diff options
Diffstat (limited to 'arch/alpha/kernel/traps.c')
| -rw-r--r-- | arch/alpha/kernel/traps.c | 994 |
1 files changed, 994 insertions, 0 deletions
diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c new file mode 100644 index 000000000..751d3197c --- /dev/null +++ b/arch/alpha/kernel/traps.c @@ -0,0 +1,994 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * arch/alpha/kernel/traps.c + * + * (C) Copyright 1994 Linus Torvalds + */ + +/* + * This file initializes the trap entry points + */ + +#include <linux/jiffies.h> +#include <linux/mm.h> +#include <linux/sched/signal.h> +#include <linux/sched/debug.h> +#include <linux/tty.h> +#include <linux/delay.h> +#include <linux/extable.h> +#include <linux/kallsyms.h> +#include <linux/ratelimit.h> + +#include <asm/gentrap.h> +#include <linux/uaccess.h> +#include <asm/unaligned.h> +#include <asm/sysinfo.h> +#include <asm/hwrpb.h> +#include <asm/mmu_context.h> +#include <asm/special_insns.h> + +#include "proto.h" + +/* Work-around for some SRMs which mishandle opDEC faults. */ + +static int opDEC_fix; + +static void +opDEC_check(void) +{ + __asm__ __volatile__ ( + /* Load the address of... */ + " br $16, 1f\n" + /* A stub instruction fault handler. Just add 4 to the + pc and continue. */ + " ldq $16, 8($sp)\n" + " addq $16, 4, $16\n" + " stq $16, 8($sp)\n" + " call_pal %[rti]\n" + /* Install the instruction fault handler. */ + "1: lda $17, 3\n" + " call_pal %[wrent]\n" + /* With that in place, the fault from the round-to-minf fp + insn will arrive either at the "lda 4" insn (bad) or one + past that (good). This places the correct fixup in %0. */ + " lda %[fix], 0\n" + " cvttq/svm $f31,$f31\n" + " lda %[fix], 4" + : [fix] "=r" (opDEC_fix) + : [rti] "n" (PAL_rti), [wrent] "n" (PAL_wrent) + : "$0", "$1", "$16", "$17", "$22", "$23", "$24", "$25"); + + if (opDEC_fix) + printk("opDEC fixup enabled.\n"); +} + +void +dik_show_regs(struct pt_regs *regs, unsigned long *r9_15) +{ + printk("pc = [<%016lx>] ra = [<%016lx>] ps = %04lx %s\n", + regs->pc, regs->r26, regs->ps, print_tainted()); + printk("pc is at %pSR\n", (void *)regs->pc); + printk("ra is at %pSR\n", (void *)regs->r26); + printk("v0 = %016lx t0 = %016lx t1 = %016lx\n", + regs->r0, regs->r1, regs->r2); + printk("t2 = %016lx t3 = %016lx t4 = %016lx\n", + regs->r3, regs->r4, regs->r5); + printk("t5 = %016lx t6 = %016lx t7 = %016lx\n", + regs->r6, regs->r7, regs->r8); + + if (r9_15) { + printk("s0 = %016lx s1 = %016lx s2 = %016lx\n", + r9_15[9], r9_15[10], r9_15[11]); + printk("s3 = %016lx s4 = %016lx s5 = %016lx\n", + r9_15[12], r9_15[13], r9_15[14]); + printk("s6 = %016lx\n", r9_15[15]); + } + + printk("a0 = %016lx a1 = %016lx a2 = %016lx\n", + regs->r16, regs->r17, regs->r18); + printk("a3 = %016lx a4 = %016lx a5 = %016lx\n", + regs->r19, regs->r20, regs->r21); + printk("t8 = %016lx t9 = %016lx t10= %016lx\n", + regs->r22, regs->r23, regs->r24); + printk("t11= %016lx pv = %016lx at = %016lx\n", + regs->r25, regs->r27, regs->r28); + printk("gp = %016lx sp = %p\n", regs->gp, regs+1); +#if 0 +__halt(); +#endif +} + +#if 0 +static char * ireg_name[] = {"v0", "t0", "t1", "t2", "t3", "t4", "t5", "t6", + "t7", "s0", "s1", "s2", "s3", "s4", "s5", "s6", + "a0", "a1", "a2", "a3", "a4", "a5", "t8", "t9", + "t10", "t11", "ra", "pv", "at", "gp", "sp", "zero"}; +#endif + +static void +dik_show_code(unsigned int *pc) +{ + long i; + + printk("Code:"); + for (i = -6; i < 2; i++) { + unsigned int insn; + if (__get_user(insn, (unsigned int __user *)pc + i)) + break; + printk("%c%08x%c", i ? ' ' : '<', insn, i ? ' ' : '>'); + } + printk("\n"); +} + +static void +dik_show_trace(unsigned long *sp, const char *loglvl) +{ + long i = 0; + printk("%sTrace:\n", loglvl); + while (0x1ff8 & (unsigned long) sp) { + extern char _stext[], _etext[]; + unsigned long tmp = *sp; + sp++; + if (tmp < (unsigned long) &_stext) + continue; + if (tmp >= (unsigned long) &_etext) + continue; + printk("%s[<%lx>] %pSR\n", loglvl, tmp, (void *)tmp); + if (i > 40) { + printk("%s ...", loglvl); + break; + } + } + printk("%s\n", loglvl); +} + +static int kstack_depth_to_print = 24; + +void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl) +{ + unsigned long *stack; + int i; + + /* + * debugging aid: "show_stack(NULL, NULL, KERN_EMERG);" prints the + * back trace for this cpu. + */ + if(sp==NULL) + sp=(unsigned long*)&sp; + + stack = sp; + for(i=0; i < kstack_depth_to_print; i++) { + if (((long) stack & (THREAD_SIZE-1)) == 0) + break; + if ((i % 4) == 0) { + if (i) + pr_cont("\n"); + printk("%s ", loglvl); + } else { + pr_cont(" "); + } + pr_cont("%016lx", *stack++); + } + pr_cont("\n"); + dik_show_trace(sp, loglvl); +} + +void +die_if_kernel(char * str, struct pt_regs *regs, long err, unsigned long *r9_15) +{ + if (regs->ps & 8) + return; +#ifdef CONFIG_SMP + printk("CPU %d ", hard_smp_processor_id()); +#endif + printk("%s(%d): %s %ld\n", current->comm, task_pid_nr(current), str, err); + dik_show_regs(regs, r9_15); + add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); + dik_show_trace((unsigned long *)(regs+1), KERN_DEFAULT); + dik_show_code((unsigned int *)regs->pc); + + if (test_and_set_thread_flag (TIF_DIE_IF_KERNEL)) { + printk("die_if_kernel recursion detected.\n"); + local_irq_enable(); + while (1); + } + make_task_dead(SIGSEGV); +} + +#ifndef CONFIG_MATHEMU +static long dummy_emul(void) { return 0; } +long (*alpha_fp_emul_imprecise)(struct pt_regs *regs, unsigned long writemask) + = (void *)dummy_emul; +EXPORT_SYMBOL_GPL(alpha_fp_emul_imprecise); +long (*alpha_fp_emul) (unsigned long pc) + = (void *)dummy_emul; +EXPORT_SYMBOL_GPL(alpha_fp_emul); +#else +long alpha_fp_emul_imprecise(struct pt_regs *regs, unsigned long writemask); +long alpha_fp_emul (unsigned long pc); +#endif + +asmlinkage void +do_entArith(unsigned long summary, unsigned long write_mask, + struct pt_regs *regs) +{ + long si_code = FPE_FLTINV; + + if (summary & 1) { + /* Software-completion summary bit is set, so try to + emulate the instruction. If the processor supports + precise exceptions, we don't have to search. */ + if (!amask(AMASK_PRECISE_TRAP)) + si_code = alpha_fp_emul(regs->pc - 4); + else + si_code = alpha_fp_emul_imprecise(regs, write_mask); + if (si_code == 0) + return; + } + die_if_kernel("Arithmetic fault", regs, 0, NULL); + + send_sig_fault(SIGFPE, si_code, (void __user *) regs->pc, 0, current); +} + +asmlinkage void +do_entIF(unsigned long type, struct pt_regs *regs) +{ + int signo, code; + + if (type == 3) { /* FEN fault */ + /* Irritating users can call PAL_clrfen to disable the + FPU for the process. The kernel will then trap in + do_switch_stack and undo_switch_stack when we try + to save and restore the FP registers. + + Given that GCC by default generates code that uses the + FP registers, PAL_clrfen is not useful except for DoS + attacks. So turn the bleeding FPU back on and be done + with it. */ + current_thread_info()->pcb.flags |= 1; + __reload_thread(¤t_thread_info()->pcb); + return; + } + if (!user_mode(regs)) { + if (type == 1) { + const unsigned int *data + = (const unsigned int *) regs->pc; + printk("Kernel bug at %s:%d\n", + (const char *)(data[1] | (long)data[2] << 32), + data[0]); + } +#ifdef CONFIG_ALPHA_WTINT + if (type == 4) { + /* If CALL_PAL WTINT is totally unsupported by the + PALcode, e.g. MILO, "emulate" it by overwriting + the insn. */ + unsigned int *pinsn + = (unsigned int *) regs->pc - 1; + if (*pinsn == PAL_wtint) { + *pinsn = 0x47e01400; /* mov 0,$0 */ + imb(); + regs->r0 = 0; + return; + } + } +#endif /* ALPHA_WTINT */ + die_if_kernel((type == 1 ? "Kernel Bug" : "Instruction fault"), + regs, type, NULL); + } + + switch (type) { + case 0: /* breakpoint */ + if (ptrace_cancel_bpt(current)) { + regs->pc -= 4; /* make pc point to former bpt */ + } + + send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc, 0, + current); + return; + + case 1: /* bugcheck */ + send_sig_fault(SIGTRAP, TRAP_UNK, (void __user *) regs->pc, 0, + current); + return; + + case 2: /* gentrap */ + switch ((long) regs->r16) { + case GEN_INTOVF: + signo = SIGFPE; + code = FPE_INTOVF; + break; + case GEN_INTDIV: + signo = SIGFPE; + code = FPE_INTDIV; + break; + case GEN_FLTOVF: + signo = SIGFPE; + code = FPE_FLTOVF; + break; + case GEN_FLTDIV: + signo = SIGFPE; + code = FPE_FLTDIV; + break; + case GEN_FLTUND: + signo = SIGFPE; + code = FPE_FLTUND; + break; + case GEN_FLTINV: + signo = SIGFPE; + code = FPE_FLTINV; + break; + case GEN_FLTINE: + signo = SIGFPE; + code = FPE_FLTRES; + break; + case GEN_ROPRAND: + signo = SIGFPE; + code = FPE_FLTUNK; + break; + + case GEN_DECOVF: + case GEN_DECDIV: + case GEN_DECINV: + case GEN_ASSERTERR: + case GEN_NULPTRERR: + case GEN_STKOVF: + case GEN_STRLENERR: + case GEN_SUBSTRERR: + case GEN_RANGERR: + case GEN_SUBRNG: + case GEN_SUBRNG1: + case GEN_SUBRNG2: + case GEN_SUBRNG3: + case GEN_SUBRNG4: + case GEN_SUBRNG5: + case GEN_SUBRNG6: + case GEN_SUBRNG7: + default: + signo = SIGTRAP; + code = TRAP_UNK; + break; + } + + send_sig_fault(signo, code, (void __user *) regs->pc, regs->r16, + current); + return; + + case 4: /* opDEC */ + if (implver() == IMPLVER_EV4) { + long si_code; + + /* The some versions of SRM do not handle + the opDEC properly - they return the PC of the + opDEC fault, not the instruction after as the + Alpha architecture requires. Here we fix it up. + We do this by intentionally causing an opDEC + fault during the boot sequence and testing if + we get the correct PC. If not, we set a flag + to correct it every time through. */ + regs->pc += opDEC_fix; + + /* EV4 does not implement anything except normal + rounding. Everything else will come here as + an illegal instruction. Emulate them. */ + si_code = alpha_fp_emul(regs->pc - 4); + if (si_code == 0) + return; + if (si_code > 0) { + send_sig_fault(SIGFPE, si_code, + (void __user *) regs->pc, 0, + current); + return; + } + } + break; + + case 5: /* illoc */ + default: /* unexpected instruction-fault type */ + ; + } + + send_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)regs->pc, 0, current); +} + +/* There is an ifdef in the PALcode in MILO that enables a + "kernel debugging entry point" as an unprivileged call_pal. + + We don't want to have anything to do with it, but unfortunately + several versions of MILO included in distributions have it enabled, + and if we don't put something on the entry point we'll oops. */ + +asmlinkage void +do_entDbg(struct pt_regs *regs) +{ + die_if_kernel("Instruction fault", regs, 0, NULL); + + force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)regs->pc, 0); +} + + +/* + * entUna has a different register layout to be reasonably simple. It + * needs access to all the integer registers (the kernel doesn't use + * fp-regs), and it needs to have them in order for simpler access. + * + * Due to the non-standard register layout (and because we don't want + * to handle floating-point regs), user-mode unaligned accesses are + * handled separately by do_entUnaUser below. + * + * Oh, btw, we don't handle the "gp" register correctly, but if we fault + * on a gp-register unaligned load/store, something is _very_ wrong + * in the kernel anyway.. + */ +struct allregs { + unsigned long regs[32]; + unsigned long ps, pc, gp, a0, a1, a2; +}; + +struct unaligned_stat { + unsigned long count, va, pc; +} unaligned[2]; + + +/* Macro for exception fixup code to access integer registers. */ +#define una_reg(r) (_regs[(r) >= 16 && (r) <= 18 ? (r)+19 : (r)]) + + +asmlinkage void +do_entUna(void * va, unsigned long opcode, unsigned long reg, + struct allregs *regs) +{ + long error, tmp1, tmp2, tmp3, tmp4; + unsigned long pc = regs->pc - 4; + unsigned long *_regs = regs->regs; + const struct exception_table_entry *fixup; + + unaligned[0].count++; + unaligned[0].va = (unsigned long) va; + unaligned[0].pc = pc; + + /* We don't want to use the generic get/put unaligned macros as + we want to trap exceptions. Only if we actually get an + exception will we decide whether we should have caught it. */ + + switch (opcode) { + case 0x0c: /* ldwu */ + __asm__ __volatile__( + "1: ldq_u %1,0(%3)\n" + "2: ldq_u %2,1(%3)\n" + " extwl %1,%3,%1\n" + " extwh %2,%3,%2\n" + "3:\n" + EXC(1b,3b,%1,%0) + EXC(2b,3b,%2,%0) + : "=r"(error), "=&r"(tmp1), "=&r"(tmp2) + : "r"(va), "0"(0)); + if (error) + goto got_exception; + una_reg(reg) = tmp1|tmp2; + return; + + case 0x28: /* ldl */ + __asm__ __volatile__( + "1: ldq_u %1,0(%3)\n" + "2: ldq_u %2,3(%3)\n" + " extll %1,%3,%1\n" + " extlh %2,%3,%2\n" + "3:\n" + EXC(1b,3b,%1,%0) + EXC(2b,3b,%2,%0) + : "=r"(error), "=&r"(tmp1), "=&r"(tmp2) + : "r"(va), "0"(0)); + if (error) + goto got_exception; + una_reg(reg) = (int)(tmp1|tmp2); + return; + + case 0x29: /* ldq */ + __asm__ __volatile__( + "1: ldq_u %1,0(%3)\n" + "2: ldq_u %2,7(%3)\n" + " extql %1,%3,%1\n" + " extqh %2,%3,%2\n" + "3:\n" + EXC(1b,3b,%1,%0) + EXC(2b,3b,%2,%0) + : "=r"(error), "=&r"(tmp1), "=&r"(tmp2) + : "r"(va), "0"(0)); + if (error) + goto got_exception; + una_reg(reg) = tmp1|tmp2; + return; + + /* Note that the store sequences do not indicate that they change + memory because it _should_ be affecting nothing in this context. + (Otherwise we have other, much larger, problems.) */ + case 0x0d: /* stw */ + __asm__ __volatile__( + "1: ldq_u %2,1(%5)\n" + "2: ldq_u %1,0(%5)\n" + " inswh %6,%5,%4\n" + " inswl %6,%5,%3\n" + " mskwh %2,%5,%2\n" + " mskwl %1,%5,%1\n" + " or %2,%4,%2\n" + " or %1,%3,%1\n" + "3: stq_u %2,1(%5)\n" + "4: stq_u %1,0(%5)\n" + "5:\n" + EXC(1b,5b,%2,%0) + EXC(2b,5b,%1,%0) + EXC(3b,5b,$31,%0) + EXC(4b,5b,$31,%0) + : "=r"(error), "=&r"(tmp1), "=&r"(tmp2), + "=&r"(tmp3), "=&r"(tmp4) + : "r"(va), "r"(una_reg(reg)), "0"(0)); + if (error) + goto got_exception; + return; + + case 0x2c: /* stl */ + __asm__ __volatile__( + "1: ldq_u %2,3(%5)\n" + "2: ldq_u %1,0(%5)\n" + " inslh %6,%5,%4\n" + " insll %6,%5,%3\n" + " msklh %2,%5,%2\n" + " mskll %1,%5,%1\n" + " or %2,%4,%2\n" + " or %1,%3,%1\n" + "3: stq_u %2,3(%5)\n" + "4: stq_u %1,0(%5)\n" + "5:\n" + EXC(1b,5b,%2,%0) + EXC(2b,5b,%1,%0) + EXC(3b,5b,$31,%0) + EXC(4b,5b,$31,%0) + : "=r"(error), "=&r"(tmp1), "=&r"(tmp2), + "=&r"(tmp3), "=&r"(tmp4) + : "r"(va), "r"(una_reg(reg)), "0"(0)); + if (error) + goto got_exception; + return; + + case 0x2d: /* stq */ + __asm__ __volatile__( + "1: ldq_u %2,7(%5)\n" + "2: ldq_u %1,0(%5)\n" + " insqh %6,%5,%4\n" + " insql %6,%5,%3\n" + " mskqh %2,%5,%2\n" + " mskql %1,%5,%1\n" + " or %2,%4,%2\n" + " or %1,%3,%1\n" + "3: stq_u %2,7(%5)\n" + "4: stq_u %1,0(%5)\n" + "5:\n" + EXC(1b,5b,%2,%0) + EXC(2b,5b,%1,%0) + EXC(3b,5b,$31,%0) + EXC(4b,5b,$31,%0) + : "=r"(error), "=&r"(tmp1), "=&r"(tmp2), + "=&r"(tmp3), "=&r"(tmp4) + : "r"(va), "r"(una_reg(reg)), "0"(0)); + if (error) + goto got_exception; + return; + } + + printk("Bad unaligned kernel access at %016lx: %p %lx %lu\n", + pc, va, opcode, reg); + make_task_dead(SIGSEGV); + +got_exception: + /* Ok, we caught the exception, but we don't want it. Is there + someone to pass it along to? */ + if ((fixup = search_exception_tables(pc)) != 0) { + unsigned long newpc; + newpc = fixup_exception(una_reg, fixup, pc); + + printk("Forwarding unaligned exception at %lx (%lx)\n", + pc, newpc); + + regs->pc = newpc; + return; + } + + /* + * Yikes! No one to forward the exception to. + * Since the registers are in a weird format, dump them ourselves. + */ + + printk("%s(%d): unhandled unaligned exception\n", + current->comm, task_pid_nr(current)); + + printk("pc = [<%016lx>] ra = [<%016lx>] ps = %04lx\n", + pc, una_reg(26), regs->ps); + printk("r0 = %016lx r1 = %016lx r2 = %016lx\n", + una_reg(0), una_reg(1), una_reg(2)); + printk("r3 = %016lx r4 = %016lx r5 = %016lx\n", + una_reg(3), una_reg(4), una_reg(5)); + printk("r6 = %016lx r7 = %016lx r8 = %016lx\n", + una_reg(6), una_reg(7), una_reg(8)); + printk("r9 = %016lx r10= %016lx r11= %016lx\n", + una_reg(9), una_reg(10), una_reg(11)); + printk("r12= %016lx r13= %016lx r14= %016lx\n", + una_reg(12), una_reg(13), una_reg(14)); + printk("r15= %016lx\n", una_reg(15)); + printk("r16= %016lx r17= %016lx r18= %016lx\n", + una_reg(16), una_reg(17), una_reg(18)); + printk("r19= %016lx r20= %016lx r21= %016lx\n", + una_reg(19), una_reg(20), una_reg(21)); + printk("r22= %016lx r23= %016lx r24= %016lx\n", + una_reg(22), una_reg(23), una_reg(24)); + printk("r25= %016lx r27= %016lx r28= %016lx\n", + una_reg(25), una_reg(27), una_reg(28)); + printk("gp = %016lx sp = %p\n", regs->gp, regs+1); + + dik_show_code((unsigned int *)pc); + dik_show_trace((unsigned long *)(regs+1), KERN_DEFAULT); + + if (test_and_set_thread_flag (TIF_DIE_IF_KERNEL)) { + printk("die_if_kernel recursion detected.