Patchwork [1/4] Add INTERNAL_SYSCALL_CALL

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Submitter Adhemerval Zanella Netto
Date Sept. 20, 2016, 3:01 p.m.
Message ID <1474383714-15187-2-git-send-email-adhemerval.zanella@linaro.org>
Download mbox | patch
Permalink /patch/15807/
State New
Headers show

Comments

Adhemerval Zanella Netto - Sept. 20, 2016, 3:01 p.m.
This patch adds two new macros for internal and inline syscall to use
within GLIBC: INTERNAL_SYSCALL_CALL and INLINE_SYSCALL_CALL.  They are
similar to the old INTERNAL_SYSCALL and INLINE_SYSCALL with the difference
the new macros accept a variable argument call and do not require to pass
the expected argument size.

The advantage is it is possible to use variable argument macros like
SYSCALL_LL{64} without the need to also handle the argument size.  So
for an ABI where SYSCALL_LL might split the argument in high and low
parts, instead of:

  INTERNAL_SYSCALL_DECL (err);
 #if ...
  INTERNAL_SYSCALL (syscall, err, 2, SYSCALL_LL (len));
 #else
  INTERNAL_SYSCALL (syscall, err, 1, SYSCALL_LL (len));
 #endif

It will be just:

  INTERNAL_SYSCALL_CALL (syscall, err, SYSCALL_LL (len));

The INLINE_SYSCALL_CALL follows the same semanthic regarding the argument
and is similar to INLINE_SYSCALL regarding setting errno.

No function currently uses these new macros, so no code change is expected.

	* sysdeps/unix/sysdep.h (__INTERNAL_SYSCALL0): New macro.
	(__INTERNAL_SYSCALL1): Likewise.
	(__INTERNAL_SYSCALL2): Likewise.
	(__INTERNAL_SYSCALL3): Likewise.
	(__INTERNAL_SYSCALL4): Likewise.
	(__INTERNAL_SYSCALL5): Likewise.
	(__INTERNAL_SYSCALL6): Likewise.
	(__INTERNAL_SYSCALL7): Likewise.
	(__INTERNAL_SYSCALL_NARGS_X): Likewise.
	(__INTERNAL_SYSCALL_NARGS): Likewise.
	(__INTERNAL_SYSCALL_CONCAT_X): Likewise.
	(__INTERNAL_SYSCALL_CONCAT): Likewise.
	(__INTERNAL_SYSCALL_DISP): Likewise.
	(INTERNAL_SYSCALL_CALL): Likewise.
	(__SYSCALL_CALL): Rename to INLINE_SYSCALL_CALL.
	(SYSCALL_CANCEL): Replace __SYSCALL_CALL with INLINE_SYSCALL_CALL.
---
 sysdeps/unix/sysdep.h | 43 ++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 40 insertions(+), 3 deletions(-)
Florian Weimer - Sept. 20, 2016, 9:36 p.m.
* Adhemerval Zanella:

> +#define __INTERNAL_SYSCALL0(name, err) \
> +  INTERNAL_SYSCALL (name, err, 0)
> +#define __INTERNAL_SYSCALL1(name, err, a1) \
> +  INTERNAL_SYSCALL (name, err, 1, a1)
> +#define __INTERNAL_SYSCALL2(name, err, a1, a2) \
> +  INTERNAL_SYSCALL (name, err, 2, a1, a2)
> +#define __INTERNAL_SYSCALL3(name, err, a1, a2, a3) \
> +  INTERNAL_SYSCALL (name, err, 3, a1, a2, a3)
> +#define __INTERNAL_SYSCALL4(name, err, a1, a2, a3, a4) \
> +  INTERNAL_SYSCALL (name, err, 4, a1, a2, a3, a4)
> +#define __INTERNAL_SYSCALL5(name, err, a1, a2, a3, a4, a5) \
> +  INTERNAL_SYSCALL (name, err, 5, a1, a2, a3, a4, a5)
> +#define __INTERNAL_SYSCALL6(name, err, a1, a2, a3, a4, a5, a6) \
> +  INTERNAL_SYSCALL (name, err, 6, a1, a2, a3, a4, a5, a6)
> +#define __INTERNAL_SYSCALL7(name, err, a1, a2, a3, a4, a5, a6, a7) \
> +  INTERNAL_SYSCALL (name, err, 7, a1, a2, a3, a4, a5, a6, a7)

It's not immediately obvious why these definitions are needed.

> +#define __INTERNAL_SYSCALL_NARGS_X(a, b, c, d, e, f, g, h, n, ...) n
> +#define __INTERNAL_SYSCALL_NARGS(...) \
> +  __INTERNAL_SYSCALL_NARGS_X (__VA_ARGS__, 7, 6, 5, 4, 3, 2, 1, 0, )
> +#define __INTERNAL_SYSCALL_CONCAT_X(a, b) a##b
> +#define __INTERNAL_SYSCALL_CONCAT(a, b)   __SYSCALL_CONCAT_X (a, b)

I think you can reuse the macros from sysdeps/unix/sysdep.h here.

