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Subject[PATCH 5/11] x86_64 ia32 vDSO: use VM_ALWAYSDUMP
Date

This patch fixes ia32 core dumps on x86_64 to include just one phdr for the
vDSO vma. Currently it writes a confused format with two phdrs for the
address, one without contents and one with. This patch removes the
special-case core writing macros for the ia32 vDSO. Instead, it uses
VM_ALWAYSDUMP in the vma. This changes core dumps so they no longer
include the non-PT_LOAD phdrs from the vDSO, consistent with fixed native
i386 core dumps.

Signed-off-by: Roland McGrath <roland@redhat.com>
---
arch/x86_64/ia32/ia32_binfmt.c | 49 ----------------------------------------
arch/x86_64/ia32/syscall32.c | 7 +++++
2 files changed, 7 insertions(+), 49 deletions(-)
diff --git a/arch/x86_64/ia32/ia32_binfmt.c b/arch/x86_64/ia32/ia32_binfmt.c
index 543ef4f..5ce0bd4 100644
--- a/arch/x86_64/ia32/ia32_binfmt.c
+++ b/arch/x86_64/ia32/ia32_binfmt.c
@@ -64,55 +64,6 @@ typedef unsigned int elf_greg_t;
#define ELF_NGREG (sizeof (struct user_regs_struct32) / sizeof(elf_greg_t))
typedef elf_greg_t elf_gregset_t[ELF_NGREG];

-/*
- * 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 (find_vma(current->mm, VSYSCALL32_BASE) ? \
- (VSYSCALL32_EHDR->e_phnum) : 0)
-#define ELF_CORE_WRITE_EXTRA_PHDRS \
-do { \
- if (find_vma(current->mm, VSYSCALL32_BASE)) { \
- const struct elf32_phdr *const vsyscall_phdrs = \
- (const struct elf32_phdr *) (VSYSCALL32_BASE \
- + VSYSCALL32_EHDR->e_phoff);\
- int i; \
- Elf32_Off ofs = 0; \
- for (i = 0; i < VSYSCALL32_EHDR->e_phnum; ++i) { \
- struct elf32_phdr phdr = vsyscall_phdrs[i]; \
- if (phdr.p_type == PT_LOAD) { \
- BUG_ON(ofs != 0); \
- ofs = phdr.p_offset = offset; \
- phdr.p_memsz = PAGE_ALIGN(phdr.p_memsz); \
- phdr.p_filesz = phdr.p_memsz; \
- offset += phdr.p_filesz; \
- } \
- 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 { \
- if (find_vma(current->mm, VSYSCALL32_BASE)) { \
- const struct elf32_phdr *const vsyscall_phdrs = \
- (const struct elf32_phdr *) (VSYSCALL32_BASE \
- + VSYSCALL32_EHDR->e_phoff); \
- int i; \
- for (i = 0; i < VSYSCALL32_EHDR->e_phnum; ++i) { \
- if (vsyscall_phdrs[i].p_type == PT_LOAD) \
- DUMP_WRITE((void *) (u64) vsyscall_phdrs[i].p_vaddr,\
- PAGE_ALIGN(vsyscall_phdrs[i].p_memsz)); \
- } \
- } \
-} while (0)
-
struct elf_siginfo
{
int si_signo; /* signal number */
diff --git a/arch/x86_64/ia32/syscall32.c b/arch/x86_64/ia32/syscall32.c
index 3e5ed20..3ac9355 100644
--- a/arch/x86_64/ia32/syscall32.c
+++ b/arch/x86_64/ia32/syscall32.c
@@ -59,6 +59,13 @@ int syscall32_setup_pages(struct linux_b
vma->vm_end = VSYSCALL32_END;
/* MAYWRITE to allow gdb to COW and set breakpoints */
vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC|VM_MAYWRITE;
+ /*
+ * Make sure the vDSO gets into every core dump.
+ * Dumping its contents makes post-mortem fully interpretable later
+ * without matching up the same kernel and hardware config to see
+ * what PC values meant.
+ */
+ vma->vm_flags |= VM_ALWAYSDUMP;
vma->vm_flags |= mm->def_flags;
vma->vm_page_prot = protection_map[vma->vm_flags & 7];
vma->vm_ops = &syscall32_vm_ops;
-
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