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Commit 8d1cf34e authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt
Browse files

powerpc/mm: Tweak PTE bit combination definitions 



This patch tweaks the way some PTE bit combinations are defined, in such a
way that the 32 and 64-bit variant become almost identical and that will
make it easier to bring in a new common pte-* file for the new variant
of the Book3-E support.

The combination of bits defining access to kernel pages are now clearly
separated from the combination used by userspace and the core VM. The
resulting generated code should remain identical unless I made a mistake.

Note: While at it, I removed a non-sensical statement related to CONFIG_KGDB
in ppc_mmu_32.c which could cause kernel mappings to be user accessible when
that option is enabled. Probably something that bitrot.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 2a7d55fd

arch/powerpc/include/asm/fixmap.h

+1 −1
Original line number Diff line number Diff line
@@ -61,7 +61,7 @@ extern void __set_fixmap (enum fixed_addresses idx, 
 * Some hardware wants to get fixmapped without caching.

 */

#define set_fixmap_nocache(idx, phys) \

		__set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)

		__set_fixmap(idx, phys, PAGE_KERNEL_NCG)



#define clear_fixmap(idx) \

		__set_fixmap(idx, 0, __pgprot(0))

arch/powerpc/include/asm/pgtable-ppc32.h

+20 −21
Original line number Diff line number Diff line
@@ -144,6 +144,13 @@ extern int icache_44x_need_flush; 
#define PMD_PAGE_SIZE(pmd)	bad_call_to_PMD_PAGE_SIZE()

#endif



#ifndef _PAGE_KERNEL_RO

#define _PAGE_KERNEL_RO	0

#endif

#ifndef _PAGE_KERNEL_RW

#define _PAGE_KERNEL_RW	(_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE)

#endif



#define _PAGE_HPTEFLAGS _PAGE_HASHPTE



/* Location of the PFN in the PTE. Most platforms use the same as _PAGE_SHIFT
@@ -186,30 +193,25 @@ extern int icache_44x_need_flush; 
#else

#define _PAGE_BASE	(_PAGE_PRESENT | _PAGE_ACCESSED)

#endif

#define _PAGE_BASE_NC	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_NO_CACHE)



#define _PAGE_WRENABLE	(_PAGE_RW | _PAGE_DIRTY | _PAGE_HWWRITE)

#define _PAGE_KERNEL	(_PAGE_BASE | _PAGE_SHARED | _PAGE_WRENABLE)

#define _PAGE_KERNEL_NC	(_PAGE_BASE_NC | _PAGE_SHARED | _PAGE_WRENABLE)



#ifdef CONFIG_PPC_STD_MMU

/* On standard PPC MMU, no user access implies kernel read/write access,

 * so to write-protect kernel memory we must turn on user access */

#define _PAGE_KERNEL_RO	(_PAGE_BASE | _PAGE_SHARED | _PAGE_USER)

#else

#define _PAGE_KERNEL_RO	(_PAGE_BASE | _PAGE_SHARED)

#endif



#define _PAGE_IO	(_PAGE_KERNEL_NC | _PAGE_GUARDED)

#define _PAGE_RAM	(_PAGE_KERNEL | _PAGE_HWEXEC)

#define _PAGE_BASE_NC	(_PAGE_PRESENT | _PAGE_ACCESSED)



/* Permission masks used for kernel mappings */

#define PAGE_KERNEL	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RW)

#define PAGE_KERNEL_NC	__pgprot(_PAGE_BASE_NC | _PAGE_KERNEL_RW | \

				 _PAGE_NO_CACHE)

#define PAGE_KERNEL_NCG	__pgprot(_PAGE_BASE_NC | _PAGE_KERNEL_RW | \

				 _PAGE_NO_CACHE | _PAGE_GUARDED)

#define PAGE_KERNEL_X __pgprot(_PAGE_BASE | _PAGE_KERNEL_RW | _PAGE_EXEC)

#define PAGE_KERNEL_RO __pgprot(_PAGE_BASE | _PAGE_KERNEL_RO)

#define PAGE_KERNEL_ROX __pgprot(_PAGE_BASE | _PAGE_KERNEL_RO | _PAGE_EXEC)



#if defined(CONFIG_KGDB) || defined(CONFIG_XMON) || defined(CONFIG_BDI_SWITCH) ||\

	defined(CONFIG_KPROBES)

/* We want the debuggers to be able to set breakpoints anywhere, so

 * don't write protect the kernel text */

#define _PAGE_RAM_TEXT	_PAGE_RAM

#define PAGE_KERNEL_TEXT	PAGE_KERNEL_X

#else

#define _PAGE_RAM_TEXT	(_PAGE_KERNEL_RO | _PAGE_HWEXEC)

#define PAGE_KERNEL_TEXT	PAGE_KERNEL_ROX

#endif



#define PAGE_NONE	__pgprot(_PAGE_BASE)
@@ -220,9 +222,6 @@ extern int icache_44x_need_flush; 
#define PAGE_COPY	__pgprot(_PAGE_BASE | _PAGE_USER)

#define PAGE_COPY_X	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)



#define PAGE_KERNEL		__pgprot(_PAGE_RAM)

#define PAGE_KERNEL_NOCACHE	__pgprot(_PAGE_IO)



/*

 * The PowerPC can only do execute protection on a segment (256MB) basis,

 * not on a page basis.  So we consider execute permission the same as read.

