ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 367 insertions, 0 deletions

diff --git a/drivers/virt/acrn/mm.c b/drivers/virt/acrn/mm.c
new file mode 100644
index 000000000..5bca500a8
--- /dev/null
+++ b/drivers/virt/acrn/mm.c
@@ -0,0 +1,367 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ACRN: Memory mapping management
+ *
+ * Copyright (C) 2020 Intel Corporation. All rights reserved.
+ *
+ * Authors:
+ *	Fei Li <lei1.li@intel.com>
+ *	Shuo Liu <shuo.a.liu@intel.com>
+ */
+
+#include <linux/io.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#include "acrn_drv.h"
+
+static int modify_region(struct acrn_vm *vm, struct vm_memory_region_op *region)
+{
+	struct vm_memory_region_batch *regions;
+	int ret;
+
+	regions = kzalloc_obj(*regions);
+	if (!regions)
+		return -ENOMEM;
+
+	regions->vmid = vm->vmid;
+	regions->regions_num = 1;
+	regions->regions_gpa = virt_to_phys(region);
+
+	ret = hcall_set_memory_regions(virt_to_phys(regions));
+	if (ret < 0)
+		dev_dbg(acrn_dev.this_device,
+			"Failed to set memory region for VM[%u]!\n", vm->vmid);
+
+	kfree(regions);
+	return ret;
+}
+
+/**
+ * acrn_mm_region_add() - Set up the EPT mapping of a memory region.
+ * @vm:			User VM.
+ * @user_gpa:		A GPA of User VM.
+ * @service_gpa:	A GPA of Service VM.
+ * @size:		Size of the region.
+ * @mem_type:		Combination of ACRN_MEM_TYPE_*.
+ * @mem_access_right:	Combination of ACRN_MEM_ACCESS_*.
+ *
+ * Return: 0 on success, <0 on error.
+ */
+int acrn_mm_region_add(struct acrn_vm *vm, u64 user_gpa, u64 service_gpa,
+		       u64 size, u32 mem_type, u32 mem_access_right)
+{
+	struct vm_memory_region_op *region;
+	int ret = 0;
+
+	region = kzalloc_obj(*region);
+	if (!region)
+		return -ENOMEM;
+
+	region->type = ACRN_MEM_REGION_ADD;
+	region->user_vm_pa = user_gpa;
+	region->service_vm_pa = service_gpa;
+	region->size = size;
+	region->attr = ((mem_type & ACRN_MEM_TYPE_MASK) |
+			(mem_access_right & ACRN_MEM_ACCESS_RIGHT_MASK));
+	ret = modify_region(vm, region);
+
+	dev_dbg(acrn_dev.this_device,
+		"%s: user-GPA[%p] service-GPA[%p] size[0x%llx].\n",
+		__func__, (void *)user_gpa, (void *)service_gpa, size);
+	kfree(region);
+	return ret;
+}
+
+/**
+ * acrn_mm_region_del() - Del the EPT mapping of a memory region.
+ * @vm:		User VM.
+ * @user_gpa:	A GPA of the User VM.
+ * @size:	Size of the region.
+ *
+ * Return: 0 on success, <0 for error.
+ */
+int acrn_mm_region_del(struct acrn_vm *vm, u64 user_gpa, u64 size)
+{
+	struct vm_memory_region_op *region;
+	int ret = 0;
+
+	region = kzalloc_obj(*region);
+	if (!region)
+		return -ENOMEM;
+
+	region->type = ACRN_MEM_REGION_DEL;
+	region->user_vm_pa = user_gpa;
+	region->service_vm_pa = 0UL;
+	region->size = size;
+	region->attr = 0U;
+
+	ret = modify_region(vm, region);
+
+	dev_dbg(acrn_dev.this_device, "%s: user-GPA[%p] size[0x%llx].\n",
+		__func__, (void *)user_gpa, size);
+	kfree(region);
+	return ret;
+}
+
+int acrn_vm_memseg_map(struct acrn_vm *vm, struct acrn_vm_memmap *memmap)
+{
+	int ret;
+
+	if (memmap->type == ACRN_MEMMAP_RAM)
+		return acrn_vm_ram_map(vm, memmap);
+
+	if (memmap->type != ACRN_MEMMAP_MMIO) {
+		dev_dbg(acrn_dev.this_device,
+			"Invalid memmap type: %u\n", memmap->type);
+		return -EINVAL;
+	}
+
+	ret = acrn_mm_region_add(vm, memmap->user_vm_pa,
+				 memmap->service_vm_pa, memmap->len,
+				 ACRN_MEM_TYPE_UC, memmap->attr);
+	if (ret < 0)
+		dev_dbg(acrn_dev.this_device,
+			"Add memory region failed, VM[%u]!\n", vm->vmid);
+
+	return ret;
+}
+
+int acrn_vm_memseg_unmap(struct acrn_vm *vm, struct acrn_vm_memmap *memmap)
+{
+	int ret;
+
+	if (memmap->type != ACRN_MEMMAP_MMIO) {
+		dev_dbg(acrn_dev.this_device,
+			"Invalid memmap type: %u\n", memmap->type);
+		return -EINVAL;
+	}
+
+	ret = acrn_mm_region_del(vm, memmap->user_vm_pa, memmap->len);
+	if (ret < 0)
+		dev_dbg(acrn_dev.this_device,
+			"Del memory region failed, VM[%u]!\n", vm->vmid);
+
+	return ret;
+}
+
+/**
+ * acrn_vm_ram_map() - Create a RAM EPT mapping of User VM.
