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[PATCH] sys_mmap2 offset argument should always be shifted 12, not PAGE_

To: Ralf Baechle <ralf@linux-mips.org>
Subject: [PATCH] sys_mmap2 offset argument should always be shifted 12, not PAGE_SHIFT
From: "H. Peter Anvin" <hpa@zytor.com>
Date: Fri, 24 Feb 2006 21:20:29 -0800
Cc: linux-mips@linux-mips.org
Original-recipient: rfc822;linux-mips@linux-mips.org
Sender: linux-mips-bounce@linux-mips.org
User-agent: Mozilla Thunderbird 1.0.7-1.1.fc4 (X11/20050929)
This patch adjusts the offset argument passed into sys_mmap2 to be always shifted 12, even when the native page size isn't 4K. This is what all existing userspace libraries expect.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
index 5f68b22..72ea5d5 100644
--- a/arch/mips/kernel/linux32.c
+++ b/arch/mips/kernel/linux32.c
@@ -106,6 +106,10 @@ sys32_mmap2(unsigned long addr, unsigned
        unsigned long error;
 
        error = -EINVAL;
+       if (pgoff & (~PAGE_MASK >> 12))
+               goto out;
+       pgoff >>= PAGE_SHIFT-12;
+
        if (!(flags & MAP_ANONYMOUS)) {
                error = -EBADF;
                file = fget(fd);
diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
index 1da2eeb..1d284fb 100644
--- a/arch/mips/kernel/syscall.c
+++ b/arch/mips/kernel/syscall.c
@@ -162,7 +162,10 @@ asmlinkage unsigned long
 sys_mmap2(unsigned long addr, unsigned long len, unsigned long prot,
           unsigned long flags, unsigned long fd, unsigned long pgoff)
 {
-       return do_mmap2(addr, len, prot, flags, fd, pgoff);
+       if (pgoff & (~PAGE_MASK >> 12))
+               return -EINVAL;
+
+       return do_mmap2(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
 }
 
 save_static_function(sys_fork);
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