> +/* Issue a syscall defined by syscall number plus any other argument required.

These comment lines are rather long.

> +   Any error will be handled using arch defined macros and errno will be se
> +   accordingly.

“will be set”

Patch

diff --git a/sysdeps/unix/sysdep.h b/sysdeps/unix/sysdep.h
index 94a2ce0..50ac4d1 100644
--- a/sysdeps/unix/sysdep.h
+++ b/sysdeps/unix/sysdep.h
@@ -24,6 +24,38 @@ 
 #define	SYSCALL__(name, args)	PSEUDO (__##name, name, args)
 #define	SYSCALL(name, args)	PSEUDO (name, name, args)
 
+#define __INTERNAL_SYSCALL0(name, err) \
+  INTERNAL_SYSCALL (name, err, 0)
+#define __INTERNAL_SYSCALL1(name, err, a1) \
+  INTERNAL_SYSCALL (name, err, 1, a1)
+#define __INTERNAL_SYSCALL2(name, err, a1, a2) \
+  INTERNAL_SYSCALL (name, err, 2, a1, a2)
+#define __INTERNAL_SYSCALL3(name, err, a1, a2, a3) \
+  INTERNAL_SYSCALL (name, err, 3, a1, a2, a3)
+#define __INTERNAL_SYSCALL4(name, err, a1, a2, a3, a4) \
+  INTERNAL_SYSCALL (name, err, 4, a1, a2, a3, a4)
+#define __INTERNAL_SYSCALL5(name, err, a1, a2, a3, a4, a5) \
+  INTERNAL_SYSCALL (name, err, 5, a1, a2, a3, a4, a5)
+#define __INTERNAL_SYSCALL6(name, err, a1, a2, a3, a4, a5, a6) \
+  INTERNAL_SYSCALL (name, err, 6, a1, a2, a3, a4, a5, a6)
+#define __INTERNAL_SYSCALL7(name, err, a1, a2, a3, a4, a5, a6, a7) \
+  INTERNAL_SYSCALL (name, err, 7, a1, a2, a3, a4, a5, a6, a7)
+
+#define __INTERNAL_SYSCALL_NARGS_X(a, b, c, d, e, f, g, h, n, ...) n
+#define __INTERNAL_SYSCALL_NARGS(...) \
+  __INTERNAL_SYSCALL_NARGS_X (__VA_ARGS__, 7, 6, 5, 4, 3, 2, 1, 0, )
+#define __INTERNAL_SYSCALL_CONCAT_X(a, b) a##b
+#define __INTERNAL_SYSCALL_CONCAT(a, b)   __SYSCALL_CONCAT_X (a, b)
+#define __INTERNAL_SYSCALL_DISP(b,err,...) \
+  __INTERNAL_SYSCALL_CONCAT (b, __SYSCALL_NARGS (__VA_ARGS__)) \
+			    (err, __VA_ARGS__)
+
+/* Issue a syscall defined by syscall number plus any other argument required.
+   It is similar to INTERNAL_SYSCALL macro, but without the need to pass the
+   expected argument number as second parameter.  */
+#define INTERNAL_SYSCALL_CALL(nr, err, ...) \
+  __INTERNAL_SYSCALL_DISP (__INTERNAL_SYSCALL, nr, err, __VA_ARGS__)
+
 #define __SYSCALL0(name) \
   INLINE_SYSCALL (name, 0)
 #define __SYSCALL1(name, a1) \
@@ -49,17 +81,22 @@ 
 #define __SYSCALL_DISP(b,...) \
   __SYSCALL_CONCAT (b,__SYSCALL_NARGS(__VA_ARGS__))(__VA_ARGS__)
 
-#define __SYSCALL_CALL(...) __SYSCALL_DISP (__SYSCALL, __VA_ARGS__)
+/* Issue a syscall defined by syscall number plus any other argument required.
+   Any error will be handled using arch defined macros and errno will be se
+   accordingly.
+   It is similar to INLINE_SYSCALL macro, but without the need to pass the
+   expected argument number as second parameter.  */
+#define INLINE_SYSCALL_CALL(...) __SYSCALL_DISP (__SYSCALL, __VA_ARGS__)
 
 #define SYSCALL_CANCEL(...) \
   ({									     \
     long int sc_ret;							     \
     if (SINGLE_THREAD_P) 						     \
-      sc_ret = __SYSCALL_CALL (__VA_ARGS__);   				     \
+      sc_ret = INLINE_SYSCALL_CALL (__VA_ARGS__); 			     \
     else								     \
       {									     \
 	int sc_cancel_oldtype = LIBC_CANCEL_ASYNC ();			     \
-	sc_ret = __SYSCALL_CALL (__VA_ARGS__);				     \
+	sc_ret = INLINE_SYSCALL_CALL (__VA_ARGS__);			     \
         LIBC_CANCEL_RESET (sc_cancel_oldtype);				     \
       }									     \
     sc_ret;								     \