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Date: Fri, 04 Oct 2013 16:00:30 +0530
From: Janani Venkataraman <jananive@...ibm.com>
To: linux-kernel@...r.kernel.org
Cc: amwang@...hat.com, rdunlap@...otime.net, andi@...stfloor.org,
aravinda@...ux.vnet.ibm.com, hch@....de, mhiramat@...hat.com,
jeremy.fitzhardinge@...rix.com, xemul@...allels.com,
suzuki@...ux.vnet.ibm.com, kosaki.motohiro@...fujitsu.com,
adobriyan@...il.com, tarundsk@...ux.vnet.ibm.com,
vapier@...too.org, roland@...k.frob.com, tj@...nel.org,
ananth@...ux.vnet.ibm.com, gorcunov@...nvz.org, avagin@...nvz.org,
oleg@...hat.com, eparis@...hat.com, d.hatayama@...fujitsu.com,
james.hogan@...tec.com, akpm@...ux-foundation.org,
torvalds@...ux-foundation.org
Subject: [PATCH 01/19] Create elfcore-common.c for ELF class independent
core generation helpers
From:Suzuki K. Poulose <suzuki@...ibm.com>
Move the common code, shared by both native and compat ELF core generation code
to a single instance.These functions could be re-used later for application
core dump infrastructure.
Signed-off-by: Suzuki K. Poulose <suzuki@...ibm.com>
---
fs/Makefile | 1
fs/binfmt_elf.c | 156 -------------------------------------
fs/elfcore-common.c | 161 ++++++++++++++++++++++++++++++++++++++
include/linux/elfcore-internal.h | 46 +++++++++++
4 files changed, 209 insertions(+), 155 deletions(-)
create mode 100644 fs/elfcore-common.c
create mode 100644 include/linux/elfcore-internal.h
diff --git a/fs/Makefile b/fs/Makefile
index 4fe6df3..70e7add 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_BINFMT_MISC) += binfmt_misc.o
obj-$(CONFIG_BINFMT_SCRIPT) += binfmt_script.o
obj-$(CONFIG_BINFMT_ELF) += binfmt_elf.o
obj-$(CONFIG_COMPAT_BINFMT_ELF) += compat_binfmt_elf.o
+obj-$(CONFIG_ELF_CORE) += elfcore-common.o
obj-$(CONFIG_BINFMT_ELF_FDPIC) += binfmt_elf_fdpic.o
obj-$(CONFIG_BINFMT_SOM) += binfmt_som.o
obj-$(CONFIG_BINFMT_FLAT) += binfmt_flat.o
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 100edcc..6c8df47 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -37,7 +37,7 @@
#include <asm/uaccess.h>
#include <asm/param.h>
#include <asm/page.h>
-
+#include <linux/elfcore-internal.h>
#ifndef user_long_t
#define user_long_t long
#endif
@@ -1095,124 +1095,6 @@ out:
* Jeremy Fitzhardinge <jeremy@...oz.au>
*/
-/*
- * The purpose of always_dump_vma() is to make sure that special kernel mappings
- * that are useful for post-mortem analysis are included in every core dump.
- * In that way we ensure that the core dump is fully interpretable later
- * without matching up the same kernel and hardware config to see what PC values
- * meant. These special mappings include - vDSO, vsyscall, and other
- * architecture specific mappings
- */
-static bool always_dump_vma(struct vm_area_struct *vma)
-{
- /* Any vsyscall mappings? */
- if (vma == get_gate_vma(vma->vm_mm))
- return true;
- /*
- * arch_vma_name() returns non-NULL for special architecture mappings,
- * such as vDSO sections.
- */
- if (arch_vma_name(vma))
- return true;
-
- return false;
-}
-
-/*
- * Decide what to dump of a segment, part, all or none.
- */
-static unsigned long vma_dump_size(struct vm_area_struct *vma,
- unsigned long mm_flags)
-{
-#define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type))
-
- /* always dump the vdso and vsyscall sections */
- if (always_dump_vma(vma))
- goto whole;
-
- if (vma->vm_flags & VM_DONTDUMP)
- return 0;
-
- /* Hugetlb memory check */
- if (vma->vm_flags & VM_HUGETLB) {
- if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))
- goto whole;
- if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE))
- goto whole;
- return 0;
- }
-
- /* Do not dump I/O mapped devices or special mappings */
- if (vma->vm_flags & VM_IO)
- return 0;
-
- /* By default, dump shared memory if mapped from an anonymous file. */
- if (vma->vm_flags & VM_SHARED) {
- if (file_inode(vma->vm_file)->i_nlink == 0 ?
- FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
- goto whole;
- return 0;
- }
-
- /* Dump segments that have been written to. */
- if (vma->anon_vma && FILTER(ANON_PRIVATE))
- goto whole;
- if (vma->vm_file == NULL)
- return 0;
-
- if (FILTER(MAPPED_PRIVATE))
- goto whole;
-
- /*
- * If this looks like the beginning of a DSO or executable mapping,
- * check for an ELF header. If we find one, dump the first page to
- * aid in determining what was mapped here.
- */
- if (FILTER(ELF_HEADERS) &&
- vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
- u32 __user *header = (u32 __user *) vma->vm_start;
- u32 word;
- mm_segment_t fs = get_fs();
- /*
- * Doing it this way gets the constant folded by GCC.
- */
- union {
- u32 cmp;
- char elfmag[SELFMAG];
- } magic;
- BUILD_BUG_ON(SELFMAG != sizeof word);
- magic.elfmag[EI_MAG0] = ELFMAG0;
- magic.elfmag[EI_MAG1] = ELFMAG1;
- magic.elfmag[EI_MAG2] = ELFMAG2;
- magic.elfmag[EI_MAG3] = ELFMAG3;
- /*
- * Switch to the user "segment" for get_user(),
- * then put back what elf_core_dump() had in place.
- */
- set_fs(USER_DS);
- if (unlikely(get_user(word, header)))
- word = 0;
- set_fs(fs);
- if (word == magic.cmp)
- return PAGE_SIZE;
- }
-
-#undef FILTER
-
- return 0;
-
-whole:
- return vma->vm_end - vma->vm_start;
-}
-
-/* An ELF note in memory */
-struct memelfnote
-{
- const char *name;
- int type;
- unsigned int datasz;
- void *data;
-};
static int notesize(struct memelfnote *en)
{
@@ -1291,16 +1173,6 @@ static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
return;
}
-static void fill_note(struct memelfnote *note, const char *name, int type,
- unsigned int sz, void *data)
-{
- note->name = name;
- note->type = type;
- note->datasz = sz;
- note->data = data;
- return;
-}
-
/*
* fill up all the fields in prstatus from the given task struct, except
* registers which need to be filled up separately.
@@ -1974,32 +1846,6 @@ static void free_note_info(struct elf_note_info *info)
#endif
-static struct vm_area_struct *first_vma(struct task_struct *tsk,
- struct vm_area_struct *gate_vma)
-{
- struct vm_area_struct *ret = tsk->mm->mmap;
-
- if (ret)
- return ret;
- return gate_vma;
-}
-/*
- * Helper function for iterating across a vma list. It ensures that the caller
- * will visit `gate_vma' prior to terminating the search.
- */
-static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
- struct vm_area_struct *gate_vma)
-{
- struct vm_area_struct *ret;
-
- ret = this_vma->vm_next;
- if (ret)
- return ret;
- if (this_vma == gate_vma)
- return NULL;
- return gate_vma;
-}
-
static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
elf_addr_t e_shoff, int segs)
{
diff --git a/fs/elfcore-common.c b/fs/elfcore-common.c
new file mode 100644
index 0000000..4886f15
--- /dev/null
+++ b/fs/elfcore-common.c
@@ -0,0 +1,161 @@
+/*
+ *
+ * Copyright 1993, 1994: Eric Youngdale (ericy@...s.com).
+ *
+ * Initial write up for ELF_CORE :
+ * Modelled on fs/exec.c:aout_core_dump()
+ * Jeremy Fitzhardinge <jeremy@...oz.au>
+ *
+ * Moved common routines used by both native and compat ELF core generation
+ * from binfmt_elf.c to a single instance.
+ * Suzuki K. Poulose <suzuki@...ibm.com>
+ */
+
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/elf.h>
+#include <asm/uaccess.h>
+#include <asm/param.h>
+#include <asm/page.h>
+#include <linux/elfcore-internal.h>
+
+static struct vm_area_struct *first_vma(struct task_struct *tsk,
+ struct vm_area_struct *gate_vma)
+{
+ struct vm_area_struct *ret = tsk->mm->mmap;
+
+ if (ret)
+ return ret;
+ return gate_vma;
+}
+
+/*
+ * Helper function for iterating across a vma list. It ensures that the caller
+ * will visit `gate_vma' prior to terminating the search.
+ */
+static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
+ struct vm_area_struct *gate_vma)
+{
+ struct vm_area_struct *ret;
+
+ ret = this_vma->vm_next;
+ if (ret)
+ return ret;
+ if (this_vma == gate_vma)
+ return NULL;
+ return gate_vma;
+}
+
+/*
+ * The purpose of always_dump_vma() is to make sure that special kernel mappings
+ * that are useful for post-mortem analysis are included in every core dump.
