elf coredump: replace ELF_CORE_EXTRA_* macros by functions

elf_core_dump() and elf_fdpic_core_dump() use #ifdef and the corresponding
macro for hiding _multiline_ logics in functions.  This patch removes
#ifdef and replaces ELF_CORE_EXTRA_* by corresponding functions.  For
architectures not implemeonting ELF_CORE_EXTRA_*, we use weak functions in
order to reduce a range of modification.

This cleanup is for my next patches, but I think this cleanup itself is
worth doing regardless of my firnal purpose.

Signed-off-by: Daisuke HATAYAMA <d.hatayama@jp.fujitsu.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

13 files changed, 191 insertions, 109 deletions

diff --git a/arch/ia64/include/asm/elf.h b/arch/ia64/include/asm/elf.h
index 4c41656..b5298eb 100644
--- a/arch/ia64/include/asm/elf.h
+++ b/arch/ia64/include/asm/elf.h
@@ -219,54 +219,6 @@ do {										\
 	NEW_AUX_ENT(AT_SYSINFO_EHDR, (unsigned long) GATE_EHDR);		\
 } while (0)
 
-
-/*
- * These macros parameterize elf_core_dump in fs/binfmt_elf.c to write out
- * extra segments containing the gate DSO contents.  Dumping its
- * contents makes post-mortem fully interpretable later without matching up
- * the same kernel and hardware config to see what PC values meant.
- * Dumping its extra ELF program headers includes all the other information
- * a debugger needs to easily find how the gate DSO was being used.
- */
-#define ELF_CORE_EXTRA_PHDRS		(GATE_EHDR->e_phnum)
-#define ELF_CORE_WRITE_EXTRA_PHDRS						\
-do {										\
-	const struct elf_phdr *const gate_phdrs =			      \
-		(const struct elf_phdr *) (GATE_ADDR + GATE_EHDR->e_phoff);   \
-	int i;									\
-	Elf64_Off ofs = 0;						      \
-	for (i = 0; i < GATE_EHDR->e_phnum; ++i) {				\
-		struct elf_phdr phdr = gate_phdrs[i];			      \
-		if (phdr.p_type == PT_LOAD) {					\
-			phdr.p_memsz = PAGE_ALIGN(phdr.p_memsz);	      \
-			phdr.p_filesz = phdr.p_memsz;			      \
-			if (ofs == 0) {					      \
-				ofs = phdr.p_offset = offset;		      \
-			offset += phdr.p_filesz;				\
-		}							      \
-		else							      \
-				phdr.p_offset = ofs;			      \
-		}							      \
-		else							      \
-			phdr.p_offset += ofs;					\
-		phdr.p_paddr = 0; /* match other core phdrs */			\
-		DUMP_WRITE(&phdr, sizeof(phdr));				\
-	}									\
-} while (0)
-#define ELF_CORE_WRITE_EXTRA_DATA					\
-do {									\
-	const struct elf_phdr *const gate_phdrs =			      \
-		(const struct elf_phdr *) (GATE_ADDR + GATE_EHDR->e_phoff);   \
-	int i;								\
-	for (i = 0; i < GATE_EHDR->e_phnum; ++i) {			\
-		if (gate_phdrs[i].p_type == PT_LOAD) {			      \
-			DUMP_WRITE((void *) gate_phdrs[i].p_vaddr,	      \
-				   PAGE_ALIGN(gate_phdrs[i].p_memsz));	      \
-			break;						      \
-		}							      \
-	}								\
-} while (0)
-
 /*
  * format for entries in the Global Offset Table
  */
diff --git a/arch/ia64/kernel/Makefile b/arch/ia64/kernel/Makefile
index 4138282..db10b1e 100644
--- a/arch/ia64/kernel/Makefile
+++ b/arch/ia64/kernel/Makefile
@@ -45,6 +45,8 @@ endif
 obj-$(CONFIG_DMAR)		+= pci-dma.o
 obj-$(CONFIG_SWIOTLB)		+= pci-swiotlb.o
 
