diff options
| author | Pratyush Anand <panand@redhat.com> | 2017-02-02 10:47:12 +1100 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2017-02-05 10:44:48 +1100 |
| commit | c9d4e5d7b7fd6c74e134ca44df8a5386efbc561c (patch) | |
| tree | a73b7ce24ee01bedd21130cca63b32bd769f6441 /fs | |
| parent | d7b993bf8ca9639035776c3228145541a184abdc (diff) | |
/proc/kcore: update physical address for kcore ram and text
Currently all the p_paddr of PT_LOAD headers are assigned to 0, which is
not true and could be misleading, since 0 is a valid physical address.
User space tools like makedumpfile needs to know physical address for
PT_LOAD segments of direct mapped regions. Therefore this patch updates
paddr for such regions. It also sets an invalid paddr (-1) for other
regions, so that user space tool can know whether a physical address
provided in PT_LOAD is correct or not.
I do not know why it was 0, which is a valid physical address. But
certainly, it might break some user space tools, and those need to be
fixed. For example, see following code from kexec-tools
kexec/kexec-elf.c:build_mem_phdrs()
435 if ((phdr->p_paddr + phdr->p_memsz) < phdr->p_paddr) {
436 /* The memory address wraps */
437 if (probe_debug) {
438 fprintf(stderr, "ELF address wrap
around\n");
439 }
440 return -1;
441 }
We do not need to perform above check for an invalid physical address.
I think, kexec-tools and makedumpfile will need fixup. I already have
those fixup which will be sent upstream once this patch makes through.
Pro with this approach is that, it will help to calculate variable like
page_offset, phys_base from PT_LOAD even when they are randomized and
therefore will reduce many variable and version specific values in user
space tools.
Link: http://lkml.kernel.org/r/f951340d2917cdd2a329fae9837a83f2059dc3b2.1485318868.git.panand@redhat.com
Signed-off-by: Pratyush Anand <panand@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/proc/kcore.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c index 0b80ad87b4d6..ea9f3d1ae830 100644 --- a/fs/proc/kcore.c +++ b/fs/proc/kcore.c @@ -373,7 +373,10 @@ static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff) phdr->p_flags = PF_R|PF_W|PF_X; phdr->p_offset = kc_vaddr_to_offset(m->addr) + dataoff; phdr->p_vaddr = (size_t)m->addr; - phdr->p_paddr = 0; + if (m->type == KCORE_RAM || m->type == KCORE_TEXT) + phdr->p_paddr = __pa(m->addr); + else + phdr->p_paddr = (elf_addr_t)-1; phdr->p_filesz = phdr->p_memsz = m->size; phdr->p_align = PAGE_SIZE; } |