reserve_crashkernel_cma() reserves CMA ranges for the
crash kernel. If allocating the requested size fails,
try to reserve in smaller pieces.
Store the reserved ranges in the crashk_cma_ranges array
and the number of ranges in crashk_cma_cnt.
Signed-off-by: Jiri Bohac <jbohac@xxxxxxx>
---
include/linux/crash_core.h | 9 +++++++
kernel/crash_core.c | 52 ++++++++++++++++++++++++++++++++++++++
2 files changed, 61 insertions(+)
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index f1edefcf7377..5afe3866d35a 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -14,6 +14,13 @@
extern struct resource crashk_res;
extern struct resource crashk_low_res;
+extern struct range crashk_cma_ranges[];
+#ifdef CONFIG_CMA
+extern int crashk_cma_cnt;
+#else
+#define crashk_cma_cnt 0
+#endif
+
#define CRASH_CORE_NOTE_NAME "CORE"
#define CRASH_CORE_NOTE_HEAD_BYTES ALIGN(sizeof(struct elf_note), 4)
#define CRASH_CORE_NOTE_NAME_BYTES ALIGN(sizeof(CRASH_CORE_NOTE_NAME), 4)
@@ -98,6 +105,8 @@ int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,
unsigned long long *low_size, unsigned long long *cma_size,
bool *high);
+void __init reserve_crashkernel_cma(unsigned long long cma_size);
+
#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
#ifndef DEFAULT_CRASH_KERNEL_LOW_SIZE
#define DEFAULT_CRASH_KERNEL_LOW_SIZE (128UL << 20)
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 1e952d2e451b..d71ecd59f16b 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -15,6 +15,7 @@
#include <linux/memblock.h>
#include <linux/kexec.h>
#include <linux/kmemleak.h>
+#include <linux/cma.h>
#include <asm/page.h>
#include <asm/sections.h>
@@ -475,6 +476,57 @@ void __init reserve_crashkernel_generic(char *cmdline,
}
#endif
+#ifdef CONFIG_CMA
+#define CRASHKERNEL_CMA_RANGES_MAX 4
+
+struct range crashk_cma_ranges[CRASHKERNEL_CMA_RANGES_MAX];
+int crashk_cma_cnt = 0;
+
+void __init reserve_crashkernel_cma(unsigned long long cma_size)
+{
+ unsigned long long request_size = roundup(cma_size, PAGE_SIZE);
+ unsigned long long reserved_size = 0;
+
+ while (cma_size > reserved_size &&
+ crashk_cma_cnt < CRASHKERNEL_CMA_RANGES_MAX) {
+
+ struct cma *res;
+
+ if (cma_declare_contiguous(0, request_size, 0, 0, 0, false,
+ "crashkernel", &res)) {
+ /* reservation failed, try half-sized blocks */
+ if (request_size <= PAGE_SIZE)
+ break;
+
+ request_size = roundup(request_size / 2, PAGE_SIZE);
+ continue;
+ }
+
+ crashk_cma_ranges[crashk_cma_cnt].start = cma_get_base(res);
+ crashk_cma_ranges[crashk_cma_cnt].end =
+ crashk_cma_ranges[crashk_cma_cnt].start +
+ cma_get_size(res) - 1;
+ ++crashk_cma_cnt;
+ reserved_size += request_size;
+ }
+
+ if (cma_size > reserved_size)
+ pr_warn("crashkernel CMA reservation failed: %lld MB requested, %lld MB reserved in %d ranges\n",
+ cma_size >> 20, reserved_size >> 20, crashk_cma_cnt);
+ else
+ pr_info("crashkernel CMA reserved: %lld MB in %d ranges\n",
+ reserved_size >> 20, crashk_cma_cnt);
+}
+
+#else /* CONFIG_CMA */
+struct range crashk_cma_ranges[0];
+void __init reserve_crashkernel_cma(unsigned long long cma_size)
+{
+ if (cma_size)
+ pr_warn("crashkernel CMA reservation failed: CMA disabled\n");
+}
+#endif
+
int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
void **addr, unsigned long *sz)
{
--
Jiri Bohac <jbohac@xxxxxxx>
SUSE Labs, Prague, Czechia
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