/* * 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. * * 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 * * ... * 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 * #include * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "unaligned.h" #define STR(x) __STR(x) #define __STR(x) #x static unsigned long ai_user; static unsigned long ai_sys; static unsigned long ai_skipped; static unsigned long ai_word; static unsigned long ai_dword; int ai_usermode = UNALIGNED_ACTION_FIXUP /*--- | UNALIGNED_WARN ---*/ ; int ai_kernelmode = UNALIGNED_ACTION_FIXUP /*--- | UNALIGNED_WARN ---*/ ; #ifdef CONFIG_DEBUG_FS u32 unaligned_instructions; #endif #define UNALIGNED_MAX_SCORE_ENTRIES 8 #if defined(UNALIGNED_MAX_SCORE_ENTRIES) /*--------------------------------------------------------------------------------*\ \*--------------------------------------------------------------------------------*/ struct _unaligned_access_score_entry { unsigned long unaligneds; unsigned long ts; unsigned short mips16; unsigned short caddr_of; /*--- > 0: pc-offset in codetable in bytes---*/ #define CODE_ENTRIES 5 unsigned int code[CODE_ENTRIES]; /*--- Code muss gesichert werden, da evtl. Virtual Memory ---*/ char shortcomm[8]; /*--- Name mal sichern falls beendet ---*/ pid_t pid; void *pc; }; static void add_unaligned_access_to_table(void *pc, struct _unaligned_access_score_entry table[], unsigned int table_entries, unsigned int usermode); static struct _unaligned_access_score_entry user_score_table[UNALIGNED_MAX_SCORE_ENTRIES], sys_score_table[UNALIGNED_MAX_SCORE_ENTRIES]; #endif/*--- #if defined(UNALIGNED_MAX_SCORE_ENTRIES) ---*/ extern void show_registers(struct pt_regs *regs); static void emulate_load_store_insn(struct pt_regs *regs, void __user *addr, unsigned int __user *pc) { union mips_instruction insn; unsigned long value; unsigned int res; siginfo_t info; regs->regs[0] = 0; /*--------------------------------------------------------------------------------------*\ * An address error exception occurs on an instruction or data access when an attempt * is made to execute one of the following: * • Fetch an instruction, load a word, or store a word that is not aligned on a word boundary • Load or store a halfword that is not aligned on a halfword boundary • Reference the kernel address space from user mode * Note that in the case of an instruction fetch that is not aligned on a word boundary, * PC is updated before the condition is detected. Therefore, both EPC and BadVAddr point * to the unaligned instruction address. In the case of a data access the exception is * taken if either an unaligned address or an address that was inaccessible in the * current processor mode was referenced by a load or store instruction. \*--------------------------------------------------------------------------------------*/ if (user_mode(regs) && !unlikely(access_ok(VERIFY_READ, pc, 4))) { printk(KERN_ERR "[%s] illegal address 0x%p (sigill)\n", __FUNCTION__, pc); goto sigill; } if(__get_user(insn.word, pc)) { printk(KERN_ERR "[%s] load from address 0x%p failed (sigbus)\n", __FUNCTION__, pc); goto sigbus; } 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; /* * DSP instructions */ case spec3_op: /*--- printk("[%s] special opcode 3 found\n", __FUNCTION__); ---*/ switch (insn.sp3_format.sp3_opcode) { case lxx_op: /*--- if(unaligned_action & UNALIGNED_WARN) { ---*/ /*--- printk(KERN_INFO "[%s] opcode group LX found opcode=0x%x base=%d index=%d rd=%d lx_opcode=0x%x sp3_opcode=0x%x at 0x%x\n", ---*/ /*--- __FUNCTION__, ---*/ /*--- insn.lx_format.opcode, insn.lx_format.base, insn.lx_format.index, insn.lx_format.rd, ---*/ /*--- insn.lx_format.lx_opcode, insn.lx_format.sp3_opcode, regs->cp0_epc); ---*/ /*--- } ---*/ switch (insn.lx_format.lx_opcode) { case lwx_op: { unsigned int dest = 0; unsigned char *base = (unsigned char *)(regs->regs[insn.lx_format.base]); unsigned int index = regs->regs[insn.lx_format.index]; if (user_mode(regs) && !access_ok(VERIFY_READ, addr, 4)) goto sigbus; __asm__ __volatile__ (".set\tnoat\n" #ifdef __BIG_ENDIAN /*--- dest |= base[index + 0] << 24; ---*/ /*--- dest |= base[index + 1] << 16; ---*/ /*--- dest |= base[index + 2] << 8; ---*/ /*--- dest |= base[index + 3] << 0; ---*/ "1:\tlbu\t$1, 0(%2)\n" "sll\t$1, 0x18\n\t" "or\t%0, $1\n\t" "2:\tlbu\t$1, 1(%2)\n\t" "sll\t$1, 0x10\n\t" "or\t%0, $1\n\t" "3:\tlbu\t$1, 2(%2)\n\t" "sll\t$1, 0x8\n\t" "or\t%0, $1\n\t" "4:\tlbu\t$1, 3(%2)\n\t" "or\t%0, $1\n\t" #endif #ifdef __LITTLE_ENDIAN /*--- dest |= base[index + 3] << 24; ---*/ /*--- dest |= base[index + 2] << 16; ---*/ /*--- dest |= base[index + 1] << 8; ---*/ /*--- dest |= base[index + 0] << 0; ---*/ "1:\tlbu\t$1, 3(%2)\n" "sll\t$1, 0x18\n\t" "or\t%0, $1\n\t" "2:\tlbu\t$1, 2(%2)\n\t" "sll\t$1, 0x10\n\t" "or\t%0, $1\n\t" "3:\tlbu\t$1, 1(%2)\n\t" "sll\t$1, 0x8\n\t" "or\t%0, $1\n\t" "4:\tlbu\t$1, 0(%2)\n\t" "or\t%0, $1\n\t" #endif "li\t%1, 0\n" "5:\t.set\tat\n\t" ".section\t.fixup,\"ax\"\n\t" "6:\tli\t%1, %3\n\t" "j\t5b\n\t" ".previous\n\t" ".section\t__ex_table,\"a\"\n\t" STR(PTR)"\t1b, 6b\n\t" STR(PTR)"\t2b, 6b\n\t" STR(PTR)"\t3b, 6b\n\t" STR(PTR)"\t4b, 6b\n\t" ".previous" : "+r" (dest), "=r" (res) : "r" (&base[index]), "i" (-EFAULT)); if (res) goto fault; regs->regs[insn.lx_format.rd] = dest; if(unaligned_action & UNALIGNED_WARN) { printk(KERN_INFO "[%s] LWX r%d, r%d ( r%d ) # 0x%lx = *(unsigned int *)(0x%lx + 0x%lx)\n", __FUNCTION__, insn.lx_format.rd, insn.lx_format.index, insn.lx_format.base, regs->regs[insn.lx_format.rd], regs->regs[insn.lx_format.index], regs->regs[insn.lx_format.base]); } } compute_return_epc(regs); break; case lhx_op: { unsigned int dest = 0; unsigned char *base = (unsigned char *)(regs->regs[insn.lx_format.base]); unsigned int index = regs->regs[insn.lx_format.index]; if (user_mode(regs) && !access_ok(VERIFY_READ, addr, 2)) goto sigbus; __asm__ __volatile__ (".set\tnoat\n" #ifdef __BIG_ENDIAN /*--- dest |= base[index + 0] << 8; ---*/ /*--- dest |= base[index + 1] << 0; ---*/ "1:\tlbu\t$1, 0(%2)\n" "sll\t$1, 0x8\n\t" "or\t%0, $1\n\t" "2:\tlbu\t$1, 1(%2)\n\t" "or\t%0, $1\n\t" #endif #ifdef __LITTLE_ENDIAN /*--- dest |= base[index + 1] << 8; ---*/ /*--- dest |= base[index + 0] << 0; ---*/ "1:\tlbu\t$1, 1(%2)\n" "sll\t$1, 0x8\n\t" "or\t%0, $1\n\t" "2:\tlbu\t$1, 0(%2)\n\t" "or\t%0, $1\n\t" #endif "li\t%1, 0\n" "3:\t.set\tat\n\t" ".section\t.fixup,\"ax\"\n\t" "4:\tli\t%1, %3\n\t" "j\t3b\n\t" ".previous\n\t" ".section\t__ex_table,\"a\"\n\t" STR(PTR)"\t1b, 4b\n\t" STR(PTR)"\t2b, 4b\n\t" ".previous" : "+r" (dest), "=r" (res) : "r" (&base[index]), "i" (-EFAULT)); if (res) goto fault; regs->regs[insn.lx_format.rd] = dest; if(unaligned_action & UNALIGNED_WARN) { printk(KERN_INFO "[%s] LHX r%d, r%d ( r%d ) # 0x%lx = (unsigned int)*(unsigned short *)(0x%lx + 0x%lx)\n", __FUNCTION__, insn.lx_format.rd, insn.lx_format.index, insn.lx_format.base, regs->regs[insn.lx_format.rd], regs->regs[insn.lx_format.index], regs->regs[insn.lx_format.base]); } } compute_return_epc(regs); break; case lbux_op: /*--- 8 Bit zugriffe können nicht analigned sein ---*/ default: printk(KERN_ERR "[%s] opcode group LX found, unknown element 0x%x.\n", __FUNCTION__, insn.lx_format.lx_opcode); goto sigbus; } break; case ext_op: case dextm_op: case dextu_op: case dext_op: case ins_op: case dinsm_op: case dinsu_op: case dins_op: case insv_op: case adduqb_op: case bshfl_op: case dbshfl_op: case extrwph_op: case rdhwr_op: default: goto sigbus; } break; /* * The remaining opcodes are the ones that are really of interest. */ case lh_op: if (user_mode(regs) && !access_ok(VERIFY_READ, addr, 2)) goto sigbus; ai_word++; __asm__ __volatile__ (".set\tnoat\n" #ifdef __BIG_ENDIAN "1:\tlb\t%0, 0(%2)\n" "2:\tlbu\t$1, 1(%2)\n\t" #endif #ifdef __LITTLE_ENDIAN "1:\tlb\t%0, 1(%2)\n" "2:\tlbu\t$1, 0(%2)\n\t" #endif "sll\t%0, 0x8\n\t" "or\t%0, $1\n\t" "li\t%1, 0\n" "3:\t.set\tat\n\t" ".section\t.fixup,\"ax\"\n\t" "4:\tli\t%1, %3\n\t" "j\t3b\n\t" ".previous\n\t" ".section\t__ex_table,\"a\"\n\t" STR(PTR)"\t1b, 4b\n\t" STR(PTR)"\t2b, 4b\n\t" ".previous" : "=&r" (value), "=r" (res) : "r" (addr), "i" (-EFAULT)); if (res) goto