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2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc 
 kernel/arch/s390/kernel/kprobes.c
....@@ -7,6 +7,7 @@
77  * s390 port, used ppc64 as template. Mike Grundy <grundym@us.ibm.com>
88  */
99 
10
+#include <linux/moduleloader.h>
1011 #include <linux/kprobes.h>
1112 #include <linux/ptrace.h>
1213 #include <linux/preempt.h>
....@@ -21,70 +22,78 @@
2122 #include <asm/set_memory.h>
2223 #include <asm/sections.h>
2324 #include <asm/dis.h>
25
+#include "entry.h"
2426 
2527 DEFINE_PER_CPU(struct kprobe *, current_kprobe);
2628 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
2729 
2830 struct kretprobe_blackpoint kretprobe_blacklist[] = { };
2931 
30
-DEFINE_INSN_CACHE_OPS(dmainsn);
32
+DEFINE_INSN_CACHE_OPS(s390_insn);
3133 
32
-static void *alloc_dmainsn_page(void)
34
+static int insn_page_in_use;
35
+
36
+void *alloc_insn_page(void)
3337 {
3438 	void *page;
3539 
36
-	page = (void *) __get_free_page(GFP_KERNEL | GFP_DMA);
37
-	if (page)
38
-		set_memory_x((unsigned long) page, 1);
40
+	page = module_alloc(PAGE_SIZE);
41
+	if (!page)
42
+		return NULL;
43
+	__set_memory((unsigned long) page, 1, SET_MEMORY_RO | SET_MEMORY_X);
3944 	return page;
4045 }
4146 
42
-static void free_dmainsn_page(void *page)
47
+void free_insn_page(void *page)
4348 {
44
-	set_memory_nx((unsigned long) page, 1);
45
-	free_page((unsigned long)page);
49
+	module_memfree(page);
4650 }
4751 
48
-struct kprobe_insn_cache kprobe_dmainsn_slots = {
49
-	.mutex = __MUTEX_INITIALIZER(kprobe_dmainsn_slots.mutex),
50
-	.alloc = alloc_dmainsn_page,
51
-	.free = free_dmainsn_page,
52
-	.pages = LIST_HEAD_INIT(kprobe_dmainsn_slots.pages),
52
+static void *alloc_s390_insn_page(void)
53
+{
54
+	if (xchg(&insn_page_in_use, 1) == 1)
55
+		return NULL;
56
+	return &kprobes_insn_page;
57
+}
58
+
59
+static void free_s390_insn_page(void *page)
60
+{
61
+	xchg(&insn_page_in_use, 0);
62
+}
63
+
64
+struct kprobe_insn_cache kprobe_s390_insn_slots = {
65
+	.mutex = __MUTEX_INITIALIZER(kprobe_s390_insn_slots.mutex),
66
+	.alloc = alloc_s390_insn_page,
67
+	.free = free_s390_insn_page,
68
+	.pages = LIST_HEAD_INIT(kprobe_s390_insn_slots.pages),
5369 	.insn_size = MAX_INSN_SIZE,
5470 };
5571 
5672 static void copy_instruction(struct kprobe *p)
5773 {
58
-	unsigned long ip = (unsigned long) p->addr;
74
+	kprobe_opcode_t insn[MAX_INSN_SIZE];
5975 	s64 disp, new_disp;
6076 	u64 addr, new_addr;
77
+	unsigned int len;
6178 
62
-	if (ftrace_location(ip) == ip) {
79
+	len = insn_length(*p->addr >> 8);
80
+	memcpy(&insn, p->addr, len);
81
+	p->opcode = insn[0];
82
+	if (probe_is_insn_relative_long(&insn[0])) {
6383 		/*
64
-		 * If kprobes patches the instruction that is morphed by
65
-		 * ftrace make sure that kprobes always sees the branch
66
-		 * "jg .+24" that skips the mcount block or the "brcl 0,0"
67
-		 * in case of hotpatch.
84
+		 * For pc-relative instructions in RIL-b or RIL-c format patch
85
+		 * the RI2 displacement field. We have already made sure that
86
+		 * the insn slot for the patched instruction is within the same
87
+		 * 2GB area as the original instruction (either kernel image or
88
+		 * module area). Therefore the new displacement will always fit.
6889 		 */
69
-		ftrace_generate_nop_insn((struct ftrace_insn *)p->ainsn.insn);
70
-		p->ainsn.is_ftrace_insn = 1;
71
-	} else
72
-		memcpy(p->ainsn.insn, p->addr, insn_length(*p->addr >> 8));
73
-	p->opcode = p->ainsn.insn[0];
74
-	if (!probe_is_insn_relative_long(p->ainsn.insn))
75
-		return;
76
-	/*
77
-	 * For pc-relative instructions in RIL-b or RIL-c format patch the
78
-	 * RI2 displacement field. We have already made sure that the insn
79
-	 * slot for the patched instruction is within the same 2GB area
80
-	 * as the original instruction (either kernel image or module area).
81
-	 * Therefore the new displacement will always fit.
