 64-bit instruction here the sdl/sdr + * would blow up, so for now we don't handle unaligned 64-bit + * instructions on 32-bit kernels. + */ + if (user && !access_ok(addr, 4)) + goto sigbus; + + LoadWU(addr, value, res); + if (res) + goto fault; + compute_return_epc(regs); + regs->regs[insn.i_format.rt] = value; + break; +#endif /* CONFIG_64BIT */ + + /* Cannot handle 64-bit instructions in 32-bit kernel */ + goto sigill; + + case ld_op: +#ifdef CONFIG_64BIT + /* + * A 32-bit kernel might be running on a 64-bit processor. But + * if we're on a 32-bit processor and an i-cache incoherency + * or race makes us see a 64-bit instruction here the sdl/sdr + * would blow up, so for now we don't handle unaligned 64-bit + * instructions on 32-bit kernels. + */ + if (user && !access_ok(addr, 8)) + goto sigbus; + + LoadDW(addr, value, res); + if (res) + goto fault; + compute_return_epc(regs); + regs->regs[insn.i_format.rt] = value; + break; +#endif /* CONFIG_64BIT */ + + /* Cannot handle 64-bit instructions in 32-bit kernel */ + goto sigill; + + case sh_op: + if (user && !access_ok(addr, 2)) + goto sigbus; + + compute_return_epc(regs); + value = regs->regs[insn.i_format.rt]; + + if (IS_ENABLED(CONFIG_EVA) && user) + StoreHWE(addr, value, res); + else + StoreHW(addr, value, res); + + if (res) + goto fault; + break; + + case sw_op: + if (user && !access_ok(addr, 4)) + goto sigbus; + + compute_return_epc(regs); + value = regs->regs[insn.i_format.rt]; + + if (IS_ENABLED(CONFIG_EVA) && user) + StoreWE(addr, value, res); + else + StoreW(addr, value, res); + + if (res) + goto fault; + break; + + case sd_op: +#ifdef CONFIG_64BIT + /* + * A 32-bit kernel might be running on a 64-bit processor. But + * if we're on a 32-bit processor and an i-cache incoherency + * or race makes us see a 64-bit instruction here the sdl/sdr + * would blow up, so for now we don't handle unaligned 64-bit + * instructions on 32-bit kernels. + */ + if (user && !access_ok(addr, 8)) + goto sigbus; + + compute_return_epc(regs); + value = regs->regs[insn.i_format.rt]; + StoreDW(addr, value, res); + if (res) + goto fault; + break; +#endif /* CONFIG_64BIT */ + + /* Cannot handle 64-bit instructions in 32-bit kernel */ + goto sigill; + +#ifdef CONFIG_MIPS_FP_SUPPORT + + case lwc1_op: + case ldc1_op: + case swc1_op: + case sdc1_op: + case cop1x_op: { + void __user *fault_addr = NULL; + + die_if_kernel("Unaligned FP access in kernel code", regs); + BUG_ON(!used_math()); + + res = fpu_emulator_cop1Handler(regs, ¤t->thread.fpu, 1, + &fault_addr); + own_fpu(1); /* Restore FPU state. */ + + /* Signal if something went wrong. */ + process_fpemu_return(res, fault_addr, 0); + + if (res == 0) + break; + return; + } +#endif /* CONFIG_MIPS_FP_SUPPORT */ + +#ifdef CONFIG_CPU_HAS_MSA + + case msa_op: { + unsigned int wd, preempted; + enum msa_2b_fmt df; + union fpureg *fpr; + + if (!cpu_has_msa) + goto sigill; + + /* + * If we've reached this point then userland should have taken + * the MSA disabled exception & initialised vector context at + * some point in the past. + */ + BUG_ON(!thread_msa_context_live()); + + df = insn.msa_mi10_format.df; + wd = insn.msa_mi10_format.wd; + fpr = ¤t->thread.fpu.fpr[wd]; + + switch (insn.msa_mi10_format.func) { + case msa_ld_op: + if (!access_ok(addr, sizeof(*fpr))) + goto sigbus; + + do { + /* + * If we have live