linux_dsm_epyc7002/arch/powerpc
Christophe Leroy ca8afd4046 powerpc/hugetlb: fix page rights verification in gup_hugepte()
gup_hugepte() checks if pages are present and readable, and
when  'write' is set, also checks if the pages are writable.

Initially this was done by checking if _PAGE_PRESENT and
_PAGE_READ were set. In addition, _PAGE_WRITE was verified for write
accesses.

The problem is that we have to handle the three following cases:
1/ The target defines __PAGE_READ and __PAGE_WRITE
2/ The target defines __PAGE_RW
3/ The target defines __PAGE_RO

In case 1/, this is obvious
In case 2/, __PAGE_READ is defined as 0 and __PAGE_WRITE as __PAGE_RW
so it works as well.
But in case 3, __PAGE_RW is defined as 0, which means __PAGE_WRITE is 0
and then the test returns true (page writable) in all cases.

A first correction was attempted in commit 6b8cb66a6a ("powerpc: Fix
usage of _PAGE_RO in hugepage"), but that fix is wrong:
instead of checking that the page is writable when write is requested,
it checks that the page is NOT writable when write is NOT requested.

This patch adds a new pte_read() helper to check whether a page is
readable or not. This avoids handling all possible cases in
gup_hugepte().

Then gup_hugepte() is modified to use pte_present(), pte_read()
and pte_write() instead of the raw flags.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-15 22:55:58 +10:00
..
boot powerpc/8xx: Getting rid of remaining use of CONFIG_8xx 2017-08-10 23:32:12 +10:00
configs powerpc/44x/fsp2: Enable eMMC arasan for fsp2 platform 2017-08-10 22:30:04 +10:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-05-02 15:53:46 -07:00
include powerpc/hugetlb: fix page rights verification in gup_hugepte() 2017-08-15 22:55:58 +10:00
kernel powerpc/mm: Implement STRICT_KERNEL_RWX on PPC32 2017-08-15 22:55:57 +10:00
kvm powerpc/mm: Update definitions of DSISR bits 2017-08-03 16:06:43 +10:00
lib powerpc/lib/sstep: Add isel instruction emulation 2017-08-10 22:30:29 +10:00
math-emu Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
mm powerpc/hugetlb: fix page rights verification in gup_hugepte() 2017-08-15 22:55:58 +10:00
net bpf: Add jited_len to struct bpf_prog 2017-06-06 15:41:24 -04:00
oprofile ktime: Cleanup ktime_set() usage 2016-12-25 17:21:22 +01:00
perf powerpc/perf/imc: Fix nest events on muti socket system 2017-08-15 20:27:28 +10:00
platforms powerpc/chrp: Store the intended structure 2017-08-15 21:13:13 +10:00
purgatory powerpc: Fix invalid use of register expressions 2017-08-10 22:29:41 +10:00
sysdev powerpc/xmon: Exclude all of xmon from ftrace 2017-08-15 15:30:17 +10:00
tools powerpc/64: Tool to check head sections location sanity 2017-05-30 14:59:51 +10:00
xmon powerpc/xmon: Exclude all of xmon from ftrace 2017-08-15 15:30:17 +10:00
Kconfig powerpc/mm: Implement STRICT_KERNEL_RWX on PPC32 2017-08-15 22:55:57 +10:00
Kconfig.debug powerpc/xmon: Enable disassembly files (compilation changes) 2017-02-15 20:02:42 +11:00
Makefile powerpc/8xx: Getting rid of remaining use of CONFIG_8xx 2017-08-10 23:32:12 +10:00
Makefile.postlink powerpc/64: Tool to check head sections location sanity 2017-05-30 14:59:51 +10:00