Re: [PATCH] powerpc: Fix missing prototype problems for "arch/powerpc/kernel/setup_64.c"

Le 15/03/2021 à 13:57, Cédric Le Goater a écrit :

On 3/15/21 1:48 PM, heying (H) wrote:

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在 2021/3/15 20:17, Christophe Leroy 写道:

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You subject doesn't match the content of the patch.

OK. I'll adapt that.

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Le 15/03/2021 à 13:04, He Ying a écrit :

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The variables 'uaccess_fulsh' and 'entry_flush' are not referenced
outside the file. So define them as static to avoid the warnings.

And add a prototype for the function 'panic_smp_self_stop' for the
same purpose.

Sparse also warns that 'rfi_flush' should be static. However, it's
referenced outside the file.

To clear that warning, you have to include asm/security_features.h, rfi_flush is declared there.

Do you mean that I should include this header in arch/powerpc/kernel/setup_64.c?

yes.

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The warnings about the file reported by sparse are as follows:
arch/powerpc/kernel/setup_64.c:422:6: warning: symbol 'panic_smp_self_stop' was not declared. Should it be static?
arch/powerpc/kernel/setup_64.c:951:6: warning: symbol 'rfi_flush' was not declared. Should it be static?
arch/powerpc/kernel/setup_64.c:952:6: warning: symbol 'entry_flush' was not declared. Should it be static?
arch/powerpc/kernel/setup_64.c:953:6: warning: symbol 'uaccess_flush' was not declared. Should it be static?

Reported-by: Hulk Robot <redacted>
Signed-off-by: He Ying <redacted>
---
   arch/powerpc/kernel/setup_64.c | 6 ++++--
   1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 560ed8b975e7..603aacd8527b 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c

@@ -71,6 +71,8 @@
     #include "setup.h"
   +extern void panic_smp_self_stop(void);
+

For function prototypes 'extern' is unneeded and deprecated.

And function prototypes should go in an header file.

panic_smp_self_stop() is called from kernel/panic.c , it should be declared in one of the generic linux header files I think.

Yes, you're right. But I have no idea which header it should be declared in. May I have your suggestions?

arch/powerpc/include/asm/bug.h looks like a good place.

Why declaring it in a powerpc header ?

It's a weak function defined in core part of kernel (kernel/panic.c).

I think it should go in a common header, just like for instance arch_thaw_secondary_cpus_begin()

C.

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   int spinning_secondaries;
   u64 ppc64_pft_size;
   @@ -949,8 +951,8 @@ static bool no_rfi_flush;
   static bool no_entry_flush;
   static bool no_uaccess_flush;
   bool rfi_flush;
-bool entry_flush;
-bool uaccess_flush;
+static bool entry_flush;
+static bool uaccess_flush;
   DEFINE_STATIC_KEY_FALSE(uaccess_flush_key);
   EXPORT_SYMBOL(uaccess_flush_key);

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