\n"); + local_irq_enable(); + while (1); + } + make_task_dead(SIGSEGV); +} + +/* + * Convert an s-floating point value in memory format to the + * corresponding value in register format. The exponent + * needs to be remapped to preserve non-finite values + * (infinities, not-a-numbers, denormals). + */ +static inline unsigned long +s_mem_to_reg (unsigned long s_mem) +{ + unsigned long frac = (s_mem >> 0) & 0x7fffff; + unsigned long sign = (s_mem >> 31) & 0x1; + unsigned long exp_msb = (s_mem >> 30) & 0x1; + unsigned long exp_low = (s_mem >> 23) & 0x7f; + unsigned long exp; + + exp = (exp_msb << 10) | exp_low; /* common case */ + if (exp_msb) { + if (exp_low == 0x7f) { + exp = 0x7ff; + } + } else { + if (exp_low == 0x00) { + exp = 0x000; + } else { + exp |= (0x7 << 7); + } + } + return (sign << 63) | (exp << 52) | (frac << 29); +} + +/* + * Convert an s-floating point value in register format to the + * corresponding value in memory format. + */ +static inline unsigned long +s_reg_to_mem (unsigned long s_reg) +{ + return ((s_reg >> 62) << 30) | ((s_reg << 5) >> 34); +} + +/* + * Handle user-level unaligned fault. Handling user-level unaligned + * faults is *extremely* slow and produces nasty messages. A user + * program *should* fix unaligned faults ASAP. + * + * Notice that we have (almost) the regular kernel stack layout here, + * so finding the appropriate registers is a little more difficult + * than in the kernel case. + * + * Finally, we handle regular integer load/stores only. In + * particular, load-linked/store-conditionally and floating point + * load/stores are not supported. The former make no sense with + * unaligned faults (they are guaranteed to fail) and I don't think + * the latter will occur in any decent program. + * + * Sigh. We *do* have to handle some FP operations, because GCC will + * uses them as temporary storage for integer memory to memory copies. + * However, we need to deal with stt/ldt and sts/lds only. + */ + +#define OP_INT_MASK ( 1L << 0x28 | 1L << 0x2c /* ldl stl */ \ + | 1L << 0x29 | 1L << 0x2d /* ldq stq */ \ + | 1L << 0x0c | 1L << 0x0d /* ldwu stw */ \ + | 1L << 0x0a | 1L << 0x0e ) /* ldbu stb */ + +#define OP_WRITE_MASK ( 1L << 0x26 | 1L << 0x27 /* sts stt */ \ + | 1L << 0x2c | 1L << 0x2d /* stl stq */ \ + | 1L << 0x0d | 1L << 0x0e ) /* stw stb */ + +#define R(x) ((size_t) &((struct pt_regs *)0)->x) + +static int unauser_reg_offsets[32] = { + R(r0), R(r1), R(r2), R(r3), R(r4), R(r5), R(r6), R(r7), R(r8), + /* r9 ... r15 are stored in front of regs. */ + -56, -48, -40, -32, -24, -16, -8, + R(r16), R(r17), R(r18), + R(r19), R(r20), R(r21), R(r22), R(r23), R(r24), R(r25), R(r26), + R(r27), R(r28), R(gp), + 0, 0 +}; + +#undef R + +asmlinkage void +do_entUnaUser(void __user * va, unsigned long opcode, + unsigned long reg, struct pt_regs *regs) +{ + static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 5); + + unsigned long tmp1, tmp2, tmp3, tmp4; + unsigned long fake_reg, *reg_addr = &fake_reg; + int si_code; + long error; + + /* Check the UAC bits to decide what the user wants us to do + with the unaliged access. */ + + if (!