[PATCH v7 2/4] mm: Introduce memblock_isolate_memory
From: Alexandre Ghiti <hidden>
Date: 2023-03-10 09:48:25
Also in:
linux-devicetree, linux-mm, linux-riscv, lkml
Subsystem:
memblock and memory management initialization, memory management, the rest · Maintainers:
Mike Rapoport, Andrew Morton, Linus Torvalds
This function allows to split a region in memblock.memory and will be useful when setting up the linear mapping with STRICT_KERNEL_RWX: it allows to isolate the kernel text/rodata and then avoid to map those regions with a PUD/P4D/PGD. Signed-off-by: Alexandre Ghiti <redacted> --- include/linux/memblock.h | 1 + mm/memblock.c | 22 +++++++++++++++++++++- 2 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 50ad19662a32..2f7ef97c0da7 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h@@ -125,6 +125,7 @@ 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); +int memblock_isolate_memory(phys_addr_t base, phys_addr_t size); void memblock_free_all(void); void memblock_free(void *ptr, size_t size);
diff --git a/mm/memblock.c b/mm/memblock.c
index 25fd0626a9e7..d8cf1c9eccf0 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c@@ -753,7 +753,8 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, int idx; struct memblock_region *rgn; - *start_rgn = *end_rgn = 0; + if (start_rgn && end_rgn) + *start_rgn = *end_rgn = 0; if (!size) return 0;
@@ -795,6 +796,9 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, memblock_get_region_node(rgn), rgn->flags); } else { + if (!end_rgn || !start_rgn) + continue; + /* @rgn is fully contained, record it */ if (!*end_rgn) *start_rgn = idx;
@@ -805,6 +809,22 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, return 0; } +/** + * memblock_isolate_memory - isolate given range from memblock.memory + * @base: base of range to isolate + * @size: size of range to isolate + * + * Call memblock_isolate_range on memblock.memory to isolate the given range. + * + * Return: + * 0 on success, -errno on failure. + */ + +int __init_memblock memblock_isolate_memory(phys_addr_t base, phys_addr_t size) +{ + return memblock_isolate_range(&memblock.memory, base, size, NULL, NULL); +} + static int __init_memblock memblock_remove_range(struct memblock_type *type, phys_addr_t base, phys_addr_t size) {
--
2.37.2
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