x86/head: Add unwind hint annotations

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commit 2704fbb672 upstream.

Jiri Slaby reported an ORC issue when unwinding from an idle task.  The
stack was:

    ffffffff811083c2 do_idle+0x142/0x1e0
    ffffffff8110861d cpu_startup_entry+0x5d/0x60
    ffffffff82715f58 start_kernel+0x3ff/0x407
    ffffffff827153e8 x86_64_start_kernel+0x14e/0x15d
    ffffffff810001bf secondary_startup_64+0x9f/0xa0

The ORC unwinder errored out at secondary_startup_64 because the head
code isn't annotated yet so there wasn't a corresponding ORC entry.

Fix that and any other head-related unwinding issues by adding unwind
hints to the head code.

Reported-by: Jiri Slaby <jslaby@suse.cz>
Tested-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/78ef000a2f68f545d6eef44ee912edceaad82ccf.1505764066.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Josh Poimboeuf 2017-09-18 21:43:37 -05:00 • committed by Greg Kroah-Hartman

parent d074a1075f

commit 5d5e60c80f

2 changed files with 12 additions and 3 deletions

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arch/x86/kernel/Makefile

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14

arch/x86/kernel/head_64.S

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