fault; compute_return_epc(regs); regs->regs[insn.i_format.rt] = value; break; case lw_op: if (user_mode(regs) && !access_ok(VERIFY_READ, addr, 4)) goto sigbus; ai_dword++; __asm__ __volatile__ ( #ifdef __BIG_ENDIAN #ifdef CONFIG_MACH_FUSIV_MIPS1 "\tli\t %1, 1\n\t" "1:\tlbu\t%0, (%2)\n" "2:\tlbu\t$23, 1(%2)\n\t" "5:\tlbu\t$22, 2(%2)\n\t" "6:\tlbu\t$21, 3(%2)\n\t" #else "1:\tlwl\t%0, (%2)\n" "2:\tlwr\t%0, 3(%2)\n\t" #endif #endif #ifdef __LITTLE_ENDIAN "1:\tlwl\t%0, 3(%2)\n" "2:\tlwr\t%0, (%2)\n\t" #endif #ifdef CONFIG_MACH_FUSIV_MIPS1 "sll\t%0,0x8\n\t" "or\t%0,$23\n\t" "sll\t%0,0x8\n\t" "or\t%0,$22\n\t" "sll\t%0,0x8\n\t" "or\t%0,$21\n\t" #endif "li\t%1, 0\n" #ifdef CONFIG_MACH_FUSIV_MIPS1 "3:\t.set\tat\n\t" "\t.section\t.fixup,\"ax\"\n\t" #else "3:\t.section\t.fixup,\"ax\"\n\t" #endif "4:\tli\t%1, %3\n\t" "j\t3b\n\t" ".previous\n\t" ".section\t__ex_table,\"a\"\n\t" STR(PTR)"\t1b, 4b\n\t" STR(PTR)"\t2b, 4b\n\t" #ifdef CONFIG_MACH_FUSIV_MIPS1 STR(PTR)"\t5b, 4b\n\t" STR(PTR)"\t6b, 4b\n\t" #endif ".previous" : "=&r" (value), "=r" (res) #ifdef CONFIG_MACH_FUSIV_MIPS1 : "r" (addr), "i" (-EFAULT) :"$23","$22","$21"); #else : "r" (addr), "i" (-EFAULT)); #endif if (res) goto fault; compute_return_epc(regs); regs->regs[insn.i_format.rt] = value; break; case lhu_op: if (user_mode(regs) && !access_ok(VERIFY_READ, addr, 2)) goto sigbus; ai_word++; __asm__ __volatile__ ( ".set\tnoat\n" #ifdef __BIG_ENDIAN "1:\tlbu\t%0, 0(%2)\n" "2:\tlbu\t$1, 1(%2)\n\t" #endif #ifdef __LITTLE_ENDIAN "1:\tlbu\t%0, 1(%2)\n" "2:\tlbu\t$1, 0(%2)\n\t" #endif "sll\t%0, 0x8\n\t" "or\t%0, $1\n\t" "li\t%1, 0\n" "3:\t.set\tat\n\t" ".section\t.fixup,\"ax\"\n\t" "4:\tli\t%1, %3\n\t" "j\t3b\n\t" ".previous\n\t" ".section\t__ex_table,\"a\"\n\t" STR(PTR)"\t1b, 4b\n\t" STR(PTR)"\t2b, 4b\n\t" ".previous" : "=&r" (value), "=r" (res) : "r" (addr), "i" (-EFAULT)); 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_mode(regs) && !access_ok(VERIFY_READ, addr, 4)) goto sigbus; __asm__ __volatile__ ( #ifdef __BIG_ENDIAN "1:\tlwl\t%0, (%2)\n" "2:\tlwr\t%0, 3(%2)\n\t" #endif #ifdef __LITTLE_ENDIAN "1:\tlwl\t%0, 3(%2)\n" "2:\tlwr\t%0, (%2)\n\t" #endif "dsll\t%0, %0, 32\n\t" "dsrl\t%0, %0, 32\n\t" "li\t%1, 0\n" "3:\t.section\t.fixup,\"ax\"\n\t" "4:\tli\t%1, %3\n\t" "j\t3b\n\t" ".previous\n\t" ".section\t__ex_table,\"a\"\n\t" STR(PTR)"\t1b, 4b\n\t" STR(PTR)"\t2b, 4b\n\t" ".previous" : "=&r" (value), "=r" (res) : "r" (addr), "i" (-EFAULT)); 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_mode(regs) && !access_ok(VERIFY_READ, addr, 8)) goto sigbus; __asm__ __volatile__ ( #ifdef __BIG_ENDIAN "1:\tldl\t%0, (%2)\n" "2:\tldr\t%0, 7(%2)\n\t" #endif #ifdef __LITTLE_ENDIAN "1:\tldl\t%0, 7(%2)\n" "2:\tldr\t%0, (%2)\n\t" #endif "li\t%1, 0\n" "3:\t.section\t.fixup,\"ax\"\n\t" "4:\tli\t%1, %3\n\t" "j\t3b\n\t" ".previous\n\t" ".section\t__ex_table,\"a\"\n\t" STR(PTR)"\t1b, 4b\n\t" STR(PTR)"\t2b, 4b\n\t" ".previous" : "=&r" (value), "=r" (res) : "r" (addr), "i" (-EFAULT)); 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_mode(regs) && !access_ok(VERIFY_WRITE, addr, 2)) goto sigbus; ai_word++; value = regs->regs[insn.i_format.rt]; __asm__ __volatile__ ( #ifdef __BIG_ENDIAN ".set\tnoat\n" "1:\tsb\t%1, 1(%2)\n\t" "srl\t$1, %1, 0x8\n" "2:\tsb\t$1, 0(%2)\n\t" ".set\tat\n\t" #endif #ifdef __LITTLE_ENDIAN ".set\tnoat\n" "1:\tsb\t%1, 0(%2)\n\t" "srl\t$1,%1, 0x8\n" "2:\tsb\t$1, 1(%2)\n\t" ".set\tat\n\t" #endif "li\t%0, 0\n" "3:\n\t" ".section\t.fixup,\"ax\"\n\t" "4:\tli\t%0, %3\n\t" "j\t3b\n\t" ".previous\n\t" ".section\t__ex_table,\"a\"\n\t" STR(PTR)"\t1b, 4b\n\t" STR(PTR)"\t2b, 4b\n\t" ".previous" : "=r" (res) : "r" (value), "r" (addr), "i" (-EFAULT)); if (res) goto fault; compute_return_epc(regs); break; case sw_op: if (user_mode(regs) && !access_ok(VERIFY_WRITE, addr, 4)) goto sigbus; ai_dword++; value = regs->regs[insn.i_format.rt]; __asm__ __volatile__ ( #ifdef __BIG_ENDIAN #ifdef CONFIG_MACH_FUSIV_MIPS1 "1:\tsb\t%1,3(%2)\n" "srl\t$23,%1,0x8\n" "2:\tsb\t$23, 2(%2)\n\t" "srl\t$23,%1,0x10\n" "5:\tsb\t$23, 1(%2)\n\t" "srl\t$23,%1,0x18\n" "6:\tsb\t$23, 