linux-kernel - [PATCH 1/8] x86/dump_pagetables: Generalize address normalization

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Date:   Mon, 17 Jul 2017 01:59:47 +0300
From:   "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Andrew Morton <akpm@...ux-foundation.org>, x86@...nel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>
Cc:     Andi Kleen <ak@...ux.intel.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Andy Lutomirski <luto@...capital.net>,
        linux-arch@...r.kernel.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCH 1/8] x86/dump_pagetables: Generalize address normalization

Modify normalize_addr to handle different sizes of virtual address
space.

It's preparation for enabling 5-level paging.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
---
 arch/x86/mm/dump_pagetables.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index 0470826d2bdc..a824d575bb84 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -188,11 +188,12 @@ static void printk_prot(struct seq_file *m, pgprot_t prot, int level, bool dmsg)
  */
 static unsigned long normalize_addr(unsigned long u)
 {
-#ifdef CONFIG_X86_64
-	return (signed long)(u << 16) >> 16;
-#else
-	return u;
-#endif
+	int shift;
+	if (!IS_ENABLED(CONFIG_X86_64))
+		return u;
+
+	shift = 64 - (__VIRTUAL_MASK_SHIFT + 1);
+	return (signed long)(u << shift) >> shift;
 }
 
 /*
-- 
2.11.0