[mirror_ubuntu-eoan-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)
{
	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)
			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)
{
	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 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)
{
	sort_extable(__start_dma_ex_table, __stop_dma_ex_table);
	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	46	{
7d256175	47	if (user_mode(regs)) {
2e1661d2	48	force_sig_fault(si_signo, si_code, get_trap_ip(regs));
5d7eccec	49	report_user_fault(regs, si_signo, 0);
1da177e4 LT	50	} else {
1da177e4 LT	51	const struct exception_table_entry *fixup;
a80313ff	52	fixup = s390_search_extables(regs->psw.addr);
1da177e4	53	if (fixup)
fecc868a	54	regs->psw.addr = extable_fixup(fixup);
c0007f1a HC	55	else {
	56	enum bug_trap_type btt;
	57
9cb1ccec	58	btt = report_bug(regs->psw.addr, regs);
c0007f1a HC	59	if (btt == BUG_TRAP_TYPE_WARN)
c0007f1a HC	60	return;
aa33c8cb	61	die(regs, str);
c0007f1a	62	}
1da177e4 LT	63	}
	64	}
	65
7a5388de	66	static void do_trap(struct pt_regs regs, int si_signo, int si_code, char str)
2a0a5b22 JW	67	{
	68	if (notify_die(DIE_TRAP, str, regs, 0,
	69	regs->int_code, si_signo) == NOTIFY_STOP)
	70	return;
	71	do_report_trap(regs, si_signo, si_code, str);
	72	}
7a5388de	73	NOKPROBE_SYMBOL(do_trap);
2a0a5b22	74
7a5388de	75	void do_per_trap(struct pt_regs *regs)
1da177e4	76	{
5e9a2692	77	if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
4ba069b8	78	return;
73b7d40f MS	79	if (!current->ptrace)
73b7d40f MS	80	return;
9507a5d0	81	force_sig_fault(SIGTRAP, TRAP_HWBKPT,
2e1661d2	82	(void __force __user *) current->thread.per_event.address);
1da177e4	83	}
7a5388de	84	NOKPROBE_SYMBOL(do_per_trap);
1da177e4	85
b01a37a7	86	void default_trap_handler(struct pt_regs *regs)
1da177e4	87	{
7d256175	88	if (user_mode(regs)) {
5d7eccec	89	report_user_fault(regs, SIGSEGV, 0);
6ea50968	90	do_exit(SIGSEGV);
1da177e4	91	} else
aa33c8cb	92	die(regs, "Unknown program exception");
1da177e4 LT	93	}
1da177e4 LT	94
1e54622e	95	#define DO_ERROR_INFO(name, signr, sicode, str) \
b01a37a7 HC	96	void name(struct pt_regs *regs) \
	97	{ \
	98	do_trap(regs, signr, sicode, str); \
1da177e4 LT	99	}
1da177e4 LT	100
1e54622e MS	101	DO_ERROR_INFO(addressing_exception, SIGILL, ILL_ILLADR,
	102	"addressing exception")
	103	DO_ERROR_INFO(execute_exception, SIGILL, ILL_ILLOPN,
	104	"execute exception")
	105	DO_ERROR_INFO(divide_exception, SIGFPE, FPE_INTDIV,
	106	"fixpoint divide exception")
	107	DO_ERROR_INFO(overflow_exception, SIGFPE, FPE_INTOVF,
	108	"fixpoint overflow exception")
	109	DO_ERROR_INFO(hfp_overflow_exception, SIGFPE, FPE_FLTOVF,
	110	"HFP overflow exception")
	111	DO_ERROR_INFO(hfp_underflow_exception, SIGFPE, FPE_FLTUND,
	112	"HFP underflow exception")
	113	DO_ERROR_INFO(hfp_significance_exception, SIGFPE, FPE_FLTRES,
	114	"HFP significance exception")
	115	DO_ERROR_INFO(hfp_divide_exception, SIGFPE, FPE_FLTDIV,
	116	"HFP divide exception")
	117	DO_ERROR_INFO(hfp_sqrt_exception, SIGFPE, FPE_FLTINV,
	118	"HFP square root exception")
	119	DO_ERROR_INFO(operand_exception, SIGILL, ILL_ILLOPN,
	120	"operand exception")
	121	DO_ERROR_INFO(privileged_op, SIGILL, ILL_PRVOPC,
	122	"privileged operation")
	123	DO_ERROR_INFO(special_op_exception, SIGILL, ILL_ILLOPN,
	124	"special operation exception")
d35339a4 MS	125	DO_ERROR_INFO(transaction_exception, SIGILL, ILL_ILLOPN,
d35339a4 MS	126	"transaction constraint exception")
d35339a4	127
9977e886	128	static inline void do_fp_trap(struct pt_regs *regs, __u32 fpc)
1da177e4	129	{
aa33c8cb	130	int si_code = 0;
1da177e4 LT	131	/* FPC[2] is Data Exception Code */
	132	if ((fpc & 0x00000300) == 0) {
	133	/* bits 6 and 7 of DXC are 0 iff IEEE exception */
	134	if (fpc & 0x8000) /* invalid fp operation */
aa33c8cb	135	si_code = FPE_FLTINV;
1da177e4	136	else if (fpc & 0x4000) /* div by 0 */
aa33c8cb	137	si_code = FPE_FLTDIV;
1da177e4	138	else if (fpc & 0x2000) /* overflow */
aa33c8cb	139	si_code = FPE_FLTOVF;
