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-rw-r--r--arch/s390/kernel/traps.c403
1 files changed, 403 insertions, 0 deletions
diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c
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+++ b/arch/s390/kernel/traps.c
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+// 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 "asm/irqflags.h"
+#include "asm/ptrace.h"
+#include <linux/kprobes.h>
+#include <linux/kdebug.h>
+#include <linux/randomize_kstack.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 <linux/entry-common.h>
+#include <asm/asm-extable.h>
+#include <asm/fpu/api.h>
+#include <asm/vtime.h>
+#include "entry.h"
+
+static inline void __user *get_trap_ip(struct pt_regs *regs)
+{
+ unsigned long address;
+
+ if (regs->int_code & 0x200)
+ address = current->thread.trap_tdb.data[3];
+ 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 {
+ if (!fixup_exception(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);
+
+static void default_trap_handler(struct pt_regs *regs)
+{
+ if (user_mode(regs)) {
+ report_user_fault(regs, SIGSEGV, 0);
+ force_exit_sig(SIGSEGV);
+ } else
+ die(regs, "Unknown program exception");
+}
+
+#define DO_ERROR_INFO(name, signr, sicode, str) \
+static 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");
+}
+
+static void translation_specification_exception(struct pt_regs *regs)
+{
+ /* May never happen. */
+ panic("Translation-Specification Exception");
+}
+
+static 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");
+
+static 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");
+}
+
+static 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");
+}
+
+static 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");
+}
+
+static void monitor_event_exception(struct pt_regs *regs)
+{
+ if (user_mode(regs))
+ return;
+
+ switch (report_bug(regs->psw.addr - (regs->int_code >> 16), regs)) {
+ case BUG_TRAP_TYPE_NONE:
+ fixup_exception(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)
+{
+ local_mcck_enable();
+ test_monitor_call();
+}
+
+static void (*pgm_check_table[128])(struct pt_regs *regs);
+
+void noinstr __do_pgm_check(struct pt_regs *regs)
+{
+ unsigned int trapnr;
+ irqentry_state_t state;
+
+ regs->int_code = S390_lowcore.pgm_int_code;
+ regs->int_parm_long = S390_lowcore.trans_exc_code;
+
+ state = irqentry_enter(regs);
+
+ if (user_mode(regs)) {
+ update_timer_sys();
+ if (!static_branch_likely(&cpu_has_bear)) {
+ if (regs->last_break < 4096)
+ regs->last_break = 1;
+ }
+ current->thread.last_break = regs->last_break;
+ }
+
+ if (S390_lowcore.pgm_code & 0x0200) {
+ /* transaction abort */
+ current->thread.trap_tdb = S390_lowcore.pgm_tdb;
+ }
+
+ if (S390_lowcore.pgm_code & PGM_INT_CODE_PER) {
+ if (user_mode(regs)) {
+ struct per_event *ev = &current->thread.per_event;
+
+ set_thread_flag(TIF_PER_TRAP);
+ ev->address = S390_lowcore.per_address;
+ ev->cause = S390_lowcore.per_code_combined;
+ ev->paid = S390_lowcore.per_access_id;
+ } else {
+ /* PER event in kernel is kprobes */
+ __arch_local_irq_ssm(regs->psw.mask & ~PSW_MASK_PER);
+ do_per_trap(regs);
+ goto out;
+ }
+ }
+
+ if (!irqs_disabled_flags(regs->psw.mask))
+ trace_hardirqs_on();
+ __arch_local_irq_ssm(regs->psw.mask & ~PSW_MASK_PER);
+
+ trapnr = regs->int_code & PGM_INT_CODE_MASK;
+ if (trapnr)
+ pgm_check_table[trapnr](regs);
+out:
+ local_irq_disable();
+ irqentry_exit(regs, state);
+}
+
+/*
+ * The program check table contains exactly 128 (0x00-0x7f) entries. Each
+ * line defines the function to be called corresponding to the program check
+ * interruption code.
+ */
+static void (*pgm_check_table[128])(struct pt_regs *regs) = {
+ [0x00] = default_trap_handler,
+ [0x01] = illegal_op,
+ [0x02] = privileged_op,
+ [0x03] = execute_exception,
+ [0x04] = do_protection_exception,
+ [0x05] = addressing_exception,
+ [0x06] = specification_exception,
+ [0x07] = data_exception,
+ [0x08] = overflow_exception,
+ [0x09] = divide_exception,
+ [0x0a] = overflow_exception,
+ [0x0b] = divide_exception,
+ [0x0c] = hfp_overflow_exception,
+ [0x0d] = hfp_underflow_exception,
+ [0x0e] = hfp_significance_exception,
+ [0x0f] = hfp_divide_exception,
+ [0x10] = do_dat_exception,
+ [0x11] = do_dat_exception,
+ [0x12] = translation_specification_exception,
+ [0x13] = special_op_exception,
+ [0x14] = default_trap_handler,
+ [0x15] = operand_exception,
+ [0x16] = default_trap_handler,
+ [0x17] = default_trap_handler,
+ [0x18] = transaction_exception,
+ [0x19] = default_trap_handler,
+ [0x1a] = default_trap_handler,
+ [0x1b] = vector_exception,
+ [0x1c] = space_switch_exception,
+ [0x1d] = hfp_sqrt_exception,
+ [0x1e ... 0x37] = default_trap_handler,
+ [0x38] = do_dat_exception,
+ [0x39] = do_dat_exception,
+ [0x3a] = do_dat_exception,
+ [0x3b] = do_dat_exception,
+ [0x3c] = default_trap_handler,
+ [0x3d] = do_secure_storage_access,
+ [0x3e] = do_non_secure_storage_access,
+ [0x3f] = do_secure_storage_violation,
+ [0x40] = monitor_event_exception,
+ [0x41 ... 0x7f] = default_trap_handler,
+};
+
+#define COND_TRAP(x) asm( \
+ ".weak " __stringify(x) "\n\t" \
+ ".set " __stringify(x) "," \
+ __stringify(default_trap_handler))
+
+COND_TRAP(do_secure_storage_access);
+COND_TRAP(do_non_secure_storage_access);
+COND_TRAP(do_secure_storage_violation);
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-01 19:49:59 +0000