All
Well, just to fan the flames a bit, here is a patch (applies on top of
vsyscall_A1)that adds a /proc/vsyscall interface which gives the address
of the vsyscall page if its mapped in. This could be then used to help
the UML folks virtualize things, as well as give a cross platform
interface that could be used. There's probably a better place in /proc
for this, but this is just something to start from.
Let me know your thoughts.
-john
diff -Nru a/arch/i386/kernel/vsyscall.c b/arch/i386/kernel/vsyscall.c
--- a/arch/i386/kernel/vsyscall.c Tue Oct 22 18:24:42 2002
+++ b/arch/i386/kernel/vsyscall.c Tue Oct 22 18:24:42 2002
@@ -23,6 +23,7 @@
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/sched.h>
+#include <linux/proc_fs.h>
#include <asm/vsyscall.h>
#include <asm/pgtable.h>
@@ -45,7 +46,7 @@
#else
long __vxtime_sequence[2] __section_vxtime_sequence;
-
+static unsigned long vsyscall_ptr;
static inline void do_vgettimeofday(struct timeval * tv)
{
long sequence;
@@ -163,6 +164,7 @@
pm = pmd_offset(pd,(unsigned long)&__last_tsc_low);
pm->pmd |= _PAGE_USER;
+ vsyscall_ptr = (unsigned long)&vgettimeofday;
}
static int __init vsyscall_init(void)
@@ -173,7 +175,7 @@
if ((unsigned long) &vtime != VSYSCALL_ADDR(__NR_vtime))
panic("vtime link addr broken");
if (VSYSCALL_ADDR(0) != __fix_to_virt(VSYSCALL_FIRST_PAGE))
- panic("fixmap first vsyscall %lx should be %lx", __fix_to_virt(VSYSCALL_FIRST_PAGE),
+ panic("fixmap first vsyscall %lx should be %x", __fix_to_virt(VSYSCALL_FIRST_PAGE),
VSYSCALL_ADDR(0));
/* XXX: we'll also need to make sure the TSC is
@@ -193,7 +195,42 @@
printk("VSYSCALL: fixmap virt addr: 0x%lx\n",
__fix_to_virt(VSYSCALL_FIRST_PAGE));
+ init_vsyscall_proc();
return 0;
}
__initcall(vsyscall_init);
+
+
+/* /proc entry */
+#define HEX_DIGITS 8
+static int vsyscall_read_proc (char *page, char **start, off_t off,
+ int count, int *eof, void *data)
+{
+ if (count < HEX_DIGITS+1)
+ return -EINVAL;
+ return sprintf (page, "0x%08lx\n", vsyscall_ptr);
+}
+static int vsyscall_write_proc (struct file *file, const char *buffer,
+ unsigned long count, void *data)
+{
+ return count;
+}
+
+void init_vsyscall_proc (void)
+{
+ struct proc_dir_entry *entry;
+ int i;
+
+ /* create /proc/vsyscall */
+ entry = create_proc_entry("vsyscall", S_IROTH, NULL);
+
+ if (!entry)
+ return;
+
+ entry->nlink = 1;
+ entry->data = NULL;
+ entry->read_proc = vsyscall_read_proc;
+ entry->write_proc = vsyscall_write_proc;
+
+}
-
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This archive was generated by hypermail 2b29 : Wed Oct 23 2002 - 22:01:01 EST