[RFC][PATCH] linux-2.6.4-pre1_vsyscall-gtod_B3-part3 (3/3)

[john stultz]

All,
	This patch implements the somewhat controversial vDSO hooks for
vsyscall-gtod. This makes LD_PRELOADing or changes to glibc unnecessary,
but requires that the system have a sysenter enabled glibc to see any
performance benifit. However the LD_PRELOAD method will still work as
well with this patch. This patch depends on both vsyscall-gtod_B3-part1
and vsyscall-gtod_B3-part2. 

thanks
-john

diff -Nru a/arch/i386/kernel/vsyscall-int80.S b/arch/i386/kernel/vsyscall-int80.S
--- a/arch/i386/kernel/vsyscall-int80.S	Wed Mar  3 15:40:05 2004
+++ b/arch/i386/kernel/vsyscall-int80.S	Wed Mar  3 15:40:05 2004
@@ -1,3 +1,6 @@
+#include <linux/config.h>
+#include <asm/unistd.h>
+#include <asm/vsyscall-gtod.h>
 /*
  * Code for the vsyscall page.  This version uses the old int $0x80 method.
  */
@@ -7,8 +10,26 @@
 	.type __kernel_vsyscall,@function
 __kernel_vsyscall:
 .LSTART_vsyscall:
+#ifdef CONFIG_VSYSCALL_GTOD
+	cmp $__NR_gettimeofday, %eax
+	je .Lvgettimeofday
+#endif /* CONFIG_VSYSCALL_GTOD */
 	int $0x80
 	ret
+
+#ifdef CONFIG_VSYSCALL_GTOD
+/* vsyscall-gettimeofday code */
+.Lvgettimeofday:
+	pushl %edx
+	pushl %ecx
+	pushl %ebx
+	call VSYSCALL_GTOD_START
+	popl %ebx
+	popl %ecx
+	popl %edx
+	ret
+#endif /* CONFIG_VSYSCALL_GTOD */
+
 .LEND_vsyscall:
 	.size __kernel_vsyscall,.-.LSTART_vsyscall
 	.previous
diff -Nru a/arch/i386/kernel/vsyscall-sysenter.S b/arch/i386/kernel/vsyscall-sysenter.S
--- a/arch/i386/kernel/vsyscall-sysenter.S	Wed Mar  3 15:40:05 2004
+++ b/arch/i386/kernel/vsyscall-sysenter.S	Wed Mar  3 15:40:05 2004
@@ -1,3 +1,6 @@
+#include <linux/config.h>
+#include <asm/unistd.h>
+#include <asm/vsyscall-gtod.h>
 /*
  * Code for the vsyscall page.  This version uses the sysenter instruction.
  */
@@ -7,6 +10,10 @@
 	.type __kernel_vsyscall,@function
 __kernel_vsyscall:
 .LSTART_vsyscall:
+#ifdef CONFIG_VSYSCALL_GTOD
+	cmp $__NR_gettimeofday, %eax
+	je .Lvgettimeofday
+#endif /* CONFIG_VSYSCALL_GTOD */
 	push %ecx
 .Lpush_ecx:
 	push %edx
@@ -31,6 +38,20 @@
 	pop %ecx
 .Lpop_ecx:
 	ret
+
+#ifdef CONFIG_VSYSCALL_GTOD
+/* vsyscall-gettimeofday code */
+.Lvgettimeofday:
+	pushl %edx
+	pushl %ecx
+	pushl %ebx
+	call VSYSCALL_GTOD_START
+	popl %ebx
+	popl %ecx
+	popl %edx
+	ret
+#endif /* CONFIG_VSYSCALL_GTOD */
+
 .LEND_vsyscall:
 	.size __kernel_vsyscall,.-.LSTART_vsyscall
 	.previous


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