Provide an arm64-specific implementation for arch_kexec_locate_mem_hole(),
using the resource tree instead of memblock, and respecting
the reservations added by EFI.
This ensures that kexec_file is finally reliable.
Reported-by: Moritz Fischer <mdf@xxxxxxxxxx>
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Reviewed-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
arch/arm64/kernel/kexec_image.c | 31 +++++++++++++++++++++++++------
1 file changed, 25 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c
index acf9cd251307..2a51a2ebd2b7 100644
--- a/arch/arm64/kernel/kexec_image.c
+++ b/arch/arm64/kernel/kexec_image.c
@@ -156,12 +156,31 @@ const struct kexec_file_ops kexec_image_ops = {
*/
int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf)
{
+ int ret;
+
+ /* Arch knows where to place */
+ if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
+ return 0;
+
/*
- * For the time being, kexec_file_load isn't reliable except
- * for crash kernel. Say sorry to the user.
+ * Crash kernels land in a well known place that has been
+ * reserved upfront.
+ *
+ * Normal kexec kernels can however land anywhere in memory.
+ * We have to be extra careful not to step over critical
+ * memory ranges that have been marked as reserved in the
+ * iomem resource tree (LPI and ACPI tables, among others),
+ * hence the use of the child-excluding iterator. This
+ * matches what the userspace version of kexec does.
*/
- if (kbuf->image->type != KEXEC_TYPE_CRASH)
- return -EADDRNOTAVAIL;
-
- return kexec_locate_mem_hole(kbuf);
+ if (kbuf->image->type == KEXEC_TYPE_CRASH)
+ ret = walk_iomem_res_desc(crashk_res.desc,
+ IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
+ crashk_res.start, crashk_res.end,
+ kbuf, kexec_locate_mem_hole_callback);
+ else
+ ret = walk_system_ram_excluding_child_res(0, ULONG_MAX, kbuf,
+ kexec_locate_mem_hole_callback);
+
+ return ret == 1 ? 0 : -EADDRNOTAVAIL;
}
--
2.30.2
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