0(%2)\n\t" #else "1:\tswl\t%1,(%2)\n" "2:\tswr\t%1, 3(%2)\n\t" #endif #endif #ifdef __LITTLE_ENDIAN "1:\tswl\t%1, 3(%2)\n" "2:\tswr\t%1, (%2)\n\t" #endif "li\t%0, 0\n" "3:\n\t" ".section\t.fixup,\"ax\"\n\t" "4:\tli\t%0, %3\n\t" "j\t3b\n\t" ".previous\n\t" ".section\t__ex_table,\"a\"\n\t" STR(PTR)"\t1b, 4b\n\t" STR(PTR)"\t2b, 4b\n\t" #ifdef CONFIG_MACH_FUSIV_MIPS1 STR(PTR)"\t5b, 4b\n\t" STR(PTR)"\t6b, 4b\n\t" #endif ".previous" : "=r" (res) #ifdef CONFIG_MACH_FUSIV_MIPS1 : "r" (value), "r" (addr), "i" (-EFAULT) : "$23"); #else : "r" (value), "r" (addr), "i" (-EFAULT)); #endif if (res) goto fault; compute_return_epc(regs); 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_mode(regs) && !access_ok(VERIFY_WRITE, addr, 8)) goto sigbus; value = regs->regs[insn.i_format.rt]; __asm__ __volatile__ ( #ifdef __BIG_ENDIAN "1:\tsdl\t%1,(%2)\n" "2:\tsdr\t%1, 7(%2)\n\t" #endif #ifdef __LITTLE_ENDIAN "1:\tsdl\t%1, 7(%2)\n" "2:\tsdr\t%1, (%2)\n\t" #endif "li\t%0, 0\n" "3:\n\t" ".section\t.fixup,\"ax\"\n\t" "4:\tli\t%0, %3\n\t" "j\t3b\n\t" ".previous\n\t" ".section\t__ex_table,\"a\"\n\t" STR(PTR)"\t1b, 4b\n\t" STR(PTR)"\t2b, 4b\n\t" ".previous" : "=r" (res) : "r" (value), "r" (addr), "i" (-EFAULT)); if (res) goto fault; compute_return_epc(regs); break; #endif /* CONFIG_64BIT */ /* Cannot handle 64-bit instructions in 32-bit kernel */ goto sigill; case lwc1_op: case ldc1_op: case swc1_op: case sdc1_op: /* * I herewith declare: this does not happen. So send SIGBUS. */ goto sigbus; case lwc2_op: case ldc2_op: case swc2_op: case sdc2_op: /* * These are the coprocessor 2 load/stores. The current * implementations don't use cp2 and cp2 should always be * disabled in c0_status. So send SIGILL. * (No longer true: The Sony Praystation uses cp2 for * 3D matrix operations. Dunno if that thingy has a MMU ...) */ 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: /* Did we have an exception handler installed? */ if (fixup_exception(regs)) return; die_if_kernel("Unhandled kernel unaligned access", regs); info.si_signo = SIGSEGV; info.si_errno = 0; info.si_code = SEGV_MAPERR; info.si_addr = (void __user *) addr; force_sig_info(SIGSEGV, &info, current); return; sigbus: die_if_kernel("Unhandled kernel unaligned access", regs); info.si_signo = SIGBUS; info.si_errno = 0; info.si_code = BUS_ADRERR; info.si_addr = (void __user *) addr; force_sig_info(SIGBUS, &info, current); return; sigill: die_if_kernel("Unhandled kernel unaligned access or invalid instruction", regs); info.si_signo = SIGILL; info.si_errno = 0; info.si_code = ILL_ILLOPC; info.si_addr = (void __user *) addr; force_sig_info(SIGILL, &info, current); } #define IS_MIPS16_EXTEND_OR_JAL(a) ((((a) >> (27 - 16)) == 30) | (((a) >> (27 - 16)) == 3)) /*--- Opcode EXTEND oder JAL ---*/ /*--------------------------------------------------------------------------------*\ \*--------------------------------------------------------------------------------*/ static int check_pc_adress(unsigned int __user *pc, unsigned int usermode) { if(((unsigned long)pc & (0xFF << 24)) == (PAGE_POISON << 24)) { return 1; } if(((unsigned long)pc & (0xFF << 24)) == (POISON_INUSE << 24)) { return 2; } if(((unsigned long)pc & (0xFF << 24)) == (POISON_FREE << 24)) { return 3; } if(((unsigned long)pc & (0xFF << 24)) == (POISON_END << 24)) { return 4; } if(((unsigned long)pc & (0xFF << 24)) == (POISON_FREE_INITMEM << 24)) { return 5; } if(!usermode && ((unsigned long)pc < 0x80000000UL)) { return 6; } return 0; } /*--------------------------------------------------------------------------------*\ \*--------------------------------------------------------------------------------*/ int print_code_range(struct seq_file *seq, const char *prefix, unsigned int __user *pc, unsigned int mips16, unsigned int usermode, int left_offset, int right_offset, unsigned long *badaddr) { int ret; if((ret = check_pc_adress(pc, usermode))) { if(seq == NULL) printk(KERN_ERR "no code-dump, address could be %s (no memory at this address).