1 files changed, 143 insertions, 0 deletions
diff --git a/mm/execmem.c b/mm/execmem.c
new file mode 100644
index 0000000000..0c4b36bc6d
--- /dev/null
+++ b/mm/execmem.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2002 Richard Henderson
+ * Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM.
+ * Copyright (C) 2023 Luis Chamberlain <mcgrof@kernel.org>
+ * Copyright (C) 2024 Mike Rapoport IBM.
+ */
+
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/execmem.h>
+#include <linux/moduleloader.h>
+
+static struct execmem_info *execmem_info __ro_after_init;
+static struct execmem_info default_execmem_info __ro_after_init;
+
+static void *__execmem_alloc(struct execmem_range *range, size_t size)
+{
+	bool kasan = range->flags & EXECMEM_KASAN_SHADOW;
+	unsigned long vm_flags  = VM_FLUSH_RESET_PERMS;
+	gfp_t gfp_flags = GFP_KERNEL | __GFP_NOWARN;
+	unsigned long start = range->start;
+	unsigned long end = range->end;
+	unsigned int align = range->alignment;
+	pgprot_t pgprot = range->pgprot;
+	void *p;
+
+	if (kasan)
+		vm_flags |= VM_DEFER_KMEMLEAK;
+
+	p = __vmalloc_node_range(size, align, start, end, gfp_flags,
+				 pgprot, vm_flags, NUMA_NO_NODE,
+				 __builtin_return_address(0));
+	if (!p && range->fallback_start) {
+		start = range->fallback_start;
+		end = range->fallback_end;
+		p = __vmalloc_node_range(size, align, start, end, gfp_flags,
+					 pgprot, vm_flags, NUMA_NO_NODE,
+					 __builtin_return_address(0));
+	}
+
+	if (!p) {
+		pr_warn_ratelimited("execmem: unable to allocate memory\n");
+		return NULL;
+	}
+
+	if (kasan && (kasan_alloc_module_shadow(p, size, GFP_KERNEL) < 0)) {
+		vfree(p);
+		return NULL;
+	}
+
+	return kasan_reset_tag(p);
+}
+
+void *execmem_alloc(enum execmem_type type, size_t size)
+{
+	struct execmem_range *range = &execmem_info->ranges[type];
+
+	return __execmem_alloc(range, size);
+}
+
+void execmem_free(void *ptr)
+{
+	/*
+	 * This memory may be RO, and freeing RO memory in an interrupt is not
+	 * supported by vmalloc.
+	 */
+	WARN_ON(in_interrupt());
+	vfree(ptr);
+}
+
+static bool execmem_validate(struct execmem_info *info)
+{
+	struct execmem_range *r = &info->ranges[EXECMEM_DEFAULT];
+
+	if (!r->alignment || !r->start || !r->end || !pgprot_val(r->pgprot)) {
+		pr_crit("Invalid parameters for execmem allocator, module loading will fail");
+		return false;
+	}
+
+	return true;
+}
+
+static void execmem_init_missing(struct execmem_info *info)
+{
+	struct execmem_range *default_range = &info->ranges[EXECMEM_DEFAULT];
+
+	for (int i = EXECMEM_DEFAULT + 1; i < EXECMEM_TYPE_MAX; i++) {
+		struct execmem_range *r = &info->ranges[i];
+
+		if (!r->start) {
+			if (i == EXECMEM_MODULE_DATA)
+				r->pgprot = PAGE_KERNEL;
+			else
+				r->pgprot = default_range->pgprot;
+			r->alignment = default_range->alignment;
+			r->start = default_range->start;
+			r->end = default_range->end;
+			r->flags = default_range->flags;
+			r->fallback_start = default_range->fallback_start;
+			r->fallback_end = default_range->fallback_end;
+		}
+	}
+}
+
+struct execmem_info * __weak execmem_arch_setup(void)
+{
+	return NULL;
+}
+
+static void __init __execmem_init(void)
+{
+	struct execmem_info *info = execmem_arch_setup();
+
+	if (!info) {
+		info = execmem_info = &default_execmem_info;
+		info->ranges[EXECMEM_DEFAULT].start = VMALLOC_START;
+		info->ranges[EXECMEM_DEFAULT].end = VMALLOC_END;
+		info->ranges[EXECMEM_DEFAULT].pgprot = PAGE_KERNEL_EXEC;
+		info->ranges[EXECMEM_DEFAULT].alignment = 1;
+	}
+
+	if (!execmem_validate(info))
+		return;
+
+	execmem_init_missing(info);
+
+	execmem_info = info;
+}
+
+#ifdef CONFIG_ARCH_WANTS_EXECMEM_LATE
+static int __init execmem_late_init(void)
+{
+	__execmem_init();
+	return 0;
+}
+core_initcall(execmem_late_init);
+#else
+void __init execmem_init(void)
+{
+	__execmem_init();
+}
+#endif