[mirror_ubuntu-bionic-kernel.git] / arch / s390 / kernel / traps.c

// 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)
{
	siginfo_t info;

	if (user_mode(regs)) {
		info.si_signo = si_signo;
		info.si_errno = 0;
		info.si_code = si_code;
		info.si_addr = get_trap_ip(regs);
		force_sig_info(si_signo, &info, current);
		report_user_fault(regs, si_signo, 0);
        } else {
                const struct exception_table_entry *fixup;
		fixup = search_exception_tables(regs->psw.addr);
                if (fixup)
			regs->psw.addr = extable_fixup(fixup);
		else {
			enum bug_trap_type btt;

			btt = report_bug(regs->psw.addr, regs);
			if (btt == BUG_TRAP_TYPE_WARN)
				return;
			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)
{
	siginfo_t info;

	if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
		return;
	if (!current->ptrace)
		return;
	info.si_signo = SIGTRAP;
	info.si_errno = 0;
	info.si_code = TRAP_HWBKPT;
	info.si_addr =
		(void __force __user *) current->thread.per_event.address;
	force_sig_info(SIGTRAP, &info, current);
}
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)
{
	siginfo_t info;
        __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) {
				info.si_signo = SIGTRAP;
				info.si_errno = 0;
				info.si_code = TRAP_BRKPT;
				info.si_addr = location;
				force_sig_info(SIGTRAP, &info, current);
			} 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)
{
	int signal = 0;

	save_fpu_regs();
	if (current->thread.fpu.fpc & FPC_DXC_MASK)
		signal = SIGFPE;
	else
		signal = SIGILL;
	if (signal == SIGFPE)
		do_fp_trap(regs, current->thread.fpu.fpc);
	else if (signal)
		do_trap(regs, signal, 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 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);

void __init trap_init(void)
{
	local_mcck_enable();
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4	2	/*
1da177e4	3	* S390 version
a53c8fab	4	* Copyright IBM Corp. 1999, 2000
1da177e4 LT	5	* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
	6	* Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
	7	*
	8	* Derived from "arch/i386/kernel/traps.c"
	9	* Copyright (C) 1991, 1992 Linus Torvalds
	10	*/
	11
	12	/*
	13	* 'Traps.c' handles hardware traps and faults after we have saved some
	14	* state in 'asm.s'.
	15	*/
1bca09f7 HC	16	#include <linux/kprobes.h>
1bca09f7 HC	17	#include <linux/kdebug.h>
dcc096c5	18	#include <linux/extable.h>
73b7d40f	19	#include <linux/ptrace.h>
1bca09f7	20	#include <linux/sched.h>
b17b0153	21	#include <linux/sched/debug.h>
1da177e4	22	#include <linux/mm.h>
80703617	23	#include <linux/slab.h>
7c0f6ba6	24	#include <linux/uaccess.h>
92acfb74	25	#include <linux/cpu.h>
b0753902	26	#include <asm/fpu/api.h>
a806170e	27	#include "entry.h"
1da177e4	28
d35339a4 MS	29	static inline void __user get_trap_ip(struct pt_regs regs)
d35339a4 MS	30	{
d35339a4 MS	31	unsigned long address;
	32
	33	if (regs->int_code & 0x200)