arch/powerpc/include/asm/pgtable-ppc64.h

+29 −17
Original line number Diff line number Diff line
@@ -81,11 +81,6 @@ 
 */

#include <asm/pte-hash64.h>



/* To make some generic powerpc code happy */

#ifndef _PAGE_HWEXEC

#define _PAGE_HWEXEC		0

#endif



/* Some other useful definitions */

#define PTE_RPN_MAX	(1UL << (64 - PTE_RPN_SHIFT))

#define PTE_RPN_MASK	(~((1UL<<PTE_RPN_SHIFT)-1))
@@ -96,28 +91,44 @@ 
#define _PAGE_CHG_MASK	(PTE_RPN_MASK | _PAGE_HPTEFLAGS | _PAGE_DIRTY | \

                         _PAGE_ACCESSED | _PAGE_SPECIAL)



#define _PAGE_BASE_NC	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_PSIZE)

#define _PAGE_BASE	(_PAGE_BASE_NC | _PAGE_COHERENT)





/* __pgprot defined in arch/powerpc/include/asm/page.h */

#define PAGE_NONE	__pgprot(_PAGE_PRESENT | _PAGE_ACCESSED)



#define PAGE_SHARED	__pgprot(_PAGE_BASE | _PAGE_RW | _PAGE_USER)

#define PAGE_SHARED_X	__pgprot(_PAGE_BASE | _PAGE_RW | _PAGE_USER | _PAGE_EXEC)

/* Permission masks used to generate the __P and __S table,

 *

 * Note:__pgprot is defined in arch/powerpc/include/asm/page.h

 */

#define PAGE_NONE	__pgprot(_PAGE_BASE)

#define PAGE_SHARED	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW)

#define PAGE_SHARED_X	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_EXEC)

#define PAGE_COPY	__pgprot(_PAGE_BASE | _PAGE_USER)

#define PAGE_COPY_X	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)

#define PAGE_READONLY	__pgprot(_PAGE_BASE | _PAGE_USER)

#define PAGE_READONLY_X	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)

#define PAGE_KERNEL	__pgprot(_PAGE_BASE | _PAGE_WRENABLE)

#define PAGE_KERNEL_CI	__pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \

			       _PAGE_WRENABLE | _PAGE_NO_CACHE | _PAGE_GUARDED)

#define PAGE_KERNEL_EXEC __pgprot(_PAGE_BASE | _PAGE_WRENABLE | _PAGE_EXEC)



#define PAGE_AGP	__pgprot(_PAGE_BASE | _PAGE_WRENABLE | _PAGE_NO_CACHE)

#define HAVE_PAGE_AGP

/* Permission masks used for kernel mappings */

#define PAGE_KERNEL	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RW)

#define PAGE_KERNEL_NC	__pgprot(_PAGE_BASE_NC | _PAGE_KERNEL_RW | \

				 _PAGE_NO_CACHE)

#define PAGE_KERNEL_NCG	__pgprot(_PAGE_BASE_NC | _PAGE_KERNEL_RW | \

				 _PAGE_NO_CACHE | _PAGE_GUARDED)

#define PAGE_KERNEL_X __pgprot(_PAGE_BASE | _PAGE_KERNEL_RW | _PAGE_EXEC)

#define PAGE_KERNEL_RO __pgprot(_PAGE_BASE | _PAGE_KERNEL_RO)

#define PAGE_KERNEL_ROX __pgprot(_PAGE_BASE | _PAGE_KERNEL_RO | _PAGE_EXEC)



/* Protection bits for use by pte_pgprot() */

#define PAGE_PROT_BITS	(_PAGE_GUARDED | _PAGE_COHERENT | \

			 _PAGE_NO_CACHE | _PAGE_WRITETHRU |		\

			 _PAGE_4K_PFN | _PAGE_USER | _PAGE_RW |		\

			 _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_EXEC)





/* We always have _PAGE_SPECIAL on 64 bit */

#define __HAVE_ARCH_PTE_SPECIAL



/* Make modules code happy. We don't set RO yet */

#define PAGE_KERNEL_EXEC	PAGE_KERNEL_X



/*

 * POWER4 and newer have per page execute protection, older chips can only
@@ -395,7 +406,8 @@ static inline void pte_clear(struct mm_struct *mm, unsigned long addr, 
static inline void __ptep_set_access_flags(pte_t *ptep, pte_t entry)

{

	unsigned long bits = pte_val(entry) &

		(_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_RW | _PAGE_EXEC);

		(_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_RW |

		 _PAGE_EXEC | _PAGE_HWEXEC);

	unsigned long old, tmp;



	__asm__ __volatile__(

arch/powerpc/include/asm/pgtable.h

+4 −0
Original line number Diff line number Diff line
@@ -25,6 +25,10 @@ static inline void assert_pte_locked(struct mm_struct *mm, unsigned long addr) 
#  include <asm/pgtable-ppc32.h>

#endif



/* Special mapping for AGP */

#define PAGE_AGP	(PAGE_KERNEL_NC)

#define HAVE_PAGE_AGP



#ifndef __ASSEMBLY__



/* Insert a PTE, top-level function is out of line. It uses an inline

arch/powerpc/include/asm/pte-8xx.h

+3 −0
Original line number Diff line number Diff line
@@ -59,6 +59,9 @@ 
/* Until my rework is finished, 8xx still needs atomic PTE updates */

#define PTE_ATOMIC_UPDATES	1



/* We need to add _PAGE_SHARED to kernel pages */

#define _PAGE_KERNEL_RO	(_PAGE_SHARED)

#define _PAGE_KERNEL_RW	(_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE)



#endif /* __KERNEL__ */

#endif /*  _ASM_POWERPC_PTE_8xx_H */