[PATCH v35 01/14] memblock: add memblock_clear_nomap()

[PATCH v35 01/14] memblock: add memblock_clear_nomap()

[AKASHI Takahiro]

This function, with a combination of memblock_mark_nomap(), will be used
in a later kdump patch for arm64 when it temporarily isolates some range
of memory from the other memory blocks in order to create a specific
kernel mapping at boot time.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 include/linux/memblock.h |  1 +
 mm/memblock.c            | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index bdfc65af4152..e82daffcfc44 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -93,6 +93,7 @@ int memblock_mark_hotplug(phys_addr_t base, phys_addr_t size);
 int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size);
 int memblock_mark_mirror(phys_addr_t base, phys_addr_t size);
 int memblock_mark_nomap(phys_addr_t base, phys_addr_t size);
+int memblock_clear_nomap(phys_addr_t base, phys_addr_t size);
 ulong choose_memblock_flags(void);
 
 /* Low level functions */
diff --git a/mm/memblock.c b/mm/memblock.c
index 696f06d17c4e..2f4ca8104ea4 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -805,6 +805,18 @@ int __init_memblock memblock_mark_nomap(phys_addr_t base, phys_addr_t size)
 }
 
 /**
+ * memblock_clear_nomap - Clear flag MEMBLOCK_NOMAP for a specified region.
+ * @base: the base phys addr of the region
+ * @size: the size of the region
+ *
+ * Return 0 on success, -errno on failure.
+ */
+int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size)
+{
+	return memblock_setclr_flag(base, size, 0, MEMBLOCK_NOMAP);
+}
+
+/**
  * __next_reserved_mem_region - next function for for_each_reserved_region()
  * @idx: pointer to u64 loop variable
  * @out_start: ptr to phys_addr_t for start address of the region, can be %NULL
-- 
2.11.1

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH v35 02/14] memblock: add memblock_cap_memory_range()

[AKASHI Takahiro]

Add memblock_cap_memory_range() which will remove all the memblock regions
except the memory range specified in the arguments. In addition, rework is
done on memblock_mem_limit_remove_map() to re-implement it using
memblock_cap_memory_range().

This function, like memblock_mem_limit_remove_map(), will not remove
memblocks with MEMMAP_NOMAP attribute as they may be mapped and accessed
later as "device memory."
See the commit a571d4eb55d8 ("mm/memblock.c: add new infrastructure to
address the mem limit issue").

This function is used, in a succeeding patch in the series of arm64 kdump
suuport, to limit the range of usable memory, or System RAM, on crash dump
kernel.
(Please note that "mem=" parameter is of little use for this purpose.)

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Dennis Chen <dennis.chen@arm.com>
Cc: linux-mm@kvack.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 include/linux/memblock.h |  1 +
 mm/memblock.c            | 44 +++++++++++++++++++++++++++++---------------
 2 files changed, 30 insertions(+), 15 deletions(-)

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index e82daffcfc44..4ce24a376262 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -336,6 +336,7 @@ phys_addr_t memblock_mem_size(unsigned long limit_pfn);
 phys_addr_t memblock_start_of_DRAM(void);
 phys_addr_t memblock_end_of_DRAM(void);
 void memblock_enforce_memory_limit(phys_addr_t memory_limit);
+void memblock_cap_memory_range(phys_addr_t base, phys_addr_t size);
 void memblock_mem_limit_remove_map(phys_addr_t limit);
 bool memblock_is_memory(phys_addr_t addr);
 int memblock_is_map_memory(phys_addr_t addr);
diff --git a/mm/memblock.c b/mm/memblock.c
index 2f4ca8104ea4..b049c9b2dba8 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1543,11 +1543,37 @@ void __init memblock_enforce_memory_limit(phys_addr_t limit)
 			      (phys_addr_t)ULLONG_MAX);
 }
 
+void __init memblock_cap_memory_range(phys_addr_t base, phys_addr_t size)
+{
+	int start_rgn, end_rgn;
+	int i, ret;
+
+	if (!size)
+		return;
+
+	ret = memblock_isolate_range(&memblock.memory, base, size,
+						&start_rgn, &end_rgn);
+	if (ret)
+		return;
+
+	/* remove all the MAP regions */
+	for (i = memblock.memory.cnt - 1; i >= end_rgn; i--)
+		if (!memblock_is_nomap(&memblock.memory.regions[i]))
+			memblock_remove_region(&memblock.memory, i);
+
+	for (i = start_rgn - 1; i >= 0; i--)
+		if (!memblock_is_nomap(&memblock.memory.regions[i]))
+			memblock_remove_region(&memblock.memory, i);
+
+	/* truncate the reserved regions */
+	memblock_remove_range(&memblock.reserved, 0, base);
+	memblock_remove_range(&memblock.reserved,
+			base + size, (phys_addr_t)ULLONG_MAX);
+}
+
 void __init memblock_mem_limit_remove_map(phys_addr_t limit)
 {
-	struct memblock_type *type = &memblock.memory;
 	phys_addr_t max_addr;
-	int i, ret, start_rgn, end_rgn;
 
 	if (!limit)
 		return;
@@ -1558,19 +1584,7 @@ void __init memblock_mem_limit_remove_map(phys_addr_t limit)
 	if (max_addr == (phys_addr_t)ULLONG_MAX)
 		return;
 
-	ret = memblock_isolate_range(type, max_addr, (phys_addr_t)ULLONG_MAX,
-				&start_rgn, &end_rgn);
-	if (ret)
-		return;
-
-	/* remove all the MAP regions above the limit */
-	for (i = end_rgn - 1; i >= start_rgn; i--) {
-		if (!memblock_is_nomap(&type->regions[i]))
-			memblock_remove_region(type, i);
-	}
-	/* truncate the reserved regions */
-	memblock_remove_range(&memblock.reserved, max_addr,
-			      (phys_addr_t)ULLONG_MAX);
+	memblock_cap_memory_range(0, max_addr);
 }
 
 static int __init_memblock memblock_search(struct memblock_type *type, phys_addr_t addr)
-- 
2.11.1

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [PATCH v35 02/14] memblock: add memblock_cap_memory_range()

[Catalin Marinas]

On Mon, Apr 03, 2017 at 11:23:55AM +0900, AKASHI Takahiro wrote:
> Add memblock_cap_memory_range() which will remove all the memblock regions
> except the memory range specified in the arguments. In addition, rework is
> done on memblock_mem_limit_remove_map() to re-implement it using
> memblock_cap_memory_range().
> 
> This function, like memblock_mem_limit_remove_map(), will not remove
> memblocks with MEMMAP_NOMAP attribute as they may be mapped and accessed
> later as "device memory."
> See the commit a571d4eb55d8 ("mm/memblock.c: add new infrastructure to
> address the mem limit issue").
> 
> This function is used, in a succeeding patch in the series of arm64 kdump
> suuport, to limit the range of usable memory, or System RAM, on crash dump
> kernel.
> (Please note that "mem=" parameter is of little use for this purpose.)
> 
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> Reviewed-by: Will Deacon <will.deacon@arm.com>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> Acked-by: Dennis Chen <dennis.chen@arm.com>
> Cc: linux-mm@kvack.org
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  include/linux/memblock.h |  1 +
>  mm/memblock.c            | 44 +++++++++++++++++++++++++++++---------------
>  2 files changed, 30 insertions(+), 15 deletions(-)

Andrew, are you ok with patches 1 and 2 in this series (touching
mm/memblock.c and include/linux/memblock.h) to go in via the arm64 tree?

Thanks.

-- 
Catalin

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>