	34	address = (unsigned long )(current->thread.trap_tdb + 24);
	35	else
	36	address = regs->psw.addr;
9cb1ccec	37	return (void __user *) (address - (regs->int_code >> 16));
d35339a4 MS	38	}
d35339a4 MS	39
c0007f1a HC	40	int is_valid_bugaddr(unsigned long addr)
	41	{
	42	return 1;
	43	}
	44
2a0a5b22	45	void do_report_trap(struct pt_regs regs, int si_signo, int si_code, char str)
aa33c8cb MS	46	{
	47	siginfo_t info;
	48
7d256175	49	if (user_mode(regs)) {
aa33c8cb MS	50	info.si_signo = si_signo;
	51	info.si_errno = 0;
	52	info.si_code = si_code;
d35339a4	53	info.si_addr = get_trap_ip(regs);
aa33c8cb	54	force_sig_info(si_signo, &info, current);
5d7eccec	55	report_user_fault(regs, si_signo, 0);
1da177e4 LT	56	} else {
1da177e4 LT	57	const struct exception_table_entry *fixup;
9cb1ccec	58	fixup = search_exception_tables(regs->psw.addr);
1da177e4	59	if (fixup)
fecc868a	60	regs->psw.addr = extable_fixup(fixup);
c0007f1a HC	61	else {
	62	enum bug_trap_type btt;
	63
9cb1ccec	64	btt = report_bug(regs->psw.addr, regs);
c0007f1a HC	65	if (btt == BUG_TRAP_TYPE_WARN)
c0007f1a HC	66	return;
aa33c8cb	67	die(regs, str);
c0007f1a	68	}
1da177e4 LT	69	}
	70	}
	71
7a5388de	72	static void do_trap(struct pt_regs regs, int si_signo, int si_code, char str)
2a0a5b22 JW	73	{
	74	if (notify_die(DIE_TRAP, str, regs, 0,
	75	regs->int_code, si_signo) == NOTIFY_STOP)
	76	return;
	77	do_report_trap(regs, si_signo, si_code, str);
	78	}
7a5388de	79	NOKPROBE_SYMBOL(do_trap);
2a0a5b22	80
7a5388de	81	void do_per_trap(struct pt_regs *regs)
1da177e4	82	{
73b7d40f MS	83	siginfo_t info;
73b7d40f MS	84
5e9a2692	85	if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
4ba069b8	86	return;
73b7d40f MS	87	if (!current->ptrace)
	88	return;
	89	info.si_signo = SIGTRAP;
	90	info.si_errno = 0;
	91	info.si_code = TRAP_HWBKPT;
3c52e49d MS	92	info.si_addr =
3c52e49d MS	93	(void __force __user *) current->thread.per_event.address;
73b7d40f	94	force_sig_info(SIGTRAP, &info, current);
1da177e4	95	}
7a5388de	96	NOKPROBE_SYMBOL(do_per_trap);
1da177e4	97
b01a37a7	98	void default_trap_handler(struct pt_regs *regs)
1da177e4	99	{
7d256175	100	if (user_mode(regs)) {
5d7eccec	101	report_user_fault(regs, SIGSEGV, 0);
6ea50968	102	do_exit(SIGSEGV);
1da177e4	103	} else
aa33c8cb	104	die(regs, "Unknown program exception");
1da177e4 LT	105	}
1da177e4 LT	106
1e54622e	107	#define DO_ERROR_INFO(name, signr, sicode, str) \
b01a37a7 HC	108	void name(struct pt_regs *regs) \
	109	{ \
	110	do_trap(regs, signr, sicode, str); \
1da177e4 LT	111	}
1da177e4 LT	112
1e54622e MS	113	DO_ERROR_INFO(addressing_exception, SIGILL, ILL_ILLADR,
	114	"addressing exception")
	115	DO_ERROR_INFO(execute_exception, SIGILL, ILL_ILLOPN,
	116	"execute exception")
	117	DO_ERROR_INFO(divide_exception, SIGFPE, FPE_INTDIV,
	118	"fixpoint divide exception")
	119	DO_ERROR_INFO(overflow_exception, SIGFPE, FPE_INTOVF,
	120	"fixpoint overflow exception")
	121	DO_ERROR_INFO(hfp_overflow_exception, SIGFPE, FPE_FLTOVF,
