[v5] dump: Add arch section and s390x PV dump

[PATCH v5 11/18] dump: Swap segment and section header locations

Janosch Frank posted 18 patches 3 years, 6 months ago

Diff against v2 v3 v4 v6
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Maintainers: "Marc-André Lureau" <marcandre.lureau@redhat.com>, Halil Pasic <pasic@linux.ibm.com>, Christian Borntraeger <borntraeger@linux.ibm.com>, Eric Farman <farman@linux.ibm.com>, Richard Henderson <richard.henderson@linaro.org>, David Hildenbrand <david@redhat.com>, Cornelia Huck <cohuck@redhat.com>, Thomas Huth <thuth@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Peter Maydell <peter.maydell@linaro.org>, "Cédric Le Goater" <clg@kaod.org>, Daniel Henrique Barboza <danielhb413@gmail.com>, David Gibson <david@gibson.dropbear.id.au>, Greg Kurz <groug@kaod.org>, Palmer Dabbelt <palmer@dabbelt.com>, Alistair Francis <alistair.francis@wdc.com>, Bin Meng <bin.meng@windriver.com>

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[PATCH v5 11/18] dump: Swap segment and section header locations

Posted by Janosch Frank 3 years, 6 months ago

For the upcoming string table and arch section support we need to
modify the elf layout a bit. Instead of the segments, i.e. the guest's
memory contents, being the last area the section data will live at
the end of the file. This will allow us to write the section data
after all guest memory has been dumped which is important for the s390
PV dump support.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 dump/dump.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/dump/dump.c b/dump/dump.c
index 0051c71d08..31eb20108c 100644
--- a/dump/dump.c
+++ b/dump/dump.c
@@ -595,6 +595,9 @@ static void dump_begin(DumpState *s, Error **errp)
      *   --------------
      *   |  memory     |
      *   --------------
+     *   |  sectn data |
+     *   --------------
+
      *
      * we only know where the memory is saved after we write elf note into
      * vmcore.
@@ -1842,17 +1845,16 @@ static void dump_init(DumpState *s, int fd, bool has_format,
     }
 
     if (dump_is_64bit(s)) {
-        s->phdr_offset = sizeof(Elf64_Ehdr);
-        s->shdr_offset = s->phdr_offset + sizeof(Elf64_Phdr) * s->phdr_num;
-        s->note_offset = s->shdr_offset + sizeof(Elf64_Shdr) * s->shdr_num;
-        s->memory_offset = s->note_offset + s->note_size;
+        s->shdr_offset = sizeof(Elf64_Ehdr);
+        s->phdr_offset = s->shdr_offset + sizeof(Elf64_Shdr) * s->shdr_num;
+        s->note_offset = s->phdr_offset + sizeof(Elf64_Phdr) * s->phdr_num;
     } else {
-
-        s->phdr_offset = sizeof(Elf32_Ehdr);
-        s->shdr_offset = s->phdr_offset + sizeof(Elf32_Phdr) * s->phdr_num;
-        s->note_offset = s->shdr_offset + sizeof(Elf32_Shdr) * s->shdr_num;
-        s->memory_offset = s->note_offset + s->note_size;
+        s->shdr_offset = sizeof(Elf32_Ehdr);
+        s->phdr_offset = s->shdr_offset + sizeof(Elf32_Shdr) * s->shdr_num;
+        s->note_offset = s->phdr_offset + sizeof(Elf32_Phdr) * s->phdr_num;
     }
+    s->memory_offset = s->note_offset + s->note_size;
+    s->section_offset = s->memory_offset + s->total_size;
 
     return;
 
-- 
2.34.1