diff options
Diffstat (limited to 'arch/s390/kernel/traps.c')
| -rw-r--r-- | arch/s390/kernel/traps.c | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c new file mode 100644 index 000000000..16934fa19 --- /dev/null +++ b/arch/s390/kernel/traps.c @@ -0,0 +1,292 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * S390 version + * Copyright IBM Corp. 1999, 2000 + * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com), + * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com), + * + * Derived from "arch/i386/kernel/traps.c" + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +/* + * 'Traps.c' handles hardware traps and faults after we have saved some + * state in 'asm.s'. + */ +#include <linux/kprobes.h> +#include <linux/kdebug.h> +#include <linux/extable.h> +#include <linux/ptrace.h> +#include <linux/sched.h> +#include <linux/sched/debug.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/uaccess.h> +#include <linux/cpu.h> +#include <asm/fpu/api.h> +#include "entry.h" + +static inline void __user *get_trap_ip(struct pt_regs *regs) +{ + unsigned long address; + + if (regs->int_code & 0x200) + address = *(unsigned long *)(current->thread.trap_tdb + 24); + else + address = regs->psw.addr; + return (void __user *) (address - (regs->int_code >> 16)); +} + +int is_valid_bugaddr(unsigned long addr) +{ + return 1; +} + +void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str) +{ + if (user_mode(regs)) { + force_sig_fault(si_signo, si_code, get_trap_ip(regs)); + report_user_fault(regs, si_signo, 0); + } else { + const struct exception_table_entry *fixup; + fixup = s390_search_extables(regs->psw.addr); + if (!fixup || !ex_handle(fixup, regs)) + die(regs, str); + } +} + +static void do_trap(struct pt_regs *regs, int si_signo, int si_code, char *str) +{ + if (notify_die(DIE_TRAP, str, regs, 0, + regs->int_code, si_signo) == NOTIFY_STOP) + return; + do_report_trap(regs, si_signo, si_code, str); +} +NOKPROBE_SYMBOL(do_trap); + +void do_per_trap(struct pt_regs *regs) +{ + if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP) + return; + if (!current->ptrace) + return; + force_sig_fault(SIGTRAP, TRAP_HWBKPT, + (void __force __user *) current->thread.per_event.address); +} +NOKPROBE_SYMBOL(do_per_trap); + +void default_trap_handler(struct pt_regs *regs) +{ + if (user_mode(regs)) { + report_user_fault(regs, SIGSEGV, 0); + do_exit(SIGSEGV); + } else + die(regs, "Unknown program exception"); +} + +#define DO_ERROR_INFO(name, signr, sicode, str) \ +void name(struct pt_regs *regs) \ +{ \ + do_trap(regs, signr, sicode, str); \ +} + +DO_ERROR_INFO(addressing_exception, SIGILL, ILL_ILLADR, + "addressing exception") +DO_ERROR_INFO(execute_exception, SIGILL, ILL_ILLOPN, + "execute exception") +DO_ERROR_INFO(divide_exception, SIGFPE, FPE_INTDIV, + "fixpoint divide exception") +DO_ERROR_INFO(overflow_exception, SIGFPE, FPE_INTOVF, + "fixpoint overflow exception") +DO_ERROR_INFO(hfp_overflow_exception, SIGFPE, FPE_FLTOVF, + "HFP overflow exception") +DO_ERROR_INFO(hfp_underflow_exception, SIGFPE, FPE_FLTUND, + "HFP underflow exception") +DO_ERROR_INFO(hfp_significance_exception, SIGFPE, FPE_FLTRES, + "HFP significance exception") +DO_ERROR_INFO(hfp_divide_exception, SIGFPE, FPE_FLTDIV, + "HFP divide exception") +DO_ERROR_INFO(hfp_sqrt_exception, SIGFPE, FPE_FLTINV, + "HFP square root exception") +DO_ERROR_INFO(operand_exception, SIGILL, ILL_ILLOPN, + "operand exception") +DO_ERROR_INFO(privileged_op, SIGILL, ILL_PRVOPC, + "privileged operation") +DO_ERROR_INFO(special_op_exception, SIGILL, ILL_ILLOPN, + "special operation exception") +DO_ERROR_INFO(transaction_exception, SIGILL, ILL_ILLOPN, + "transaction constraint exception") + +static inline void do_fp_trap(struct pt_regs *regs, __u32 fpc) +{ + int si_code = 0; + /* FPC[2] is Data Exception Code */ + if ((fpc & 0x00000300) == 0) { + /* bits 6 and 7 of DXC are 0 iff