riscv: kdump: use generic interface to simplify crashkernel reservation

With the help of newly changed function parse_crashkernel() and generic
reserve_crashkernel_generic(), crashkernel reservation can be simplified
by steps:

1) Add a new header file <asm/crash_core.h>, and define CRASH_ALIGN,
   CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX and
   DEFAULT_CRASH_KERNEL_LOW_SIZE in <asm/crash_core.h>;

2) Add arch_reserve_crashkernel() to call parse_crashkernel() and
   reserve_crashkernel_generic();

3) Add ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION Kconfig in
   arch/riscv/Kconfig.

The old reserve_crashkernel_low() and reserve_crashkernel() can be
removed.

[chenjiahao16@huawei.com: fix crashkernel reserving problem on RISC-V]
  Link: https://lkml.kernel.org/r/20230925024333.730964-1-chenjiahao16@huawei.com
Link: https://lkml.kernel.org/r/20230914033142.676708-9-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Chen Jiahao <chenjiahao16@huawei.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Jiahao <chenjiahao16@huawei.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/arch/riscv/include/asm/crash_core.h b/arch/riscv/include/asm/crash_core.h
new file mode 100644
index 000000000000..e1874b23feaf
--- /dev/null
+++ b/arch/riscv/include/asm/crash_core.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _RISCV_CRASH_CORE_H
+#define _RISCV_CRASH_CORE_H
+
+#define CRASH_ALIGN			PMD_SIZE
+
+#define CRASH_ADDR_LOW_MAX		dma32_phys_limit
+#define CRASH_ADDR_HIGH_MAX		memblock_end_of_DRAM()
+
+extern phys_addr_t memblock_end_of_DRAM(void);
+#endif