Commit 26deb043 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc: prepare string/mem functions for KASAN 



CONFIG_KASAN implements wrappers for memcpy() memmove() and memset()
Those wrappers are doing the verification then call respectively
__memcpy() __memmove() and __memset(). The arches are therefore
expected to rename their optimised functions that way.

For files on which KASAN is inhibited, #defines are used to allow
them to directly call optimised versions of the functions without
going through the KASAN wrappers.

See commit 393f203f ("x86_64: kasan: add interceptors for
memset/memmove/memcpy functions") for details.

Other string / mem functions do not (yet) have kasan wrappers,
we therefore have to fallback to the generic versions when
KASAN is active, otherwise KASAN checks will be skipped.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
[mpe: Fixups to keep selftests working]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent d69ca6ba

arch/powerpc/include/asm/kasan.h

0 → 100644
+15 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef __ASM_KASAN_H

#define __ASM_KASAN_H



#ifdef CONFIG_KASAN

#define _GLOBAL_KASAN(fn)	_GLOBAL(__##fn)

#define _GLOBAL_TOC_KASAN(fn)	_GLOBAL_TOC(__##fn)

#define EXPORT_SYMBOL_KASAN(fn)	EXPORT_SYMBOL(__##fn)

#else

#define _GLOBAL_KASAN(fn)	_GLOBAL(fn)

#define _GLOBAL_TOC_KASAN(fn)	_GLOBAL_TOC(fn)

#define EXPORT_SYMBOL_KASAN(fn)

#endif



#endif

arch/powerpc/include/asm/string.h

+29 −3
Original line number Diff line number Diff line
@@ -4,14 +4,17 @@ 


#ifdef __KERNEL__



#ifndef CONFIG_KASAN

#define __HAVE_ARCH_STRNCPY

#define __HAVE_ARCH_STRNCMP

#define __HAVE_ARCH_MEMCHR

#define __HAVE_ARCH_MEMCMP

#define __HAVE_ARCH_MEMSET16

#endif



#define __HAVE_ARCH_MEMSET

#define __HAVE_ARCH_MEMCPY

#define __HAVE_ARCH_MEMMOVE

#define __HAVE_ARCH_MEMCMP

#define __HAVE_ARCH_MEMCHR

#define __HAVE_ARCH_MEMSET16

#define __HAVE_ARCH_MEMCPY_FLUSHCACHE



extern char * strcpy(char *,const char *);
@@ -27,7 +30,27 @@ extern int memcmp(const void *,const void *,__kernel_size_t); 
extern void * memchr(const void *,int,__kernel_size_t);

extern void * memcpy_flushcache(void *,const void *,__kernel_size_t);



void *__memset(void *s, int c, __kernel_size_t count);

void *__memcpy(void *to, const void *from, __kernel_size_t n);

void *__memmove(void *to, const void *from, __kernel_size_t n);



#if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)

/*

 * For files that are not instrumented (e.g. mm/slub.c) we

 * should use not instrumented version of mem* functions.

 */

#define memcpy(dst, src, len) __memcpy(dst, src, len)

#define memmove(dst, src, len) __memmove(dst, src, len)

#define memset(s, c, n) __memset(s, c, n)



#ifndef __NO_FORTIFY

#define __NO_FORTIFY /* FORTIFY_SOURCE uses __builtin_memcpy, etc. */

#endif



#endif



#ifdef CONFIG_PPC64

#ifndef CONFIG_KASAN

#define __HAVE_ARCH_MEMSET32

#define __HAVE_ARCH_MEMSET64
@@ -49,8 +72,11 @@ static inline void *memset64(uint64_t *p, uint64_t v, __kernel_size_t n) 
{

	return __memset64(p, v, n * 8);

}

#endif

#else

#ifndef CONFIG_KASAN

#define __HAVE_ARCH_STRLEN

#endif



extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);

#endif

arch/powerpc/kernel/prom_init_check.sh

+9 −1
Original line number Diff line number Diff line
@@ -16,8 +16,16 @@ 
# If you really need to reference something from prom_init.o add

