Re: [PATCH v7 2/4] mm: Introduce memblock_isolate_memory
From: Mike Rapoport <rppt@kernel.org>
Date: 2023-03-12 09:36:06
Also in:
linux-devicetree, linux-mm, linux-riscv, lkml
Hi Alexandre, On Fri, Mar 10, 2023 at 10:45:37AM +0100, Alexandre Ghiti wrote:
quoted hunk ↗ jump to hunk
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;
Generally, it's possible that either start_rgn or end_rgn will be a valid pointer and this should be handled here and below. My preference, though would be to leave memblock_isolate_range() as is and have unused start_rgn and end_rgn in memblock_isolate_memory().
quoted hunk ↗ jump to hunk
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
I think it'd better to use "... range in 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.
Please elaborate that isolate means that the range does not share regions with other ranges.
+ *
+ * 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-- Sincerely yours, Mike. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel