Add in my little patch for 2.4.x to make sysinfo binary compatable (again)

 -Erik


git-svn-id: svn://busybox.net/trunk/busybox@685 69ca8d6d-28ef-0310-b511-8ec308f3f277

2 files changed, 88 insertions, 0 deletions

diff --git a/examples/kernel-patches/2.4.x-revert-sysinfo.patch b/examples/kernel-patches/2.4.x-revert-sysinfo.patch
new file mode 100644
index 000000000..c7cd5a770
--- /dev/null
+++ b/examples/kernel-patches/2.4.x-revert-sysinfo.patch
@@ -0,0 +1,77 @@
+I have a version of free I wrote for BusyBox that uses sysinfo (rather then
+/proc) to get its information.  Under 2.2.x it reports normal stuff, i.e.
+    [andersen@dillweed busybox]$ ./free
+                  total         used         free       shared      buffers
+      Mem:       127800       124268         3532        16956         7544
+     Swap:       128516        13584       114932
+    Total:       256316       137852       118464
+
+while under 2.2.0-test1-ac7 it reports wierd numbers (~ #/4096)
+    [andersen@dillweed busybox]$ ./free
+                  total         used         free       shared      buffers
+      Mem:           30           11           19            0            1
+     Swap:           31            0           31
+    Total:           61           11           50
+
+After investigating the problem, it turns out that somewhere during 2.3.x the
+values for memory stored in struct sysinfo changed from being stored as bytes
+to being units of PAGE_SIZE, but kernel/info.c was never updated to reflect
+this change in definition.
+
+Breaking free isn't that big of a deal, but I also use sysinfo in init to check
+that the box has enough ram from within the init process (and no, mounting
+/proc from within init and reading /proc/meminfo is not a good solution.
+BusyBox is often used in embedded systems where /proc is not compiled in).
+
+The following patch reinstates the traditional sysinfo(2) interface by
+returning bytes (not units of PAGE_SIZE) for memory values.
+
+An additional patch suggestion (not included here) would be to eliminate the
+supurfluous "mem_unit" variable from struct_sysinfo in include/linux/kernel.h
+and arch/*/mm/init.c.
+
+ -Erik
+
+--
+Erik B. Andersen   Web:    http://www.xmission.com/~andersen/
+                   email:  andersee@debian.org
+--This message was written using 73% post-consumer electrons--
+
+--- linux/kernel/info.c.orig    Mon Aug 23 12:15:53 1999
++++ linux/kernel/info.c Sun Jun  4 01:13:11 2000
+@@ -2,6 +2,8 @@
+  * linux/kernel/info.c
+  *
+  * Copyright (C) 1992 Darren Senn
++ * Fixed to once again return bytes instead of page counts,
++ * June 2000, by Erik Andersen <andersee@debian.org>
+  */
+
+ /* This implements the sysinfo() system call */
+@@ -10,7 +12,6 @@
+ #include <linux/unistd.h>
+ #include <linux/swap.h>
+ #include <linux/smp_lock.h>
+-
+ #include <asm/uaccess.h>
+
+ asmlinkage long sys_sysinfo(struct sysinfo *info)
+@@ -31,6 +32,17 @@
+
+        si_meminfo(&val);
+        si_swapinfo(&val);
++
++       /* These are in units of PAGE_SIZE, but this interface
++        * has always returned bytes.  Make it return bytes */
++       val.totalram*=PAGE_SIZE;
++       val.freeram*=PAGE_SIZE;
++       val.sharedram*=PAGE_SIZE;
++       val.bufferram*=PAGE_SIZE;
++       val.totalswap*=PAGE_SIZE;
++       val.freeswap*=PAGE_SIZE;
++       val.totalhigh*=PAGE_SIZE;
++       val.freehigh*=PAGE_SIZE;
+
+        if (copy_to_user(info, &val, sizeof(struct sysinfo)))
+                return -EFAULT;
+
diff --git a/examples/kernel-patches/WillThisGoIntoTheKernel b/examples/kernel-patches/WillThisGoIntoTheKernel
index f67fe4a75..33ee8b47e 100644
--- a/examples/kernel-patches/WillThisGoIntoTheKernel
+++ b/examples/kernel-patches/WillThisGoIntoTheKernel
@@ -1,3 +1,14 @@
+I have been asked several times whether the devps patch will go into the
+mainline Linux kernel.  The following emails from Alan Cox and Linux Torvalds
+make it clear that it is not going to happen.  This does not mean this patch
+had no value -- it does.  It just means that those that like it get to apply it
+themselves...
+
+ -Erik
+
+
+-------------------------------
+
 From alan@lxorguk.ukuu.org.uk  Thu Apr 13 08:07:22 2000
 Return-Path: <alan@lxorguk.ukuu.org.uk>
 Delivered-To: andersen@dillweed.dsl.xmission.com