\n", ret == 1 ? "PAGE_POISON" : ret == 2 ? "POISON_INUSE" : ret == 3 ? "POISON_FREE" : ret == 4 ? "POISON_END" : ret == 5 ? "POISON_FREE_INITMEM" : "INVAL_KSEGx"); return 0; } if(!mips16) { signed int i; unsigned long access_addr = (unsigned long)pc + sizeof(unsigned int) * left_offset; if(seq == NULL) printk(KERN_ERR"Code(0x%08lx):", access_addr); for(i = left_offset; i < right_offset; i++) { unsigned int pc_value; access_addr = (unsigned long)pc + sizeof(unsigned int) * i; if(usermode && !unlikely(access_ok(VERIFY_READ, access_addr, 4))) { if(seq == NULL)printk(KERN_ERR "[%s] illegal address 0x%lx (sigill)\n", prefix, access_addr); *badaddr = (unsigned long)access_addr; return -1; /*--- sigill; ---*/ } if(__get_user(pc_value, (unsigned int __user *)access_addr)) { if(seq == NULL)printk(KERN_ERR "[%s] load from address 0x%lx failed (sigbus)\n", prefix, access_addr); *badaddr = (unsigned long)access_addr; return -2; /*--- sigbus; ---*/ } if(seq) { seq_printf(seq, "%s %s0x%08x%s", i == left_offset ? prefix : "", i == 0 ? "<" : "", pc_value, i == 0 ? ">" : ""); } else { printk(" %s0x%08x%s", i == 0 ? "<" : "", pc_value, i == 0 ? ">" : ""); } } } else { /*--- wegen EXT-Code nur step by step vorhangeln: ---*/ unsigned short code0, code1; unsigned long pc_addr = (unsigned long)pc & ~0x1; unsigned long access_addr = (unsigned long)pc & ~0x1; unsigned long end_addr = ((unsigned long)pc & ~0x1) + sizeof(unsigned short) * right_offset; while(left_offset < 0) { if(usermode && !unlikely(access_ok(VERIFY_READ, access_addr, 4))) { if(seq == NULL)printk(KERN_ERR "[%s] illegal address 0x%lx (sigill)\n", prefix, access_addr); *badaddr = (unsigned long)access_addr; return -1; /*--- sigill; ---*/ } if(__get_user(code1, (unsigned short __user *)(access_addr - sizeof(short)))) { if(seq == NULL)printk(KERN_ERR "[%s] load from 16 bit address 0x%lx failed (sigbus)\n", prefix, access_addr); *badaddr = (unsigned long)access_addr; return -2; /*--- sigbus; ---*/ } if(__get_user(code0, (unsigned short __user *)(access_addr - 2 * sizeof(short)))) { if(seq == NULL)printk(KERN_ERR "[%s] load from 16 bit address 0x%lx failed (sigbus)\n", prefix, access_addr); *badaddr = (unsigned long)access_addr; return -2; /*--- sigbus; ---*/ } if(IS_MIPS16_EXTEND_OR_JAL(code0)) { access_addr -= 2 * sizeof(short); } else { access_addr -= sizeof(short); } left_offset++; } if(seq) { seq_printf(seq, "%s", prefix); } else { printk(KERN_ERR"Code(0x%08lx):", access_addr); } while(access_addr < end_addr) { if(__get_user(code0, (unsigned short __user *)(access_addr))) { if(seq == NULL)printk(KERN_ERR "[%s] load from 16 bit address 0x%lx failed (sigbus)\n", prefix, access_addr); *badaddr = (unsigned long)access_addr; return -2; /*--- sigbus; ---*/ } if(access_addr == pc_addr) { if(IS_MIPS16_EXTEND_OR_JAL(code0)) { access_addr += sizeof(short); if(__get_user(code1, (unsigned short __user *)(access_addr))) { if(seq == NULL)printk(KERN_ERR "[%s] load from 16 bit address 0x%lx failed (sigbus)\n", prefix, access_addr); *badaddr = (unsigned long)access_addr; return -2; /*--- sigbus; ---*/ } if(seq) { seq_printf(seq, " <0x%04x %04x>", code0, code1); } else { printk(" <0x%04x %04x>", code0, code1); } } else { if(seq) { seq_printf(seq, " <0x%04x>", code0); } else { printk(" <0x%04x>", code0); } } } else { if(seq) { seq_printf(seq, " 0x%04x", code0); } else { printk(" 0x%04x", code0); } } access_addr += sizeof(short); } } if(seq == NULL) printk("\n"); return 0; } /*--------------------------------------------------------------------------------*\ \*--------------------------------------------------------------------------------*/ int print_mem_config(struct mm_struct *mmm, unsigned long addr) { struct vm_area_struct *vm; unsigned int i = 0; if(mmm == NULL) return 0; vm = mmm->mmap; while(vm) { if((addr >= vm->vm_start) && (addr < vm->vm_end)) { printk(KERN_ERR"Adresse-Segment(%d): 0x%lx: 0x%lx :0x%lx (offset 0x%lx)", i, vm->vm_start, addr, vm->vm_end, addr - vm->vm_start); if(vm->vm_file) { printk(" Path='%s'", vm->vm_file->f_path.dentry->d_name.name); } printk("\n"); return 0; } vm = vm->vm_next; i++; } return 