Re: [PATCH V2] selftests/sgx: Fix build error caused by missing dependency

[Shuah Khan <skhan@linuxfoundation.org>]

On 12/14/21 12:26 PM, Reinette Chatre wrote:
> Commit f0ff2447b861 ("selftests/sgx: Add a new kselftest:
> Unclobbered_vdso_oversubscribed") depends on __cpuid() without
> providing the dependency and thus introduces a build error:
> 
> $ make
> gcc -Wall -Werror -g -I../../../../tools/include -fPIC -z noexecstack -c main.c -o ../linux/tools/testing/selftests/sgx/main.o
> main.c: In function ‘get_total_epc_mem’:
> main.c:296:3: error: implicit declaration of function ‘__cpuid’ [-Werror=implicit-function-declaration]
>    296 |   __cpuid(&eax, &ebx, &ecx, &edx);
>        |   ^~~~~~~
> cc1: all warnings being treated as errors
> make: *** [Makefile:33: ../linux/tools/testing/selftests/sgx/main.o] Error 1
> $
> 
> Clone kernel's __cpuid() implementation to the self-test in order
> to make it available to the EPC enumeration code.
> 
> Fixes: f0ff2447b861 ("selftests/sgx: Add a new kselftest: Unclobbered_vdso_oversubscribed")
> Reported-by: Jarkko Sakkinen <jarkko@kernel.org>
> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
> ---
> 
> The commit introducing the issue can be found on
> the x86/sgx branch of tip.git.
> 
> Changes since V1:
> - V1: https://lore.kernel.org/linux-sgx/797ff1331cfe540fc378fcc4a4a7b00ff5099fbe.1638905135.git.reinette.chatre@intel.com/
> - Improve commit message. (Jarkko)
> 
>   tools/testing/selftests/sgx/main.c | 12 ++++++++++++
>   1 file changed, 12 insertions(+)
> 
> diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c
> index 7e912db4c6c5..6dead57a3121 100644
> --- a/tools/testing/selftests/sgx/main.c
> +++ b/tools/testing/selftests/sgx/main.c
> @@ -73,6 +73,18 @@ static bool vdso_get_symtab(void *addr, struct vdso_symtab *symtab)
>   	return true;
>   }
>   
> +static inline void __cpuid(unsigned int *eax, unsigned int *ebx,
> +			   unsigned int *ecx, unsigned int *edx)
> +{
> +	asm volatile("cpuid"
> +	    : "=a" (*eax),
> +	      "=b" (*ebx),
> +	      "=c" (*ecx),
> +	      "=d" (*edx)
> +	    : "0" (*eax), "2" (*ecx)
> +	    : "memory");
> +}
> +
>   static unsigned long elf_sym_hash(const char *name)
>   {
>   	unsigned long h = 0, high;
> 

Let's not add one more __cpuid() define to the individual tests.
We so far have:

tools/testing/selftests/vm/pkey-x86.h
selftests/x86/corrupt_xstate_header.c

Let's move the defines to kselftest.h and remove all these duplicate
defines.

For now you could include vm/pkey-x86.h just to fix the build error
and do the proper cleanup.

There has been a proliferation of defines in tools and selftests.
I just fixed/remove 25+ ARRAY_SIZE duplicate define in selftests.
  
thanks,
-- Shuah