+obj-$(CONFIG_BINFMT_ELF)	+= elfcore.o
+
 # fp_emulate() expects f2-f5,f16-f31 to contain the user-level state.
 CFLAGS_traps.o  += -mfixed-range=f2-f5,f16-f31
 
diff --git a/arch/ia64/kernel/elfcore.c b/arch/ia64/kernel/elfcore.c
new file mode 100644
index 0000000..57a2298
--- /dev/null
+++ b/arch/ia64/kernel/elfcore.c
@@ -0,0 +1,64 @@
+#include <linux/elf.h>
+#include <linux/coredump.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+
+#include <asm/elf.h>
+
+
+Elf64_Half elf_core_extra_phdrs(void)
+{
+	return GATE_EHDR->e_phnum;
+}
+
+int elf_core_write_extra_phdrs(struct file *file, loff_t offset, size_t *size,
+			       unsigned long limit)
+{
+	const struct elf_phdr *const gate_phdrs =
+		(const struct elf_phdr *) (GATE_ADDR + GATE_EHDR->e_phoff);
+	int i;
+	Elf64_Off ofs = 0;
+
+	for (i = 0; i < GATE_EHDR->e_phnum; ++i) {
+		struct elf_phdr phdr = gate_phdrs[i];
+
+		if (phdr.p_type == PT_LOAD) {
+			phdr.p_memsz = PAGE_ALIGN(phdr.p_memsz);
+			phdr.p_filesz = phdr.p_memsz;
+			if (ofs == 0) {
+				ofs = phdr.p_offset = offset;
+				offset += phdr.p_filesz;
+			} else {
+				phdr.p_offset = ofs;
+			}
+		} else {
+			phdr.p_offset += ofs;
+		}
+		phdr.p_paddr = 0; /* match other core phdrs */
+		*size += sizeof(phdr);
+		if (*size > limit || !dump_write(file, &phdr, sizeof(phdr)))
+			return 0;
+	}
+	return 1;
+}
+
+int elf_core_write_extra_data(struct file *file, size_t *size,
+			      unsigned long limit)
+{
+	const struct elf_phdr *const gate_phdrs =
+		(const struct elf_phdr *) (GATE_ADDR + GATE_EHDR->e_phoff);
+	int i;
+
+	for (i = 0; i < GATE_EHDR->e_phnum; ++i) {
+		if (gate_phdrs[i].p_type == PT_LOAD) {
+			void *addr = (void *)gate_phdrs[i].p_vaddr;
+			size_t memsz = PAGE_ALIGN(gate_phdrs[i].p_memsz);
+
+			*size += memsz;
+			if (*size > limit || !dump_write(file, addr, memsz))
+				return 0;
+			break;
+		}
+	}
+	return 1;
+}
diff --git a/arch/um/sys-i386/Makefile b/arch/um/sys-i386/Makefile
index 1b549bc..804b28d 100644
--- a/arch/um/sys-i386/Makefile
+++ b/arch/um/sys-i386/Makefile
@@ -6,6 +6,8 @@ obj-y = bug.o bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \
 	ptrace_user.o setjmp.o signal.o stub.o stub_segv.o syscalls.o sysrq.o \
 	sys_call_table.o tls.o
 
+obj-$(CONFIG_BINFMT_ELF) += elfcore.o
+
 subarch-obj-y = lib/semaphore_32.o lib/string_32.o
 subarch-obj-$(CONFIG_HIGHMEM) += mm/highmem_32.o
 subarch-obj-$(CONFIG_MODULES) += kernel/module.o
diff --git a/arch/um/sys-i386/asm/elf.h b/arch/um/sys-i386/asm/elf.h
index 7708854..e64cd41 100644
--- a/arch/um/sys-i386/asm/elf.h
+++ b/arch/um/sys-i386/asm/elf.h
@@ -116,47 +116,4 @@ do {								\
 	}							\
 } while (0)
 