MSA context keep track of + * whether we get preempted in order to avoid + * the register context we load being clobbered + * by the live context as it's saved during + * preemption. If we don't have live context + * then it can't be saved to clobber the value + * we load. + */ + preempted = test_thread_flag(TIF_USEDMSA); + + res = __copy_from_user_inatomic(fpr, addr, + sizeof(*fpr)); + if (res) + goto fault; + + /* + * Update the hardware register if it is in use + * by the task in this quantum, in order to + * avoid having to save & restore the whole + * vector context. + */ + preempt_disable(); + if (test_thread_flag(TIF_USEDMSA)) { + write_msa_wr(wd, fpr, df); + preempted = 0; + } + preempt_enable(); + } while (preempted); + break; + + case msa_st_op: + if (!access_ok(addr, sizeof(*fpr))) + goto sigbus; + + /* + * Update from the hardware register if it is in use by + * the task in this quantum, in order to avoid having to + * save & restore the whole vector context. + */ + preempt_disable(); + if (test_thread_flag(TIF_USEDMSA)) + read_msa_wr(wd, fpr, df); + preempt_enable(); + + res = __copy_to_user_inatomic(addr, fpr, sizeof(*fpr)); + if (res) + goto fault; + break; + + default: + goto sigbus; + } + + compute_return_epc(regs); + break; + } +#endif /* CONFIG_CPU_HAS_MSA */ + +#ifndef CONFIG_CPU_MIPSR6 + /* + * COP2 is available to implementor for application specific use. + * It's up to applications to register a notifier chain and do + * whatever they have to do, including possible sending of signals. + * + * This instruction has been reallocated in Release 6 + */ + case lwc2_op: + cu2_notifier_call_chain(CU2_LWC2_OP, regs); + break; + + case ldc2_op: + cu2_notifier_call_chain(CU2_LDC2_OP, regs); + break; + + case swc2_op: + cu2_notifier_call_chain(CU2_SWC2_OP, regs); + break; + + case sdc2_op: + cu2_notifier_call_chain(CU2_SDC2_OP, regs); + break; +#endif + default: + /* + * Pheeee... We encountered an yet unknown instruction or + * cache coherence problem. Die sucker, die ... + */ + goto sigill; + } + +#ifdef CONFIG_DEBUG_FS + unaligned_instructions++; +#endif + + return; + +fault: + /* roll back jump/branch */ + regs->cp0_epc = origpc; + regs->regs[31] = orig31; + /* Did we have an exception handler installed? */ + if (fixup_exception(regs)) + return; + + die_if_kernel("Unhandled kernel unaligned access", regs); + force_sig(SIGSEGV); + + return; + +sigbus: + die_if_kernel("Unhandled kernel unaligned access", regs); + force_sig(SIGBUS); + + return; + +sigill: + die_if_kernel + ("Unhandled kernel unaligned access or invalid instruction", regs); + force_sig(SIGILL); +} + +/* Recode table from 16-bit register notation to 32-bit GPR. */ +const int reg16to32[] = { 16, 17, 2, 3, 4, 5, 6, 7 }; + +/* Recode table from 16-bit STORE register notation to 32-bit GPR. */ +static const int reg16to32st[] = { 0, 17, 2, 3, 4, 5, 6, 7 }; + +static void emulate_load_store_microMIPS(struct pt_regs *regs, + void __user *addr) +{ + unsigned long value; + unsigned int res; + int i; + unsigned int reg = 0, rvar; + unsigned long orig31; + u16 __user *pc16; + u16 halfword; + unsigned int word; + unsigned long origpc, contpc; + union mips_instruction insn; + struct mm_decoded_insn mminsn; + bool user = user_mode(regs); + + origpc = regs->cp0_epc; + orig31 = regs->regs[31]; + + mminsn.micro_mips_mode = 