1; } asmlinkage void do_ade(struct pt_regs *regs) { unsigned int __user *pc; mm_segment_t seg; siginfo_t info; unsigned long addr = 0UL; /* * Did we catch a fault trying to load an instruction? * Or are we running in MIPS16 mode? */ if (regs->cp0_badvaddr == regs->cp0_epc) goto sigbus; pc = (unsigned int __user *) exception_epc(regs); /*--- if (user_mode(regs) && !test_thread_flag(TIF_FIXADE)) { ---*/ /*--- goto sigbus; ---*/ /*--- } ---*/ if (!user_mode(regs)) { ai_sys++; #if defined(UNALIGNED_MAX_SCORE_ENTRIES) add_unaligned_access_to_table(pc, sys_score_table, ARRAY_SIZE(sys_score_table), 0); #endif/*--- #if defined(UNALIGNED_MAX_SCORE_ENTRIES) ---*/ if(ai_kernelmode & UNALIGNED_WARN) { int ret; printk(KERN_ERR "[kernel-unaligned %lu] pc=0x%p(%pF) addr=0x%08lx task=%s pid=%d ra=0x%08lx(%pF)\n", ai_sys, pc, pc, regs->cp0_badvaddr, current->comm, current->pid, regs->regs[31], (void *)regs->regs[31] ); ret = print_code_range(NULL, "kernel-unaligned", pc, regs->cp0_epc & 0x1, user_mode(regs), -2, 3, &addr); if(ret == -1) { goto sigill; } else if(ret == -2) { goto sigbus; } if(print_mem_config(current->active_mm, (unsigned long)pc)) print_mem_config(current->mm, (unsigned long)pc); if(ai_kernelmode & UNALIGNED_BACKTRACE) { show_backtrace(current, regs); } } } else { ai_user++; #if defined(UNALIGNED_MAX_SCORE_ENTRIES) add_unaligned_access_to_table(pc, user_score_table, ARRAY_SIZE(user_score_table), 1 + (regs->cp0_epc & 0x1)); #endif/*--- #if defined(UNALIGNED_MAX_SCORE_ENTRIES) ---*/ if(unaligned_action & UNALIGNED_WARN) { int ret; printk(KERN_ERR"Alignment trap: %s (%d) PC=0x%p Address=0x%08lx\n", current->comm, task_pid_nr(current), pc, regs->cp0_badvaddr); ret = print_code_range(NULL, "kernel-unaligned", pc, regs->cp0_epc & 0x1, user_mode(regs), -2, 3, &addr); if(ret == -1) { goto sigill; } else if(ret == -2) { goto sigbus; } if(print_mem_config(current->active_mm, (unsigned long)pc)) print_mem_config(current->mm, (unsigned long)pc); /*--- show_registers(regs); ---*/ } switch(unaligned_action) { case UNALIGNED_ACTION_IGNORED: case UNALIGNED_ACTION_IGNORED_WARN: ai_skipped++; return; case UNALIGNED_ACTION_SIGNAL: case UNALIGNED_ACTION_SIGNAL_WARN: goto sigbus; case UNALIGNED_ACTION_FIXUP: case UNALIGNED_ACTION_FIXUP_WARN: break; } } /* * Do branch emulation only if we didn't forward the exception. * This is all so but ugly ... */ seg = get_fs(); if (!user_mode(regs)) { set_fs(KERNEL_DS); } if (regs->cp0_epc & 0x1) { emulate_load_store_insn_mips16(regs, (void __user *)regs->cp0_badvaddr, pc); } else { emulate_load_store_insn(regs, (void __user *)regs->cp0_badvaddr, pc); } set_fs(seg); return; sigill: die_if_kernel("Unhandled kernel unaligned access or invalid instruction", regs); info.si_signo = SIGILL; info.si_errno = 0; info.si_code = ILL_ILLOPC; info.si_addr = (void __user *) addr; force_sig_info(SIGILL, &info, current); return; sigbus: die_if_kernel("Unhandled kernel unaligned access", regs); info.si_signo = SIGBUS; info.si_errno = 0; info.si_code = BUS_ADRERR; info.si_addr = (void __user *) addr; force_sig_info(SIGBUS, &info, current); return; } #if defined(UNALIGNED_MAX_SCORE_ENTRIES) #define LEFT_CODE_OFFSET 2 #define RIGHT_CODE_OFFSET(a) min((a), CODE_ENTRIES - LEFT_CODE_OFFSET) /*--------------------------------------------------------------------------------*\ * 0: Fehler * sonst: liefert byte-offset zum pc \*--------------------------------------------------------------------------------*/ static unsigned short cpy_code_range(unsigned int __user *pc, unsigned int usermode, unsigned int codetable[], unsigned int code_entries, int left_offset) { signed int i; unsigned int idx = 0; int right_offset; unsigned short ret = 0; int mips16_offset = ((unsigned long)pc) & 0x2; unsigned long access_addr = ((unsigned long)pc) & ~0x3; right_offset = left_offset + code_entries; if(check_pc_adress(pc, usermode)) { memset(codetable, 0, code_entries * sizeof(unsigned int)); return ret; } access_addr += sizeof(unsigned int) * left_offset; for(i = left_offset; i < right_offset; i++) { unsigned int