IEEE exception */ + if (fpc & 0x8000) /* invalid fp operation */ + si_code = FPE_FLTINV; + else if (fpc & 0x4000) /* div by 0 */ + si_code = FPE_FLTDIV; + else if (fpc & 0x2000) /* overflow */ + si_code = FPE_FLTOVF; + else if (fpc & 0x1000) /* underflow */ + si_code = FPE_FLTUND; + else if (fpc & 0x0800) /* inexact */ + si_code = FPE_FLTRES; + } + do_trap(regs, SIGFPE, si_code, "floating point exception"); +} + +void translation_exception(struct pt_regs *regs) +{ + /* May never happen. */ + panic("Translation exception"); +} + +void illegal_op(struct pt_regs *regs) +{ + __u8 opcode[6]; + __u16 __user *location; + int is_uprobe_insn = 0; + int signal = 0; + + location = get_trap_ip(regs); + + if (user_mode(regs)) { + if (get_user(*((__u16 *) opcode), (__u16 __user *) location)) + return; + if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) { + if (current->ptrace) + force_sig_fault(SIGTRAP, TRAP_BRKPT, location); + else + signal = SIGILL; +#ifdef CONFIG_UPROBES + } else if (*((__u16 *) opcode) == UPROBE_SWBP_INSN) { + is_uprobe_insn = 1; +#endif + } else + signal = SIGILL; + } + /* + * We got either an illegal op in kernel mode, or user space trapped + * on a uprobes illegal instruction. See if kprobes or uprobes picks + * it up. If not, SIGILL. + */ + if (is_uprobe_insn || !user_mode(regs)) { + if (notify_die(DIE_BPT, "bpt", regs, 0, + 3, SIGTRAP) != NOTIFY_STOP) + signal = SIGILL; + } + if (signal) + do_trap(regs, signal, ILL_ILLOPC, "illegal operation"); +} +NOKPROBE_SYMBOL(illegal_op); + +DO_ERROR_INFO(specification_exception, SIGILL, ILL_ILLOPN, + "specification exception"); + +void vector_exception(struct pt_regs *regs) +{ + int si_code, vic; + + if (!MACHINE_HAS_VX) { + do_trap(regs, SIGILL, ILL_ILLOPN, "illegal operation"); + return; + } + + /* get vector interrupt code from fpc */ + save_fpu_regs(); + vic = (current->thread.fpu.fpc & 0xf00) >> 8; + switch (vic) { + case 1: /* invalid vector operation */ + si_code = FPE_FLTINV; + break; + case 2: /* division by zero */ + si_code = FPE_FLTDIV; + break; + case 3: /* overflow */ + si_code = FPE_FLTOVF; + break; + case 4: /* underflow */ + si_code = FPE_FLTUND; + break; + case 5: /* inexact */ + si_code = FPE_FLTRES; + break; + default: /* unknown cause */ + si_code = 0; + } + do_trap(regs, SIGFPE, si_code, "vector exception"); +} + +void data_exception(struct pt_regs *regs) +{ + save_fpu_regs(); + if (current->thread.fpu.fpc & FPC_DXC_MASK) + do_fp_trap(regs, current->thread.fpu.fpc); + else + do_trap(regs, SIGILL, ILL_ILLOPN, "data exception"); +} + +void space_switch_exception(struct pt_regs *regs) +{ + /* Set user psw back to home space mode. */ + if (user_mode(regs)) + regs->psw.mask |= PSW_ASC_HOME; + /* Send SIGILL. */ + do_trap(regs, SIGILL, ILL_PRVOPC, "space switch event"); +} + +void monitor_event_exception(struct pt_regs *regs) +{ + const struct exception_table_entry *fixup; + + if (user_mode(regs)) + return; + + switch (report_bug(regs->psw.addr - (regs->int_code >> 16), regs)) { + case BUG_TRAP_TYPE_NONE: + fixup = s390_search_extables(regs->psw.addr); + if (fixup) + ex_handle(fixup, regs); + break; + case BUG_TRAP_TYPE_WARN: + break; + case BUG_TRAP_TYPE_BUG: + die(regs, "monitor event"); + break; + } +} + +void kernel_stack_overflow(struct pt_regs *regs) +{ + bust_spinlocks(1); + printk("Kernel stack overflow.\n"); + show_regs(regs); + bust_spinlocks(0); + panic("Corrupt kernel stack, can't continue."); +} +NOKPROBE_SYMBOL(kernel_stack_overflow); + +static void __init test_monitor_call(void) +{ + int val = 1; + + if (!IS_ENABLED(CONFIG_BUG)) + return; + asm volatile( + " mc 0,0\n" + "0: xgr %0,%0\n" + "1:\n" + EX_TABLE(0b,1b) + : "+d" (val)); + if (!val) + panic("Monitor call doesn't work!\n"); +} + +void __init trap_init(void) +{ + sort_extable(__start_dma_ex_table, __stop_dma_ex_table); + local_mcck_enable(); + test_monitor_call(); +} |