kernel/kexec_file.c: move purgatories sha256 to common code

The code to verify the new kernels sha digest is applicable for all
architectures.  Move it to common code.

One problem is the string.c implementation on x86.  Currently sha256
includes x86/boot/string.h which defines memcpy and memset to be gcc
builtins.  By moving the sha256 implementation to common code and
changing the include to linux/string.h both functions are no longer
defined.  Thus definitions have to be provided in x86/purgatory/string.c

Link: http://lkml.kernel.org/r/20180321112751.22196-12-prudo@linux.vnet.ibm.com
Signed-off-by: Philipp Rudo <prudo@linux.vnet.ibm.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index d70c15de417b269983a433713faf6bfcffd717ac..2e9ee023e6bcff25055bf5e05b0fc597d75f49bb 100644 (file)
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -6,6 +6,9 @@ purgatory-y := purgatory.o stack.o setup-x86_$(BITS).o sha256.o entry64.o string
 targets += $(purgatory-y)
 PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y))
 
+$(obj)/sha256.o: $(srctree)/lib/sha256.c
+       $(call if_changed_rule,cc_o_c)
+
 LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined -nostdlib -z nodefaultlib
 targets += purgatory.ro
 

diff --git a/arch/x86/purgatory/purgatory.c b/arch/x86/purgatory/purgatory.c
index 470edad96bb9560a218affd4c0922888f9200dba..025c34ac0d848f642a4b4b1c2c9577c52aa72614 100644 (file)
--- a/arch/x86/purgatory/purgatory.c
+++ b/arch/x86/purgatory/purgatory.c
@@ -11,9 +11,9 @@
  */
 
 #include <linux/bug.h>
+#include <linux/sha256.h>
 #include <asm/purgatory.h>
 
-#include "sha256.h"
 #include "../boot/string.h"
 
 unsigned long purgatory_backup_dest __section(.kexec-purgatory);

diff --git a/arch/x86/purgatory/string.c b/arch/x86/purgatory/string.c
index d886b1fa36f009d173d33dc84a4213ef61d44c14..795ca4f2cb3c912e37f214802cde76fc4fea7985 100644 (file)
--- a/arch/x86/purgatory/string.c
+++ b/arch/x86/purgatory/string.c
@@ -10,4 +10,16 @@
  * Version 2.  See the file COPYING for more details.
  */
 
+#include <linux/types.h>
+
 #include "../boot/string.c"
+
+void *memcpy(void *dst, const void *src, size_t len)
+{
+       return __builtin_memcpy(dst, src, len);
+}
+
+void *memset(void *dst, int c, size_t len)
+{
+       return __builtin_memset(dst, c, len);
+}

diff --git a/arch/x86/purgatory/sha256.h b/include/linux/sha256.h
similarity index 62%
rename from arch/x86/purgatory/sha256.h
rename to include/linux/sha256.h
index 2867d9825a57e5f1f734bfb4a5777bc31810b090..244fe01a65fb95f54f2aac9860268538f766e2ce 100644 (file)
--- a/arch/x86/purgatory/sha256.h
+++ b/include/linux/sha256.h
@@ -13,9 +13,18 @@
 #include <linux/types.h>
 #include <crypto/sha.h>
 
+/*
+ * Stand-alone implementation of the SHA256 algorithm. It is designed to
+ * have as little dependencies as possible so it can be used in the
+ * kexec_file purgatory. In other cases you should use the implementation in
+ * crypto/.
+ *
+ * For details see lib/sha256.c
+ */
+
 extern int sha256_init(struct sha256_state *sctx);
 extern int sha256_update(struct sha256_state *sctx, const u8 *input,
-                               unsigned int length);
+                        unsigned int length);
 extern int sha256_final(struct sha256_state *sctx, u8 *hash);
 
 #endif /* SHA256_H */

diff --git a/arch/x86/purgatory/sha256.c b/lib/sha256.c
similarity index 99%
rename from arch/x86/purgatory/sha256.c
rename to lib/sha256.c
index 548ca675a14a131b78c8025b8c7185f23cd4a602..4400c832e2aaa36338e9e661910f644c11e69e66 100644 (file)
--- a/arch/x86/purgatory/sha256.c
+++ b/lib/sha256.c
@@ -16,9 +16,9 @@
  */
 
 #include <linux/bitops.h>
+#include <linux/sha256.h>
+#include <linux/string.h>
 #include <asm/byteorder.h>
-#include "sha256.h"
-#include "../boot/string.h"
 
 static inline u32 Ch(u32 x, u32 y, u32 z)
 {