[tip:core/urgent] x86/head/64: Annotate start_cpu0() as non-callable

From: tip-bot for Josh Poimboeuf
Date: Thu Jul 18 2019 - 15:11:28 EST

Commit-ID: 61a73f5cd1a5794626d216cc56e20a1b195c5d0c
Gitweb: https://git.kernel.org/tip/61a73f5cd1a5794626d216cc56e20a1b195c5d0c
Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate: Wed, 17 Jul 2019 20:36:41 -0500
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 18 Jul 2019 21:01:04 +0200

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@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/6b1b4505fcb90571a55fa1b52d71fb458ca24454.1563413318.git.jpoimboe@xxxxxxxxxx

arch/x86/kernel/head_64.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index bcd206c8ac90..66b4a7757397 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -253,10 +253,10 @@ END(secondary_startup_64)
* start_secondary() via .Ljump_to_C_code.
- movq initial_stack(%rip), %rsp
+ movq initial_stack(%rip), %rsp
jmp .Ljump_to_C_code

/* Both SMP bootup and ACPI suspend change these variables */