linux-toradex.git/tools/objtool, branch v4.9.106

objtool: header file sync-up

2018-06-05T08:28:58+00:00

When building tools/objtool/ it rightly complains about a number of
files being out of sync.  Fix this up by syncing them properly with the
relevant in-kernel versions.

Signed-off-by: Greg Kroah-Hartman

objtool: Fix "noreturn" detection for recursive sibling calls

2018-06-05T08:28:57+00:00

commit 0afd0d9e0e7879d666c1df2fa1bea4d8716909fe upstream.

Objtool has some crude logic for detecting static "noreturn" functions
(aka "dead ends").  This is necessary for being able to correctly follow
GCC code flow when such functions are called.

It's remotely possible for two functions to call each other via sibling
calls.  If they don't have RET instructions, objtool's noreturn
detection logic goes into a recursive loop:

  drivers/char/ipmi/ipmi_ssif.o: warning: objtool: return_hosed_msg()+0x0: infinite recursion (objtool bug!)
  drivers/char/ipmi/ipmi_ssif.o: warning: objtool: deliver_recv_msg()+0x0: infinite recursion (objtool bug!)

Instead of reporting an error in this case, consider the functions to be
non-dead-ends.

Reported-and-tested-by: Randy Dunlap 
Signed-off-by: Josh Poimboeuf 
Acked-by: Peter Zijlstra (Intel) 
Cc: Arnd Bergmann 
Cc: David Laight 
Cc: Greg KH 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: damian 
Link: http://lkml.kernel.org/r/7cc156408c5781a1f62085d352ced1fe39fe2f91.1525923412.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

objtool: Detect RIP-relative switch table references, part 2

2018-06-05T08:28:57+00:00

commit 7dec80ccbe310fb7e225bf21c48c672bb780ce7b upstream.

With the following commit:

  fd35c88b7417 ("objtool: Support GCC 8 switch tables")

I added a "can't find switch jump table" warning, to stop covering up
silent failures if add_switch_table() can't find anything.

That warning found yet another bug in the objtool switch table detection
logic.  For cases 1 and 2 (as described in the comments of
find_switch_table()), the find_symbol_containing() check doesn't adjust
the offset for RIP-relative switch jumps.

Incidentally, this bug was already fixed for case 3 with:

  6f5ec2993b1f ("objtool: Detect RIP-relative switch table references")

However, that commit missed the fix for cases 1 and 2.

The different cases are now starting to look more and more alike.  So
fix the bug by consolidating them into a single case, by checking the
original dynamic jump instruction in the case 3 loop.

This also simplifies the code and makes it more robust against future
switch table detection issues -- of which I'm sure there will be many...

Switch table detection has been the most fragile area of objtool, by
far.  I long for the day when we'll have a GCC plugin for annotating
switch tables.  Linus asked me to delay such a plugin due to the
flakiness of the plugin infrastructure in older versions of GCC, so this
rickety code is what we're stuck with for now.  At least the code is now
a little simpler than it was.

Reported-by: kbuild test robot 
Signed-off-by: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/f400541613d45689086329432f3095119ffbc328.1526674218.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

objtool: Detect RIP-relative switch table references

2018-06-05T08:28:57+00:00

commit 6f5ec2993b1f39aed12fa6fd56e8dc2272ee8a33 upstream.

Typically a switch table can be found by detecting a .rodata access
followed an indirect jump:

    1969:	4a 8b 0c e5 00 00 00 	mov    0x0(,%r12,8),%rcx
    1970:	00
			196d: R_X86_64_32S	.rodata+0x438
    1971:	e9 00 00 00 00       	jmpq   1976 
			1972: R_X86_64_PC32	__x86_indirect_thunk_rcx-0x4

Randy Dunlap reported a case (seen with GCC 4.8) where the .rodata
access uses RIP-relative addressing:

    19bd:	48 8b 3d 00 00 00 00 	mov    0x0(%rip),%rdi        # 19c4 
			19c0: R_X86_64_PC32	.rodata+0x45c
    19c4:	e9 00 00 00 00       	jmpq   19c9 
			19c5: R_X86_64_PC32	__x86_indirect_thunk_rdi-0x4

In this case the relocation addend needs to be adjusted accordingly in
order to find the location of the switch table.

