Re: [PATCH v3 8/9] riscv: kdump: use generic interface to simplify crashkernel reservation
From: chenjiahao (C)
Date: Wed Sep 20 2023 - 22:36:49 EST
On 2023/9/14 11:31, Baoquan He wrote:
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.
Hi Baoquan,
Sorry for the late response. The refactor code has unified multiple
arch via generic interface, which looks great!
However when I tested on my risc-v QEMU environment, a little problem
occurred with following messages:
[ 0.000000] crashkernel low memory reserved: 0xf8000000 - 0x100000000 (128 MB)
[ 0.000000] crashkernel reserved: 0x0000000177e00000 - 0x0000000277e00000 (4096 MB)
[ 0.000000] ------------[ cut here ]------------
[ 0.000000] WARNING: CPU: 0 PID: 0 at kernel/resource.c:779 __insert_resource+0x8e/0xd0
[ 0.000000] Modules linked in:
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 6.6.0-rc2-next-20230920 #1
[ 0.000000] Hardware name: riscv-virtio,qemu (DT)
[ 0.000000] epc : __insert_resource+0x8e/0xd0
[ 0.000000] ra : insert_resource+0x28/0x4e
[ 0.000000] epc : ffffffff80017344 ra : ffffffff8001742e sp : ffffffff81203db0
[ 0.000000] gp : ffffffff812ece98 tp : ffffffff8120dac0 t0 : ff600001f7ff2b00
[ 0.000000] t1 : 0000000000000000 t2 : 3428203030303030 s0 : ffffffff81203dc0
[ 0.000000] s1 : ffffffff81211e18 a0 : ffffffff81211e18 a1 : ffffffff81289380
[ 0.000000] a2 : 0000000277dfffff a3 : 0000000177e00000 a4 : 0000000177e00000
[ 0.000000] a5 : ffffffff81289380 a6 : 0000000277dfffff a7 : 0000000000000078
[ 0.000000] s2 : ffffffff81289380 s3 : ffffffff80a0bac8 s4 : ff600001f7ff2880
[ 0.000000] s5 : 0000000000000280 s6 : 8000000a00006800 s7 : 000000000000007f
[ 0.000000] s8 : 0000000080017038 s9 : 0000000080038ea0 s10: 0000000000000000
[ 0.000000] s11: 0000000000000000 t3 : ffffffff80a0bc00 t4 : ffffffff80a0bc00
[ 0.000000] t5 : ffffffff80a0bbd0 t6 : ffffffff80a0bc00
[ 0.000000] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000003
[ 0.000000] [<ffffffff80017344>] __insert_resource+0x8e/0xd0
[ 0.000000] ---[ end trace 0000000000000000 ]---
[ 0.000000] Failed to add a Crash kernel resource at 177e00000
The crashkernel memory has been allocated successfully, whereas
it seems failed to insert into iomem_resource. This should due to
the unique reserving logic in risc-v arch specific code, i.e.
crashk_res/crashk_low_res will be added into iomem_resource
later in init_resources(), which is not aligned with the
unified reserving logic.
My simple solution here is removing the arch specific code within
#ifdef CONFIG_KEXEC_CORE in init_resources(), which has been tested
OK with all your testcases. Or do you have any other idea?