+ * @vm:		The User VM pointer
+ * @memmap:	Info of the EPT mapping
+ *
+ * Return: 0 on success, <0 for error.
+ */
+int acrn_vm_ram_map(struct acrn_vm *vm, struct acrn_vm_memmap *memmap)
+{
+	struct vm_memory_region_batch *regions_info;
+	int nr_pages, i, order, nr_regions = 0;
+	struct vm_memory_mapping *region_mapping;
+	struct vm_memory_region_op *vm_region;
+	struct page **pages = NULL, *page;
+	void *remap_vaddr;
+	int ret, pinned;
+	u64 user_vm_pa;
+	struct vm_area_struct *vma;
+
+	if (!vm || !memmap)
+		return -EINVAL;
+
+	/* Get the page number of the map region */
+	nr_pages = memmap->len >> PAGE_SHIFT;
+	if (!nr_pages)
+		return -EINVAL;
+
+	mmap_read_lock(current->mm);
+	vma = vma_lookup(current->mm, memmap->vma_base);
+	if (vma && ((vma->vm_flags & VM_PFNMAP) != 0)) {
+		unsigned long start_pfn, cur_pfn;
+		bool writable;
+
+		if ((memmap->vma_base + memmap->len) > vma->vm_end) {
+			mmap_read_unlock(current->mm);
+			return -EINVAL;
+		}
+
+		for (i = 0; i < nr_pages; i++) {
+			struct follow_pfnmap_args args = {
+				.vma = vma,
+				.address = memmap->vma_base + i * PAGE_SIZE,
+			};
+
+			ret = follow_pfnmap_start(&args);
+			if (ret)
+				break;
+
+			cur_pfn = args.pfn;
+			if (i == 0)
+				start_pfn = cur_pfn;
+			writable = args.writable;
+			follow_pfnmap_end(&args);
+
+			/* Disallow write access if the PTE is not writable. */
+			if (!writable &&
+			    (memmap->attr & ACRN_MEM_ACCESS_WRITE)) {
+				ret = -EFAULT;
+				break;
+			}
+
+			/* Disallow refcounted pages. */
+			if (pfn_valid(cur_pfn) &&
+			    !PageReserved(pfn_to_page(cur_pfn))) {
+				ret = -EFAULT;
+				break;
+			}
+
+			/* Disallow non-contiguous ranges. */
+			if (cur_pfn != start_pfn + i) {
+				ret = -EINVAL;
+				break;
+			}
+		}
+		mmap_read_unlock(current->mm);
+
+		if (ret) {
+			dev_dbg(acrn_dev.this_device,
+				"Failed to lookup PFN at VMA:%p.\n", (void *)memmap->vma_base);
+			return ret;
+		}
+
+		return acrn_mm_region_add(vm, memmap->user_vm_pa,
+			 PFN_PHYS(start_pfn), memmap->len,
+			 ACRN_MEM_TYPE_WB, memmap->attr);
+	}
+	mmap_read_unlock(current->mm);
+
+	pages = vzalloc(array_size(nr_pages, sizeof(*pages)));
+	if (!pages)
+		return -ENOMEM;
+
+	/* Lock the pages of user memory map region */
+	pinned = pin_user_pages_fast(memmap->vma_base,
+				     nr_pages, FOLL_WRITE | FOLL_LONGTERM,
+				     pages);
+	if (pinned < 0) {
+		ret = pinned;
+		goto free_pages;
+	} else if (pinned != nr_pages) {
+		ret = -EFAULT;
+		goto put_pages;
+	}
+
+	/* Create a kernel map for the map region */
+	remap_vaddr = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
+	if (!remap_vaddr) {
+		ret = -ENOMEM;
+		goto put_pages;
+	}
+
+	/* Record Service VM va <-> User VM pa mapping */
+	mutex_lock(&vm->regions_mapping_lock);
+	region_mapping = &vm->regions_mapping[vm->regions_mapping_count];
+	if (vm->regions_mapping_count < ACRN_MEM_MAPPING_MAX) {
+		region_mapping->pages = pages;
