diff mbox series

[SRU,J,7/7] arm64: kdump: Support crashkernel=X fall back to reserve region above DMA zones

Message ID 20230710125612.37735-8-ioanna-maria.alifieraki@canonical.com
State New
Headers show
Series kdump fails on arm64 when offset is not specified | expand

Commit Message

Ioanna Alifieraki July 10, 2023, 12:56 p.m. UTC 
From: Zhen Lei <thunder.leizhen@huawei.com>

BugLink: https://bugs.launchpad.net/bugs/2024479

For crashkernel=X without '@offset', select a region within DMA zones
first, and fall back to reserve region above DMA zones. This allows
users to use the same configuration on multiple platforms.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Acked-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20221116121044.1690-3-thunder.leizhen@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
(cherry picked from commit a9ae89df737756d92f0e14873339cf393f7f7eb0)
Signed-off-by: Ioanna Alifieraki <ioanna-maria.alifieraki@canonical.com>
---
 Documentation/admin-guide/kernel-parameters.txt |  2 +-
 arch/arm64/mm/init.c                            | 17 ++++++++++++++++-
 2 files changed, 17 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 839be687b768..124bfb3cc870 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -784,7 +784,7 @@ 
 			memory region [offset, offset + size] for that kernel
 			image. If '@offset' is omitted, then a suitable offset
 			is selected automatically.
-			[KNL, X86-64] Select a region under 4G first, and
+			[KNL, X86-64, ARM64] Select a region under 4G first, and
 			fall back to reserve region above 4G when '@offset'
 			hasn't been specified.
 			See Documentation/admin-guide/kdump/kdump.rst for further details.
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 76ad3ea9507d..e2b41581e5cd 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -132,6 +132,7 @@  static void __init reserve_crashkernel(void)
 	unsigned long long crash_max = CRASH_ADDR_LOW_MAX;
 	char *cmdline = boot_command_line;
 	int ret;
+	bool fixed_base = false;
 
 	if (!IS_ENABLED(CONFIG_KEXEC_CORE))
 		return;
@@ -163,12 +164,26 @@  static void __init reserve_crashkernel(void)
 	crash_size = PAGE_ALIGN(crash_size);
 
 	/* User specifies base address explicitly. */
-	if (crash_base)
+	if (crash_base) {
+		fixed_base = true;
 		crash_max = crash_base + crash_size;
+	}
 
+retry:
 	crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
 					       crash_base, crash_max);
 	if (!crash_base) {
+		/*
+		 * If the first attempt was for low memory, fall back to
+		 * high memory, the minimum required low memory will be
+		 * reserved later.
+		 */
+		if (!fixed_base && (crash_max == CRASH_ADDR_LOW_MAX)) {
+			crash_max = CRASH_ADDR_HIGH_MAX;
+			crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
+			goto retry;
+		}
+
 		pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
 			crash_size);
 		return;