linux/tools/objtool
Josh Poimboeuf fd35c88b74 objtool: Support GCC 8 switch tables
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 <arnd@arndb.de>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: damian <damian.tometzki@icloud.com>
Link: http://lkml.kernel.org/r/20180510224849.xwi34d6tzheb5wgw@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-05-14 10:20:54 +02:00
..
arch/x86 objtool, kprobes/x86: Sync the latest <asm/insn.h> header with tools/objtool/arch/x86/include/asm/insn.h 2018-05-14 10:15:54 +02:00
Documentation x86/asm: Fix inline asm call constraints for Clang 2017-09-23 15:06:20 +02:00
.gitignore objtool: Move synced files to their original relative locations 2017-11-07 10:48:23 +01:00
arch.h objtool: Assume unannotated UD2 instructions are dead ends 2017-07-28 08:33:32 +02:00
Build objtool: Add ORC unwind table generation 2017-07-18 10:57:43 +02:00
builtin-check.c objtool: Add module specific retpoline rules 2018-02-21 09:05:05 +01:00
builtin-orc.c objtool: Use existing global variables for options 2018-02-21 09:05:04 +01:00
builtin.h objtool: Add module specific retpoline rules 2018-02-21 09:05:05 +01:00
cfi.h objtool: Handle GCC stack pointer adjustment bug 2017-08-30 10:48:41 +02:00
check.c objtool: Support GCC 8 switch tables 2018-05-14 10:20:54 +02:00
check.h objtool: Add retpoline validation 2018-02-21 09:05:04 +01:00
elf.c objtool: Support GCC 8's cold subfunctions 2018-05-14 10:20:53 +02:00
elf.h objtool: Support GCC 8's cold subfunctions 2018-05-14 10:20:53 +02:00
Makefile objtool: Support HOSTCFLAGS and HOSTLDFLAGS 2018-04-17 07:59:42 +02:00
objtool.c objtool: Print top level commands on incorrect usage 2017-10-18 15:22:26 +02:00
orc_dump.c objtool: Fix 64-bit build on 32-bit host 2017-12-06 22:38:14 +01:00
orc_gen.c objtool: Warn on stripped section symbol 2018-01-30 15:09:23 +01:00
orc.h objtool: Move synced files to their original relative locations 2017-11-07 10:48:23 +01:00
special.c objtool: Implement stack validation 2.0 2017-06-30 10:19:19 +02:00
special.h objtool: Add tool to perform compile-time stack metadata validation 2016-02-29 08:35:12 +01:00
sync-check.sh objtool: Move kernel headers/code sync check to a script 2017-11-07 10:48:34 +01:00
warn.h objtool: Implement stack validation 2.0 2017-06-30 10:19:19 +02:00