[PATCH v1 1/8] s390/kdump: Enable crashkernel CMA infrastructure

[Mikhail Zaslonko]

Select ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION to build the generic
crashkernel CMA code: reserve_crashkernel_cma() and crashk_cma_ranges[].

s390 keeps its own reserve_crashkernel(), the CRASH_* definitions in the
new asm/crash_reserve.h are only there to satisfy the generic header.
arch_add_crash_res_to_iomem() returns false because setup_resources()
already inserts the crashkernel resource.

Signed-off-by: Mikhail Zaslonko <zaslonko@xxxxxxxxxxxxx>
---
 arch/s390/Kconfig                     |  3 +++
 arch/s390/include/asm/crash_reserve.h | 24 ++++++++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 arch/s390/include/asm/crash_reserve.h

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 7138d923d86f..1a99fcf520bf 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -331,6 +331,9 @@ config ARCH_SUPPORTS_CRASH_DUMP
 	  This option also enables s390 zfcpdump.
 	  See also <file:Documentation/arch/s390/zfcpdump.rst>
 
+config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
+	def_bool CRASH_RESERVE
+
 config ARCH_DEFAULT_CRASH_DUMP
 	def_bool y
 
diff --git a/arch/s390/include/asm/crash_reserve.h b/arch/s390/include/asm/crash_reserve.h
new file mode 100644
index 000000000000..7e04db630bc6
--- /dev/null
+++ b/arch/s390/include/asm/crash_reserve.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_S390_CRASH_RESERVE_H
+#define _ASM_S390_CRASH_RESERVE_H
+/*
+ * s390 crashkernel alignment and address limits.
+ */
+
+#define CRASH_ALIGN		HPAGE_SIZE	/* matches KEXEC_CRASH_MEM_ALIGN */
+
+#define CRASH_ADDR_LOW_MAX	(4UL << 30)	/* 4 GB */
+#define CRASH_ADDR_HIGH_MAX	ULONG_MAX
+
+/*
+ * s390 keeps its own reserve_crashkernel() and manages its own
+ * iomem resources via setup_resources(). Prevent the generic
+ * insert_crashkernel_resources() from inserting duplicates.
+ */
+#define arch_add_crash_res_to_iomem arch_add_crash_res_to_iomem
+static inline bool arch_add_crash_res_to_iomem(void)
+{
+	return false;
+}
+
+#endif /* _ASM_S390_CRASH_RESERVE_H */
-- 
2.55.0