Re: [PATCH v6 4/4] powerpc: Book3S 64-bit "heavyweight" KASAN support

Christophe Leroy [off-list ref] writes:

Le 12/02/2020 à 11:12, Daniel Axtens a écrit :

quoted

Christophe Leroy [off-list ref] writes:

quoted

Le 12/02/2020 à 06:47, Daniel Axtens a écrit :

quoted

diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
index fbff9ff9032e..2911fdd3a6a0 100644
--- a/arch/powerpc/include/asm/kasan.h
+++ b/arch/powerpc/include/asm/kasan.h

@@ -2,6 +2,8 @@
   #ifndef __ASM_KASAN_H
   #define __ASM_KASAN_H
   
+#include <asm/page.h>
+
   #ifdef CONFIG_KASAN
   #define _GLOBAL_KASAN(fn)	_GLOBAL(__##fn)
   #define _GLOBAL_TOC_KASAN(fn)	_GLOBAL_TOC(__##fn)

@@ -14,29 +16,41 @@
   
   #ifndef __ASSEMBLY__
   
-#include <asm/page.h>
-
   #define KASAN_SHADOW_SCALE_SHIFT	3
   
   #define KASAN_SHADOW_START	(KASAN_SHADOW_OFFSET + \
   				 (PAGE_OFFSET >> KASAN_SHADOW_SCALE_SHIFT))
   
+#ifdef CONFIG_KASAN_SHADOW_OFFSET
   #define KASAN_SHADOW_OFFSET	ASM_CONST(CONFIG_KASAN_SHADOW_OFFSET)
+#endif
   
+#ifdef CONFIG_PPC32
   #define KASAN_SHADOW_END	0UL
   
-#define KASAN_SHADOW_SIZE	(KASAN_SHADOW_END - KASAN_SHADOW_START)
+#ifdef CONFIG_KASAN
+void kasan_late_init(void);
+#else
+static inline void kasan_late_init(void) { }
+#endif
+
+#endif
+
+#ifdef CONFIG_PPC_BOOK3S_64
+#define KASAN_SHADOW_END	(KASAN_SHADOW_OFFSET + \
+				 (RADIX_VMEMMAP_END >> KASAN_SHADOW_SCALE_SHIFT))
+
+static inline void kasan_late_init(void) { }
+#endif
   
   #ifdef CONFIG_KASAN
   void kasan_early_init(void);
   void kasan_mmu_init(void);
   void kasan_init(void);
-void kasan_late_init(void);
   #else
   static inline void kasan_init(void) { }
   static inline void kasan_mmu_init(void) { }
-static inline void kasan_late_init(void) { }
   #endif

Why modify all this kasan_late_init() stuff ?

This function is only called from kasan init_32.c, it is never called by
PPC64, so you should not need to modify anything at all.

I got a compile error for a missing symbol. I'll repro it and attach it.

Oops, sorry. I looked too quickly. It is defined in kasan_init_32.c and 
called from mm/mem.c

We don't have a performance issue here, since this is called only once 
during startup. Could you define an empty kasan_late_init() in 
init_book3s_64.c instead ?

Yeah, I can do that, will respin tomorrow.

Would you mind having a quick check of the documentation changes in
patches 2 and 4? I just want to confirm I've accurately captured the
state of ppc32 kasan work.

Thanks!
Daniel

Christophe