+ * In that way we ensure that the core dump is fully interpretable later
+ * without matching up the same kernel and hardware config to see what PC values
+ * meant. These special mappings include - vDSO, vsyscall, and other
+ * architecture specific mappings
+ */
+static bool always_dump_vma(struct vm_area_struct *vma)
+{
+ /* Any vsyscall mappings? */
+ if (vma == get_gate_vma(vma->vm_mm))
+ return true;
+ /*
+ * arch_vma_name() returns non-NULL for special architecture mappings,
+ * such as vDSO sections.
+ */
+ if (arch_vma_name(vma))
+ return true;
+
+ return false;
+}
+
+/*
+ * Decide what to dump of a segment, part, all or none.
+ */
+static unsigned long vma_dump_size(struct vm_area_struct *vma,
+ unsigned long mm_flags)
+{
+#define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type))
+
+ /* always dump the vdso and vsyscall sections */
+ if (always_dump_vma(vma))
+ goto whole;
+
+ if (vma->vm_flags & VM_DONTDUMP)
+ return 0;
+
+ /* Hugetlb memory check */
+ if (vma->vm_flags & VM_HUGETLB) {
+ if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))
+ goto whole;
+ if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE))
+ goto whole;
+ return 0;
+ }
+
+ /* Do not dump I/O mapped devices or special mappings */
+ if (vma->vm_flags & VM_IO)
+ return 0;
+
+ /* By default, dump shared memory if mapped from an anonymous file. */
+ if (vma->vm_flags & VM_SHARED) {
+ if (file_inode(vma->vm_file)->i_nlink == 0 ?
+ FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
+ goto whole;
+ return 0;
+ }
+
+ /* Dump segments that have been written to. */
+ if (vma->anon_vma && FILTER(ANON_PRIVATE))
+ goto whole;
+ if (vma->vm_file == NULL)
+ return 0;
+
+ if (FILTER(MAPPED_PRIVATE))
+ goto whole;
+
+ /*
+ * If this looks like the beginning of a DSO or executable mapping,
+ * check for an ELF header. If we find one, dump the first page to
+ * aid in determining what was mapped here.
+ */
+ if (FILTER(ELF_HEADERS) &&
+ vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
+ u32 __user *header = (u32 __user *) vma->vm_start;
+
+ u32 word;
+ mm_segment_t fs = get_fs();
+ /*
+ * Doing it this way gets the constant folded by GCC.
+ */
+ union {
+ u32 cmp;
+ char elfmag[SELFMAG];
+ } magic;
+ BUILD_BUG_ON(SELFMAG != sizeof word);
+ magic.elfmag[EI_MAG0] = ELFMAG0;
+ magic.elfmag[EI_MAG1] = ELFMAG1;
+ magic.elfmag[EI_MAG2] = ELFMAG2;
+ magic.elfmag[EI_MAG3] = ELFMAG3;
+ /*
+ * Switch to the user "segment" for get_user(),
+ * then put back what elf_core_dump() had in place.
+ */
+ set_fs(USER_DS);
+ if (unlikely(get_user(word, header)))
+ word = 0;
+ set_fs(fs);
+ if (word == magic.cmp)
+ return PAGE_SIZE;
+ }
+
+#undef FILTER
+
+ return 0;
+
+whole:
+ return vma->vm_end - vma->vm_start;
+}
+
diff --git a/include/linux/elfcore-internal.h b/include/linux/elfcore-internal.h
new file mode 100644
index 0000000..f6354f0
--- /dev/null
+++ b/include/linux/elfcore-internal.h
@@ -0,0 +1,46 @@
+/*
+ * Common routines for native and compat elf core generation.
+ *
+ * Copyright 1993, 1994: Eric Youngdale (ericy@...s.com).
+ *
+ * Modelled on fs/exec.c:aout_core_dump()
+ * Jeremy Fitzhardinge <jeremy@...oz.au>
+ *
+ * Moved the common routines from binfmt_elf.c to elfcore-common.c
+ * - Suzuki K. Poulose <suzuki@...ibm.com>
+ */
+
+#ifndef __ELF_CORE_INTERNAL_H
+#define __ELF_CORE_INTERNAL_H
+
+#ifdef __KERNEL__
+
+/* An ELF note in memory */
+struct memelfnote
+{
+ const char *name;
+ int type;
+ unsigned int datasz;
+ void *data;
+};
+
+static void fill_note(struct memelfnote *note, const char *name, int type,
+ unsigned int sz, void *data)
+{
+ note->name = name;
+ note->type = type;
+ note->datasz = sz;
+ note->data = data;
+ return;
+}
+
+extern struct vm_area_struct *first_vma(struct task_struct *tsk,
+ struct vm_area_struct *gate_vma);
+extern struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
+ struct vm_area_struct *gate_vma);
+extern unsigned long vma_dump_size(struct vm_area_struct *vma,
+ unsigned long mm_flags);
+
+#endif
+#endif
+
--
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