# it to the list below:



grep "^CONFIG_KASAN=y$" .config >/dev/null

if [ $? -eq 0 ]

then

	MEM_FUNCS="__memcpy __memset"

else

	MEM_FUNCS="memcpy memset"

fi



WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush

_end enter_prom memcpy memset reloc_offset __secondary_hold

_end enter_prom $MEM_FUNCS reloc_offset __secondary_hold

__secondary_hold_acknowledge __secondary_hold_spinloop __start

strcmp strcpy strlcpy strlen strncmp strstr kstrtobool logo_linux_clut224

reloc_got2 kernstart_addr memstart_addr linux_banner _stext

arch/powerpc/lib/Makefile

+8 −3
Original line number Diff line number Diff line
@@ -8,9 +8,14 @@ ccflags-$(CONFIG_PPC64) := $(NO_MINIMAL_TOC) 
CFLAGS_REMOVE_code-patching.o = $(CC_FLAGS_FTRACE)

CFLAGS_REMOVE_feature-fixups.o = $(CC_FLAGS_FTRACE)



obj-y += string.o alloc.o code-patching.o feature-fixups.o

obj-y += alloc.o code-patching.o feature-fixups.o



obj-$(CONFIG_PPC32)	+= div64.o copy_32.o crtsavres.o strlen_32.o

ifndef CONFIG_KASAN

obj-y	+=	string.o memcmp_$(BITS).o

obj-$(CONFIG_PPC32)	+= strlen_32.o

endif



obj-$(CONFIG_PPC32)	+= div64.o copy_32.o crtsavres.o



obj-$(CONFIG_FUNCTION_ERROR_INJECTION)	+= error-inject.o
@@ -34,7 +39,7 @@ obj64-$(CONFIG_KPROBES_SANITY_TEST) += test_emulate_step.o \ 
					   test_emulate_step_exec_instr.o



obj-y			+= checksum_$(BITS).o checksum_wrappers.o \

			   string_$(BITS).o memcmp_$(BITS).o

			   string_$(BITS).o



obj-y			+= sstep.o ldstfp.o quad.o

obj64-y			+= quad.o

arch/powerpc/lib/copy_32.S

+9 −3
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <asm/ppc_asm.h>

#include <asm/export.h>

#include <asm/code-patching-asm.h>

#include <asm/kasan.h>



#define COPY_16_BYTES		\

	lwz	r7,4(r4);	\
@@ -68,6 +69,7 @@ CACHELINE_BYTES = L1_CACHE_BYTES 
LG_CACHELINE_BYTES = L1_CACHE_SHIFT

CACHELINE_MASK = (L1_CACHE_BYTES-1)



#ifndef CONFIG_KASAN

_GLOBAL(memset16)

	rlwinm.	r0 ,r5, 31, 1, 31

	addi	r6, r3, -4
@@ -81,6 +83,7 @@ _GLOBAL(memset16) 
	sth	r4, 4(r6)

	blr

EXPORT_SYMBOL(memset16)

#endif



/*

 * Use dcbz on the complete cache lines in the destination
@@ -91,7 +94,7 @@ EXPORT_SYMBOL(memset16) 
 * We therefore skip the optimised bloc that uses dcbz. This jump is

 * replaced by a nop once cache is active. This is done in machine_init()

 */

_GLOBAL(memset)

_GLOBAL_KASAN(memset)

	cmplwi	0,r5,4

	blt	7f
@@ -151,6 +154,7 @@ _GLOBAL(memset) 
	bdnz	9b

	blr

EXPORT_SYMBOL(memset)

EXPORT_SYMBOL_KASAN(memset)



/*

 * This version uses dcbz on the complete cache lines in the
@@ -163,12 +167,12 @@ EXPORT_SYMBOL(memset) 
 * We therefore jump to generic_memcpy which doesn't use dcbz. This jump is

 * replaced by a nop once cache is active. This is done in machine_init()

 */

_GLOBAL(memmove)

_GLOBAL_KASAN(memmove)

	cmplw	0,r3,r4

	bgt	backwards_memcpy

	/* fall through */



_GLOBAL(memcpy)

_GLOBAL_KASAN(memcpy)

1:	b	generic_memcpy

	patch_site	1b, patch__memcpy_nocache
@@ -244,6 +248,8 @@ _GLOBAL(memcpy) 
65:	blr

EXPORT_SYMBOL(memcpy)

EXPORT_SYMBOL(memmove)

EXPORT_SYMBOL_KASAN(memcpy)

EXPORT_SYMBOL_KASAN(memmove)



generic_memcpy:

	srwi.	r7,r5,3

CRA Git | Maintained and supported by SUSTech CRA and CCSE