	122	"HFP overflow exception")
	123	DO_ERROR_INFO(hfp_underflow_exception, SIGFPE, FPE_FLTUND,
	124	"HFP underflow exception")
	125	DO_ERROR_INFO(hfp_significance_exception, SIGFPE, FPE_FLTRES,
	126	"HFP significance exception")
	127	DO_ERROR_INFO(hfp_divide_exception, SIGFPE, FPE_FLTDIV,
	128	"HFP divide exception")
	129	DO_ERROR_INFO(hfp_sqrt_exception, SIGFPE, FPE_FLTINV,
	130	"HFP square root exception")
	131	DO_ERROR_INFO(operand_exception, SIGILL, ILL_ILLOPN,
	132	"operand exception")
	133	DO_ERROR_INFO(privileged_op, SIGILL, ILL_PRVOPC,
	134	"privileged operation")
	135	DO_ERROR_INFO(special_op_exception, SIGILL, ILL_ILLOPN,
	136	"special operation exception")
d35339a4 MS	137	DO_ERROR_INFO(transaction_exception, SIGILL, ILL_ILLOPN,
d35339a4 MS	138	"transaction constraint exception")
d35339a4	139
9977e886	140	static inline void do_fp_trap(struct pt_regs *regs, __u32 fpc)
1da177e4	141	{
aa33c8cb	142	int si_code = 0;
1da177e4 LT	143	/* FPC[2] is Data Exception Code */
	144	if ((fpc & 0x00000300) == 0) {
	145	/* bits 6 and 7 of DXC are 0 iff IEEE exception */
	146	if (fpc & 0x8000) /* invalid fp operation */
aa33c8cb	147	si_code = FPE_FLTINV;
1da177e4	148	else if (fpc & 0x4000) /* div by 0 */
aa33c8cb	149	si_code = FPE_FLTDIV;
1da177e4	150	else if (fpc & 0x2000) /* overflow */
aa33c8cb	151	si_code = FPE_FLTOVF;
1da177e4	152	else if (fpc & 0x1000) /* underflow */
aa33c8cb	153	si_code = FPE_FLTUND;
1da177e4	154	else if (fpc & 0x0800) /* inexact */
aa33c8cb	155	si_code = FPE_FLTRES;
1da177e4	156	}
aa33c8cb	157	do_trap(regs, SIGFPE, si_code, "floating point exception");
1da177e4 LT	158	}
1da177e4 LT	159
e56da345 HC	160	void translation_exception(struct pt_regs *regs)
	161	{
	162	/* May never happen. */
e1d12d70	163	panic("Translation exception");
e56da345 HC	164	}
e56da345 HC	165
7a5388de	166	void illegal_op(struct pt_regs *regs)
1da177e4 LT	167	{
	168	siginfo_t info;
	169	__u8 opcode[6];
d2c993d8	170	__u16 __user *location;
2a0a5b22	171	int is_uprobe_insn = 0;
1da177e4 LT	172	int signal = 0;
1da177e4 LT	173
d35339a4	174	location = get_trap_ip(regs);
1da177e4	175
7d256175	176	if (user_mode(regs)) {
12bae235 HC	177	if (get_user(((__u16 ) opcode), (__u16 __user *) location))
12bae235 HC	178	return;
1da177e4	179	if (((__u16 ) opcode) == S390_BREAKPOINT_U16) {
73b7d40f MS	180	if (current->ptrace) {
	181	info.si_signo = SIGTRAP;
	182	info.si_errno = 0;
	183	info.si_code = TRAP_BRKPT;
	184	info.si_addr = location;
	185	force_sig_info(SIGTRAP, &info, current);
	186	} else
1da177e4	187	signal = SIGILL;
2a0a5b22 JW	188	#ifdef CONFIG_UPROBES
	189	} else if (((__u16 ) opcode) == UPROBE_SWBP_INSN) {
	190	is_uprobe_insn = 1;
1da177e4 LT	191	#endif
	192	} else
	193	signal = SIGILL;
2a0a5b22 JW	194	}
	195	/*
	196	* We got either an illegal op in kernel mode, or user space trapped
	197	* on a uprobes illegal instruction. See if kprobes or uprobes picks
	198	* it up. If not, SIGILL.