-/*
- * These macros parameterize elf_core_dump in fs/binfmt_elf.c to write out
- * extra segments containing the vsyscall DSO contents.  Dumping its
- * contents makes post-mortem fully interpretable later without matching up
- * the same kernel and hardware config to see what PC values meant.
- * Dumping its extra ELF program headers includes all the other information
- * a debugger needs to easily find how the vsyscall DSO was being used.
- */
-#define ELF_CORE_EXTRA_PHDRS						      \
-	(vsyscall_ehdr ? (((struct elfhdr *)vsyscall_ehdr)->e_phnum) : 0 )
-
-#define ELF_CORE_WRITE_EXTRA_PHDRS					      \
-if ( vsyscall_ehdr ) {							      \
-	const struct elfhdr *const ehdrp = (struct elfhdr *)vsyscall_ehdr;    \
-	const struct elf_phdr *const phdrp =				      \
-		(const struct elf_phdr *) (vsyscall_ehdr + ehdrp->e_phoff);   \
-	int i;								      \
-	Elf32_Off ofs = 0;						      \
-	for (i = 0; i < ehdrp->e_phnum; ++i) {				      \
-		struct elf_phdr phdr = phdrp[i];			      \
-		if (phdr.p_type == PT_LOAD) {				      \
-			ofs = phdr.p_offset = offset;			      \
-			offset += phdr.p_filesz;			      \
-		}							      \
-		else							      \
-			phdr.p_offset += ofs;				      \
-		phdr.p_paddr = 0; /* match other core phdrs */		      \
-		DUMP_WRITE(&phdr, sizeof(phdr));			      \
-	}								      \
-}
-#define ELF_CORE_WRITE_EXTRA_DATA					      \
-if ( vsyscall_ehdr ) {							      \
-	const struct elfhdr *const ehdrp = (struct elfhdr *)vsyscall_ehdr;    \
-	const struct elf_phdr *const phdrp =				      \
-		(const struct elf_phdr *) (vsyscall_ehdr + ehdrp->e_phoff);   \
-	int i;								      \
-	for (i = 0; i < ehdrp->e_phnum; ++i) {				      \
-		if (phdrp[i].p_type == PT_LOAD)				      \
-			DUMP_WRITE((void *) phdrp[i].p_vaddr,		      \
-				   phdrp[i].p_filesz);			      \
-	}								      \
-}
-
 #endif
diff --git a/arch/um/sys-i386/elfcore.c b/arch/um/sys-i386/elfcore.c
new file mode 100644
index 0000000..30cac52
--- /dev/null
+++ b/arch/um/sys-i386/elfcore.c
@@ -0,0 +1,67 @@
+#include <linux/elf.h>
+#include <linux/coredump.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+
+#include <asm/elf.h>
+
+
+Elf32_Half elf_core_extra_phdrs(void)
+{
+	return vsyscall_ehdr ? (((struct elfhdr *)vsyscall_ehdr)->e_phnum) : 0;
+}
+
+int elf_core_write_extra_phdrs(struct file *file, loff_t offset, size_t *size,
+			       unsigned long limit)
+{
+	if ( vsyscall_ehdr ) {
+		const struct elfhdr *const ehdrp =
+			(struct elfhdr *) vsyscall_ehdr;
+		const struct elf_phdr *const phdrp =
+			(const struct elf_phdr *) (vsyscall_ehdr + ehdrp->e_phoff);
+		int i;
+		Elf32_Off ofs = 0;
+
+		for (i = 0; i < ehdrp->e_phnum; ++i) {
+			struct elf_phdr phdr = phdrp[i];
+
+			if (phdr.p_type == PT_LOAD) {
+				ofs = phdr.p_offset = offset;
+				offset += phdr.p_filesz;
+			} else {
+				phdr.p_offset += ofs;
+			}
+			phdr.p_paddr = 0; /* match other core phdrs */
+			*size += sizeof(phdr);
+			if (*size > limit
+			    || !dump_write(file, &phdr, sizeof(phdr)))
+				return 0;
+		}
+	}
+	return 1;
+}
+
+int elf_core_write_extra_data(struct file *file, size_t *size,
+			      unsigned long limit)
+{
+	if ( vsyscall_ehdr ) {
+		const struct elfhdr *const ehdrp =
+			(struct elfhdr *) vsyscall_ehdr;
+		const struct elf_phdr *const phdrp =
+			(const struct elf_phdr *) (vsyscall_ehdr + ehdrp->e_phoff);
+		int i;
+
+		for (i = 0; i < ehdrp->e_phnum; ++i) {
+			if (phdrp[i].p_type == PT_LOAD) {
+				void *addr = (void *) phdrp[i].p_vaddr;
+				size_t filesz = phdrp[i].p_filesz;
+
+				*size += filesz;
+				if (*size > limit
+				    || !dump_write(file, addr, filesz))
+					return 0;
+			}
+		}
+	}
+	return 1;
+}
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 0bcfbb0..c1a4995 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1878,9 +1878,7 @@ static int elf_core_dump(struct coredump_params *cprm)
 	 * Please check DEFAULT_MAX_MAP_COUNT definition when you modify here.
 	 */
 	segs = current->mm->map_count;
-#ifdef ELF_CORE_EXTRA_PHDRS
-	segs += ELF_CORE_EXTRA_PHDRS;
-#endif
+	segs += elf_core_extra_phdrs();
 
