linux.git/tools/objtool, branch v4.14.149

objtool: Clobber user CFLAGS variable

2019-10-05T10:47:35+00:00

commit f73b3cc39c84220e6dccd463b5c8279b03514646 upstream.

If the build user has the CFLAGS variable set in their environment,
objtool blindly appends to it, which can cause unexpected behavior.

Clobber CFLAGS to ensure consistent objtool compilation behavior.

Reported-by: Valdis Kletnieks 
Tested-by: Valdis Kletnieks 
Signed-off-by: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: https://lkml.kernel.org/r/83a276df209962e6058fcb6c615eef9d401c21bc.1567121311.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar 
CC: Nathan Chancellor 
Signed-off-by: Greg Kroah-Hartman

objtool: Query pkg-config for libelf location

2019-10-05T10:47:32+00:00

commit 056d28d135bca0b1d0908990338e00e9dadaf057 upstream.

If it is not in the default location, compilation fails at several points.

Signed-off-by: Rolf Eike Beer 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Thomas Gleixner 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/91a25e992566a7968fedc89ec80e7f4c83ad0548.1553622500.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman

objtool: Add rewind_stack_do_exit() to the noreturn list

2019-08-09T15:53:33+00:00

commit 4fa5ecda2bf96be7464eb406df8aba9d89260227 upstream.

This fixes the following warning seen on GCC 7.3:

  arch/x86/kernel/dumpstack.o: warning: objtool: oops_end() falls through to next function show_regs()

Reported-by: kbuild test robot 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Thomas Gleixner 
Cc: Peter Zijlstra 
Link: https://lkml.kernel.org/r/3418ebf5a5a9f6ed7e80954c741c0b904b67b5dc.1554398240.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman

objtool: Add machine_real_restart() to the noreturn list

2019-08-09T15:53:33+00:00

commit 684fb246578b9e81fc7b4ca5c71eae22edb650b2 upstream.

machine_real_restart() is annotated as '__noreturn", so add it to the
objtool noreturn list.  This fixes the following warning with clang and
CONFIG_CC_OPTIMIZE_FOR_SIZE=y:

  arch/x86/kernel/reboot.o: warning: objtool: native_machine_emergency_restart() falls through to next function machine_power_off()

Reported-by: Matthias Kaehlcke 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Thomas Gleixner 
Tested-by: Matthias Kaehlcke 
Reviewed-by: Matthias Kaehlcke 
Link: https://lkml.kernel.org/r/791712792aa4431bdd55bf1beb33a169ddf3b4a2.1529423255.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman

objtool: Support GCC 9 cold subfunction naming scheme

2019-08-06T17:05:28+00:00

commit bcb6fb5da77c2a228adf07cc9cb1a0c2aa2001c6 upstream.

Starting with GCC 8, a lot of unlikely code was moved out of line to
"cold" subfunctions in .text.unlikely.

For example, the unlikely bits of:

  irq_do_set_affinity()

are moved out to the following subfunction:

  irq_do_set_affinity.cold.49()

Starting with GCC 9, the numbered suffix has been removed.  So in the
above example, the cold subfunction is instead:

  irq_do_set_affinity.cold()

Tweak the objtool subfunction detection logic so that it detects both
GCC 8 and GCC 9 naming schemes.

Reported-by: Peter Zijlstra (Intel) 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Thomas Gleixner 
Tested-by: Peter Zijlstra (Intel) 
Acked-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/015e9544b1f188d36a7f02fa31e9e95629aa5f50.1541040800.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman

objtool: Support per-function rodata sections

2019-06-25T03:36:50+00:00

commit 4a60aa05a0634241ce17f957bf9fb5ac1eed6576 upstream.

Add support for processing switch jump tables in objects with multiple
.rodata sections, such as those created by '-ffunction-sections' and
'-fdata-sections'. Currently, objtool always looks in .rodata for jump
table information, which results in many "sibling call from callable
instruction with modified stack frame" warnings with objects compiled
using those flags.

The fix is comprised of three parts:

1. Flagging all .rodata sections when importing ELF information for
easier checking later.

2. Keeping a reference to the section each relocation is from in order
to get the list_head for the other relocations in that section.

3. Finding jump tables by following relocations to .rodata sections,
rather than always referencing a single global .rodata section.

The patch has been tested without data sections enabled and no
differences in the resulting orc unwind information were seen.