	199	*/
	200	if (is_uprobe_insn \|\| !user_mode(regs)) {
aa33c8cb	201	if (notify_die(DIE_BPT, "bpt", regs, 0,
35df8d53 HC	202	3, SIGTRAP) != NOTIFY_STOP)
	203	signal = SIGILL;
	204	}
aa33c8cb MS	205	if (signal)
aa33c8cb MS	206	do_trap(regs, signal, ILL_ILLOPC, "illegal operation");
1da177e4	207	}
7a5388de	208	NOKPROBE_SYMBOL(illegal_op);
1da177e4	209
1e54622e MS	210	DO_ERROR_INFO(specification_exception, SIGILL, ILL_ILLOPN,
1e54622e MS	211	"specification exception");
1da177e4	212
80703617 MS	213	void vector_exception(struct pt_regs *regs)
	214	{
	215	int si_code, vic;
	216
	217	if (!MACHINE_HAS_VX) {
	218	do_trap(regs, SIGILL, ILL_ILLOPN, "illegal operation");
	219	return;
	220	}
	221
	222	/* get vector interrupt code from fpc */
d0164ee2	223	save_fpu_regs();
904818e2	224	vic = (current->thread.fpu.fpc & 0xf00) >> 8;
80703617 MS	225	switch (vic) {
	226	case 1: /* invalid vector operation */
	227	si_code = FPE_FLTINV;
	228	break;
	229	case 2: /* division by zero */
	230	si_code = FPE_FLTDIV;
	231	break;
	232	case 3: /* overflow */
	233	si_code = FPE_FLTOVF;
	234	break;
	235	case 4: /* underflow */
	236	si_code = FPE_FLTUND;
	237	break;
	238	case 5: /* inexact */
	239	si_code = FPE_FLTRES;
	240	break;
	241	default: /* unknown cause */
	242	si_code = 0;
	243	}
	244	do_trap(regs, SIGFPE, si_code, "vector exception");
	245	}
	246
b01a37a7	247	void data_exception(struct pt_regs *regs)
1da177e4	248	{
1da177e4 LT	249	int signal = 0;
1da177e4 LT	250
d0164ee2	251	save_fpu_regs();
904818e2	252	if (current->thread.fpu.fpc & FPC_DXC_MASK)
1da177e4 LT	253	signal = SIGFPE;
	254	else
	255	signal = SIGILL;
5a79859a	256	if (signal == SIGFPE)
904818e2	257	do_fp_trap(regs, current->thread.fpu.fpc);
aa33c8cb MS	258	else if (signal)
aa33c8cb MS	259	do_trap(regs, signal, ILL_ILLOPN, "data exception");
1da177e4 LT	260	}
1da177e4 LT	261
b01a37a7	262	void space_switch_exception(struct pt_regs *regs)
1da177e4	263	{
1da177e4	264	/* Set user psw back to home space mode. */
7d256175	265	if (user_mode(regs))
1da177e4 LT	266	regs->psw.mask \|= PSW_ASC_HOME;
1da177e4 LT	267	/* Send SIGILL. */
aa33c8cb	268	do_trap(regs, SIGILL, ILL_PRVOPC, "space switch event");
1da177e4 LT	269	}
1da177e4 LT	270
7a5388de	271	void kernel_stack_overflow(struct pt_regs *regs)
1da177e4	272	{
77eb65cb HC	273	bust_spinlocks(1);
	274	printk("Kernel stack overflow.\n");
	275	show_regs(regs);
	276	bust_spinlocks(0);
1da177e4 LT	277	panic("Corrupt kernel stack, can't continue.");
1da177e4 LT	278	}
7a5388de	279	NOKPROBE_SYMBOL(kernel_stack_overflow);
1da177e4	280
1da177e4 LT	281	void __init trap_init(void)
1da177e4 LT	282	{
f3e1a273	283	local_mcck_enable();
1da177e4	284	}