The fix is for case 3 (as described in the comments), but also make the
existing case 1 & 2 checks more precise by only adjusting the addend for
R_X86_64_PC32 relocations.

This fixes the following warnings:

  drivers/video/fbdev/omap2/omapfb/dss/dispc.o: warning: objtool: dispc_runtime_suspend()+0xbb8: sibling call from callable instruction with modified stack frame
  drivers/video/fbdev/omap2/omapfb/dss/dispc.o: warning: objtool: dispc_runtime_resume()+0xcc5: sibling call from callable instruction with modified stack frame

Reported-by: Randy Dunlap 
Signed-off-by: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/b6098294fd67afb69af8c47c9883d7a68bf0f8ea.1526305958.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

objtool: Support GCC 8 switch tables

2018-06-05T08:28:57+00:00

commit fd35c88b74170d9335530d9abf271d5d73eb5401 upstream.

With GCC 8, some issues were found with the objtool switch table
detection.

1) In the .rodata section, immediately after the switch table, there can
   be another object which contains a pointer to the function which had
   the switch statement.  In this case objtool wrongly considers the
   function pointer to be part of the switch table.  Fix it by:

   a) making sure there are no pointers to the beginning of the
      function; and

   b) making sure there are no gaps in the switch table.

   Only the former was needed, the latter adds additional protection for
   future optimizations.

2) In find_switch_table(), case 1 and case 2 are missing the check to
   ensure that the .rodata switch table data is anonymous, i.e. that it
   isn't already associated with an ELF symbol.  Fix it by adding the
   same find_symbol_containing() check which is used for case 3.

This fixes the following warnings with GCC 8:

  drivers/block/virtio_blk.o: warning: objtool: virtio_queue_rq()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+72
  net/ipv6/icmp.o: warning: objtool: icmpv6_rcv()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+64
  drivers/usb/core/quirks.o: warning: objtool: quirks_param_set()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+48
  drivers/mtd/nand/raw/nand_hynix.o: warning: objtool: hynix_nand_decode_id()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+24
  drivers/mtd/nand/raw/nand_samsung.o: warning: objtool: samsung_nand_decode_id()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+32
  drivers/gpu/drm/nouveau/nvkm/subdev/top/gk104.o: warning: objtool: gk104_top_oneinit()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+64

Reported-by: Arnd Bergmann 
Reported-by: kbuild test robot 
Signed-off-by: Josh Poimboeuf 
Acked-by: Peter Zijlstra (Intel) 
Cc: David Laight 
Cc: Greg KH 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Randy Dunlap 
Cc: Thomas Gleixner 
Cc: damian 
Link: http://lkml.kernel.org/r/20180510224849.xwi34d6tzheb5wgw@treble
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

objtool: Support GCC 8's cold subfunctions

2018-06-05T08:28:57+00:00

commit 13810435b9a7014fb92eb715f77da488f3b65b99 upstream.

GCC 8 moves a lot of unlikely code out of line to "cold" subfunctions in
.text.unlikely.  Properly detect the new subfunctions and treat them as
extensions of the original functions.

