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Commit 1bcdd854 authored by Helge Deller's avatar Helge Deller Committed by Kyle McMartin
Browse files

[PARISC] Add CONFIG_DEBUG_RODATA to protect read-only data 



Add the parisc version of the "mark rodata section read only" patches.
Based on code from and Signed-off-by Arjan van de Ven
<arjan@infradead.org>, Ingo Molnar <mingo@elte.hu>, Andi Kleen <ak@muc.de>,
Andrew Morton <akpm@osdl.org>, Linus Torvalds <torvalds@osdl.org>.

Signed-off-by: default avatarHelge Deller <deller@parisc-linux.org>
Signed-off-by: default avatarKyle McMartin <kyle@parisc-linux.org>
parent a2bb214d

arch/parisc/Kconfig.debug

+10 −0
Original line number Diff line number Diff line
@@ -11,4 +11,14 @@ config DEBUG_RWLOCK 
          too many attempts.  If you suspect a rwlock problem or a kernel

          hacker asks for this option then say Y.  Otherwise say N.



config DEBUG_RODATA

       bool "Write protect kernel read-only data structures"

       depends on DEBUG_KERNEL

       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. This option may have a slight performance impact because a

         portion of the kernel code won't be covered by a TLB anymore.

         If in doubt, say "N".



endmenu

arch/parisc/hpux/entry_hpux.S

+1 −2
Original line number Diff line number Diff line
@@ -22,10 +22,9 @@ 
#include <linux/linkage.h>

#include <asm/unistd.h>



	.text



#define ENTRY_NAME(_name_) .word _name_



	.section .rodata,"a"

	.align 4

	.export hpux_call_table

	.import hpux_unimplemented_wrapper

arch/parisc/kernel/syscall.S

+2 −0
Original line number Diff line number Diff line
@@ -650,6 +650,8 @@ end_linux_gateway_page: 
#define LWS_ENTRY(_name_) .word  (lws_##_name_ - linux_gateway_page)

#endif



	.section .rodata,"a"



	.align 4096

	/* Light-weight-syscall table */

	/* Start of lws table. */

arch/parisc/mm/init.c

+14 −1
Original line number Diff line number Diff line
@@ -417,6 +417,19 @@ void free_initmem(void) 
#endif

}





#ifdef CONFIG_DEBUG_RODATA

void mark_rodata_ro(void)

{

	extern char __start_rodata, __end_rodata;

	/* rodata memory was already mapped with KERNEL_RO access rights by

           pagetable_init() and map_pages(). No need to do additional stuff here */

	printk (KERN_INFO "Write protecting the kernel read-only data: %luk\n",

		(unsigned long)(&__end_rodata - &__start_rodata) >> 10);

}

#endif





/*

 * Just an arbitrary offset to serve as a "hole" between mapping areas

 * (between top of physical memory and a potential pcxl dma mapping
@@ -685,7 +698,7 @@ static void __init pagetable_init(void) 


#ifdef CONFIG_BLK_DEV_INITRD

	if (initrd_end && initrd_end > mem_limit) {

		printk("initrd: mapping %08lx-%08lx\n", initrd_start, initrd_end);

		printk(KERN_INFO "initrd: mapping %08lx-%08lx\n", initrd_start, initrd_end);

		map_pages(initrd_start, __pa(initrd_start),

			initrd_end - initrd_start, PAGE_KERNEL);

	}

include/asm-parisc/cacheflush.h

+6 −0
Original line number Diff line number Diff line
@@ -183,4 +183,10 @@ flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr, unsigned long 
		__flush_cache_page(vma, vmaddr);



}



#ifdef CONFIG_DEBUG_RODATA

void mark_rodata_ro(void);

#endif



#endif /* _PARISC_CACHEFLUSH_H */