linux-kernel - [RFC 2/3] arm64/mm: Define arch_get_addressable

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Date:   Mon, 23 Nov 2020 07:58:48 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     linux-mm@...ck.org, akpm@...ux-foundation.org, david@...hat.com
Cc:     Anshuman Khandual <anshuman.khandual@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Ard Biesheuvel <ardb@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [RFC 2/3] arm64/mm: Define arch_get_addressable_range()

This overrides arch_get_addressable_range() on arm64 platform which will be
used with recently added generic framework. It drops inside_linear_region()
and subsequent check in arch_add_memory() which are no longer required.

Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will@...nel.org>
Cc: Ard Biesheuvel <ardb@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>
Cc: David Hildenbrand <david@...hat.com>
Cc: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
---
 arch/arm64/include/asm/memory.h |  3 +++
 arch/arm64/mm/mmu.c             | 19 +++++++++++--------
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index cd61239bae8c..0ef7948eb58c 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -328,6 +328,9 @@ static inline void *phys_to_virt(phys_addr_t x)
 })
 
 void dump_mem_limit(void);
+
+#define arch_get_addressable_range arch_get_addressable_range
+struct range arch_get_addressable_range(bool need_mapping);
 #endif /* !ASSEMBLY */
 
 /*
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index ca692a815731..a6433caf337f 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1444,16 +1444,24 @@ static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size)
 	free_empty_tables(start, end, PAGE_OFFSET, PAGE_END);
 }
 
-static bool inside_linear_region(u64 start, u64 size)
+struct range arch_get_addressable_range(bool need_mapping)
 {
+	struct range memhp_range;
+
 	/*
 	 * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)]
 	 * accommodating both its ends but excluding PAGE_END. Max physical
 	 * range which can be mapped inside this linear mapping range, must
 	 * also be derived from its end points.
 	 */
-	return start >= __pa(_PAGE_OFFSET(vabits_actual)) &&
-	       (start + size - 1) <= __pa(PAGE_END - 1);
+	if (need_mapping) {
+		memhp_range.start = __pa(_PAGE_OFFSET(vabits_actual));
+		memhp_range.end =  __pa(PAGE_END - 1);
+	} else {
+		memhp_range.start = 0;
+		memhp_range.end = (1ULL << (MAX_PHYSMEM_BITS + 1)) - 1;
+	}
+	return memhp_range;
 }
 
 int arch_add_memory(int nid, u64 start, u64 size,
@@ -1461,11 +1469,6 @@ int arch_add_memory(int nid, u64 start, u64 size,
 {
 	int ret, flags = 0;
 
-	if (!inside_linear_region(start, size)) {
-		pr_err("[%llx %llx] is outside linear mapping region\n", start, start + size);
-		return -EINVAL;
-	}
-
 	if (rodata_full || debug_pagealloc_enabled())
 		flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
 
-- 
2.20.1