mm/execmem, arch: convert remaining overrides of module_alloc to execmem

Extend execmem parameters to accommodate more complex overrides of
module_alloc() by architectures.

This includes specification of a fallback range required by arm, arm64
and powerpc, EXECMEM_MODULE_DATA type required by powerpc, support for
allocation of KASAN shadow required by s390 and x86 and support for
late initialization of execmem required by arm64.

The core implementation of execmem_alloc() takes care of suppressing
warnings when the initial allocation fails but there is a fallback range
defined.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Tested-by: Liviu Dudau <liviu@dudau.co.uk>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

1 files changed, 62 insertions, 12 deletions

diff --git a/mm/execmem.c b/mm/execmem.c
index 80e61c1e7319..0c4b36bc6d10 100644
--- a/mm/execmem.c
+++ b/mm/execmem.c
@@ -12,27 +12,49 @@
 #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 __vmalloc_node_range(size, align, start, end,
-				    GFP_KERNEL, pgprot, VM_FLUSH_RESET_PERMS,
-				    NUMA_NO_NODE, __builtin_return_address(0));
+	return kasan_reset_tag(p);
 }
 
 void *execmem_alloc(enum execmem_type type, size_t size)
 {
-	struct execmem_range *range;
-
-	if (!execmem_info)
-		return module_alloc(size);
-
-	range = &execmem_info->ranges[type];
+	struct execmem_range *range = &execmem_info->ranges[type];
 
 	return __execmem_alloc(range, size);
 }
@@ -67,10 +89,16 @@ static void execmem_init_missing(struct execmem_info *info)
 		struct execmem_range *r = &info->ranges[i];
 
 		if (!r->start) {
-			r->pgprot = default_range->pgprot;
+			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;
 		}
 	}
 }
@@ -80,14 +108,36 @@ struct execmem_info * __weak execmem_arch_setup(void)
 	return NULL;
 }
 
-void __init execmem_init(void)
+static void __init __execmem_init(void)
 {
 	struct execmem_info *info = execmem_arch_setup();
 
-	if (!info || !execmem_validate(info))
+	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