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>

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

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

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;
+}