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* [PATCH] selftests/x86: Simplify the code of getting vdso base address in sgx
@ 2021-01-18 13:33 Tianjia Zhang
  2021-01-20 14:34 ` Jarkko Sakkinen
  0 siblings, 1 reply; 2+ messages in thread
From: Tianjia Zhang @ 2021-01-18 13:33 UTC (permalink / raw)
  To: Jarkko Sakkinen, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
	H. Peter Anvin, Andrew Morton, Shuah Khan, haitao.huang,
	Kai Huang, x86, linux-sgx, linux-kernel, linux-mm,
	linux-kselftest, Jia Zhang
  Cc: Tianjia Zhang

The base address of vDSO can be obtained through the library function
`getauxval()`, so use `getauxval(AT_SYSINFO_EHDR)` instead of a custom
implementation to simplify the code.

Reported-by: Jia Zhang <zhang.jia@linux.alibaba.com>
Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
---
 tools/testing/selftests/sgx/main.c | 24 ++++--------------------
 1 file changed, 4 insertions(+), 20 deletions(-)

diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c
index 724cec700926..365d01dea67b 100644
--- a/tools/testing/selftests/sgx/main.c
+++ b/tools/testing/selftests/sgx/main.c
@@ -15,6 +15,7 @@
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/types.h>
+#include <sys/auxv.h>
 #include "defines.h"
 #include "main.h"
 #include "../kselftest.h"
@@ -28,24 +29,6 @@ struct vdso_symtab {
 	Elf64_Word *elf_hashtab;
 };
 
-static void *vdso_get_base_addr(char *envp[])
-{
-	Elf64_auxv_t *auxv;
-	int i;
-
-	for (i = 0; envp[i]; i++)
-		;
-
-	auxv = (Elf64_auxv_t *)&envp[i + 1];
-
-	for (i = 0; auxv[i].a_type != AT_NULL; i++) {
-		if (auxv[i].a_type == AT_SYSINFO_EHDR)
-			return (void *)auxv[i].a_un.a_val;
-	}
-
-	return NULL;
-}
-
 static Elf64_Dyn *vdso_get_dyntab(void *addr)
 {
 	Elf64_Ehdr *ehdr = addr;
@@ -162,7 +145,7 @@ static int user_handler(long rdi, long rsi, long rdx, long ursp, long r8, long r
 	return 0;
 }
 
-int main(int argc, char *argv[], char *envp[])
+int main(int argc, char *argv[])
 {
 	struct sgx_enclave_run run;
 	struct vdso_symtab symtab;
@@ -203,7 +186,8 @@ int main(int argc, char *argv[], char *envp[])
 	memset(&run, 0, sizeof(run));
 	run.tcs = encl.encl_base;
 
-	addr = vdso_get_base_addr(envp);
+	/* Get vDSO base address */
+	addr = (void *)(uintptr_t)getauxval(AT_SYSINFO_EHDR);
 	if (!addr)
 		goto err;
 
-- 
2.19.1.3.ge56e4f7


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] selftests/x86: Simplify the code of getting vdso base address in sgx
  2021-01-18 13:33 [PATCH] selftests/x86: Simplify the code of getting vdso base address in sgx Tianjia Zhang
@ 2021-01-20 14:34 ` Jarkko Sakkinen
  0 siblings, 0 replies; 2+ messages in thread
From: Jarkko Sakkinen @ 2021-01-20 14:34 UTC (permalink / raw)
  To: Tianjia Zhang
  Cc: Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	Andrew Morton, Shuah Khan, haitao.huang, Kai Huang, x86,
	linux-sgx, linux-kernel, linux-mm, linux-kselftest, Jia Zhang

On Mon, Jan 18, 2021 at 09:33:21PM +0800, Tianjia Zhang wrote:
> The base address of vDSO can be obtained through the library function
> `getauxval()`, so use `getauxval(AT_SYSINFO_EHDR)` instead of a custom
> implementation to simplify the code.
> 
> Reported-by: Jia Zhang <zhang.jia@linux.alibaba.com>
> Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>

- Remove reported-by, as there is no regression.
- Please write to the long description what the commit does.
  It's lacking that. I.e. instead of passive form: "Obtain the
  base address...".

/Jarkko

> ---
>  tools/testing/selftests/sgx/main.c | 24 ++++--------------------
>  1 file changed, 4 insertions(+), 20 deletions(-)
> 
> diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c
> index 724cec700926..365d01dea67b 100644
> --- a/tools/testing/selftests/sgx/main.c
> +++ b/tools/testing/selftests/sgx/main.c
> @@ -15,6 +15,7 @@
>  #include <sys/stat.h>
>  #include <sys/time.h>
>  #include <sys/types.h>
> +#include <sys/auxv.h>
>  #include "defines.h"
>  #include "main.h"
>  #include "../kselftest.h"
> @@ -28,24 +29,6 @@ struct vdso_symtab {
>  	Elf64_Word *elf_hashtab;
>  };
>  
> -static void *vdso_get_base_addr(char *envp[])
> -{
> -	Elf64_auxv_t *auxv;
> -	int i;
> -
> -	for (i = 0; envp[i]; i++)
> -		;
> -
> -	auxv = (Elf64_auxv_t *)&envp[i + 1];
> -
> -	for (i = 0; auxv[i].a_type != AT_NULL; i++) {
> -		if (auxv[i].a_type == AT_SYSINFO_EHDR)
> -			return (void *)auxv[i].a_un.a_val;
> -	}
> -
> -	return NULL;
> -}
> -
>  static Elf64_Dyn *vdso_get_dyntab(void *addr)
>  {
>  	Elf64_Ehdr *ehdr = addr;
> @@ -162,7 +145,7 @@ static int user_handler(long rdi, long rsi, long rdx, long ursp, long r8, long r
>  	return 0;
>  }
>  
> -int main(int argc, char *argv[], char *envp[])
> +int main(int argc, char *argv[])
>  {
>  	struct sgx_enclave_run run;
>  	struct vdso_symtab symtab;
> @@ -203,7 +186,8 @@ int main(int argc, char *argv[], char *envp[])
>  	memset(&run, 0, sizeof(run));
>  	run.tcs = encl.encl_base;
>  
> -	addr = vdso_get_base_addr(envp);
> +	/* Get vDSO base address */
> +	addr = (void *)(uintptr_t)getauxval(AT_SYSINFO_EHDR);
>  	if (!addr)
>  		goto err;
>  
> -- 
> 2.19.1.3.ge56e4f7
> 
> 

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2021-01-18 13:33 [PATCH] selftests/x86: Simplify the code of getting vdso base address in sgx Tianjia Zhang
2021-01-20 14:34 ` Jarkko Sakkinen

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