1; + + /* + * This load never faults. + */ + pc16 = (unsigned short __user *)msk_isa16_mode(regs->cp0_epc); + __get_user(halfword, pc16); + pc16++; + contpc = regs->cp0_epc + 2; + word = ((unsigned int)halfword << 16); + mminsn.pc_inc = 2; + + if (!mm_insn_16bit(halfword)) { + __get_user(halfword, pc16); + pc16++; + contpc = regs->cp0_epc + 4; + mminsn.pc_inc = 4; + word |= halfword; + } + mminsn.insn = word; + + if (get_user(halfword, pc16)) + goto fault; + mminsn.next_pc_inc = 2; + word = ((unsigned int)halfword << 16); + + if (!mm_insn_16bit(halfword)) { + pc16++; + if (get_user(halfword, pc16)) + goto fault; + mminsn.next_pc_inc = 4; + word |= halfword; + } + mminsn.next_insn = word; + + insn = (union mips_instruction)(mminsn.insn); + if (mm_isBranchInstr(regs, mminsn, &contpc)) + insn = (union mips_instruction)(mminsn.next_insn); + + /* Parse instruction to find what to do */ + + switch (insn.mm_i_format.opcode) { + + case mm_pool32a_op: + switch (insn.mm_x_format.func) { + case mm_lwxs_op: + reg = insn.mm_x_format.rd; + goto loadW; + } + + goto sigbus; + + case mm_pool32b_op: + switch (insn.mm_m_format.func) { + case mm_lwp_func: + reg = insn.mm_m_format.rd; + if (reg == 31) + goto sigbus; + + if (user && !access_ok(addr, 8)) + goto sigbus; + + LoadW(addr, value, res); + if (res) + goto fault; + regs->regs[reg] = value; + addr += 4; + LoadW(addr, value, res); + if (res) + goto fault; + regs->regs[reg + 1] = value; + goto success; + + case mm_swp_func: + reg = insn.mm_m_format.rd; + if (reg == 31) + goto sigbus; + + if (user && !access_ok(addr, 8)) + goto sigbus; + + value = regs->regs[reg]; + StoreW(addr, value, res); + if (res) + goto fault; + addr += 4; + value = regs->regs[reg + 1]; + StoreW(addr, value, res); + if (res) + goto fault; + goto success; + + case mm_ldp_func: +#ifdef CONFIG_64BIT + reg = insn.mm_m_format.rd; + if (reg == 31) + goto sigbus; + + if (user && !access_ok(addr, 16)) + goto sigbus; + + LoadDW(addr, value, res); + if (res) + goto fault; + regs->regs[reg] = value; + addr += 8; + LoadDW(addr, value, res); + if (res) + goto fault; + regs->regs[reg + 1] = value; + goto success; +#endif /* CONFIG_64BIT */ + + goto sigill; + + case mm_sdp_func: +#ifdef CONFIG_64BIT + reg = insn.mm_m_format.rd; + if (reg == 31) + goto sigbus; + + if (user && !access_ok(addr, 16)) + goto sigbus; + + value = regs->regs[reg]; + StoreDW(addr, value, res); + if (res) + goto fault; + addr += 8; + value = regs->regs[reg + 1]; + StoreDW(addr, value, res); + if (res) + goto fault; + goto success; +#endif /* CONFIG_64BIT */ + + goto sigill; + + case mm_lwm32_func: + reg = insn.mm_m_format.rd; + rvar = reg & 0xf; + if ((rvar > 9) || !reg) + goto sigill; + if (reg & 0x10) { + if (user && !access_ok(addr, 4 * (rvar + 1))) + goto sigbus; + } else { + if (user && !access_ok(addr, 4 * rvar)) + goto sigbus; + } + if (rvar == 9) + rvar = 8; + for (i = 16; rvar; rvar--, i++) { + LoadW(addr, value, res); + if (res) + goto fault; + addr += 4; + regs->regs[i] = value; + } + if ((reg & 0xf) == 9) { + LoadW(addr, value, res); + if (res) + goto fault; + addr += 4; + regs->regs[30] = value; + } + if (reg & 0x10) { + LoadW(addr, value, res); + if (res) + goto fault; + regs->regs[31] = value; + } + goto success; + + case mm_swm32_func: + reg = insn.mm_m_format.rd; + rvar = reg & 0xf; + if ((rvar > 