Note that as objtool adds terminators to end of each .text section the
unwind information generated between a function+data sections build and
a normal build aren't directly comparable. Manual inspection suggests
that objtool is now generating the correct information, or at least
making more of an effort to do so than it did previously.

Signed-off-by: Allan Xavier
Signed-off-by: Josh Poimboeuf
Signed-off-by: Thomas Gleixner
Link: https://lkml.kernel.org/r/099bdc375195c490dda04db777ee0b95d566ded1.1536325914.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman

objtool: Don't use ignore flag for fake jumps

2019-06-15T09:54:52+00:00

[ Upstream commit e6da9567959e164f82bc81967e0d5b10dee870b4 ]

The ignore flag is set on fake jumps in order to keep
add_jump_destinations() from setting their jump_dest, since it already
got set when the fake jump was created.

But using the ignore flag is a bit of a hack.  It's normally used to
skip validation of an instruction, which doesn't really make sense for
fake jumps.

Also, after the next patch, using the ignore flag for fake jumps can
trigger a false "why am I validating an ignored function?" warning.

Instead just add an explicit check in add_jump_destinations() to skip
fake jumps.

Signed-off-by: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/71abc072ff48b2feccc197723a9c52859476c068.1557766718.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

objtool: Allow AR to be overridden with HOSTAR

2019-05-25T16:25:26+00:00

commit 8ea58f1e8b11cca3087b294779bf5959bf89cc10 upstream.

Currently, this Makefile hardcodes GNU ar, meaning that if it is not
available, there is no way to supply a different one and the build will
fail.

  $ make AR=llvm-ar CC=clang LD=ld.lld HOSTAR=llvm-ar HOSTCC=clang \
         HOSTLD=ld.lld HOSTLDFLAGS=-fuse-ld=lld defconfig modules_prepare
  ...
    AR       /out/tools/objtool/libsubcmd.a
  /bin/sh: 1: ar: not found
  ...

Follow the logic of HOST{CC,LD} and allow the user to specify a
different ar tool via HOSTAR (which is used elsewhere in other
tools/ Makefiles).

Signed-off-by: Nathan Chancellor 
Signed-off-by: Josh Poimboeuf 
Reviewed-by: Nick Desaulniers 
Reviewed-by: Mukesh Ojha 
Cc: 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/80822a9353926c38fd7a152991c6292491a9d0e8.1558028966.git.jpoimboe@redhat.com
Link: https://github.com/ClangBuiltLinux/linux/issues/481
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

objtool: Fix function fallthrough detection

2019-05-21T16:50:13+00:00

commit e6f393bc939d566ce3def71232d8013de9aaadde upstream.

When a function falls through to the next function due to a compiler
bug, objtool prints some obscure warnings.  For example:

  drivers/regulator/core.o: warning: objtool: regulator_count_voltages()+0x95: return with modified stack frame
  drivers/regulator/core.o: warning: objtool: regulator_count_voltages()+0x0: stack state mismatch: cfa1=7+32 cfa2=7+8

Instead it should be printing:

  drivers/regulator/core.o: warning: objtool: regulator_supply_is_couple() falls through to next function regulator_count_voltages()

This used to work, but was broken by the following commit:

  13810435b9a7 ("objtool: Support GCC 8's cold subfunctions")

The padding nops at the end of a function aren't actually part of the
function, as defined by the symbol table.  So the 'func' variable in
validate_branch() is getting cleared to NULL when a padding nop is
encountered, breaking the fallthrough detection.

If the current instruction doesn't have a function associated with it,
just consider it to be part of the previously detected function by not
overwriting the previous value of 'func'.

Reported-by: kbuild test robot 
Signed-off-by: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: 
Fixes: 13810435b9a7 ("objtool: Support GCC 8's cold subfunctions")
Link: http://lkml.kernel.org/r/546d143820cd08a46624ae8440d093dd6c902cae.1557766718.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

objtool: Move objtool_file struct off the stack

2019-03-27T05:13:52+00:00

commit 0c671812f152b628bd87c0af49da032cc2a2c319 upstream.

Objtool uses over 512k of stack, thanks to the hash table embedded in
the objtool_file struct.  This causes an unnecessarily large stack
allocation and breaks users with low stack limits.

Move the struct off the stack.

Fixes: 042ba73fe7eb ("objtool: Add several performance improvements")
Reported-by: Vassili Karpov 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Thomas Gleixner 
Cc: Peter Zijlstra 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/df92dcbc4b84b02ffa252f46876df125fb56e2d7.1552954176.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman