linux-kernel - [PATCH v2 2/2] PCI: Check phys_addr for pci_remap

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Date:   Sat, 31 Mar 2018 15:12:23 +0800
From:   Yisheng Xie <xieyisheng1@...wei.com>
To:     <bhelgaas@...gle.com>, <rjw@...ysocki.net>, <lenb@...nel.org>
CC:     <linux-pci@...r.kernel.org>, <linux-acpi@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <guohanjun@...wei.com>,
        <jcm@...hat.com>, <toshi.kani@....com>, <tanxiaojun@...wei.com>,
        <wangzhou1@...ilicon.com>, Yisheng Xie <xieyisheng1@...wei.com>
Subject: [PATCH v2 2/2] PCI: Check phys_addr for pci_remap_iospace

If phys_addr is not page aligned, ioremap_page_range() will align down it
when get pfn by phys_addr >> PAGE_SHIFT. An example in arm64 system with
64KB page size:

 phys_addr:  0xefff8000
 res->start: 0x0
 res->end:   0x0ffff
 PCI_IOBASE: 0xffff7fdffee00000

This will remap virtual address 0xffff7fdffee00000 to phys_addr 0xefff0000,
but what we really want is 0xefff8000, which makes later IO access to a
mess. And users may even donot know this until find some odd phenemenon.

This patch checks whether phys_addr is PAGE_ALIGNED or not to find the
primary scene.

Signed-off-by: Zhou Wang <wangzhou1@...ilicon.com>
Signed-off-by: Yisheng Xie <xieyisheng1@...wei.com>
---
 drivers/pci/pci.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index f6a4dd1..deb91f0 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3576,6 +3576,9 @@ int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
 	if (res->end > IO_SPACE_LIMIT)
 		return -EINVAL;
 
+	if (!PAGE_ALIGNED(phys_addr))
+		return -EINVAL;
+
 	return ioremap_page_range(vaddr, vaddr + resource_size(res), phys_addr,
 				  pgprot_device(PAGE_KERNEL));
 #else
-- 
1.7.12.4