[PATCH 1/3] x86: Honour passed pgprot in track_pfn_insert() and track_pfn_remap()

From	Matthew Wilcox <matthew.r.wilcox@intel.com>
Newsgroups	linux.kernel
Subject	[PATCH 1/3] x86: Honour passed pgprot in track_pfn_insert() and track_pfn_remap()
Date	2016-01-25 18:30 +0100
Message-ID	<qUT7I-7lX-5@gated-at.bofh.it> (permalink)
References	<qUT7I-7lX-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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From: Matthew Wilcox <willy@linux.intel.com>

track_pfn_insert() overwrites the pgprot that is passed in with a value
based on the VMA's page_prot.  This is a problem for people trying to
do clever things with the new vm_insert_pfn_prot() as it will simply
overwrite the passed protection flags.  If we use the current value of
the pgprot as the base, then it will behave as people are expecting.

Also fix track_pfn_remap() in the same way.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
---
 arch/x86/mm/pat.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index f4ae536..04e2e71 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -943,7 +943,7 @@ int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 			return -EINVAL;
 	}
 
-	*prot = __pgprot((pgprot_val(vma->vm_page_prot) & (~_PAGE_CACHE_MASK)) |
+	*prot = __pgprot((pgprot_val(*prot) & (~_PAGE_CACHE_MASK)) |
 			 cachemode2protval(pcm));
 
 	return 0;
@@ -959,7 +959,7 @@ int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 
 	/* Set prot based on lookup */
 	pcm = lookup_memtype(pfn_t_to_phys(pfn));
-	*prot = __pgprot((pgprot_val(vma->vm_page_prot) & (~_PAGE_CACHE_MASK)) |
+	*prot = __pgprot((pgprot_val(*prot) & (~_PAGE_CACHE_MASK)) |
 			 cachemode2protval(pcm));
 
 	return 0;
-- 
2.7.0.rc3

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[PATCH 1/3] x86: Honour passed pgprot in track_pfn_insert() and track_pfn_remap() Matthew Wilcox <matthew.r.wilcox@intel.com> - 2016-01-25 18:30 +0100
  Re: [PATCH 1/3] x86: Honour passed pgprot in track_pfn_insert() and track_pfn_remap() Andy Lutomirski <luto@amacapital.net> - 2016-01-25 18:40 +0100
    Re: [PATCH 1/3] x86: Honour passed pgprot in track_pfn_insert() and track_pfn_remap() Andy Lutomirski <luto@amacapital.net> - 2016-01-25 18:50 +0100
    Re: [PATCH 1/3] x86: Honour passed pgprot in track_pfn_insert() and  track_pfn_remap() Matthew Wilcox <willy@linux.intel.com> - 2016-01-27 05:50 +0100
      Re: [PATCH 1/3] x86: Honour passed pgprot in track_pfn_insert() and track_pfn_remap() Andy Lutomirski <luto@amacapital.net> - 2016-01-27 06:50 +0100

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