linuxppc-dev.lists.ozlabs.org archive mirror
 help / color / mirror / Atom feed
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au
Cc: linuxppc-dev@lists.ozlabs.org,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Subject: [PATCH 03/65] powerpc/mm/subpage: Clear RWX bit to indicate no access
Date: Sun, 27 Mar 2016 13:53:11 +0530	[thread overview]
Message-ID: <1459067053-10835-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com> (raw)
In-Reply-To: <1459067053-10835-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>

Subpage protection used to depend on _PAGE_USER bit to implement no
access mode. This patch switch that to use _PAGE_RWX. We clear READ,
Write and Execute access from pte instead of clearing _PAGE_USER now.
This was done so that we can switch to _PAGE_PRIVILEGED in later patch.
subpage_protection() returns pte bits that need to be cleared.
Instead of updating the interface to handle no-access in a separate way,
it appears simple to clear RWX acecss to indicate no access.

We still don't insert hash pte for no access implied by !_PAGE_RWX.
Hence we should not get PROT_FAULT with change.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/hash_utils_64.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index ea23403b3fc0..ec37f4b0a8ff 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -917,7 +917,7 @@ void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
  * Userspace sets the subpage permissions using the subpage_prot system call.
  *
  * Result is 0: full permissions, _PAGE_RW: read-only,
- * _PAGE_USER or _PAGE_USER|_PAGE_RW: no access.
+ * _PAGE_RWX: no access.
  */
 static int subpage_protection(struct mm_struct *mm, unsigned long ea)
 {
@@ -943,8 +943,13 @@ static int subpage_protection(struct mm_struct *mm, unsigned long ea)
 	/* extract 2-bit bitfield for this 4k subpage */
 	spp >>= 30 - 2 * ((ea >> 12) & 0xf);
 
-	/* turn 0,1,2,3 into combination of _PAGE_USER and _PAGE_RW */
-	spp = ((spp & 2) ? _PAGE_USER : 0) | ((spp & 1) ? _PAGE_RW : 0);
+	/*
+	 * 0 -> full premission
+	 * 1 -> Read only
+	 * 2 -> no access.
+	 * We return the flag that need to be cleared.
+	 */
+	spp = ((spp & 2) ? _PAGE_RWX : 0) | ((spp & 1) ? _PAGE_WRITE : 0);
 	return spp;
 }
 
-- 
2.5.0

  parent reply	other threads:[~2016-03-27  8:24 UTC|newest]