 	gate_vma = get_gate_vma(current);
 	if (gate_vma != NULL)
@@ -1958,9 +1956,8 @@ static int elf_core_dump(struct coredump_params *cprm)
 			goto end_coredump;
 	}
 
-#ifdef ELF_CORE_WRITE_EXTRA_PHDRS
-	ELF_CORE_WRITE_EXTRA_PHDRS;
-#endif
+	if (!elf_core_write_extra_phdrs(cprm->file, offset, &size, cprm->limit))
+		goto end_coredump;
 
  	/* write out the notes section */
 	if (!write_note_info(&info, cprm->file, &foffset))
@@ -1999,9 +1996,8 @@ static int elf_core_dump(struct coredump_params *cprm)
 		}
 	}
 
-#ifdef ELF_CORE_WRITE_EXTRA_DATA
-	ELF_CORE_WRITE_EXTRA_DATA;
-#endif
+	if (!elf_core_write_extra_data(cprm->file, &size, cprm->limit))
+		goto end_coredump;
 
 end_coredump:
 	set_fs(fs);
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 63edf40..952699a 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1664,9 +1664,7 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
 	elf_core_copy_regs(&prstatus->pr_reg, cprm->regs);
 
 	segs = current->mm->map_count;
-#ifdef ELF_CORE_EXTRA_PHDRS
-	segs += ELF_CORE_EXTRA_PHDRS;
-#endif
+	segs += elf_core_extra_phdrs();
 
 	/* Set up header */
 	fill_elf_fdpic_header(elf, segs + 1);	/* including notes section */
@@ -1773,9 +1771,8 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
 			goto end_coredump;
 	}
 
-#ifdef ELF_CORE_WRITE_EXTRA_PHDRS
-	ELF_CORE_WRITE_EXTRA_PHDRS;
-#endif
+	if (!elf_core_write_extra_phdrs(cprm->file, offset, &size, cprm->limit))
+		goto end_coredump;
 
  	/* write out the notes section */
 	for (i = 0; i < numnote; i++)
@@ -1799,9 +1796,8 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
 				    mm_flags) < 0)
 		goto end_coredump;
 
-#ifdef ELF_CORE_WRITE_EXTRA_DATA
-	ELF_CORE_WRITE_EXTRA_DATA;
-#endif
+	if (!elf_core_write_extra_data(cprm->file, &size, cprm->limit))
+		goto end_coredump;
 
 	if (cprm->file->f_pos != offset) {
 		/* Sanity check */
diff --git a/fs/compat_binfmt_elf.c b/fs/compat_binfmt_elf.c
index 0adced2..112e45a 100644
--- a/fs/compat_binfmt_elf.c
+++ b/fs/compat_binfmt_elf.c
@@ -28,10 +28,12 @@
 