9) || !reg) + goto sigill; + if (reg & 0x10) { + if (user && !access_ok(addr, 4 * (rvar + 1))) + goto sigbus; + } else { + if (user && !access_ok(addr, 4 * rvar)) + goto sigbus; + } + if (rvar == 9) + rvar = 8; + for (i = 16; rvar; rvar--, i++) { + value = regs->regs[i]; + StoreW(addr, value, res); + if (res) + goto fault; + addr += 4; + } + if ((reg & 0xf) == 9) { + value = regs->regs[30]; + StoreW(addr, value, res); + if (res) + goto fault; + addr += 4; + } + if (reg & 0x10) { + value = regs->regs[31]; + StoreW(addr, value, res); + if (res) + goto fault; + } + goto success; + + case mm_ldm_func: +#ifdef CONFIG_64BIT + reg = insn.mm_m_format.rd; + rvar = reg & 0xf; + if ((rvar > 9) || !reg) + goto sigill; + if (reg & 0x10) { + if (user && !access_ok(addr, 8 * (rvar + 1))) + goto sigbus; + } else { + if (user && !access_ok(addr, 8 * rvar)) + goto sigbus; + } + if (rvar == 9) + rvar = 8; + + for (i = 16; rvar; rvar--, i++) { + LoadDW(addr, value, res); + if (res) + goto fault; + addr += 4; + regs->regs[i] = value; + } + if ((reg & 0xf) == 9) { + LoadDW(addr, value, res); + if (res) + goto fault; + addr += 8; + regs->regs[30] = value; + } + if (reg & 0x10) { + LoadDW(addr, value, res); + if (res) + goto fault; + regs->regs[31] = value; + } + goto success; +#endif /* CONFIG_64BIT */ + + goto sigill; + + case mm_sdm_func: +#ifdef CONFIG_64BIT + reg = insn.mm_m_format.rd; + rvar = reg & 0xf; + if ((rvar > 9) || !reg) + goto sigill; + if (reg & 0x10) { + if (user && !access_ok(addr, 8 * (rvar + 1))) + goto sigbus; + } else { + if (user && !access_ok(addr, 8 * rvar)) + goto sigbus; + } + if (rvar == 9) + rvar = 8; + + for (i = 16; rvar; rvar--, i++) { + value = regs->regs[i]; + StoreDW(addr, value, res); + if (res) + goto fault; + addr += 8; + } + if ((reg & 0xf) == 9) { + value = regs->regs[30]; + StoreDW(addr, value, res); + if (res) + goto fault; + addr += 8; + } + if (reg & 0x10) { + value = regs->regs[31]; + StoreDW(addr, value, res); + if (res) + goto fault; + } + goto success; +#endif /* CONFIG_64BIT */ + + goto sigill; + + /* LWC2, SWC2, LDC2, SDC2 are not serviced */ + } + + goto sigbus; + + case mm_pool32c_op: + switch (insn.mm_m_format.func) { + case mm_lwu_func: + reg = insn.mm_m_format.rd; + goto loadWU; + } + + /* LL,SC,LLD,SCD are not serviced */ + goto sigbus; + +#ifdef CONFIG_MIPS_FP_SUPPORT + case mm_pool32f_op: + switch (insn.mm_x_format.func) { + case mm_lwxc1_func: + case mm_swxc1_func: + case mm_ldxc1_func: + case mm_sdxc1_func: + goto fpu_emul; + } + + goto sigbus; + + case mm_ldc132_op: + case mm_sdc132_op: + case mm_lwc132_op: + case mm_swc132_op: { + void __user *fault_addr = NULL; + +fpu_emul: + /* roll back jump/branch */ + regs->cp0_epc = origpc; + regs->regs[31] = orig31; + + die_if_kernel("Unaligned FP access in kernel code", regs); + BUG_ON(!used_math()); + BUG_ON(!is_fpu_owner()); + + res = fpu_emulator_cop1Handler(regs, ¤t->thread.fpu, 1, + &fault_addr); + own_fpu(1); /* restore FPU state */ + + /* If something went wrong, signal */ + process_fpemu_return(res, fault_addr, 0); + + if (res == 0) + goto success; + return; + } +#endif /* CONFIG_MIPS_FP_SUPPORT */ + + case mm_lh32_op: + reg = insn.mm_i_format.rt; + goto loadHW; + + case mm_lhu32_op: + reg = insn.mm_i_format.rt; + goto loadHWU; + + case mm_lw32_op: + reg = insn.mm_i_format.rt; + goto loadW; + + case