+		region_mapping->npages = nr_pages;
+		region_mapping->size = memmap->len;
+		region_mapping->service_vm_va = remap_vaddr;
+		region_mapping->user_vm_pa = memmap->user_vm_pa;
+		vm->regions_mapping_count++;
+	} else {
+		dev_warn(acrn_dev.this_device,
+			"Run out of memory mapping slots!\n");
+		ret = -ENOMEM;
+		mutex_unlock(&vm->regions_mapping_lock);
+		goto unmap_no_count;
+	}
+	mutex_unlock(&vm->regions_mapping_lock);
+
+	/* Calculate count of vm_memory_region_op */
+	for (i = 0; i < nr_pages; i += 1 << order) {
+		page = pages[i];
+		VM_BUG_ON_PAGE(PageTail(page), page);
+		order = compound_order(page);
+		nr_regions++;
+	}
+
+	/* Prepare the vm_memory_region_batch */
+	regions_info = kzalloc_flex(*regions_info, regions_op, nr_regions);
+	if (!regions_info) {
+		ret = -ENOMEM;
+		goto unmap_kernel_map;
+	}
+	regions_info->regions_num = nr_regions;
+
+	/* Fill each vm_memory_region_op */
+	vm_region = regions_info->regions_op;
+	regions_info->vmid = vm->vmid;
+	regions_info->regions_gpa = virt_to_phys(vm_region);
+	user_vm_pa = memmap->user_vm_pa;
+	for (i = 0; i < nr_pages; i += 1 << order) {
+		u32 region_size;
+
+		page = pages[i];
+		VM_BUG_ON_PAGE(PageTail(page), page);
+		order = compound_order(page);
+		region_size = PAGE_SIZE << order;
+		vm_region->type = ACRN_MEM_REGION_ADD;
+		vm_region->user_vm_pa = user_vm_pa;
+		vm_region->service_vm_pa = page_to_phys(page);
+		vm_region->size = region_size;
+		vm_region->attr = (ACRN_MEM_TYPE_WB & ACRN_MEM_TYPE_MASK) |
+				  (memmap->attr & ACRN_MEM_ACCESS_RIGHT_MASK);
+
+		vm_region++;
+		user_vm_pa += region_size;
+	}
+
+	/* Inform the ACRN Hypervisor to set up EPT mappings */
+	ret = hcall_set_memory_regions(virt_to_phys(regions_info));
+	if (ret < 0) {
+		dev_dbg(acrn_dev.this_device,
+			"Failed to set regions, VM[%u]!\n", vm->vmid);
+		goto unset_region;
+	}
+	kfree(regions_info);
+
+	dev_dbg(acrn_dev.this_device,
+		"%s: VM[%u] service-GVA[%p] user-GPA[%p] size[0x%llx]\n",
+		__func__, vm->vmid,
+		remap_vaddr, (void *)memmap->user_vm_pa, memmap->len);
+	return ret;
+
+unset_region:
+	kfree(regions_info);
+unmap_kernel_map:
+	mutex_lock(&vm->regions_mapping_lock);
+	vm->regions_mapping_count--;
+	mutex_unlock(&vm->regions_mapping_lock);
+unmap_no_count:
+	vunmap(remap_vaddr);
+put_pages:
+	for (i = 0; i < pinned; i++)
+		unpin_user_page(pages[i]);
+free_pages:
+	vfree(pages);
+	return ret;
+}
+
+/**
+ * acrn_vm_all_ram_unmap() - Destroy a RAM EPT mapping of User VM.
+ * @vm:	The User VM
+ */
+void acrn_vm_all_ram_unmap(struct acrn_vm *vm)
+{
+	struct vm_memory_mapping *region_mapping;
+	int i, j;
+
+	mutex_lock(&vm->regions_mapping_lock);
+	for (i = 0; i < vm->regions_mapping_count; i++) {
+		region_mapping = &vm->regions_mapping[i];
+		vunmap(region_mapping->service_vm_va);
+		for (j = 0; j < region_mapping->npages; j++)
+			unpin_user_page(region_mapping->pages[j]);
+		vfree(region_mapping->pages);
+	}
+	mutex_unlock(&vm->regions_mapping_lock);
+}