pc_value; if(usermode && !unlikely(access_ok(VERIFY_READ, access_addr, 4))) { return ret; } if(__get_user(pc_value, (unsigned int __user *)access_addr)) { return ret; } codetable[idx] = pc_value; if(i == 0) { ret = (unsigned char *)&codetable[idx] - (unsigned char *)&codetable[0] + mips16_offset; } idx++; access_addr += sizeof(unsigned int); } return ret; } /*--------------------------------------------------------------------------------*\ * usermode: 0 Kernel * 1 MIPS32 * 2 MIPS16 \*--------------------------------------------------------------------------------*/ static void add_unaligned_access_to_table(void *pc, struct _unaligned_access_score_entry table[], unsigned int table_entries, unsigned int usermode) { unsigned int ts_idx = 0, ts_score = 0; unsigned int i; for(i = 0; i < table_entries; i++) { if(table[i].unaligneds) { if(usermode) { if(task_pid_nr(current) != table[i].pid) { continue; } } if(pc == table[i].pc) { table[i].unaligneds++; /*--- printk(KERN_ERR "%s:[%u]add %s %s pid=%u pc=%p %lu\n", __func__, i, usermode ? "USER" : "KERNEL", current->comm, table[i].pid, pc, table[i].unaligneds); ---*/ return; } continue; } /*--- printk(KERN_ERR "%s:[%u]initial %s %s pc=%p pid=%u\n", __func__, i, usermode ? "USER" : "KERNEL", current->comm, pc, table[i].pid); ---*/ ts_idx = i; goto table_settings; } /*--- alle besetzt: bewerte per unaligneds / per time ---*/ for(i = 0; i < table_entries; i++) { unsigned long diff = jiffies - table[i].ts; unsigned int score = diff / (table[i].unaligneds | 0x1); /*--- printk(KERN_ERR "%s:[%u]score %d diff %u unaligneds=%lu ts_score %u idx=%u\n", __func__, i, score, diff, table[i].unaligneds, ts_score, ts_idx); ---*/ if(score > ts_score) { ts_score = score; ts_idx = i; } } /*--- printk(KERN_ERR "%s:[%u]replace %s old: unaligneds=%lu pc=%p pid=%u ts_score=%u new=%s pc=%p\n", __func__, ts_idx, usermode ? "USER" : "KERNEL", table[ts_idx].unaligneds, table[ts_idx].pc, table[ts_idx].pid, ts_score, current->comm, pc); ---*/ table_settings: table[ts_idx].unaligneds = 1; table[ts_idx].pc = pc; table[ts_idx].ts = jiffies; table[ts_idx].pid = task_pid_nr(current); table[ts_idx].mips16 = usermode & 0x2 ? 1 : 0; table[ts_idx].caddr_of = cpy_code_range(pc, usermode, table[ts_idx].code, ARRAY_SIZE(table[ts_idx].code), -LEFT_CODE_OFFSET); strncpy(table[ts_idx].shortcomm, current->comm, sizeof(table[ts_idx].shortcomm)); } /*--------------------------------------------------------------------------------*\ \*--------------------------------------------------------------------------------*/ static unsigned long show_unaligned_access_table(struct seq_file *seq, struct _unaligned_access_score_entry table[], unsigned int table_entries, unsigned int usermode) { char comm[sizeof(table[0].shortcomm) + 1]; unsigned int i; unsigned long sum = 0; unsigned long address; seq_printf(seq, "%s:\nunaligneds\t unaligneds/hour\t\n", usermode ? "User-Scorelist" : "System-Scorelist"); for(i = 0; i < table_entries; i++) { if(table[i].unaligneds) { unsigned int diff_hour = (jiffies - table[i].ts) / HZ / 3600; unsigned long unaligneds_per_hour = table[i].unaligneds; sum += table[i].unaligneds; if(diff_hour) { unaligneds_per_hour /= diff_hour; } if(usermode) { struct pid *ppid; struct task_struct *tsk; char *pcomm; if((ppid = find_get_pid(table[i].pid)) && (tsk = get_pid_task(ppid, PIDTYPE_PID))) { pcomm = tsk->comm; } else { memcpy(comm, table[i].shortcomm, sizeof(comm) - 1); comm[sizeof(comm) - 1] = 0; pcomm = comm; tsk = NULL; } seq_printf(seq, "%10lu \t%10lu \t %s(%u) pc=0x%p ", table[i].unaligneds, unaligneds_per_hour, pcomm, table[i].pid, table[i].pc); if(table[i].caddr_of) { print_code_range(seq, ":", (unsigned int __user *)((unsigned long )&table[i].code + table[i].caddr_of), table[i].mips16, 0 /* use copy in kernel space */, -LEFT_CODE_OFFSET, RIGHT_CODE_OFFSET(2), &address); } if(tsk) { put_task_struct(tsk); } if(ppid) { put_pid(ppid); } seq_printf(seq, "\n"); } else { seq_printf(seq, "%10lu \t%10lu \t 0x%p(%pF) ", table[i].unaligneds, unaligneds_per_hour, table[i].pc, table[i].pc); if(table[i].caddr_of) { print_code_range(seq, ":", (unsigned