82
-	 */
83
-	disp = *(s32 *)&p->ainsn.insn[1];
84
-	addr = (u64)(unsigned long)p->addr;
85
-	new_addr = (u64)(unsigned long)p->ainsn.insn;
86
-	new_disp = ((addr + (disp * 2)) - new_addr) / 2;
87
-	*(s32 *)&p->ainsn.insn[1] = new_disp;
90
+		disp = *(s32 *)&insn[1];
91
+		addr = (u64)(unsigned long)p->addr;
92
+		new_addr = (u64)(unsigned long)p->ainsn.insn;
93
+		new_disp = ((addr + (disp * 2)) - new_addr) / 2;
94
+		*(s32 *)&insn[1] = new_disp;
95
+	}
96
+	s390_kernel_write(p->ainsn.insn, &insn, len);
8897 }
8998 NOKPROBE_SYMBOL(copy_instruction);
9099 
....@@ -102,7 +111,7 @@
102111 	 */
103112 	p->ainsn.insn = NULL;
104113 	if (is_kernel_addr(p->addr))
105
-		p->ainsn.insn = get_dmainsn_slot();
114
+		p->ainsn.insn = get_s390_insn_slot();
106115 	else if (is_module_addr(p->addr))
107116 		p->ainsn.insn = get_insn_slot();
108117 	return p->ainsn.insn ? 0 : -ENOMEM;
....@@ -114,7 +123,7 @@
114123 	if (!p->ainsn.insn)
115124 		return;
116125 	if (is_kernel_addr(p->addr))
117
-		free_dmainsn_slot(p->ainsn.insn, 0);
126
+		free_s390_insn_slot(p->ainsn.insn, 0);
118127 	else
119128 		free_insn_slot(p->ainsn.insn, 0);
120129 	p->ainsn.insn = NULL;
....@@ -135,11 +144,6 @@
135144 }
136145 NOKPROBE_SYMBOL(arch_prepare_kprobe);
137146 
138
-int arch_check_ftrace_location(struct kprobe *p)
139
-{
140
-	return 0;
141
-}
142
-
143147 struct swap_insn_args {
144148 	struct kprobe *p;
145149 	unsigned int arm_kprobe : 1;
....@@ -148,28 +152,11 @@
148152 static int swap_instruction(void *data)
149153 {
150154 	struct swap_insn_args *args = data;
151
-	struct ftrace_insn new_insn, *insn;
152155 	struct kprobe *p = args->p;
153
-	size_t len;
156
+	u16 opc;
154157 
155
-	new_insn.opc = args->arm_kprobe ? BREAKPOINT_INSTRUCTION : p->opcode;
156
-	len = sizeof(new_insn.opc);
157
-	if (!p->ainsn.is_ftrace_insn)
158
-		goto skip_ftrace;
159
-	len = sizeof(new_insn);
160
-	insn = (struct ftrace_insn *) p->addr;
161
-	if (args->arm_kprobe) {
162
-		if (is_ftrace_nop(insn))
163
-			new_insn.disp = KPROBE_ON_FTRACE_NOP;
164
-		else
165
-			new_insn.disp = KPROBE_ON_FTRACE_CALL;
166
-	} else {
167
-		ftrace_generate_call_insn(&new_insn, (unsigned long)p->addr);
168
-		if (insn->disp == KPROBE_ON_FTRACE_NOP)
169
-			ftrace_generate_nop_insn(&new_insn);
170
-	}
171
-skip_ftrace:
172
-	s390_kernel_write(p->addr, &new_insn, len);
158
+	opc = args->arm_kprobe ? BREAKPOINT_INSTRUCTION : p->opcode;
159
+	s390_kernel_write(p->addr, &opc, sizeof(opc));
173160 	return 0;
174161 }
175162 NOKPROBE_SYMBOL(swap_instruction);
....@@ -254,12 +241,14 @@
254241 {
255242 	__this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
256243 	kcb->kprobe_status = kcb->prev_kprobe.status;
244
+	kcb->prev_kprobe.kp = NULL;
257245 }
258246 NOKPROBE_SYMBOL(pop_kprobe);
259247 
260248 void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs)
261249 {
262250 	ri->ret_addr = (kprobe_opcode_t *) regs->gprs[14];
251
+	ri->fp = NULL;
263252 
264253 	/* Replace the return addr with trampoline addr */
265254 	regs->gprs[14] = (unsigned long) &kretprobe_trampoline;
....@@ -363,83 +352,7 @@
363352  */
364353 static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
365354 {
366
-	struct kretprobe_instance *ri;
367
-	struct hlist_head *head, empty_rp;
368
-	struct hlist_node *tmp;
369
-	unsigned long flags, orig_ret_address;
370
-	unsigned long trampoline_address;
371
-	kprobe_opcode_t *correct_ret_addr;
372
-
373
-	INIT_HLIST_HEAD(&empty_rp);
374
-	kretprobe_hash_lock(current, &head, &flags);
375
-
376
-	/*
377
-	 * It is possible to have multiple instances associated with a given
378
-	 * task either because an multiple functions in the call path
379
-	 * have a return probe installed on them, and/or more than one return
380
-	 * return probe was registered for a target function.
