From: Xishi Qiu <qiuxishi@huawei.com>
To: LKML <linux-kernel@vger.kernel.org>, Linux MM <linux-mm@kvack.org>
Subject: x86: a question about protection_map
Date: Sun, 13 Dec 2015 16:41:07 +0800 [thread overview]
Message-ID: <566D2F23.4030302@huawei.com> (raw)
When we use mprotect to change the page prot, I find "__P001" and "__P011"
are the same. So how we detect the write/read?
pgprot_t protection_map[16] = {
__P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
__S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
};
pgprot_t vm_get_page_prot(unsigned long vm_flags)
{
return __pgprot(pgprot_val(protection_map[vm_flags &
(VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
pgprot_val(arch_vm_get_page_prot(vm_flags)));
}
#define __P001 PAGE_READONLY
#define __P011 PAGE_COPY
#define PAGE_COPY_NOEXEC __pgprot(_PAGE_PRESENT | _PAGE_USER | \
_PAGE_ACCESSED | _PAGE_NX)
#define PAGE_COPY PAGE_COPY_NOEXEC
#define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_USER | \
_PAGE_ACCESSED | _PAGE_NX)
Thanks,
Xishi Qiu
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reply other threads:[~2015-12-13 8:44 UTC|newest]
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