linux-kernel - [PATCH 3/4] x86/mm: Cleanup pgprot_4k_2_large and pgprot_large_2

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Message-Id: <20200408152745.1565832-4-hch@lst.de>
Date:   Wed,  8 Apr 2020 17:27:44 +0200
From:   Christoph Hellwig <hch@....de>
To:     x86@...nel.org, Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 3/4] x86/mm: Cleanup pgprot_4k_2_large and pgprot_large_2_4k

Make use of lower level helpers that operate on the raw protection
values to make the code a little easier to understand, and to also
avoid extra conversions in a few callers.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 arch/x86/include/asm/pgtable_types.h | 26 +++++++++++++-------------
 arch/x86/mm/init_64.c                |  2 +-
 arch/x86/mm/pgtable.c                |  8 ++------
 3 files changed, 16 insertions(+), 20 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 75fe903124f8..a3b78d84b26a 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -488,24 +488,24 @@ static inline pgprot_t cachemode2pgprot(enum page_cache_mode pcm)
 {
 	return __pgprot(cachemode2protval(pcm));
 }
-static inline pgprot_t pgprot_4k_2_large(pgprot_t pgprot)
+static inline unsigned long protval_4k_2_large(unsigned long val)
 {
-	pgprotval_t val = pgprot_val(pgprot);
-	pgprot_t new;
-
-	pgprot_val(new) = (val & ~(_PAGE_PAT | _PAGE_PAT_LARGE)) |
+	return (val & ~(_PAGE_PAT | _PAGE_PAT_LARGE)) |
 		((val & _PAGE_PAT) << (_PAGE_BIT_PAT_LARGE - _PAGE_BIT_PAT));
-	return new;
+}
+static inline pgprot_t pgprot_4k_2_large(pgprot_t pgprot)
+{
+	return __pgprot(protval_4k_2_large(pgprot_val(pgprot)));
+}
+static inline unsigned long protval_large_2_4k(unsigned long val)
+{
+	return (val & ~(_PAGE_PAT | _PAGE_PAT_LARGE)) |
+		((val & _PAGE_PAT_LARGE) >>
+		 (_PAGE_BIT_PAT_LARGE - _PAGE_BIT_PAT));
 }
 static inline pgprot_t pgprot_large_2_4k(pgprot_t pgprot)
 {
-	pgprotval_t val = pgprot_val(pgprot);
-	pgprot_t new;
-
-	pgprot_val(new) = (val & ~(_PAGE_PAT | _PAGE_PAT_LARGE)) |
-			  ((val & _PAGE_PAT_LARGE) >>
-			   (_PAGE_BIT_PAT_LARGE - _PAGE_BIT_PAT));
-	return new;
+	return __pgprot(protval_large_2_4k(pgprot_val(pgprot)));
 }
 
 
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 0a14711d3a93..3420377c7fd9 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -367,7 +367,7 @@ static void __init __init_extra_mapping(unsigned long phys, unsigned long size,
 	pgprot_t prot;
 
 	pgprot_val(prot) = pgprot_val(PAGE_KERNEL_LARGE) |
-		pgprot_val(pgprot_4k_2_large(cachemode2pgprot(cache)));
+		protval_4k_2_large(cachemode2protval(cache));
 	BUG_ON((phys & ~PMD_MASK) || (size & ~PMD_MASK));
 	for (; size; phys += PMD_SIZE, size -= PMD_SIZE) {
 		pgd = pgd_offset_k((unsigned long)__va(phys));
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 7bd2c3a52297..edf9cea4871f 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -706,11 +706,9 @@ int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
 	if (pud_present(*pud) && !pud_huge(*pud))
 		return 0;
 
-	prot = pgprot_4k_2_large(prot);
-
 	set_pte((pte_t *)pud, pfn_pte(
 		(u64)addr >> PAGE_SHIFT,
-		__pgprot(pgprot_val(prot) | _PAGE_PSE)));
+		__pgprot(protval_4k_2_large(pgprot_val(prot) | _PAGE_PSE))));
 
 	return 1;
 }
@@ -738,11 +736,9 @@ int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
 	if (pmd_present(*pmd) && !pmd_huge(*pmd))
 		return 0;
 
-	prot = pgprot_4k_2_large(prot);
-
 	set_pte((pte_t *)pmd, pfn_pte(
 		(u64)addr >> PAGE_SHIFT,
-		__pgprot(pgprot_val(prot) | _PAGE_PSE)));
+		__pgprot(protval_4k_2_large(pgprot_val(prot)) | _PAGE_PSE)));
 
 	return 1;
 }
-- 
2.25.1