Allow DEBUG_RODATA and KPROBES to co-exist
Do not mark the kernel text read only if KPROBES is in the kernel;
kprobes needs to hot-patch the kernel text to insert it's
instrumentation.
In this case, only mark the .rodata segment as read only.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Tested-by: S. P. Prasanna <prasanna@in.ibm.com>
Cc: Andi Kleen <ak@suse.de>
Cc: William Cohen <wcohen@redhat.com>
Cc: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/i386/Kconfig.debug b/arch/i386/Kconfig.debug
index 6293920..b31c080 100644
--- a/arch/i386/Kconfig.debug
+++ b/arch/i386/Kconfig.debug
@@ -49,7 +49,6 @@
config DEBUG_RODATA
bool "Write protect kernel read-only data structures"
depends on DEBUG_KERNEL
- depends on !KPROBES # temporary for 2.6.22
help
Mark the kernel read-only data as write-protected in the pagetables,
in order to catch accidental (and incorrect) writes to such const
diff --git a/arch/i386/mm/init.c b/arch/i386/mm/init.c
index b22ce8d..7135946 100644
--- a/arch/i386/mm/init.c
+++ b/arch/i386/mm/init.c
@@ -799,6 +799,7 @@
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)
@@ -808,7 +809,7 @@
size >> PAGE_SHIFT, PAGE_KERNEL_RX);
printk("Write protecting the kernel text: %luk\n", size >> 10);
}
-
+#endif
start += size;
size = (unsigned long)__end_rodata - start;
change_page_attr(virt_to_page(start),
diff --git a/arch/x86_64/Kconfig.debug b/arch/x86_64/Kconfig.debug
index 8a86775..775d211 100644
--- a/arch/x86_64/Kconfig.debug
+++ b/arch/x86_64/Kconfig.debug
@@ -9,7 +9,6 @@
config DEBUG_RODATA
bool "Write protect kernel read-only data structures"
depends on DEBUG_KERNEL
- depends on !KPROBES # temporary for 2.6.22
help
Mark the kernel read-only data as write-protected in the pagetables,
in order to catch accidental (and incorrect) writes to such const data.
diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index efb6e84..9a0e98a 100644
--- a/arch/x86_64/mm/init.c
+++ b/arch/x86_64/mm/init.c
@@ -605,6 +605,11 @@
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;