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

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

[Reinette Chatre]

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 /path/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: /path/linux/tools/testing/selftests/sgx/main.o] Error 1
$

Make the kernel's __cpuid() available locally in support of the
test's usage.

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.

 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;
-- 
2.25.1

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

[Jarkko Sakkinen]

On Tue, 2021-12-07 at 11:40 -0800, 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 /path/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: /path/linux/tools/testing/selftests/sgx/main.o] Error 1
> $
> 
> Make the kernel's __cpuid() available locally in support of the
> test's usage.

It's too abstract, rather

"Clone kernel's __cpuid() implementation to the self-test in order
 to make it available for 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 code change is acceptable.

/Jarkko

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

[Reinette Chatre]

Hi Jarkko,

On 12/11/2021 12:15 AM, Jarkko Sakkinen wrote:
> On Tue, 2021-12-07 at 11:40 -0800, 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 /path/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: /path/linux/tools/testing/selftests/sgx/main.o] Error 1
>> $
>>
>> Make the kernel's __cpuid() available locally in support of the
>> test's usage.
> 
> It's too abstract, rather
> 
> "Clone kernel's __cpuid() implementation to the self-test in order
>   to make it available for the EPC enumeration code."

Will do. Thank you.

> 
>> 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 code change is acceptable.

Thank you.

Reinette