From: Mark Rutland <mark.rutland@arm.com>
Date: Mon, 25 Jan 2016 11:45:05 +0000 (+0000)
Subject: UPSTREAM: arm64: mm: avoid redundant __pa(__va(x))
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=1845f62c4eb95f0dd288ac54bba784e0acb53171;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git

UPSTREAM: arm64: mm: avoid redundant __pa(__va(x))

When we "upgrade" to a section mapping, we free any table we made
redundant by giving it back to memblock. To get the PA, we acquire the
physical address and convert this to a VA, then subsequently convert
this back to a PA.

This works currently, but will not work if the tables are not accessed
via linear map VAs (e.g. is we use fixmap slots).

This patch uses {pmd,pud}_page_paddr to acquire the PA. This avoids the
__pa(__va()) round trip, saving some work and avoiding reliance on the
linear mapping.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Bug: 30369029
Patchset: rework-pagetable

(cherry picked from commit 316b39db06718d59d82736df9fc65cf05b467cc7)
Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
Change-Id: I26ed77790b5b00a15ea09a5a23a176de5b73a002
---

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index c0a4160331f8..fa2471ac191a 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -171,7 +171,7 @@ static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
 			if (!pmd_none(old_pmd)) {
 				flush_tlb_all();
 				if (pmd_table(old_pmd)) {
-					phys_addr_t table = __pa(pte_offset_map(&old_pmd, 0));
+					phys_addr_t table = pmd_page_paddr(old_pmd);
 					if (!WARN_ON_ONCE(slab_is_available()))
 						memblock_free(table, PAGE_SIZE);
 				}
@@ -232,7 +232,7 @@ static void alloc_init_pud(struct mm_struct *mm, pgd_t *pgd,
 			if (!pud_none(old_pud)) {
 				flush_tlb_all();
 				if (pud_table(old_pud)) {
-					phys_addr_t table = __pa(pmd_offset(&old_pud, 0));
+					phys_addr_t table = pud_page_paddr(old_pud);
 					if (!WARN_ON_ONCE(slab_is_available()))
 						memblock_free(table, PAGE_SIZE);
 				}