Minor purgatory updates

Hi Simon,

Here are a few minor updates for purgatory. I think the no-zero-initialized-in-bss flag and the printf type checking should be considered seriously. The symbol and map files less important, but I found them useful in figuring out problems with purgatory.

-Geoff

The following changes since commit 236e30b2b4dcb3e78c5f5219b66d90c7e9c464fd:

kexec: iomem: fix callbacks params for sh and x86 archs (2015-02-25 13:41:32 +0900)

are available in the git repository at:

git://git.kernel.org/pub/scm/linux/kernel/git/geoff/kexec-tools.git for-merge

for you to fetch changes up to 6859689cd7561950eda3a0fef52a2eedd22c14fb:

purgatory: Add printf type checking (2015-03-18 15:47:25 -0700)

----------------------------------------------------------------
Geoff Levand (4):
purgatory: Add no-zero-initialized-in-bss flag
purgatory: Generate symbol file
purgatory: Generate map file
purgatory: Add printf type checking

 purgatory/Makefile            | 12 +++++++-----
 purgatory/include/purgatory.h |  5 +++--
 2 files changed, 10 insertions(+), 7 deletions(-)

2.1.0


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It seems some toolchains will put zero-initialized variables like purgatory's sha256_regions into the BSS section. These symbols cannot be processed by machine_apply_elf_rel() and lead to build errors. To avoid this problem add the compiler flag no-zero-initialized-in-bss to the purgatory CFLAGS.

Fixes build errors like these:

Symbol: sha256_regions is in a bss section cannot set

Reported here:

http://lists.infradead.org/pipermail/kexec/2014-November/013052.html

---
 purgatory/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

index 1945702..1c7d2c0 100644
@@ -47,7 +47,8 @@ purgatory/sha256.o: $(srcdir)/util_lib/sha256.c
 $(PURGATORY): CC=$(TARGET_CC)
 $(PURGATORY): CFLAGS+=$(PURGATORY_EXTRA_CFLAGS) \
 		      $($(ARCH)_PURGATORY_EXTRA_CFLAGS) \
-		      -Os -fno-builtin -ffreestanding
+		      -Os -fno-builtin -ffreestanding \
+		      -fno-zero-initialized-in-bss
 
 $(PURGATORY): CPPFLAGS=$($(ARCH)_PURGATORY_EXTRA_CFLAGS) \
 			-I$(srcdir)/purgatory/include \

2.1.0



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To aid in debugging purgatory update its makefile to generate a stand alone symbol file that can me loaded by a debugger.

---
 purgatory/Makefile | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

index 1c7d2c0..6b17e71 100644
@@ -63,10 +63,9 @@ $(PURGATORY): LDFLAGS=$($(ARCH)_PURGATORY_EXTRA_CFLAGS)\
 
 $(PURGATORY): $(PURGATORY_OBJS)
 	$(MKDIR) -p $(@D)
-	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^
-
+	$(CC) $(CFLAGS) $(LDFLAGS) -o [email protected] $^
 #	$(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) --no-undefined -e purgatory_start -r -o $@ $(PURGATORY_OBJS) $(UTIL_LIB)
-	$(STRIP) --strip-debug $@
+	$(STRIP) --strip-debug -o $@ [email protected]
 
 echo::
 	@echo "PURGATORY_SRCS $(PURGATORY_SRCS)"

2.1.0



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To aid in debugging purgatory and its relocation generate a linker map file when purgatory is built.

---
 purgatory/Makefile | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

index 6b17e71..2d6b2c0 100644
@@ -12,6 +12,7 @@ PURGATORY_SRCS =
 PURGATORY_SRCS += purgatory/purgatory.c
 PURGATORY_SRCS += purgatory/printf.c
 PURGATORY_SRCS += purgatory/string.c
+PURGATORY_MAP = purgatory/purgatory.map
 
 dist += purgatory/Makefile $(PURGATORY_SRCS)				\
 	purgatory/include/purgatory.h purgatory/include/string.h

@@ -59,7 +60,8 @@ $(PURGATORY): CPPFLAGS=$($(ARCH)_PURGATORY_EXTRA_CFLAGS) \
 			-I$(shell $(CC) -print-file-name=include)
 $(PURGATORY): LDFLAGS=$($(ARCH)_PURGATORY_EXTRA_CFLAGS)\
 			-Wl,--no-undefined -nostartfiles -nostdlib \
-			-nodefaultlibs -e purgatory_start -r
+			-nodefaultlibs -e purgatory_start -r \
+			-Wl,-Map=$(PURGATORY_MAP)
 
 $(PURGATORY): $(PURGATORY_OBJS)
 	$(MKDIR) -p $(@D)

2.1.0



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To better catch coding problems add stricter type checking to the purgatory printf routines.

---
 purgatory/include/purgatory.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

index ed50dc4..788ce49 100644
@@ -2,8 +2,9 @@
 #define PURGATORY_H
 
 void putchar(int ch);
-void sprintf(char *buffer, const char *fmt, ...);
-void printf(const char *fmt, ...);
+void sprintf(char *buffer, const char *fmt, ...)
+	__attribute__ ((format (printf, 2, 3)));
+void printf(const char *fmt, ...) __attribute__ ((format (printf, 1, 2)));
 void setup_arch(void);
 void post_verification_setup_arch(void);
 

2.1.0


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Thanks Geoff,

these all seem reasonable to me. I have applied the entire series.

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