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Date: Thu, 10 Jan 2019 14:09:36 -0700
From: Khalid Aziz <khalid.aziz@...cle.com>
To: juergh@...il.com, tycho@...ho.ws, jsteckli@...zon.de, ak@...ux.intel.com,
torvalds@...ux-foundation.org, liran.alon@...cle.com,
keescook@...gle.com, konrad.wilk@...cle.com
Cc: Juerg Haefliger <juerg.haefliger@...onical.com>,
deepa.srinivasan@...cle.com, chris.hyser@...cle.com,
tyhicks@...onical.com, dwmw@...zon.co.uk, andrew.cooper3@...rix.com,
jcm@...hat.com, boris.ostrovsky@...cle.com, kanth.ghatraju@...cle.com,
joao.m.martins@...cle.com, jmattson@...gle.com,
pradeep.vincent@...cle.com, john.haxby@...cle.com, tglx@...utronix.de,
kirill.shutemov@...ux.intel.com, hch@....de, steven.sistare@...cle.com,
kernel-hardening@...ts.openwall.com, linux-mm@...ck.org,
linux-kernel@...r.kernel.org, Tycho Andersen <tycho@...ker.com>,
Khalid Aziz <khalid.aziz@...cle.com>
Subject: [RFC PATCH v7 04/16] swiotlb: Map the buffer if it was unmapped by XPFO
From: Juerg Haefliger <juerg.haefliger@...onical.com>
v6: * guard against lookup_xpfo() returning NULL
CC: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Signed-off-by: Juerg Haefliger <juerg.haefliger@...onical.com>
Signed-off-by: Tycho Andersen <tycho@...ker.com>
Signed-off-by: Khalid Aziz <khalid.aziz@...cle.com>
---
include/linux/xpfo.h | 4 ++++
kernel/dma/swiotlb.c | 3 ++-
mm/xpfo.c | 15 +++++++++++++++
3 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/include/linux/xpfo.h b/include/linux/xpfo.h
index a39259ce0174..e38b823f44e3 100644
--- a/include/linux/xpfo.h
+++ b/include/linux/xpfo.h
@@ -35,6 +35,8 @@ void xpfo_kunmap(void *kaddr, struct page *page);
void xpfo_alloc_pages(struct page *page, int order, gfp_t gfp);
void xpfo_free_pages(struct page *page, int order);
+bool xpfo_page_is_unmapped(struct page *page);
+
#else /* !CONFIG_XPFO */
static inline void xpfo_kmap(void *kaddr, struct page *page) { }
@@ -42,6 +44,8 @@ static inline void xpfo_kunmap(void *kaddr, struct page *page) { }
static inline void xpfo_alloc_pages(struct page *page, int order, gfp_t gfp) { }
static inline void xpfo_free_pages(struct page *page, int order) { }
+static inline bool xpfo_page_is_unmapped(struct page *page) { return false; }
+
#endif /* CONFIG_XPFO */
#endif /* _LINUX_XPFO_H */
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 045930e32c0e..820a54b57491 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -396,8 +396,9 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
{
unsigned long pfn = PFN_DOWN(orig_addr);
unsigned char *vaddr = phys_to_virt(tlb_addr);
+ struct page *page = pfn_to_page(pfn);
- if (PageHighMem(pfn_to_page(pfn))) {
+ if (PageHighMem(page) || xpfo_page_is_unmapped(page)) {
/* The buffer does not have a mapping. Map it in and copy */
unsigned int offset = orig_addr & ~PAGE_MASK;
char *buffer;
diff --git a/mm/xpfo.c b/mm/xpfo.c
index bff24afcaa2e..cdbcbac582d5 100644
--- a/mm/xpfo.c
+++ b/mm/xpfo.c
@@ -220,3 +220,18 @@ void xpfo_kunmap(void *kaddr, struct page *page)
spin_unlock(&xpfo->maplock);
}
EXPORT_SYMBOL(xpfo_kunmap);
+
+bool xpfo_page_is_unmapped(struct page *page)
+{
+ struct xpfo *xpfo;
+
+ if (!static_branch_unlikely(&xpfo_inited))
+ return false;
+
+ xpfo = lookup_xpfo(page);
+ if (unlikely(!xpfo) && !xpfo->inited)
+ return false;
+
+ return test_bit(XPFO_PAGE_UNMAPPED, &xpfo->flags);
+}
+EXPORT_SYMBOL(xpfo_page_is_unmapped);
--
2.17.1
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