int __user *)((unsigned long )&table[i].code + table[i].caddr_of), table[i].mips16, 0, -LEFT_CODE_OFFSET, RIGHT_CODE_OFFSET(2), &address); } seq_printf(seq, "\n"); } } } return sum; } #endif/*--- #if defined(UNALIGNED_MAX_SCORE_ENTRIES) ---*/ #ifdef CONFIG_DEBUG_FS extern struct dentry *mips_debugfs_dir; static int __init debugfs_unaligned(void) { struct dentry *d; if (!mips_debugfs_dir) return -ENODEV; d = debugfs_create_u32("unaligned_instructions", S_IRUGO, mips_debugfs_dir, &unaligned_instructions); if (!d) return -ENOMEM; d = debugfs_create_u32("unaligned_action", S_IRUGO | S_IWUSR, mips_debugfs_dir, &unaligned_action); if (!d) return -ENOMEM; return 0; } __initcall(debugfs_unaligned); #endif #ifdef CONFIG_PROC_FS static const char *map_mode(enum _unaligned_mode mode) { switch(mode) { case UNALIGNED_ACTION_IGNORED: return "(ignored) "; case UNALIGNED_ACTION_IGNORED_WARN: return "(ignored+warn)"; case UNALIGNED_ACTION_FIXUP: return "(fixup) "; case UNALIGNED_ACTION_FIXUP_WARN: return "(fixup+warn) "; case UNALIGNED_ACTION_SIGNAL: return "(signal) "; case UNALIGNED_ACTION_SIGNAL_WARN: return "(signal+warn) "; case UNALIGNED_ACTION_FIXUP_WARN_BT: return "(fixup+warn+backtrace)"; } return ""; } static int alignment_proc_read(struct seq_file *seq, void *ref __maybe_unused) { seq_printf(seq, "User:\t\t%lu\n", ai_user); seq_printf(seq, "System:\t\t%lu\n", ai_sys); seq_printf(seq, "Skipped:\t%lu\n", ai_skipped); seq_printf(seq, "Word:\t\t%lu\n", ai_word); seq_printf(seq, "DWord:\t\t%lu\n", ai_dword); seq_printf(seq, "User faults:\t%i %s\n", ai_usermode, map_mode(ai_usermode)); seq_printf(seq, "Kernel faults:\t%i %s\n", ai_kernelmode, map_mode(ai_kernelmode)); #if defined(UNALIGNED_MAX_SCORE_ENTRIES) if(ai_user) { if(show_unaligned_access_table(seq, user_score_table, ARRAY_SIZE(user_score_table), 1) != ai_user) { seq_printf(seq, "... only the newest user-unaligneds shown\n"); } } if(ai_sys) { if(show_unaligned_access_table(seq, sys_score_table, ARRAY_SIZE(sys_score_table), 0) != ai_sys) { seq_printf(seq, "... only the newest kernel-unaligneds shown\n"); } } #endif/*--- #if defined(UNALIGNED_MAX_SCORE_ENTRIES) ---*/ return 0; } static int alignment_proc_open(struct inode *inode, struct file *file) { return single_open(file, alignment_proc_read, NULL); } static ssize_t alignment_proc_write(struct file *file, const char __user *buffer, size_t count, loff_t *offset __maybe_unused) { char mode; if (count > 0) { if (get_user(mode, buffer)) return -EFAULT; if (mode >= '0' && mode <= '5') { ai_usermode = mode - '0'; printk(KERN_ERR "set user unaligned-mode: %s\n", map_mode(ai_usermode)); } else if (mode >= '6' && mode <= '8') { ai_kernelmode = mode == '6' ? UNALIGNED_ACTION_FIXUP : mode == '7' ? UNALIGNED_ACTION_FIXUP_WARN : UNALIGNED_ACTION_FIXUP_WARN_BT; printk(KERN_ERR "set kernel unaligned-mode: %s\n", map_mode(ai_kernelmode)); } else { printk(KERN_ERR "parameter: user '2' %s '3' %s '4' %s '5' %s \n", map_mode(UNALIGNED_ACTION_FIXUP), map_mode(UNALIGNED_ACTION_FIXUP_WARN), map_mode(UNALIGNED_ACTION_SIGNAL), map_mode(UNALIGNED_ACTION_SIGNAL_WARN)); printk(KERN_ERR " system '6' %s '7' %s '8' %s\n", map_mode(UNALIGNED_ACTION_FIXUP), map_mode(UNALIGNED_ACTION_FIXUP_WARN), map_mode(UNALIGNED_ACTION_FIXUP_WARN_BT)); } } return count; } static struct file_operations alignment_proc_fops = { .open = alignment_proc_open, .read = seq_read, .llseek = seq_lseek, .release = single_release, .write = alignment_proc_write }; /* * This needs to be done after sysctl_init, otherwise sys/ will be * overwritten. Actually, this shouldn't be in sys/ at all since * it isn't a sysctl, and it doesn't contain sysctl information. * We now locate it in /proc/cpu/alignment instead. */ static int __init alignment_init(void) { struct proc_dir_entry *res; res = proc_mkdir("cpu", NULL); if (!res) return -ENOMEM; proc_create("alignment", 0, res, &alignment_proc_fops); if (!res) return -ENOMEM; return 0; } __initcall(alignment_init); #endif /* CONFIG_PROC_FS */