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SubjectRe: [PATCH 01/31] Disable const sections for PA-RISC
> > +config BROKEN_RODATA
> > + bool
> > + default y
>
> Could you please change this so we have a commonly defined HAVE_BROKEN_RODATA
> symbol. Then arch's that have broken RO data can select this symbol.
> If we experience tomorrow that sparc have the same issue then with
> this patch sparc has to create a local definition of this symbol.

Here's an updated patch with the config placed in init/Kconfig.
I'm not going to repost the whole series.

-Andi

---

Disable const sections for PA-RISC v2

The PA-RISC tool chain seems to have some problem with correct read/write
attributes on sections. This causes problems when the const sections
are fixed up for other architecture to only contain truly read-only
data.

Disable const sections for PA-RISC

This can cause a bit of noise with modpost.

v2: Move config to init/Kconfig
Cc: James.Bottomley@HansenPartnership.com
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
arch/parisc/Kconfig | 1 +
include/linux/init.h | 27 +++++++++++++++++++--------
init/Kconfig | 6 ++++++
3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 3ff21b5..77f9c81 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -19,6 +19,7 @@ config PARISC
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select GENERIC_SMP_IDLE_THREAD
select GENERIC_STRNCPY_FROM_USER
+ select BROKEN_RODATA

help
The PA-RISC microprocessor is designed by Hewlett-Packard and used
diff --git a/include/linux/init.h b/include/linux/init.h
index 5e664f6..c2f06b3 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -43,10 +43,21 @@
discard it in modules) */
#define __init __section(.init.text) __cold notrace
#define __initdata __section(.init.data)
-#define __initconst __section(.init.rodata)
+#define __initconst __constsection(.init.rodata)
#define __exitdata __section(.exit.data)
#define __exit_call __used __section(.exitcall.exit)

+/*
+ * Some architecture have tool chains which do not handle rodata attributes
+ * correctly. For those disable special sections for const, so that other
+ * architectures can annotate correctly.
+ */
+#ifdef CONFIG_BROKEN_RODATA
+#define __constsection(x)
+#else
+#define __constsection(x) __section(x)
+#endif
+
/*
* modpost check for section mismatches during the kernel build.
* A section mismatch happens when there are references from a
@@ -66,7 +77,7 @@
*/
#define __ref __section(.ref.text) noinline
#define __refdata __section(.ref.data)
-#define __refconst __section(.ref.rodata)
+#define __refconst __constsection(.ref.rodata)

/* compatibility defines */
#define __init_refok __ref
@@ -85,26 +96,26 @@
/* Used for HOTPLUG */
#define __devinit __section(.devinit.text) __cold notrace
#define __devinitdata __section(.devinit.data)
-#define __devinitconst __section(.devinit.rodata)
+#define __devinitconst __constsection(.devinit.rodata)
#define __devexit __section(.devexit.text) __exitused __cold notrace
#define __devexitdata __section(.devexit.data)
-#define __devexitconst __section(.devexit.rodata)
+#define __devexitconst __constsection(.devexit.rodata)

/* Used for HOTPLUG_CPU */
#define __cpuinit __section(.cpuinit.text) __cold notrace
#define __cpuinitdata __section(.cpuinit.data)
-#define __cpuinitconst __section(.cpuinit.rodata)
+#define __cpuinitconst __constsection(.cpuinit.rodata)
#define __cpuexit __section(.cpuexit.text) __exitused __cold notrace
#define __cpuexitdata __section(.cpuexit.data)
-#define __cpuexitconst __section(.cpuexit.rodata)
+#define __cpuexitconst __constsection(.cpuexit.rodata)

/* Used for MEMORY_HOTPLUG */
#define __meminit __section(.meminit.text) __cold notrace
#define __meminitdata __section(.meminit.data)
-#define __meminitconst __section(.meminit.rodata)
+#define __meminitconst __constsection(.meminit.rodata)
#define __memexit __section(.memexit.text) __exitused __cold notrace
#define __memexitdata __section(.memexit.data)
-#define __memexitconst __section(.memexit.rodata)
+#define __memexitconst __constsection(.memexit.rodata)

/* For assembly routines */
#define __HEAD .section ".head.text","ax"
diff --git a/init/Kconfig b/init/Kconfig
index af6c7f8..a8785db 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1612,4 +1612,10 @@ config PADATA
depends on SMP
bool

+# Can be selected by architectures with broken toolchains
+# that get confused by correct const<->read_only section
+# mappings
+config BROKEN_RODATA
+ bool
+
source "kernel/Kconfig.locks"
--
1.7.10.4


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