linux-toradex.git/include/linux/regset.h, branch v5.10-rc3

regset: kill user_regset_copyout{,_zero}()

2020-07-27T18:31:13+00:00

no callers left

Signed-off-by: Al Viro

regset(): kill ->get_size()

2020-07-27T18:31:13+00:00

not used anymore

Signed-off-by: Al Viro

regset: kill ->get()

2020-07-27T18:31:12+00:00

no instances left

Signed-off-by: Al Viro

regset: new method and helpers for it

2020-07-27T18:31:07+00:00

->regset_get() takes task+regset+buffer, returns the amount of free space
left in the buffer on success and -E... on error.

buffer is represented as struct membuf - a pair of (kernel) pointer
and amount of space left

Primitives for writing to such:
	* membuf_write(buf, data, size)
	* membuf_zero(buf, size)
	* membuf_store(buf, value)

These are implemented as inlines (in case of membuf_store - a macro).
All writes are sequential; they become no-ops when there's no space
left.  Return value of all primitives is the amount of space left
after the operation, so they can be used as return values of ->regset_get().

Example of use:

// stores pt_regs of task + 64 bytes worth of zeroes + 32bit PID of task
int foo_get(struct task_struct *task, const struct regset *regset,
	    struct membuf to)
{
	membuf_write(&to, task_pt_regs(task), sizeof(struct pt_regs));
	membuf_zero(&to, 64);
	return membuf_store(&to, (u32)task_tgid_vnr(task));
}

regset_get()/regset_get_alloc() taught to use that thing if present.
By the end of the series all users of ->get() will be converted;
then ->get() and ->get_size() can go.

Note that unlike ->get() this thing always starts at offset 0 and,
since it only writes to kernel buffer, can't fail on copyout.
It can, of course, fail for other reasons, but those tend to
be less numerous.

The caller guarantees that the buffer size won't be bigger than
regset->n * regset->size.  That simplifies life for quite a few
instances.

Signed-off-by: Al Viro

copy_regset_to_user(): do all copyout at once.

2020-07-27T18:31:07+00:00

Turn copy_regset_to_user() into regset_get_alloc() + copy_to_user().
Now all ->get() calls have a kernel buffer as destination.

Note that we'd already eliminated the callers of copy_regset_to_user()
with non-zero offset; now that argument is simply unused.

Uninlined, while we are at it.

Signed-off-by: Al Viro

introduction of regset ->get() wrappers, switching ELF coredumps to those

2020-07-27T18:24:50+00:00

Two new helpers: given a process and regset, dump into a buffer.
regset_get() takes a buffer and size, regset_get_alloc() takes size
and allocates a buffer.

Return value in both cases is the amount of data actually dumped in
case of success or -E...  on error.

In both cases the size is capped by regset->n * regset->size, so
->get() is called with offset 0 and size no more than what regset
expects.

binfmt_elf.c callers of ->get() are switched to using those; the other
caller (copy_regset_to_user()) will need some preparations to switch.

Signed-off-by: Al Viro

user_regset_copyout_zero(): use clear_user()

2020-06-03T20:59:31+00:00

that's the only caller of __clear_user() in generic code, and it's
not hot enough to bother with skipping access_ok().

Signed-off-by: Al Viro

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 193

2019-05-30T18:29:21+00:00

Based on 1 normalized pattern(s):

  this copyrighted material is made available to anyone wishing to use
  modify copy or redistribute it subject to the terms and conditions
  of the gnu general public license v 2

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 45 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Richard Fontana 
Reviewed-by: Allison Randal 
Reviewed-by: Steve Winslow 
Reviewed-by: Alexios Zavras 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528170027.342746075@linutronix.de
Signed-off-by: Greg Kroah-Hartman

Remove 'type' argument from access_ok() function

2019-01-04T02:57:57+00:00

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.

It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access.  But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.

A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model.  And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.

This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.

There were a couple of notable cases:

 - csky still had the old "verify_area()" name as an alias.

 - the iter_iov code had magical hardcoded knowledge of the actual
   values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
   really used it)

 - microblaze used the type argument for a debug printout

but other than those oddities this should be a total no-op patch.

I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something.  Any missed conversion should be trivially fixable, though.

Signed-off-by: Linus Torvalds

regset: Add support for dynamically sized regsets

2017-11-03T15:24:11+00:00

Currently the regset API doesn't allow for the possibility that
regsets (or at least, the amount of meaningful data in a regset)
may change in size.

In particular, this results in useless padding being added to
coredumps if a regset's current size is smaller than its
theoretical maximum size.

This patch adds a get_size() function to struct user_regset.
Individual regset implementations can implement this function to
return the current size of the regset data.  A regset_size()
function is added to provide callers with an abstract interface for
determining the size of a regset without needing to know whether
the regset is dynamically sized or not.

The only affected user of this interface is the ELF coredump code:
This patch ports ELF coredump to dump regsets with their actual
size in the coredump.  This has no effect except for new regsets
that are dynamically sized and provide a get_size() implementation.

Signed-off-by: Dave Martin 
Reviewed-by: Catalin Marinas 
Cc: Oleg Nesterov 
Cc: Alexander Viro 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: Dmitry Safonov 
Cc: H. J. Lu 
Signed-off-by: Will Deacon