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x86/head/64: Annotate start_cpu0() as non-callable 

After an objtool improvement, it complains about the fact that
start_cpu0() jumps to code which has an LRET instruction.

  arch/x86/kernel/head_64.o: warning: objtool: .head.text+0xe4: unsupported instruction in callable function

Technically, start_cpu0() is callable, but it acts nothing like a
callable function.  Prevent objtool from treating it like one by
removing its ELF function annotation.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/6b1b4505fcb90571a55fa1b52d71fb458ca24454.1563413318.git.jpoimboe@redhat.com
This commit is contained in:
Josh Poimboeuf 2019-07-17 20:36:41 -05:00 committed by Thomas Gleixner
parent e6dd473944
commit 61a73f5cd1
1 changed files with 2 additions and 2 deletions
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arch/x86/kernel/head_64.S
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@ -253,10 +253,10 @@ END(secondary_startup_64)
* start_secondary() via .Ljump_to_C_code.
*/
ENTRY(start_cpu0)
movq initial_stack(%rip), %rsp
UNWIND_HINT_EMPTY
movq initial_stack(%rip), %rsp
jmp .Ljump_to_C_code
ENDPROC(start_cpu0)
END(start_cpu0)
#endif
/* Both SMP bootup and ACPI suspend change these variables */