Author: jilles
Date: Sat Aug 17 19:24:58 2013
New Revision: 254463
URL: http://svnweb.freebsd.org/changeset/base/254463
Log:
libc: Access _logname_valid more efficiently.
The variable _logname_valid is not exported via the version script;
therefore, change C and i386/amd64 assembler code to remove indirection
(which allowed interposition). This makes the code slightly smaller and
faster.
Also, remove #define PIC_GOT from i386/amd64 in !PIC mode. Without PIC,
there is no place containing the address of each variable, so there is no
possible definition for PIC_GOT.
Modified:
head/lib/libc/amd64/sys/setlogin.S
head/lib/libc/gen/getlogin.c
head/lib/libc/i386/sys/setlogin.S
head/sys/amd64/include/asm.h
head/sys/i386/include/asm.h
Modified: head/lib/libc/amd64/sys/setlogin.S
==============================================================================
--- head/lib/libc/amd64/sys/setlogin.S Sat Aug 17 19:23:35 2013
(r254462)
+++ head/lib/libc/amd64/sys/setlogin.S Sat Aug 17 19:24:58 2013
(r254463)
@@ -48,12 +48,7 @@ ENTRY(__sys_setlogin)
mov $SYS_setlogin,%rax
KERNCALL
jb HIDENAME(cerror)
-#ifdef PIC
- movq PIC_GOT(CNAME(_logname_valid)),%rdx
- movl $0,(%rdx)
-#else
movl $0,CNAME(_logname_valid)(%rip)
-#endif
ret /* setlogin(name) */
END(__sys_setlogin)
Modified: head/lib/libc/gen/getlogin.c
==============================================================================
--- head/lib/libc/gen/getlogin.c Sat Aug 17 19:23:35 2013
(r254462)
+++ head/lib/libc/gen/getlogin.c Sat Aug 17 19:24:58 2013
(r254463)
@@ -50,7 +50,7 @@ __FBSDID("$FreeBSD$");
extern int _getlogin(char *, int);
-int _logname_valid; /* known to setlogin() */
+int _logname_valid __hidden; /* known to setlogin() */
static pthread_mutex_t logname_mutex = PTHREAD_MUTEX_INITIALIZER;
static char *
Modified: head/lib/libc/i386/sys/setlogin.S
==============================================================================
--- head/lib/libc/i386/sys/setlogin.S Sat Aug 17 19:23:35 2013
(r254462)
+++ head/lib/libc/i386/sys/setlogin.S Sat Aug 17 19:24:58 2013
(r254463)
@@ -41,16 +41,9 @@ __FBSDID("$FreeBSD$");
.globl CNAME(_logname_valid) /* in _getlogin() */
SYSCALL(setlogin)
-#ifdef PIC
PIC_PROLOGUE
- pushl %eax
- movl PIC_GOT(CNAME(_logname_valid)),%eax
- movl $0,(%eax)
- popl %eax
+ movl $0,PIC_GOTOFF(CNAME(_logname_valid))
PIC_EPILOGUE
-#else
- movl $0,CNAME(_logname_valid)
-#endif
ret /* setlogin(name) */
END(__sys_setlogin)
Modified: head/sys/amd64/include/asm.h
==============================================================================
--- head/sys/amd64/include/asm.h Sat Aug 17 19:23:35 2013
(r254462)
+++ head/sys/amd64/include/asm.h Sat Aug 17 19:24:58 2013
(r254463)
@@ -43,7 +43,6 @@
#define PIC_GOT(x) x@GOTPCREL(%rip)
#else
#define PIC_PLT(x) x
-#define PIC_GOT(x) x
#endif
/*
Modified: head/sys/i386/include/asm.h
==============================================================================
--- head/sys/i386/include/asm.h Sat Aug 17 19:23:35 2013 (r254462)
+++ head/sys/i386/include/asm.h Sat Aug 17 19:24:58 2013 (r254463)
@@ -49,11 +49,12 @@
popl %ebx
#define PIC_PLT(x) x@PLT
#define PIC_GOT(x) x@GOT(%ebx)
+#define PIC_GOTOFF(x) x@GOTOFF(%ebx)
#else
#define PIC_PROLOGUE
#define PIC_EPILOGUE
#define PIC_PLT(x) x
-#define PIC_GOT(x) x
+#define PIC_GOTOFF(x) x
#endif
/*
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