Re: [PATCH v2 0/2] Linker script cleanup patches for parisc

From: Helge Deller
Date: Sun Sep 27 2009 - 18:39:57 EST


On 09/27/2009 11:25 PM, Tim Abbott wrote:
On Sun, 27 Sep 2009, Helge Deller wrote:

Tim, thanks for your work!

Sadly it broke the parisc build in two places:
a) THREAD_SIZE can't be used in the vmlinux.lds.S file
b) It generates linker errors like "local symbol 0: discarded in section
`.exit.text' from kernel/built-in.o".

Sorry about that -- I should have tried harder to get someone to test this
one, since parisc is one of the architectures for which I don't have a
cross-compiler.

No problem. It was on my todo-list to test your patch, but then it
already got merged :-)

Attached patch below fixes both issues. Tested with 32- and 64-bit parisc
kernel.

The .exit.text change looks fine.

Good.

[...]
Rather than adding a new definition in asm-offsets.c, I think it'll be
better to do something like the following to make the normal THREAD_SIZE
definition available in the linker script and other assembly files:

-Tim Abbott

parisc: Make THREAD_SIZE available to assembly files and linker scripts.

Signed-off-by: Tim Abbott<tabbott@xxxxxxxxxxx>

Yes, much better.
Acked-by: Helge Deller <deller@xxxxxx>

But with this change, the vmlinux.lds.S file needs to include
the <asm/thread_info.h> file as well. I've added the adjusted patch
to vmlinux.lds.S below.

---
arch/parisc/include/asm/thread_info.h | 10 +++++-----
1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/parisc/include/asm/thread_info.h b/arch/parisc/include/asm/thread_info.h
index ac775a7..51bca20 100644
--- a/arch/parisc/include/asm/thread_info.h
+++ b/arch/parisc/include/asm/thread_info.h
@@ -32,6 +32,11 @@ struct thread_info {
#define init_thread_info (init_thread_union.thread_info)
#define init_stack (init_thread_union.stack)

+/* how to get the thread information struct from C */
+#define current_thread_info() ((struct thread_info *)mfctl(30))
+
+#endif /* !__ASSEMBLY */
+
/* thread information allocation */

#define THREAD_SIZE_ORDER 2
@@ -40,11 +45,6 @@ struct thread_info {
#define THREAD_SIZE (PAGE_SIZE<< THREAD_SIZE_ORDER)
#define THREAD_SHIFT (PAGE_SHIFT + THREAD_SIZE_ORDER)

-/* how to get the thread information struct from C */
-#define current_thread_info() ((struct thread_info *)mfctl(30))
-
-#endif /* !__ASSEMBLY */
-
#define PREEMPT_ACTIVE_BIT 28
#define PREEMPT_ACTIVE (1<< PREEMPT_ACTIVE_BIT)


Adjusted patch to vmlinux.lds.S:

parisc: Fix linker script breakage.

Signed-off-by: Helge Deller <deller@xxxxxx>

diff --git a/arch/parisc/kernel/vmlinux.lds.S b/arch/parisc/kernel/vmlinux.lds.S
index 775be27..7fc2c3d 100644
--- a/arch/parisc/kernel/vmlinux.lds.S
+++ b/arch/parisc/kernel/vmlinux.lds.S
@@ -28,6 +28,7 @@
#include <asm/cache.h>
#include <asm/page.h>
#include <asm/asm-offsets.h>
+#include <asm/thread_info.h>

/* ld script to make hppa Linux kernel */
#ifndef CONFIG_64BIT
@@ -135,6 +136,16 @@ SECTIONS
INIT_TEXT_SECTION(16384)
INIT_DATA_SECTION(16)
+ /* we have to discard exit text and such at runtime, not link time */
+ .exit.text :
+ {
+ EXIT_TEXT
+ }
+ .exit.data :
+ {
+ EXIT_DATA
+ }
+
PERCPU(PAGE_SIZE)
. = ALIGN(PAGE_SIZE);
__init_end = .;
--
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