[patch 2/2] x86 - Enhance DEBUG_RODATA support for hotplug and kprobes

From: Mathieu Desnoyers
Date: Sat Feb 02 2008 - 15:45:00 EST


Standardize DEBUG_RODATA, removing special cases for hotplug and kprobes.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
CC: Andi Kleen <andi@xxxxxxxxxxxxxx>
CC: pageexec@xxxxxxxxxxx
CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CC: Ingo Molnar <mingo@xxxxxxxxxx>
CC: H. Peter Anvin <hpa@xxxxxxxxx>
CC: Ingo Molnar <mingo@xxxxxxx>
---
arch/x86/mm/init_32.c | 24 ++++++++----------------
arch/x86/mm/init_64.c | 20 +++-----------------
2 files changed, 11 insertions(+), 33 deletions(-)

Index: linux-2.6-lttng/arch/x86/mm/init_32.c
===================================================================
--- linux-2.6-lttng.orig/arch/x86/mm/init_32.c 2008-02-02 15:33:24.000000000 -0500
+++ linux-2.6-lttng/arch/x86/mm/init_32.c 2008-02-02 15:33:34.000000000 -0500
@@ -740,25 +740,17 @@ void mark_rodata_ro(void)
unsigned long start = PFN_ALIGN(_text);
unsigned long size = PFN_ALIGN(_etext) - start;

-#ifndef CONFIG_KPROBES
-#ifdef CONFIG_HOTPLUG_CPU
- /* It must still be possible to apply SMP alternatives. */
- if (num_possible_cpus() <= 1)
-#endif
- {
- set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
- printk(KERN_INFO "Write protecting the kernel text: %luk\n",
- size >> 10);
+ set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
+ printk(KERN_INFO "Write protecting the kernel text: %luk\n",
+ size >> 10);

#ifdef CONFIG_CPA_DEBUG
- printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
- start, start+size);
- set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
+ printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
+ start, start+size);
+ set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);

- printk(KERN_INFO "Testing CPA: write protecting again\n");
- set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
-#endif
- }
+ printk(KERN_INFO "Testing CPA: write protecting again\n");
+ set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
#endif
start += size;
size = (unsigned long)__end_rodata - start;
Index: linux-2.6-lttng/arch/x86/mm/init_64.c
===================================================================
--- linux-2.6-lttng.orig/arch/x86/mm/init_64.c 2008-02-02 15:33:39.000000000 -0500
+++ linux-2.6-lttng/arch/x86/mm/init_64.c 2008-02-02 15:33:59.000000000 -0500
@@ -618,23 +618,8 @@ EXPORT_SYMBOL_GPL(rodata_test_data);

void mark_rodata_ro(void)
{
- unsigned long start = (unsigned long)_stext, end;
-
-#ifdef CONFIG_HOTPLUG_CPU
- /* It must still be possible to apply SMP alternatives. */
- if (num_possible_cpus() > 1)
- start = (unsigned long)_etext;
-#endif
-
-#ifdef CONFIG_KPROBES
- start = (unsigned long)__start_rodata;
-#endif
-
- end = (unsigned long)__end_rodata;
- start = (start + PAGE_SIZE - 1) & PAGE_MASK;
- end &= PAGE_MASK;
- if (end <= start)
- return;
+ unsigned long start = PFN_ALIGN(_stext),
+ end = PFN_ALIGN(__end_rodata);

set_memory_ro(start, (end - start) >> PAGE_SHIFT);

@@ -651,6 +636,7 @@ void mark_rodata_ro(void)
set_memory_ro(start, (end-start) >> PAGE_SHIFT);
#endif
}
+
#endif

#ifdef CONFIG_BLK_DEV_INITRD

--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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