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From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	ruscur@russell.cc
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v2 05/10] powerpc/8xx: Only define APG0 and APG1
Date: Mon, 11 Mar 2019 08:30:32 +0000 (UTC)	[thread overview]
Message-ID: <769dcafeb871ff0ab2e7a932a51e6fb125bdafed.1552292207.git.christophe.leroy@c-s.fr> (raw)
In-Reply-To: <cover.1552292207.git.christophe.leroy@c-s.fr>

Since the 8xx implements hardware page table walk assistance,
the PGD entries always point to a 4k aligned page, so the 2 upper
bits of the APG are not clobbered anymore and remain 0. Therefore
only APG0 and APG1 are used and need a definition. We set the
other APG to the lowest permission level.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
index 0a1a3fc54e54..fc5a653d5dd2 100644
--- a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
@@ -35,11 +35,11 @@
  * Then we use the APG to say whether accesses are according to Page rules or
  * "all Supervisor" rules (Access to all)
  * Therefore, we define 2 APG groups. lsb is _PMD_USER
- * 0 => No user => 01 (all accesses performed according to page definition)
+ * 0 => Kernel => 01 (all accesses performed according to page definition)
  * 1 => User => 00 (all accesses performed as supervisor iaw page definition)
- * We define all 16 groups so that all other bits of APG can take any value
+ * 2-16 => NA => 11 (all accesses performed as user iaw page definition)
  */
-#define MI_APG_INIT	0x44444444
+#define MI_APG_INIT	0x4fffffff
 
 /* The effective page number register.  When read, contains the information
  * about the last instruction TLB miss.  When MI_RPN is written, bits in
@@ -108,11 +108,11 @@
  * Then we use the APG to say whether accesses are according to Page rules or
  * "all Supervisor" rules (Access to all)
  * Therefore, we define 2 APG groups. lsb is _PMD_USER
- * 0 => No user => 01 (all accesses performed according to page definition)
+ * 0 => Kernel => 01 (all accesses performed according to page definition)
  * 1 => User => 00 (all accesses performed as supervisor iaw page definition)
- * We define all 16 groups so that all other bits of APG can take any value
+ * 2-16 => NA => 11 (all accesses performed as user iaw page definition)
  */
-#define MD_APG_INIT	0x44444444
+#define MD_APG_INIT	0x4fffffff
 
 /* The effective page number register.  When read, contains the information
  * about the last instruction TLB miss.  When MD_RPN is written, bits in
-- 
2.13.3


  parent reply	other threads:[~2019-03-11  8:30 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-11  8:30 [PATCH v2 00/10] Kernel Userspace protection for PPC32 Christophe Leroy
2019-03-11  8:30 ` [PATCH v2 01/10] powerpc/6xx: fix setup and use of SPRN_SPRG_PGDIR for hash32 Christophe Leroy
2019-03-20 13:04   ` [v2, " Michael Ellerman
2019-03-11  8:30 ` [PATCH v2 02/10] powerpc/mm: Detect bad KUAP faults (Squash of v5 series) Christophe Leroy
2019-03-11  8:30 ` [PATCH v2 03/10] powerpc/32: Remove MSR_PR test when returning from syscall Christophe Leroy
2019-04-21 14:18   ` [v2, " Michael Ellerman
2019-03-11  8:30 ` [PATCH v2 04/10] powerpc/32: Prepare for Kernel Userspace Access Protection Christophe Leroy
2019-03-11  8:30 ` Christophe Leroy [this message]
2019-03-11  8:30 ` [PATCH v2 06/10] powerpc/8xx: Add Kernel Userspace Execution Prevention Christophe Leroy
2019-03-11  8:30 ` [PATCH v2 07/10] powerpc/8xx: Add Kernel Userspace Access Protection Christophe Leroy
2019-04-18  6:53   ` Michael Ellerman
2019-03-11  8:30 ` [PATCH v2 08/10] powerpc/32s: Implement Kernel Userspace Execution Prevention Christophe Leroy
2019-03-11  8:30 ` [PATCH v2 09/10] powerpc/32s: Prepare Kernel Userspace Access Protection Christophe Leroy
2019-03-11  8:30 ` [PATCH v2 10/10] powerpc/32s: Implement " Christophe Leroy
2019-04-18  6:55   ` Michael Ellerman
2019-04-23  9:26     ` Christophe Leroy
2020-01-21 17:22     ` GCC bug ? " Christophe Leroy
2020-01-21 19:55       ` Segher Boessenkool
2020-01-22  6:52         ` Christophe Leroy
2020-01-22 13:36           ` Segher Boessenkool
2020-01-22 14:45             ` Christophe Leroy
2020-01-22  6:57         ` Christophe Leroy
2020-01-22 13:18           ` Segher Boessenkool

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