mm_sh32_op: + reg = insn.mm_i_format.rt; + goto storeHW; + + case mm_sw32_op: + reg = insn.mm_i_format.rt; + goto storeW; + + case mm_ld32_op: + reg = insn.mm_i_format.rt; + goto loadDW; + + case mm_sd32_op: + reg = insn.mm_i_format.rt; + goto storeDW; + + case mm_pool16c_op: + switch (insn.mm16_m_format.func) { + case mm_lwm16_op: + reg = insn.mm16_m_format.rlist; + rvar = reg + 1; + if (user && !access_ok(addr, 4 * rvar)) + goto sigbus; + + for (i = 16; rvar; rvar--, i++) { + LoadW(addr, value, res); + if (res) + goto fault; + addr += 4; + regs->regs[i] = value; + } + LoadW(addr, value, res); + if (res) + goto fault; + regs->regs[31] = value; + + goto success; + + case mm_swm16_op: + reg = insn.mm16_m_format.rlist; + rvar = reg + 1; + if (user && !access_ok(addr, 4 * rvar)) + goto sigbus; + + for (i = 16; rvar; rvar--, i++) { + value = regs->regs[i]; + StoreW(addr, value, res); + if (res) + goto fault; + addr += 4; + } + value = regs->regs[31]; + StoreW(addr, value, res); + if (res) + goto fault; + + goto success; + + } + + goto sigbus; + + case mm_lhu16_op: + reg = reg16to32[insn.mm16_rb_format.rt]; + goto loadHWU; + + case mm_lw16_op: + reg = reg16to32[insn.mm16_rb_format.rt]; + goto loadW; + + case mm_sh16_op: + reg = reg16to32st[insn.mm16_rb_format.rt]; + goto storeHW; + + case mm_sw16_op: + reg = reg16to32st[insn.mm16_rb_format.rt]; + goto storeW; + + case mm_lwsp16_op: + reg = insn.mm16_r5_format.rt; + goto loadW; + + case mm_swsp16_op: + reg = insn.mm16_r5_format.rt; + goto storeW; + + case mm_lwgp16_op: + reg = reg16to32[insn.mm16_r3_format.rt]; + goto loadW; + + default: + goto sigill; + } + +loadHW: + if (user && !access_ok(addr, 2)) + goto sigbus; + + LoadHW(addr, value, res); + if (res) + goto fault; + regs->regs[reg] = value; + goto success; + +loadHWU: + if (user && !access_ok(addr, 2)) + goto sigbus; + + LoadHWU(addr, value, res); + if (res) + goto fault; + regs->regs[reg] = value; + goto success; + +loadW: + if (user && !access_ok(addr, 4)) + goto sigbus; + + LoadW(addr, value, res); + if (res) + goto fault; + regs->regs[reg] = value; + goto success; + +loadWU: +#ifdef CONFIG_64BIT + /* + * A 32-bit kernel might be running on a 64-bit processor. But + * if we're on a 32-bit processor and an i-cache incoherency + * or race makes us see a 64-bit instruction here the sdl/sdr + * would blow up, so for now we don't handle unaligned 64-bit + * instructions on 32-bit kernels. + */ + if (user && !access_ok(addr, 4)) + goto sigbus; + + LoadWU(addr, value, res); + if (res) + goto fault; + regs->regs[reg] = value; + goto success; +#endif /* CONFIG_64BIT */ + + /* Cannot handle 64-bit instructions in 32-bit kernel */ + goto sigill; + +loadDW: +#ifdef CONFIG_64BIT + /* + * A 32-bit kernel might be running on a 64-bit processor. But + * if we're on a 32-bit processor and an i-cache incoherency + * or race makes us see a 64-bit instruction here the sdl/sdr + * would blow up, so for now we don't handle unaligned 64-bit + * instructions on 32-bit kernels. + */ + if (user && !access_ok(addr, 8)) + goto sigbus; + + LoadDW(addr, value, res); + if (res) + goto fault; + regs->regs[reg] = value; + goto success; +#endif /* CONFIG_64BIT */ + + /* Cannot handle 64-bit instructions in 32-bit kernel */ + goto sigill; + +storeHW: + if (user && !access_ok(addr, 2)) + goto sigbus; + + value = regs->regs[reg]; + StoreHW(addr, value, res); + if (res) + goto fault; + goto success; + +storeW: + if (user && !access_ok(addr, 4)) + goto sigbus; + + value = regs->regs[reg]; + StoreW(addr, value, res); + if (res) + goto fault; + goto success; + +storeDW: +#ifdef CONFIG_64BIT + /* + * A 32-bit kernel might be running on a 64-bit processor. But + * if we're on a 32-bit processor and an i-cache incoherency + * or race makes us see a 64-bit instruction here the sdl/sdr + * would blow up, so for now we don't handle unaligned 64-bit + * instructions on 32-bit kernels. + */ + if (user && !access_ok(addr, 8)) + goto sigbus; + + value = regs->regs[reg]; + StoreDW(addr, value, res); + if (res) + goto fault; + goto success; +#endif /* CONFIG_64BIT */ + + /* Cannot handle 64-bit instructions in 32-bit kernel */ + goto sigill; + +success: + regs->cp0_epc = contpc; /* advance or branch */ + +#ifdef CONFIG_DEBUG_FS + unaligned_instructions++; +#endif + return; + +fault: + /* roll back jump/branch */ + regs->cp0_epc = origpc; + regs->regs[31] = orig31; + /* Did we have an exception handler installed? */ + if (fixup_exception(regs)) + return; + + die_if_kernel("Unhandled kernel unaligned access", regs); + force_sig(SIGSEGV); + + return; + +sigbus: + die_if_kernel("Unhandled kernel unaligned access", regs); + force_sig(SIGBUS); + + return; + +sigill: + die_if_kernel + ("Unhandled kernel unaligned access or invalid instruction", regs); + force_sig(SIGILL); +} + +static void emulate_load_store_MIPS16e(struct pt_regs *regs, void __user * addr) +{ + unsigned long value; + unsigned int res; + int reg; + unsigned long orig31; + u16 __user *pc16; + unsigned long origpc; + union mips16e_instruction mips16inst, oldinst; + unsigned int opcode; + int extended = 0; + bool user = user_mode(regs); + + origpc = regs->cp0_epc; + orig31 = regs->regs[31]; + pc16 = (unsigned short __user *)msk_isa16_mode(origpc); + /* + * This load never faults. + */ + __get_user(mips16inst.full, pc16); + oldinst = mips16inst; + + /* skip EXTEND instruction */ + if (mips16inst.ri.opcode == MIPS16e_extend_op) { + extended = 1; + pc16++; + __get_user(mips16inst.full, pc16); + } else if (delay_slot(regs)) { + /* skip jump instructions */ + /* JAL/JALX are 32 bits but have OPCODE in first short int */ + if (mips16inst.ri.opcode == MIPS16e_jal_op) + pc16++; + pc16++; + if (get_user(mips16inst.full, pc16)) + goto sigbus; + } + + opcode = mips16inst.ri.opcode; + switch (opcode) { + case MIPS16e_i64_op: /* I64 or RI64 instruction */ + switch (mips16inst.i64.func) { /* I64/RI64 func field check */ + case MIPS16e_ldpc_func: + case MIPS16e_ldsp_func: + reg = reg16to32[mips16inst.ri64.ry]; + goto loadDW; + + case MIPS16e_sdsp_func: + reg = reg16to32[mips16inst.ri64.ry]; + goto writeDW; + + case MIPS16e_sdrasp_func: + reg = 29; /* GPRSP */ + goto writeDW; + } + + goto sigbus; + + case MIPS16e_swsp_op: + reg = reg16to32[mips16inst.ri.rx]; + if (extended && cpu_has_mips16e2) + switch (mips16inst.ri.imm >> 5) { + case 0: /* SWSP */ + case 1: /* SWGP */ + break; + case 2: /* SHGP */ + opcode = MIPS16e_sh_op; + break; + default: + goto sigbus; + } + break; + + case MIPS16e_lwpc_op: + reg = reg16to32[mips16inst.ri.rx]; + break; + + case MIPS16e_lwsp_op: + reg = reg16to32[mips16inst.ri.rx]; + if (extended && cpu_has_mips16e2) + switch (mips16inst.ri.imm >> 5) { + case 