Thread overview: 92+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-27  8:23 [PATCH 01/65] powerpc/mm: Use big endian page table for book3s 64 Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 02/65] powerpc/mm: use _PAGE_READ to indicate Read access Aneesh Kumar K.V
2016-03-27 15:35   ` Ian Munsie
2016-03-31  0:57   ` Balbir Singh
2016-04-04 14:55     ` Aneesh Kumar K.V
2016-04-05  3:25       ` Balbir Singh
2016-03-27  8:23 ` Aneesh Kumar K.V [this message]
2016-03-31  1:42   ` [PATCH 03/65] powerpc/mm/subpage: Clear RWX bit to indicate no access Balbir Singh
2016-04-04 14:59     ` Aneesh Kumar K.V
2016-04-05  3:30       ` Balbir Singh
2016-03-27  8:23 ` [PATCH 04/65] powerpc/mm: Use pte_user instead of opencoding Aneesh Kumar K.V
2016-03-31  1:45   ` Balbir Singh
2016-04-04 15:00     ` Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 05/65] powerpc/mm: Replace _PAGE_USER with _PAGE_PRIVILEGED Aneesh Kumar K.V
2016-03-27 15:41   ` Ian Munsie
2016-03-27  8:23 ` [PATCH 06/65] powerpc/cxl: Use REGION_ID instead of opencoding Aneesh Kumar K.V
2016-03-27 15:48   ` Ian Munsie
2016-03-27  8:23 ` [PATCH 07/65] powerpc/mm: Remove RPN_SHIFT and RPN_SIZE Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 08/65] powerpc/mm: Update _PAGE_KERNEL_RO Aneesh Kumar K.V
2016-04-05  7:45   ` Balbir Singh
2016-03-27  8:23 ` [PATCH 09/65] powerpc/mm: Use helper for finding pte bits mapping I/O area Aneesh Kumar K.V
2016-04-05 11:47   ` Balbir Singh
2016-03-27  8:23 ` [PATCH 10/65] powerpc/mm: Drop WIMG in favour of new constants Aneesh Kumar K.V
2016-04-05 13:25   ` Balbir Singh
2016-03-27  8:23 ` [PATCH 11/65] powerpc/mm: Use generic version of pmdp_clear_flush_young Aneesh Kumar K.V
2016-04-05 23:51   ` Balbir Singh
2016-03-27  8:23 ` [PATCH 12/65] powerpc/mm: Use generic version of ptep_clear_flush_young Aneesh Kumar K.V
2016-04-05 23:53   ` Balbir Singh
2016-03-27  8:23 ` [PATCH 13/65] powerpc/mm: Move common data structure between radix and hash to book3s 64 generic headers Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 14/65] powerpc/mm/power9: Add partition table format Aneesh Kumar K.V
2016-04-06  6:11   ` Balbir Singh
2016-03-27  8:23 ` [PATCH 15/65] powerpc/mm/hash: Add support for POWER9 hash Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 16/65] powerpc/mm: Move hash and no hash code to separate files Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 17/65] powerpc/mm/book3s: Rename hash specific PTE bits to carry H_ prefix Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 18/65] powerpc/mm: Handle _PTE_NONE_MASK Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 19/65] powerpc/mm: Move common pte bits and accessors to book3s/64/pgtable.h Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 20/65] powerpc/mm: Move pte accessors that operate on common pte bits to pgtable.h Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 21/65] powerpc/mm: Make page table size a variable Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 22/65] powerpc/mm: Move page table index and and vaddr to pgtable.h Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 23/65] powerpc/mm: Move pte related function together Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 24/65] powerpc/mm/radix: Add radix pte defines Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 25/65] powerpc/mm/radix: Dummy radix_enabled() Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 26/65] powerpc/mm: Add radix callbacks to pte accessors Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 27/65] powerpc/mm: Move hugetlb and THP related pmd accessors to pgtable.h Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 28/65] powerpc/mm/radix: Add radix callback for pmd accessors Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 29/65] powerpc/mm: Abstraction for early init routines Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 30/65] powerpc/mm/radix: Add radix callback " Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 31/65] powerpc/mm: Abstraction for vmemmap and map_kernel_page Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 32/65] powerpc/mm/radix: Add radix callback for vmemmap and map_kernel page Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 33/65] powerpc/mm: Abstraction for switch_mmu_context Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 34/65] powerpc/mm/radix: Add mmu context handling callback for radix Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 35/65] powerpc/mm: Rename mmu_context_hash64.c to mmu_context_book3s64.c Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 36/65] powerpc/mm: Hash linux abstraction for tlbflush routines Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 37/65] powerpc/mm/radix: Add " Aneesh Kumar K.V
2016-03-27 10:00   ` kbuild test robot
2016-03-28 17:58     ` Aneesh Kumar K.V
2016-03-27 10:09   ` kbuild test robot
2016-03-27 10:11   ` kbuild test robot
2016-03-27  8:23 ` [PATCH 38/65] powerpc/mm/radix: Add MMU_FTR_RADIX Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 39/65] powerpc/mm/radix: Use STD_MMU_64 to properly isolate hash related code Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 40/65] powerpc/mm/radix: Isolate hash table function from pseries guest code Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 41/65] powerpc/mm/radix: Add checks in slice code to catch radix usage Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 42/65] powerpc/mm/radix: Limit paca allocation in radix Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 43/65] powerpc/mm/radix: Pick the address layout for radix config Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 44/65] powerpc/mm/radix: Update secondary PTCR Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 45/65] powerpc/mm: Make a copy of pgalloc.h for 32 and 64 book3s Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 46/65] powerpc/mm: revert changes made to generic pgalloc-64.h Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 47/65] powerpc/mm: Copy pgalloc (part 2) Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 48/65] powerpc/mm: Simplify the code dropping 4 level table #ifdef Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 49/65] powerpc/mm: Rename function to indicate we are allocating fragments Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 50/65] powerpc/mm: make 4k and 64k use pte_t for pgtable_t Aneesh Kumar K.V
2016-03-27  8:23 ` [PATCH 51/65] powerpc/mm: Add radix pgalloc details Aneesh Kumar K.V
2016-03-27  8:24 ` [PATCH 52/65] powerpc/mm: Update pte filter for radix Aneesh Kumar K.V
2016-03-27  8:24 ` [PATCH 53/65] powerpc/mm: VMALLOC abstraction Aneesh Kumar K.V
2016-03-27  8:24 ` [PATCH 54/65] powerpc/radix: update mmu cache Aneesh Kumar K.V
2016-03-27  8:24 ` [PATCH 55/65] powerpc/mm: pte_frag abstraction Aneesh Kumar K.V
2016-03-27  8:24 ` [PATCH 56/65] powerpc/mm: Fix vma_mmu_pagesize for radix Aneesh Kumar K.V
2016-03-27  8:24 ` [PATCH 57/65] powerpc/mm: Add radix support for hugetlb Aneesh Kumar K.V
2016-03-27  8:24 ` [PATCH 58/65] powerpc/mm/radix: Make sure swapper pgdir is properly aligned Aneesh Kumar K.V
2016-03-27  8:24 ` [PATCH 59/65] powerpc/mm/radix: Add hugetlb support 4K page size Aneesh Kumar K.V
2016-03-27  8:24 ` [PATCH 60/65] powerpc/mm: Drop PTE_ATOMIC_UPDATES from pmd_hugepage_update Aneesh Kumar K.V
2016-03-27  8:24 ` [PATCH 61/65] powerpc/mm: THP is only available on hash64 as of now Aneesh Kumar K.V
2016-03-27  8:24 ` [PATCH 62/65] powerpc/mm/thp: Abstraction for THP functions Aneesh Kumar K.V
2016-03-27  8:24 ` [PATCH 63/65] powerpc/mm/radix: Add radix THP callbacks Aneesh Kumar K.V
2016-03-27  8:24 ` [PATCH 64/65] powerpc/mm/radix: Add THP support for 4k linux page size Aneesh Kumar K.V
2016-03-27  8:24 ` [PATCH 65/65] powerpc/mm/radix: Cputable update for radix Aneesh Kumar K.V
2016-03-30  1:01   ` Michael Neuling
2016-04-01  6:25   ` Michael Ellerman
2016-04-01  9:34     ` Aneesh Kumar K.V
2018-06-28 23:55       ` Benjamin Herrenschmidt
2016-03-30 10:53 ` [PATCH 01/65] powerpc/mm: Use big endian page table for book3s 64 Balbir Singh
2016-04-04 15:03   ` Aneesh Kumar K.V

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1459067053-10835-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com \
    --to=aneesh.kumar@linux.vnet.ibm.com \
    --cc=benh@kernel.crashing.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=mpe@ellerman.id.au \
    --cc=paulus@samba.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).