Use the BSR instruction on i386 to get the page shiftklibc-0.151

3 files changed, 5 insertions, 51 deletions

diff --git a/klibc/getpageshift.c b/klibc/getpageshift.c
deleted file mode 100644
index 40e857486ef29..0000000000000
--- a/klibc/getpageshift.c
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- * getpageshift.c
- *
- * Return the current page size as a shift count
- */
-
-#include <klibc/compiler.h>
-#include <sys/syscall.h>
-#include <unistd.h>
-
-int __getpageshift(void)
-{
-  static int page_shift;
-  int page_size;
-
-  if ( __likely(page_shift) )
-    return page_shift;
-
-  page_size = getpagesize();
-
-  while ( page_size > 1 ) {
-    page_shift++;
-    page_size >>= 1;
-  }
-
-  return page_shift;
-}
diff --git a/klibc/getpagesize.c b/klibc/getpagesize.c
deleted file mode 100644
index 98e814fa182b0..0000000000000
--- a/klibc/getpagesize.c
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
- * getpagesize.c
- */
-
-#include <klibc/compiler.h>
-#include <sys/syscall.h>
-#include <unistd.h>
-#include <sys/sysinfo.h>
-
-int getpagesize(void)
-{
-  static int page_size;
-  struct sysinfo si;
-  int rv;
-
-  if ( __likely(page_size) )
-    return page_size;
-
-  rv = sysinfo(&si);
-  if ( rv == -1 )
-    return -1;
-
-  return (page_size = si.mem_unit);
-}
diff --git a/klibc/libc_init.c b/klibc/libc_init.c
index 494d8cc48b930..444097db36a01 100644
--- a/klibc/libc_init.c
+++ b/klibc/libc_init.c
@@ -65,10 +65,15 @@ __noreturn __libc_init(uintptr_t *elfdata, void (*onexit)(void))
   }
 
   __page_size = page_size;
+
+#if defined(__i386__) || defined(__x86_64__)
+  asm("bsrl %1,%0" : "=r" (page_shift) : "rm" (page_size));
+#else
   while ( page_size > 1 ) {
     page_shift++;
     page_size >>= 1;
   }
+#endif
   __page_shift = page_shift;
 
   environ = envp;