381
-	 *
382
-	 * We can handle this because:
383
-	 *     - instances are always inserted at the head of the list
384
-	 *     - when multiple return probes are registered for the same
385
-	 *	 function, the first instance's ret_addr will point to the
386
-	 *	 real return address, and all the rest will point to
387
-	 *	 kretprobe_trampoline
388
-	 */
389
-	ri = NULL;
390
-	orig_ret_address = 0;
391
-	correct_ret_addr = NULL;
392
-	trampoline_address = (unsigned long) &kretprobe_trampoline;
393
-	hlist_for_each_entry_safe(ri, tmp, head, hlist) {
394
-		if (ri->task != current)
395
-			/* another task is sharing our hash bucket */
396
-			continue;
397
-
398
-		orig_ret_address = (unsigned long) ri->ret_addr;
399
-
400
-		if (orig_ret_address != trampoline_address)
401
-			/*
402
-			 * This is the real return address. Any other
403
-			 * instances associated with this task are for
404
-			 * other calls deeper on the call stack
405
-			 */
406
-			break;
407
-	}
408
-
409
-	kretprobe_assert(ri, orig_ret_address, trampoline_address);
410
-
411
-	correct_ret_addr = ri->ret_addr;
412
-	hlist_for_each_entry_safe(ri, tmp, head, hlist) {
413
-		if (ri->task != current)
414
-			/* another task is sharing our hash bucket */
415
-			continue;
416
-
417
-		orig_ret_address = (unsigned long) ri->ret_addr;
418
-
419
-		if (ri->rp && ri->rp->handler) {
420
-			ri->ret_addr = correct_ret_addr;
421
-			ri->rp->handler(ri, regs);
422
-		}
423
-
424
-		recycle_rp_inst(ri, &empty_rp);
425
-
426
-		if (orig_ret_address != trampoline_address)
427
-			/*
428
-			 * This is the real return address. Any other
429
-			 * instances associated with this task are for
430
-			 * other calls deeper on the call stack
431
-			 */
432
-			break;
433
-	}
434
-
435
-	regs->psw.addr = orig_ret_address;
436
-
437
-	kretprobe_hash_unlock(current, &flags);
438
-
439
-	hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
440
-		hlist_del(&ri->hlist);
441
-		kfree(ri);
442
-	}
355
+	regs->psw.addr = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
443356 	/*
444357 	 * By returning a non-zero value, we are telling
445358 	 * kprobe_handler() that we don't want the post_handler
....@@ -462,24 +375,6 @@
462375 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
463376 	unsigned long ip = regs->psw.addr;
464377 	int fixup = probe_get_fixup_type(p->ainsn.insn);
465
-
466
-	/* Check if the kprobes location is an enabled ftrace caller */
467
-	if (p->ainsn.is_ftrace_insn) {
468
-		struct ftrace_insn *insn = (struct ftrace_insn *) p->addr;
469
-		struct ftrace_insn call_insn;
470
-
471
-		ftrace_generate_call_insn(&call_insn, (unsigned long) p->addr);
472
-		/*
473
-		 * A kprobe on an enabled ftrace call site actually single
474
-		 * stepped an unconditional branch (ftrace nop equivalent).
475
-		 * Now we need to fixup things and pretend that a brasl r0,...
476
-		 * was executed instead.
477
-		 */
478
-		if (insn->disp == KPROBE_ON_FTRACE_CALL) {
479
-			ip += call_insn.disp * 2 - MCOUNT_INSN_SIZE;
480
-			regs->gprs[0] = (unsigned long)p->addr + sizeof(*insn);
481
-		}
482
-	}
483378 
484379 	if (fixup & FIXUP_PSW_NORMAL)
485380 		ip += (unsigned long) p->addr - (unsigned long) p->ainsn.insn;
....@@ -508,12 +403,11 @@
508403 	if (!p)
509404 		return 0;
510405 
406
+	resume_execution(p, regs);
511407 	if (kcb->kprobe_status != KPROBE_REENTER && p->post_handler) {
512408 		kcb->kprobe_status = KPROBE_HIT_SSDONE;
513409 		p->post_handler(p, regs, 0);
514410 	}
515
-
516
-	resume_execution(p, regs);
517411 	pop_kprobe(kcb);
518412 	preempt_enable_no_resched();
519413 
....@@ -572,11 +466,9 @@
572466 		 * In case the user-specified fault handler returned
573467 		 * zero, try to fix up.
574468 		 */
575
-		entry = search_exception_tables(regs->psw.addr);
576
-		if (entry) {
577
-			regs->psw.addr = extable_fixup(entry);
469
+		entry = s390_search_extables(regs->psw.addr);
470
+		if (entry && ex_handle(entry, regs))
578471 			return 1;
579
-		}
580472 
581473 		/*
582474 		 * fixup_exception() could not handle it,