This fixes a bunch of warnings like:

  kernel/cgroup/cgroup.o: warning: objtool: parse_cgroup_root_flags()+0x33: sibling call from callable instruction with modified stack frame
  kernel/cgroup/cgroup.o: warning: objtool: cgroup_addrm_files()+0x290: sibling call from callable instruction with modified stack frame
  kernel/cgroup/cgroup.o: warning: objtool: cgroup_apply_control_enable()+0x25b: sibling call from callable instruction with modified stack frame
  kernel/cgroup/cgroup.o: warning: objtool: rebind_subsystems()+0x325: sibling call from callable instruction with modified stack frame

Reported-and-tested-by: damian 
Reported-by: Arnd Bergmann 
Signed-off-by: Josh Poimboeuf 
Acked-by: Peter Zijlstra (Intel) 
Cc: David Laight 
Cc: Greg KH 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Randy Dunlap 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/0965e7fcfc5f31a276f0c7f298ff770c19b68706.1525923412.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

objtool: sync up with the 4.14.47 version of objtool

2018-06-05T08:28:57+00:00

There are pros and cons of dealing with tools in the kernel directory.
The pros are the fact that development happens fast, and new features
can be added to the kernel and the tools at the same times.  The cons
are when dealing with backported kernel patches, it can be necessary to
backport parts of the tool changes as well.

For 4.9.y so far, we have backported individual patches.  That quickly
breaks down when there are minor differences between how backports were
handled, so grabbing 40+ patch long series can be difficult, not
impossible, but really frustrating to attempt.

To help mitigate this mess, here's a single big patch to sync up the
objtool logic to the 4.14.47 version of the tool.  From this point
forward (after some other minor header file patches are applied), the
tool should be in sync and much easier to maintain over time.

This has survivied my limited testing, and as the codebase is identical
to 4.14.47, I'm pretty comfortable dropping this big change in here in
4.9.y.  Hopefully all goes well...

Cc: Josh Poimboeuf 
Signed-off-by: Greg Kroah-Hartman

objtool: Move checking code to check.c

2018-06-05T08:28:55+00:00

commit dcc914f44f065ef73685b37e59877a5bb3cb7358 upstream.

In preparation for the new 'objtool undwarf generate' command, which
will rely on 'objtool check', move the checking code from
builtin-check.c to check.c where it can be used by other commands.

Signed-off-by: Josh Poimboeuf 
Reviewed-by: Jiri Slaby 
Cc: Andy Lutomirski 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/294c5c695fd73c1a5000bbe5960a7c9bec4ee6b4.1498659915.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar 
[backported by hand to 4.9, this was a pain... - gregkh]
Signed-off-by: Greg Kroah-Hartman

objtool: Improve detection of BUG() and other dead ends

2018-06-05T08:28:55+00:00

commit d1091c7fa3d52ebce4dd3f15d04155b3469b2f90 upstream.

The BUG() macro's use of __builtin_unreachable() via the unreachable()
macro tells gcc that the instruction is a dead end, and that it's safe
to assume the current code path will not execute past the previous
instruction.

On x86, the BUG() macro is implemented with the 'ud2' instruction.  When
objtool's branch analysis sees that instruction, it knows the current
code path has come to a dead end.

Peter Zijlstra has been working on a patch to change the WARN macros to
use 'ud2'.  That patch will break objtool's assumption that 'ud2' is
always a dead end.

Generally it's best for objtool to avoid making those kinds of
assumptions anyway.  The more ignorant it is of kernel code internals,
the better.

So create a more generic way for objtool to detect dead ends by adding
an annotation to the unreachable() macro.  The annotation stores a
pointer to the end of the unreachable code path in an '__unreachable'
section.  Objtool can read that section to find the dead ends.

Tested-by: Peter Zijlstra (Intel) 
Signed-off-by: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/41a6d33971462ebd944a1c60ad4bf5be86c17b77.1487712920.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

objtool: Improve error message for bad file argument

2018-01-23T18:57:05+00:00

commit 385d11b152c4eb638eeb769edcb3249533bb9a00 upstream.

If a nonexistent file is supplied to objtool, it complains with a
non-helpful error:

  open: No such file or directory

Improve it to:

  objtool: Can't open 'foo': No such file or directory

Reported-by: Markus 
Signed-off-by: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/406a3d00a21225eee2819844048e17f68523ccf6.1516025651.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman