[PATCH]x86: make relocatable kernel work with new binutils -resend

From: Shaohua Li
Date: Sun Jan 16 2011 - 21:46:29 EST


last post is lost, resend it.

The CONFIG_RELOCATABLE is broken with new binutils, which will make boot
panic. According to Lu Hongjiu, the affected binutils are from
2.20.51.0.12 to 2.21.51.0.3, which are release since Oct 22 this year.
At least ubuntu 10.10 is using such binutils. see:
http://sourceware.org/bugzilla/show_bug.cgi?id=12327
The reason of boot panic is we have 'jiffies = jiffies_64;' in
vmlinux.lds.S. The jiffies isn't in any section. In kernel build, there
is warning saying jiffies is an absolute address and can't be
relocatable. At runtime, jiffies will have virtual address 0.

Signed-off-by: Shaohua Li<shaohua.li@xxxxxxxxx>

---
arch/x86/kernel/vmlinux.lds.S | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

Index: linux/arch/x86/kernel/vmlinux.lds.S
===================================================================
--- linux.orig/arch/x86/kernel/vmlinux.lds.S 2011-01-17 09:13:58.000000000 +0800
+++ linux/arch/x86/kernel/vmlinux.lds.S 2011-01-17 09:58:28.000000000 +0800
@@ -34,11 +34,9 @@ OUTPUT_FORMAT(CONFIG_OUTPUT_FORMAT, CONF
#ifdef CONFIG_X86_32
OUTPUT_ARCH(i386)
ENTRY(phys_startup_32)
-jiffies = jiffies_64;
#else
OUTPUT_ARCH(i386:x86-64)
ENTRY(phys_startup_64)
-jiffies_64 = jiffies;
#endif

#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
@@ -142,6 +140,11 @@ SECTIONS
CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)

DATA_DATA
+#ifdef CONFIG_X86_32
+ jiffies = jiffies_64;
+#else
+ jiffies_64 = jiffies;
+#endif
CONSTRUCTORS

/* rarely changed data like cpu maps */


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