[tip: x86/percpu] x86/percpu: Declare const_pcpu_hot as extern const variable

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/percpu branch of tip:

Commit-ID:     4604c052b84d66407f5e68045a1939685eac401e
Gitweb:        https://git.kernel.org/tip/4604c052b84d66407f5e68045a1939685eac401e
Author:        Uros Bizjak <ubizjak@xxxxxxxxx>
AuthorDate:    Thu, 30 Nov 2023 17:27:35 +01:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Thu, 30 Nov 2023 20:19:33 +01:00

x86/percpu: Declare const_pcpu_hot as extern const variable

const_pcpu_hot is aliased by linker to pcpu_hot, so there is no need
to use the DECLARE_PER_CPU_ALIGNED() macro. Also, declare const_pcpu_hot
as extern to avoid allocating storage space for the aliased structure.

Fixes: ed2f752e0e0a ("x86/percpu: Introduce const-qualified const_pcpu_hot to micro-optimize code generation")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20231130162949.83518-1-ubizjak@xxxxxxxxx
Closes: https://lore.kernel.org/oe-kbuild-all/202311302257.tSFtZnly-lkp@xxxxxxxxx/
---
 arch/x86/include/asm/current.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/current.h b/arch/x86/include/asm/current.h
index 0538d24..9fbd7cb 100644
--- a/arch/x86/include/asm/current.h
+++ b/arch/x86/include/asm/current.h
@@ -37,8 +37,7 @@ static_assert(sizeof(struct pcpu_hot) == 64);
 DECLARE_PER_CPU_ALIGNED(struct pcpu_hot, pcpu_hot);
 
 /* const-qualified alias to pcpu_hot, aliased by linker. */
-DECLARE_PER_CPU_ALIGNED(const struct pcpu_hot __percpu_seg_override,
-			const_pcpu_hot);
+extern const struct pcpu_hot __percpu_seg_override const_pcpu_hot;
 
 static __always_inline struct task_struct *get_current(void)
 {