Re: [tip:x86/urgent] x86: Fix section mismatch on load_ucode_ap

From: Yinghai Lu
Date: Wed Jun 19 2013 - 20:02:51 EST


On Wed, Jun 19, 2013 at 3:03 PM, tip-bot for Paul Gortmaker
<tipbot@xxxxxxxxx> wrote:
> Commit-ID: 949785996ec2250fa958fc3a924e5186e9a8fa2c
> Gitweb: http://git.kernel.org/tip/949785996ec2250fa958fc3a924e5186e9a8fa2c
> Author: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
> AuthorDate: Wed, 19 Jun 2013 11:15:26 -0400
> Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
> CommitDate: Wed, 19 Jun 2013 14:43:59 -0700
>
> x86: Fix section mismatch on load_ucode_ap
>
> We are in the process of removing all the __cpuinit annotations.
> While working on making that change, an existing problem was
> made evident:
>
> WARNING: arch/x86/kernel/built-in.o(.text+0x198f2): Section mismatch
> in reference from the function cpu_init() to the function
> .init.text:load_ucode_ap() The function cpu_init() references
> the function __init load_ucode_ap(). This is often because cpu_init
> lacks a __init annotation or the annotation of load_ucode_ap is wrong.
>
> This now appears because in my working tree, cpu_init() is no longer
> tagged as __cpuinit, and so the audit picks up the mismatch. The 2nd
> hypothesis from the audit is the correct one, as there was an incorrect
> __init tag on the prototype in the header (but __cpuinit was used on
> the function itself.)
>
> The audit is telling us that the prototype's __init annotation took
> effect and the function did land in the .init.text section. Checking
> with objdump on a mainline tree that still has __cpuinit shows that
> the __cpuinit on the function takes precedence over the __init on the
> prototype, but that won't be true once we make __cpuinit a no-op.
>
> Even though we are removing __cpuinit, we temporarily align both
> the function and the prototype on __cpuinit so that the changeset
> can be applied to stable trees if desired.
>
> [ hpa: build fix only, no object code change ]
>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
> Cc: stable <stable@xxxxxxxxxxxxxxx> # 3.9+
> Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
> Link: http://lkml.kernel.org/r/1371654926-11729-1-git-send-email-paul.gortmaker@xxxxxxxxxxxxx
> Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
> ---
> arch/x86/include/asm/microcode.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
> index 6825e2e..6bc3985 100644
> --- a/arch/x86/include/asm/microcode.h
> +++ b/arch/x86/include/asm/microcode.h
> @@ -60,11 +60,11 @@ static inline void __exit exit_amd_microcode(void) {}
> #ifdef CONFIG_MICROCODE_EARLY
> #define MAX_UCODE_COUNT 128
> extern void __init load_ucode_bsp(void);
> -extern __init void load_ucode_ap(void);
> +extern void __cpuinit load_ucode_ap(void);

why not just dropping __init in header file?


> extern int __init save_microcode_in_initrd(void);
> #else
> static inline void __init load_ucode_bsp(void) {}
> -static inline __init void load_ucode_ap(void) {}
> +static inline void __cpuinit load_ucode_ap(void) {}
> static inline int __init save_microcode_in_initrd(void)
> {
> return 0;
> --
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