 #undef	elfhdr
 #undef	elf_phdr
+#undef	elf_shdr
 #undef	elf_note
 #undef	elf_addr_t
 #define elfhdr		elf32_hdr
 #define elf_phdr	elf32_phdr
+#define elf_shdr	elf32_shdr
 #define elf_note	elf32_note
 #define elf_addr_t	Elf32_Addr
 
diff --git a/include/linux/elf.h b/include/linux/elf.h
index ad990c5..ccde3fd 100644
--- a/include/linux/elf.h
+++ b/include/linux/elf.h
@@ -396,6 +396,7 @@ extern Elf32_Dyn _DYNAMIC [];
 #define elf_phdr	elf32_phdr
 #define elf_note	elf32_note
 #define elf_addr_t	Elf32_Off
+#define Elf_Half	Elf32_Half
 
 #else
 
@@ -404,6 +405,7 @@ extern Elf64_Dyn _DYNAMIC [];
 #define elf_phdr	elf64_phdr
 #define elf_note	elf64_note
 #define elf_addr_t	Elf64_Off
+#define Elf_Half	Elf64_Half
 
 #endif
 
diff --git a/include/linux/elfcore.h b/include/linux/elfcore.h
index 00d6a68..cfda74f 100644
--- a/include/linux/elfcore.h
+++ b/include/linux/elfcore.h
@@ -8,6 +8,8 @@
 #include <linux/user.h>
 #endif
 #include <linux/ptrace.h>
+#include <linux/elf.h>
+#include <linux/fs.h>
 
 struct elf_siginfo
 {
@@ -150,5 +152,19 @@ static inline int elf_core_copy_task_xfpregs(struct task_struct *t, elf_fpxregse
 
 #endif /* __KERNEL__ */
 
+/*
+ * These functions parameterize elf_core_dump in fs/binfmt_elf.c to write out
+ * extra segments containing the gate DSO contents.  Dumping its
+ * contents makes post-mortem fully interpretable later without matching up
+ * the same kernel and hardware config to see what PC values meant.
+ * Dumping its extra ELF program headers includes all the other information
+ * a debugger needs to easily find how the gate DSO was being used.
+ */
+extern Elf_Half elf_core_extra_phdrs(void);
+extern int
+elf_core_write_extra_phdrs(struct file *file, loff_t offset, size_t *size,
+			   unsigned long limit);
+extern int
+elf_core_write_extra_data(struct file *file, size_t *size, unsigned long limit);
 
 #endif /* _LINUX_ELFCORE_H */
diff --git a/kernel/Makefile b/kernel/Makefile
index 7b97469..a987aa1 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -91,6 +91,9 @@ obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
 obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o
 obj-$(CONFIG_TRACEPOINTS) += tracepoint.o
 obj-$(CONFIG_LATENCYTOP) += latencytop.o
+obj-$(CONFIG_BINFMT_ELF) += elfcore.o
+obj-$(CONFIG_COMPAT_BINFMT_ELF) += elfcore.o
+obj-$(CONFIG_BINFMT_ELF_FDPIC) += elfcore.o
 obj-$(CONFIG_FUNCTION_TRACER) += trace/
 obj-$(CONFIG_TRACING) += trace/
 obj-$(CONFIG_X86_DS) += trace/
diff --git a/kernel/elfcore.c b/kernel/elfcore.c
new file mode 100644
index 0000000..5445741
--- /dev/null
+++ b/kernel/elfcore.c
@@ -0,0 +1,23 @@
+#include <linux/elf.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+
+#include <asm/elf.h>
+
+
+Elf_Half __weak elf_core_extra_phdrs(void)
+{
+	return 0;
+}
+
+int __weak elf_core_write_extra_phdrs(struct file *file, loff_t offset, size_t *size,
+				      unsigned long limit)
+{
+	return 1;
+}
+
+int __weak elf_core_write_extra_data(struct file *file, size_t *size,
+				     unsigned long limit)
+{
+	return 1;
+}