0: /* LWSP */ + case 1: /* LWGP */ + break; + case 2: /* LHGP */ + opcode = MIPS16e_lh_op; + break; + case 4: /* LHUGP */ + opcode = MIPS16e_lhu_op; + break; + default: + goto sigbus; + } + break; + + case MIPS16e_i8_op: + if (mips16inst.i8.func != MIPS16e_swrasp_func) + goto sigbus; + reg = 29; /* GPRSP */ + break; + + default: + reg = reg16to32[mips16inst.rri.ry]; + break; + } + + switch (opcode) { + + case MIPS16e_lb_op: + case MIPS16e_lbu_op: + case MIPS16e_sb_op: + goto sigbus; + + case MIPS16e_lh_op: + if (user && !access_ok(addr, 2)) + goto sigbus; + + LoadHW(addr, value, res); + if (res) + goto fault; + MIPS16e_compute_return_epc(regs, &oldinst); + regs->regs[reg] = value; + break; + + case MIPS16e_lhu_op: + if (user && !access_ok(addr, 2)) + goto sigbus; + + LoadHWU(addr, value, res); + if (res) + goto fault; + MIPS16e_compute_return_epc(regs, &oldinst); + regs->regs[reg] = value; + break; + + case MIPS16e_lw_op: + case MIPS16e_lwpc_op: + case MIPS16e_lwsp_op: + if (user && !access_ok(addr, 4)) + goto sigbus; + + LoadW(addr, value, res); + if (res) + goto fault; + MIPS16e_compute_return_epc(regs, &oldinst); + regs->regs[reg] = value; + break; + + case MIPS16e_lwu_op: +#ifdef CONFIG_64BIT + /* + * A 32-bit kernel might be running on a 64-bit processor. But + * if we're on a 32-bit processor and an i-cache incoherency + * or race makes us see a 64-bit instruction here the sdl/sdr + * would blow up, so for now we don't handle unaligned 64-bit + * instructions on 32-bit kernels. + */ + if (user && !access_ok(addr, 4)) + goto sigbus; + + LoadWU(addr, value, res); + if (res) + goto fault; + MIPS16e_compute_return_epc(regs, &oldinst); + regs->regs[reg] = value; + break; +#endif /* CONFIG_64BIT */ + + /* Cannot handle 64-bit instructions in 32-bit kernel */ + goto sigill; + + case MIPS16e_ld_op: +loadDW: +#ifdef CONFIG_64BIT + /* + * A 32-bit kernel might be running on a 64-bit processor. But + * if we're on a 32-bit processor and an i-cache incoherency + * or race makes us see a 64-bit instruction here the sdl/sdr + * would blow up, so for now we don't handle unaligned 64-bit + * instructions on 32-bit kernels. + */ + if (user && !access_ok(addr, 8)) + goto sigbus; + + LoadDW(addr, value, res); + if (res) + goto fault; + MIPS16e_compute_return_epc(regs, &oldinst); + regs->regs[reg] = value; + break; +#endif /* CONFIG_64BIT */ + + /* Cannot handle 64-bit instructions in 32-bit kernel */ + goto sigill; + + case MIPS16e_sh_op: + if (user && !access_ok(addr, 2)) + goto sigbus; + + MIPS16e_compute_return_epc(regs, &oldinst); + value = regs->regs[reg]; + StoreHW(addr, value, res); + if (res) + goto fault; + break; + + case MIPS16e_sw_op: + case MIPS16e_swsp_op: + case MIPS16e_i8_op: /* actually - MIPS16e_swrasp_func */ + if (user && !access_ok(addr, 4)) + goto sigbus; + + MIPS16e_compute_return_epc(regs, &oldinst); + value = regs->regs[reg]; + StoreW(addr, value, res); + if (res) + goto fault; + break; + + case MIPS16e_sd_op: +writeDW: +#ifdef CONFIG_64BIT + /* + * A 32-bit kernel might be running on a 64-bit processor. But + * if we're on a 32-bit processor and an i-cache incoherency + * or race makes us see a 64-bit instruction here the sdl/sdr + * would blow up, so for now we don't handle unaligned 64-bit + * instructions on 32-bit kernels. + */ + if (user && !access_ok(addr, 