klibc - Jan 2014 - [klibc:master] auxv: convert auxiliary vector into an array; define getauxval()

Commit-ID:  45e09deb6a0a4fcb3a56efb7e18807b2800e358f
Gitweb:    
http://git.kernel.org/?p=libs/klibc/klibc.git;a=commit;h=45e09deb6a0a4fcb3a56efb7e18807b2800e358f
Author:     H. Peter Anvin <hpa at zytor.com>
AuthorDate: Fri, 24 Jan 2014 20:26:04 -0800
Committer:  H. Peter Anvin <hpa at zytor.com>
CommitDate: Fri, 24 Jan 2014 20:28:23 -0800

auxv: convert auxiliary vector into an array; define getauxval()

Convert the ELF auxiliary vector into an array.  Define getauxval() as
an inline accessor to that array.

Signed-off-by: H. Peter Anvin <hpa at zytor.com>

---
 usr/include/sys/auxv.h      | 16 ++++++++++++++++
 usr/include/sys/elfcommon.h |  2 ++
 usr/klibc/libc_init.c       | 25 ++++++++++++-------------
 3 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/usr/include/sys/auxv.h b/usr/include/sys/auxv.h
new file mode 100644
index 0000000..08fcfcf
--- /dev/null
+++ b/usr/include/sys/auxv.h
@@ -0,0 +1,16 @@
+#ifndef _SYS_AUXV_H
+#define _SYS_AUXV_H
+
+#include <klibc/compiler.h>
+#include <elf.h>
+
+#define _AUXVAL_MAX	AT_SYSINFO_EHDR
+
+__extern unsigned long __auxval[_AUXVAL_MAX];
+
+__static_inline unsigned long getauxval(unsigned long __t)
+{
+	return (__t >= _AUXVAL_MAX) ? 0 : __auxval[__t];
+}
+
+#endif /* _SYS_AUXV_H */
diff --git a/usr/include/sys/elfcommon.h b/usr/include/sys/elfcommon.h
index 300ff4e..603b0ce 100644
--- a/usr/include/sys/elfcommon.h
+++ b/usr/include/sys/elfcommon.h
@@ -107,6 +107,8 @@
 #define AT_CLKTCK 	17	/* frequency at which times() increments */
 /* 18..22 = ? */
 #define AT_SECURE 	23	/* secure mode boolean */
+#define AT_SYSINFO	32	/* vdso entry point address */
+#define AT_SYSINFO_EHDR	33	/* vdso header address */
 
 /* Program header permission flags */
 #define PF_X            0x1
diff --git a/usr/klibc/libc_init.c b/usr/klibc/libc_init.c
index 8d18820..1087f95 100644
--- a/usr/klibc/libc_init.c
+++ b/usr/klibc/libc_init.c
@@ -24,6 +24,7 @@
 #include <stdint.h>
 #include <klibc/compiler.h>
 #include <elf.h>
+#include <sys/auxv.h>
 #include "atexit.h"
 
 /* This file is included from __static_init.c or __shared_init.c */
@@ -35,12 +36,14 @@ char **environ;
 unsigned int __page_size, __page_shift;
 
 struct auxentry {
-	uintptr_t type;
-	uintptr_t v;
+	unsigned long type;
+	unsigned long v;
 };
 
 extern void __init_stdio(void);
 
+unsigned long __auxval[_AUXVAL_MAX];
+
 __noreturn __libc_init(uintptr_t * elfdata, void (*onexit) (void))
 {
 	int argc;
@@ -76,20 +79,16 @@ __noreturn __libc_init(uintptr_t * elfdata, void (*onexit)
(void))
 	auxentry = (struct auxentry *)(envend + 1);
 
 	while (auxentry->type) {
-		switch (auxentry->type) {
-#if SHARED
-		case AT_ENTRY:
-			MAIN = (main_t) (auxentry->v);
-			break;
-#endif
-		case AT_PAGESZ:
-			page_size = (unsigned int)(auxentry->v);
-			break;
-		}
+		if (auxentry->type < _AUXVAL_MAX)
+			__auxval[auxentry->type] = auxentry->v;
 		auxentry++;
 	}
 
-	__page_size = page_size;
+#if SHARED
+	MAIN = (main_t) __auxval[AT_ENTRY];
+#endif
+
+	__page_size = page_size = __auxval[AT_PAGESZ];
 
 #if __GNUC__ >= 4
 	/* unsigned int is 32 bits on all our architectures */