kasan: add wrappers for vmalloc hooks

Add wrappers around functions that [un]poison memory for vmalloc
allocations.  These functions will be used by HW_TAGS KASAN and therefore
need to be disabled when kasan=off command line argument is provided.

This patch does no functional changes for software KASAN modes.

Link: https://lkml.kernel.org/r/3b8728eac438c55389fb0f9a8a2145d71dd77487.1643047180.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

include/linux/kasan.h

@@ -424,8 +424,21 @@ void kasan_release_vmalloc(unsigned long start, unsigned long end,
 			   unsigned long free_region_start,
 			   unsigned long free_region_end);
 
-void kasan_unpoison_vmalloc(const void *start, unsigned long size);
-void kasan_poison_vmalloc(const void *start, unsigned long size);
+void __kasan_unpoison_vmalloc(const void *start, unsigned long size);
+static __always_inline void kasan_unpoison_vmalloc(const void *start,
+						   unsigned long size)
+{
+	if (kasan_enabled())
+		__kasan_unpoison_vmalloc(start, size);
+}
+
+void __kasan_poison_vmalloc(const void *start, unsigned long size);
+static __always_inline void kasan_poison_vmalloc(const void *start,
+						 unsigned long size)
+{
+	if (kasan_enabled())
+		__kasan_poison_vmalloc(start, size);
+}
 
 #else /* CONFIG_KASAN_VMALLOC */
 

mm/kasan/shadow.c

@@ -475,8 +475,7 @@ void kasan_release_vmalloc(unsigned long start, unsigned long end,
 	}
 }
 
-
-void kasan_unpoison_vmalloc(const void *start, unsigned long size)
+void __kasan_unpoison_vmalloc(const void *start, unsigned long size)
 {
 	if (!is_vmalloc_or_module_addr(start))
 		return;
@@ -488,7 +487,7 @@ void kasan_unpoison_vmalloc(const void *start, unsigned long size)
  * Poison the shadow for a vmalloc region. Called as part of the
  * freeing process at the time the region is freed.
  */
-void kasan_poison_vmalloc(const void *start, unsigned long size)
+void __kasan_poison_vmalloc(const void *start, unsigned long size)
 {
 	if (!is_vmalloc_or_module_addr(start))
 		return;