(current_thread_info()->status & TS_UAC_NOPRINT)) { + if (__ratelimit(&ratelimit)) { + printk("%s(%d): unaligned trap at %016lx: %p %lx %ld\n", + current->comm, task_pid_nr(current), + regs->pc - 4, va, opcode, reg); + } + } + if ((current_thread_info()->status & TS_UAC_SIGBUS)) + goto give_sigbus; + /* Not sure why you'd want to use this, but... */ + if ((current_thread_info()->status & TS_UAC_NOFIX)) + return; + + /* Don't bother reading ds in the access check since we already + know that this came from the user. Also rely on the fact that + the page at TASK_SIZE is unmapped and so can't be touched anyway. */ + if ((unsigned long)va >= TASK_SIZE) + goto give_sigsegv; + + ++unaligned[1].count; + unaligned[1].va = (unsigned long)va; + unaligned[1].pc = regs->pc - 4; + + if ((1L << opcode) & OP_INT_MASK) { + /* it's an integer load/store */ + if (reg < 30) { + reg_addr = (unsigned long *) + ((char *)regs + unauser_reg_offsets[reg]); + } else if (reg == 30) { + /* usp in PAL regs */ + fake_reg = rdusp(); + } else { + /* zero "register" */ + fake_reg = 0; + } + } + + /* We don't want to use the generic get/put unaligned macros as + we want to trap exceptions. Only if we actually get an + exception will we decide whether we should have caught it. */ + + switch (opcode) { + case 0x0c: /* ldwu */ + __asm__ __volatile__( + "1: ldq_u %1,0(%3)\n" + "2: ldq_u %2,1(%3)\n" + " extwl %1,%3,%1\n" + " extwh %2,%3,%2\n" + "3:\n" + EXC(1b,3b,%1,%0) + EXC(2b,3b,%2,%0) + : "=r"(error), "=&r"(tmp1), "=&r"(tmp2) + : "r"(va), "0"(0)); + if (error) + goto give_sigsegv; + *reg_addr = tmp1|tmp2; + break; + + case 0x22: /* lds */ + __asm__ __volatile__( + "1: ldq_u %1,0(%3)\n" + "2: ldq_u %2,3(%3)\n" + " extll %1,%3,%1\n" + " extlh %2,%3,%2\n" + "3:\n" + EXC(1b,3b,%1,%0) + EXC(2b,3b,%2,%0) + : "=r"(error), "=&r"(tmp1), "=&r"(tmp2) + : "r"(va), "0"(0)); + if (error) + goto give_sigsegv; + alpha_write_fp_reg(reg, s_mem_to_reg((int)(tmp1|tmp2))); + return; + + case 0x23: /* ldt */ + __asm__ __volatile__( + "1: ldq_u %1,0(%3)\n" + "2: ldq_u %2,7(%3)\n" + " extql %1,%3,%1\n" + " extqh %2,%3,%2\n" + "3:\n" + EXC(1b,3b,%1,%0) + EXC(2b,3b,%2,%0) + : "=r"(error), "=&r"(tmp1), "=&r"(tmp2) + : "r"(va), "0"(0)); + if (error) + goto give_sigsegv; + alpha_write_fp_reg(reg, tmp1|tmp2); + return; + + case 0x28: /* ldl */ + __asm__ __volatile__( + "1: ldq_u %1,0(%3)\n" + "2: ldq_u %2,3(%3)\n" + " extll %1,%3,%1\n" + " extlh %2,%3,%2\n" + "3:\n" + EXC(1b,3b,%1,%0) + EXC(2b,3b,%2,%0) + : "=r"(error), "=&r"(tmp1), "=&r"(tmp2) + : "r"(va), "0"(0)); + if (error) + goto give_sigsegv; + *reg_addr = (int)(tmp1|tmp2); + break; + + case 0x29: /* ldq */ + __asm__ __volatile__( + "1: ldq_u %1,0(%3)\n" + "2: ldq_u %2,7(%3)\n" + " extql %1,%3,%1\n" + " extqh %2,%3,%2\n" + "3:\n" + EXC(1b,3b,%1,%0) + EXC(2b,3b,%2,%0) + : "=r"(error), "=&r"(tmp1), "=&r"(tmp2) + : "r"(va), "0"(0)); + if (error) + goto give_sigsegv; + *reg_addr = tmp1|tmp2; + break; + + /* Note that the store sequences do not indicate that they change + memory because it _should_ be affecting nothing in this context. + (Otherwise we have other, much larger, problems.) */ + case 0x0d: /* stw */ + __asm__ __volatile__( + "1: ldq_u %2,1(%5)\n" + "2: ldq_u %1,0(%5)\n" + " inswh %6,%5,%4\n" + " inswl %6,%5,%3\n" + " mskwh %2,%5,%2\n" + " mskwl %1,%5,%1\n" + " or %2,%4,%2\n" + " or %1,%3,%1\n" + "3: stq_u %2,1(%5)\n" + "4: stq_u %1,0(%5)\n" + "5:\n" + EXC(1b,5b,%2,%0) + EXC(2b,5b,%1,%0) + EXC(3b,5b,$31,%0) + EXC(4b,5b,$31,%0) + : "=r"(error), "=&r"(tmp1), "=&r"(tmp2), + "=&r"(tmp3), "=&r"(tmp4) + : "r"(va), "r"(*reg_addr), "0"(0)); + if (error) + goto give_sigsegv; + return; + + case 0x26: /* sts */ + fake_reg = s_reg_to_mem(alpha_read_fp_reg(reg)); + fallthrough; + + case 0x2c: /* stl */ + __asm__ __volatile__( + "1: ldq_u %2,3(%5)\n" + "2: ldq_u %1,0(%5)\n" + " inslh %6,%5,%4\n" + " insll %6,%5,%3\n" + " msklh %2,%5,%2\n" + " mskll %1,%5,%1\n" + " or %2,%4,%2\n" + " or %1,%3,%1\n" + "3: stq_u %2,3(%5)\n" + "4: stq_u %1,0(%5)\n" + "5:\n" + EXC(1b,5b,%2,%0) + EXC(2b,5b,%1,%0) + EXC(3b,5b,$31,%0) + EXC(4b,5b,$31,%0) + : "=r"(error), "=&r"(tmp1), "=&r"(tmp2), + "=&r"(tmp3), "=&r"(tmp4) + : "r"(va), "r"(*reg_addr), "0"(0)); + if (error) + goto give_sigsegv; + return; + + case 0x27: /* stt */ + fake_reg = alpha_read_fp_reg(reg); + fallthrough; + + case 0x2d: /* stq */ + __asm__ __volatile__( + "1: ldq_u %2,7(%5)\n" + "2: ldq_u %1,0(%5)\n" + " insqh %6,%5,%4\n" + " insql %6,%5,%3\n" + " mskqh %2,%5,%2\n" + " mskql %1,%5,%1\n" + " or %2,%4,%2\n" + " or %1,%3,%1\n" + "3: stq_u %2,7(%5)\n" + "4: stq_u %1,0(%5)\n" + "5:\n" + EXC(1b,5b,%2,%0) + EXC(2b,5b,%1,%0) + EXC(3b,5b,$31,%0) + EXC(4b,5b,$31,%0) + : "=r"(error), "=&r"(tmp1), "=&r"(tmp2), + "=&r"(tmp3), "=&r"(tmp4) + : "r"(va), "r"(*reg_addr), "0"(0)); + if (error) + goto give_sigsegv; + return; + + default: + /* What instruction were you trying to use, exactly? */ + goto give_sigbus; + } + + /* Only integer loads should get here; everyone else returns early. */ + if (reg == 30) + wrusp(fake_reg); + return; + +give_sigsegv: + regs->pc -= 4; /* make pc point to faulting insn */ + + /* We need to replicate some of the logic in mm/fault.c, + since we don't have access to the fault code in the + exception handling return path. */ + if ((unsigned long)va >= TASK_SIZE) + si_code = SEGV_ACCERR; + else { + struct mm_struct *mm = current->mm; + mmap_read_lock(mm); + if (find_vma(mm, (unsigned long)va)) + si_code = SEGV_ACCERR; + else + si_code = SEGV_MAPERR; + mmap_read_unlock(mm); + } + send_sig_fault(SIGSEGV, si_code, va, 0, current); + return; + +give_sigbus: + regs->pc -= 4; + send_sig_fault(SIGBUS, BUS_ADRALN, va, 0, current); + return; +} + +void +trap_init(void) +{ + /* Tell PAL-code what global pointer we want in the kernel. */ + register unsigned long gptr __asm__("$29"); + wrkgp(gptr); + + /* Hack for Multia (UDB) and JENSEN: some of their SRMs have + a bug in the handling of the opDEC fault. Fix it up if so. */ + if (implver() == IMPLVER_EV4) + opDEC_check(); + + wrent(entArith, 1); + wrent(entMM, 2); + wrent(entIF, 3); + wrent(entUna, 4); + wrent(entSys, 5); + wrent(entDbg, 6); +} |