1da177e4	140	else if (fpc & 0x1000) /* underflow */
aa33c8cb	141	si_code = FPE_FLTUND;
1da177e4	142	else if (fpc & 0x0800) /* inexact */
aa33c8cb	143	si_code = FPE_FLTRES;
1da177e4	144	}
aa33c8cb	145	do_trap(regs, SIGFPE, si_code, "floating point exception");
1da177e4 LT	146	}
1da177e4 LT	147
e56da345 HC	148	void translation_exception(struct pt_regs *regs)
	149	{
	150	/* May never happen. */
e1d12d70	151	panic("Translation exception");
e56da345 HC	152	}
e56da345 HC	153
7a5388de	154	void illegal_op(struct pt_regs *regs)
1da177e4	155	{
1da177e4	156	__u8 opcode[6];
d2c993d8	157	__u16 __user *location;
2a0a5b22	158	int is_uprobe_insn = 0;
1da177e4 LT	159	int signal = 0;
1da177e4 LT	160
d35339a4	161	location = get_trap_ip(regs);
1da177e4	162
7d256175	163	if (user_mode(regs)) {
12bae235 HC	164	if (get_user(((__u16 ) opcode), (__u16 __user *) location))
12bae235 HC	165	return;
1da177e4	166	if (((__u16 ) opcode) == S390_BREAKPOINT_U16) {
9507a5d0	167	if (current->ptrace)
2e1661d2	168	force_sig_fault(SIGTRAP, TRAP_BRKPT, location);
9507a5d0	169	else
1da177e4	170	signal = SIGILL;
2a0a5b22 JW	171	#ifdef CONFIG_UPROBES
	172	} else if (((__u16 ) opcode) == UPROBE_SWBP_INSN) {
	173	is_uprobe_insn = 1;
1da177e4 LT	174	#endif
	175	} else
	176	signal = SIGILL;
2a0a5b22 JW	177	}
	178	/*
	179	* We got either an illegal op in kernel mode, or user space trapped
	180	* on a uprobes illegal instruction. See if kprobes or uprobes picks
	181	* it up. If not, SIGILL.
	182	*/
	183	if (is_uprobe_insn \|\| !user_mode(regs)) {
aa33c8cb	184	if (notify_die(DIE_BPT, "bpt", regs, 0,
35df8d53 HC	185	3, SIGTRAP) != NOTIFY_STOP)
	186	signal = SIGILL;
	187	}
aa33c8cb MS	188	if (signal)
aa33c8cb MS	189	do_trap(regs, signal, ILL_ILLOPC, "illegal operation");
1da177e4	190	}
7a5388de	191	NOKPROBE_SYMBOL(illegal_op);
1da177e4	192
1e54622e MS	193	DO_ERROR_INFO(specification_exception, SIGILL, ILL_ILLOPN,
1e54622e MS	194	"specification exception");
1da177e4	195
80703617 MS	196	void vector_exception(struct pt_regs *regs)
	197	{
	198	int si_code, vic;
	199
	200	if (!MACHINE_HAS_VX) {
	201	do_trap(regs, SIGILL, ILL_ILLOPN, "illegal operation");
	202	return;
	203	}
	204
	205	/* get vector interrupt code from fpc */
d0164ee2	206	save_fpu_regs();
904818e2	207	vic = (current->thread.fpu.fpc & 0xf00) >> 8;
80703617 MS	208	switch (vic) {
	209	case 1: /* invalid vector operation */
	210	si_code = FPE_FLTINV;
	211	break;
	212	case 2: /* division by zero */
	213	si_code = FPE_FLTDIV;
	214	break;
	215	case 3: /* overflow */
	216	si_code = FPE_FLTOVF;
	217	break;
	218	case 4: /* underflow */
	219	si_code = FPE_FLTUND;
	220	break;
	221	case 5: /* inexact */
	222	si_code = FPE_FLTRES;
	223	break;
	224	default: /* unknown cause */
	225	si_code = 0;
	226	}
	227	do_trap(regs, SIGFPE, si_code, "vector exception");
	228	}
	229
b01a37a7	230	void data_exception(struct pt_regs *regs)
1da177e4	231	{
d0164ee2	232	save_fpu_regs();
904818e2	233	if (current->thread.fpu.fpc & FPC_DXC_MASK)
904818e2	234	do_fp_trap(regs, current->thread.fpu.fpc);
b4e3133b VG	235	else
b4e3133b VG	236	do_trap(regs, SIGILL, ILL_ILLOPN, "data exception");
1da177e4 LT	237	}
1da177e4 LT	238
b01a37a7	239	void space_switch_exception(struct pt_regs *regs)
1da177e4	240	{
1da177e4	241	/* Set user psw back to home space mode. */
7d256175	242	if (user_mode(regs))
1da177e4 LT	243	regs->psw.mask \|= PSW_ASC_HOME;
1da177e4 LT	244	/* Send SIGILL. */
aa33c8cb	245	do_trap(regs, SIGILL, ILL_PRVOPC, "space switch event");
1da177e4 LT	246	}
1da177e4 LT	247
7a5388de	248	void kernel_stack_overflow(struct pt_regs *regs)
1da177e4	249	{
77eb65cb HC	250	bust_spinlocks(1);
	251	printk("Kernel stack overflow.\n");
	252	show_regs(regs);
	253	bust_spinlocks(0);
1da177e4 LT	254	panic("Corrupt kernel stack, can't continue.");
1da177e4 LT	255	}
7a5388de	256	NOKPROBE_SYMBOL(kernel_stack_overflow);
1da177e4	257
1da177e4 LT	258	void __init trap_init(void)
1da177e4 LT	259	{
a80313ff	260	sort_extable(__start_dma_ex_table, __stop_dma_ex_table);
f3e1a273	261	local_mcck_enable();
1da177e4	262	}