8)) + goto sigbus; + + MIPS16e_compute_return_epc(regs, &oldinst); + value = regs->regs[reg]; + StoreDW(addr, value, res); + if (res) + goto fault; + break; +#endif /* CONFIG_64BIT */ + + /* Cannot handle 64-bit instructions in 32-bit kernel */ + goto sigill; + + default: + /* + * Pheeee... We encountered an yet unknown instruction or + * cache coherence problem. Die sucker, die ... + */ + goto sigill; + } + +#ifdef CONFIG_DEBUG_FS + unaligned_instructions++; +#endif + + return; + +fault: + /* roll back jump/branch */ + regs->cp0_epc = origpc; + regs->regs[31] = orig31; + /* Did we have an exception handler installed? */ + if (fixup_exception(regs)) + return; + + die_if_kernel("Unhandled kernel unaligned access", regs); + force_sig(SIGSEGV); + + return; + +sigbus: + die_if_kernel("Unhandled kernel unaligned access", regs); + force_sig(SIGBUS); + + return; + +sigill: + die_if_kernel + ("Unhandled kernel unaligned access or invalid instruction", regs); + force_sig(SIGILL); +} + +asmlinkage void do_ade(struct pt_regs *regs) +{ + enum ctx_state prev_state; + unsigned int *pc; + + prev_state = exception_enter(); + perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, + 1, regs, regs->cp0_badvaddr); + +#ifdef CONFIG_64BIT + /* + * check, if we are hitting space between CPU implemented maximum + * virtual user address and 64bit maximum virtual user address + * and do exception handling to get EFAULTs for get_user/put_user + */ + if ((regs->cp0_badvaddr >= (1UL << cpu_vmbits)) && + (regs->cp0_badvaddr < XKSSEG)) { + if (fixup_exception(regs)) { + current->thread.cp0_baduaddr = regs->cp0_badvaddr; + return; + } + goto sigbus; + } +#endif + + /* + * Did we catch a fault trying to load an instruction? + */ + if (regs->cp0_badvaddr == regs->cp0_epc) + goto sigbus; + + if (user_mode(regs) && !test_thread_flag(TIF_FIXADE)) + goto sigbus; + if (unaligned_action == UNALIGNED_ACTION_SIGNAL) + goto sigbus; + + /* + * Do branch emulation only if we didn't forward the exception. + * This is all so but ugly ... + */ + + /* + * Are we running in microMIPS mode? + */ + if (get_isa16_mode(regs->cp0_epc)) { + /* + * Did we catch a fault trying to load an instruction in + * 16-bit mode? + */ + if (regs->cp0_badvaddr == msk_isa16_mode(regs->cp0_epc)) + goto sigbus; + if (unaligned_action == UNALIGNED_ACTION_SHOW) + show_registers(regs); + + if (cpu_has_mmips) { + emulate_load_store_microMIPS(regs, + (void __user *)regs->cp0_badvaddr); + return; + } + + if (cpu_has_mips16) { + emulate_load_store_MIPS16e(regs, + (void __user *)regs->cp0_badvaddr); + return; + } + + goto sigbus; + } + + if (unaligned_action == UNALIGNED_ACTION_SHOW) + show_registers(regs); + pc = (unsigned int *)exception_epc(regs); + + emulate_load_store_insn(regs, (void __user *)regs->cp0_badvaddr, pc); + + return; + +sigbus: + die_if_kernel("Kernel unaligned instruction access", regs); + force_sig(SIGBUS); + + /* + * XXX On return from the signal handler we should advance the epc + */ + exception_exit(prev_state); +} + +#ifdef CONFIG_DEBUG_FS +static int __init debugfs_unaligned(void) +{ + debugfs_create_u32("unaligned_instructions", S_IRUGO, mips_debugfs_dir, + &unaligned_instructions); + debugfs_create_u32("unaligned_action", S_IRUGO | S_IWUSR, + mips_debugfs_dir, &unaligned_action); + return 0; +} +arch_initcall(debugfs_unaligned); +#endif |