Re: [PATCH 04/15] binfmt_flat: remove flat_old_ram_flag

From: Greg Ungerer
Date: Tue Jun 11 2019 - 09:12:12 EST

On 11/6/19 5:36 pm, Christoph Hellwig wrote:
On Tue, Jun 11, 2019 at 04:04:39PM +1000, Greg Ungerer wrote:
index c0e4535dc1ec..18d82fd5f57c 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -488,7 +488,8 @@ static int load_flat_file(struct linux_binprm *bprm,
* fix up the flags for the older format, there were all kinds
* of endian hacks, this only works for the simple cases
- if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))

The flags are from the binary file header here, so this is going to lose
that check for most platforms (except h8300 where it would always have
been true).

Indeed. The old code is:

if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
flags = FLAT_FLAG_RAM;

which for !h8300 evaluates to:

if (rev == OLD_FLAT_VERSION && flags)
flags = FLAT_FLAG_RAM;

so basically if any flag was set it was turned into FLAT_FLAG_RAM.
Was that really intentional?

Probably not, looking at the flags. For the compressed flag it
makes some sense. But I don't think many of the others need load
to RAM behavior.

I guess even if it wasn't the is no
point in changing this historic behavior now.

So I guess what we could do it something like:

if (rev == OLD_FLAT_VERSION &&
flags = FLAT_FLAG_RAM;

Yeah, that to looks to preserve the old behavior.