linux-kernel - Re: [RFC PATCH v2 2/3] mm: make pXd_addr_end() functions page-table entry aware

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Date:   Tue, 8 Sep 2020 16:25:30 +0200
From:   Alexander Gordeev <agordeev@...ux.ibm.com>
To:     Christophe Leroy <christophe.leroy@...roup.eu>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     Gerald Schaefer <gerald.schaefer@...ux.ibm.com>,
        Jason Gunthorpe <jgg@...pe.ca>,
        John Hubbard <jhubbard@...dia.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        linux-mm <linux-mm@...ck.org>, Paul Mackerras <paulus@...ba.org>,
        linux-sparc <sparclinux@...r.kernel.org>,
        Claudio Imbrenda <imbrenda@...ux.ibm.com>,
        Will Deacon <will@...nel.org>,
        linux-arch <linux-arch@...r.kernel.org>,
        linux-s390 <linux-s390@...r.kernel.org>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Richard Weinberger <richard@....at>,
        linux-x86 <x86@...nel.org>, Russell King <linux@...linux.org.uk>,
        Christian Borntraeger <borntraeger@...ibm.com>,
        Ingo Molnar <mingo@...hat.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Arnd Bergmann <arnd@...db.de>, Jeff Dike <jdike@...toit.com>,
        linux-um <linux-um@...ts.infradead.org>,
        Borislav Petkov <bp@...en8.de>,
        Andy Lutomirski <luto@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-arm <linux-arm-kernel@...ts.infradead.org>,
        linux-power <linuxppc-dev@...ts.ozlabs.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Mike Rapoport <rppt@...nel.org>
Subject: Re: [RFC PATCH v2 2/3] mm: make pXd_addr_end() functions page-table
 entry aware

On Tue, Sep 08, 2020 at 07:14:38AM +0200, Christophe Leroy wrote:
[...]
> You forgot arch/powerpc/mm/book3s64/subpage_prot.c it seems.

If this one would be okay?

diff --git a/arch/powerpc/mm/book3s64/subpage_prot.c b/arch/powerpc/mm/book3s64/subpage_prot.c
index 60c6ea16..3690d22 100644
--- a/arch/powerpc/mm/book3s64/subpage_prot.c
+++ b/arch/powerpc/mm/book3s64/subpage_prot.c
@@ -88,6 +88,7 @@ static void hpte_flush_range(struct mm_struct *mm, unsigned long addr,
 static void subpage_prot_clear(unsigned long addr, unsigned long len)
 {
 	struct mm_struct *mm = current->mm;
+	pmd_t *pmd = pmd_off(mm, addr);
 	struct subpage_prot_table *spt;
 	u32 **spm, *spp;
 	unsigned long i;
@@ -103,8 +104,8 @@ static void subpage_prot_clear(unsigned long addr, unsigned long len)
 	limit = addr + len;
 	if (limit > spt->maxaddr)
 		limit = spt->maxaddr;
-	for (; addr < limit; addr = next) {
-		next = pmd_addr_end(addr, limit);
+	for (; addr < limit; addr = next, pmd++) {
+		next = pmd_addr_end(*pmd, addr, limit);
 		if (addr < 0x100000000UL) {
 			spm = spt->low_prot;
 		} else {
@@ -191,6 +192,7 @@ static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
 		unsigned long, len, u32 __user *, map)
 {
 	struct mm_struct *mm = current->mm;
+	pmd_t *pmd = pmd_off(mm, addr);
 	struct subpage_prot_table *spt;
 	u32 **spm, *spp;
 	unsigned long i;
@@ -236,8 +238,8 @@ static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
 	}
 
 	subpage_mark_vma_nohuge(mm, addr, len);
-	for (limit = addr + len; addr < limit; addr = next) {
-		next = pmd_addr_end(addr, limit);
+	for (limit = addr + len; addr < limit; addr = next, pmd++) {
+		next = pmd_addr_end(*pmd, addr, limit);
 		err = -ENOMEM;
 		if (addr < 0x100000000UL) {
 			spm = spt->low_prot;

Thanks!

> Christophe