Best regards,
Jiahao
Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
---
arch/riscv/Kconfig | 3 +
arch/riscv/include/asm/crash_core.h | 11 +++
arch/riscv/include/asm/processor.h | 2 +
arch/riscv/mm/init.c | 141 +++-------------------------
4 files changed, 27 insertions(+), 130 deletions(-)
create mode 100644 arch/riscv/include/asm/crash_core.h
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index d607ab0f7c6d..25474f8c12b7 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -694,6 +694,9 @@ config ARCH_SUPPORTS_KEXEC_PURGATORY
config ARCH_SUPPORTS_CRASH_DUMP
def_bool y
+config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
+ def_bool CRASH_CORE
+
config COMPAT
bool "Kernel support for 32-bit U-mode"
default 64BIT
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
diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
index 3e23e1786d05..441da1839c94 100644
--- a/arch/riscv/include/asm/processor.h
+++ b/arch/riscv/include/asm/processor.h
@@ -116,6 +116,8 @@ static inline void wait_for_interrupt(void)
__asm__ __volatile__ ("wfi");
}
+extern phys_addr_t dma32_phys_limit;
+
struct device_node;
int riscv_of_processor_hartid(struct device_node *node, unsigned long *hartid);
int riscv_early_of_processor_hartid(struct device_node *node, unsigned long *hartid);
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 9fe448900059..d9a4e8702864 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -65,7 +65,7 @@ extern char _start[];
void *_dtb_early_va __initdata;
uintptr_t _dtb_early_pa __initdata;
-static phys_addr_t dma32_phys_limit __initdata;
+phys_addr_t dma32_phys_limit __initdata;
static void __init zone_sizes_init(void)
{
@@ -1333,28 +1333,6 @@ static inline void setup_vm_final(void)
}
#endif /* CONFIG_MMU */
-/* Reserve 128M low memory by default for swiotlb buffer */
-#define DEFAULT_CRASH_KERNEL_LOW_SIZE (128UL << 20)
-
-static int __init reserve_crashkernel_low(unsigned long long low_size)
-{
- unsigned long long low_base;
-
- low_base = memblock_phys_alloc_range(low_size, PMD_SIZE, 0, dma32_phys_limit);
- if (!low_base) {
- pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size);
- return -ENOMEM;
- }
-
- pr_info("crashkernel low memory reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
- low_base, low_base + low_size, low_size >> 20);
-
- crashk_low_res.start = low_base;
- crashk_low_res.end = low_base + low_size - 1;
-
- return 0;
-}
-
/*
* reserve_crashkernel() - reserves memory for crash kernel
*
@@ -1362,122 +1340,25 @@ static int __init reserve_crashkernel_low(unsigned long long low_size)
* line parameter. The memory reserved is used by dump capture kernel when
* primary kernel is crashing.
*/
-static void __init reserve_crashkernel(void)
+static void __init arch_reserve_crashkernel(void)
{
- unsigned long long crash_base = 0;
- unsigned long long crash_size = 0;
- unsigned long long crash_low_size = 0;
- unsigned long search_start = memblock_start_of_DRAM();
- unsigned long search_end = (unsigned long)dma32_phys_limit;
+ unsigned long long low_size = 0;
+ unsigned long long crash_base, crash_size;
char *cmdline = boot_command_line;
- bool fixed_base = false;
bool high = false;
-
- int ret = 0;
+ int ret;
if (!IS_ENABLED(CONFIG_KEXEC_CORE))
return;
- /*
- * Don't reserve a region for a crash kernel on a crash kernel
- * since it doesn't make much sense and we have limited memory
- * resources.
- */
- if (is_kdump_kernel()) {
- pr_info("crashkernel: ignoring reservation request\n");
- return;
- }
ret = parse_crashkernel(cmdline, memblock_phys_mem_size(),
- &crash_size, &crash_base, NULL, NULL);
- if (ret == -ENOENT) {
- /* Fallback to crashkernel=X,[high,low] */
- ret = parse_crashkernel_high(cmdline, 0, &crash_size, &crash_base);
- if (ret || !crash_size)
- return;
-
- /*
- * crashkernel=Y,low is valid only when crashkernel=X,high
- * is passed.
- */
- ret = parse_crashkernel_low(cmdline, 0, &crash_low_size, &crash_base);
- if (ret == -ENOENT)
- crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
- else if (ret)
- return;
-
- search_start = (unsigned long)dma32_phys_limit;
- search_end = memblock_end_of_DRAM();
- high = true;
- } else if (ret || !crash_size) {
- /* Invalid argument value specified */
+ &crash_size, &crash_base,
+ &low_size, &high);
+ if (ret)
return;
- }
-
- crash_size = PAGE_ALIGN(crash_size);
-
- if (crash_base) {
- fixed_base = true;
- search_start = crash_base;
- search_end = crash_base + crash_size;
- }
-
- /*
- * Current riscv boot protocol requires 2MB alignment for
- * RV64 and 4MB alignment for RV32 (hugepage size)
- *
- * Try to alloc from 32bit addressible physical memory so that
- * swiotlb can work on the crash kernel.
- */
- crash_base = memblock_phys_alloc_range(crash_size, PMD_SIZE,
- search_start, search_end);
- if (crash_base == 0) {
- /*
- * For crashkernel=size[KMG]@offset[KMG], print out failure
- * message if can't reserve the specified region.
- */
- if (fixed_base) {
- pr_warn("crashkernel: allocating failed with given size@offset\n");
- return;
- }
-
- if (high) {
- /*
- * For crashkernel=size[KMG],high, if the first attempt was
- * for high memory, fall back to low memory.
- */
- search_start = memblock_start_of_DRAM();
- search_end = (unsigned long)dma32_phys_limit;
- } else {
- /*
- * For crashkernel=size[KMG], if the first attempt was for
- * low memory, fall back to high memory, the minimum required
- * low memory will be reserved later.
- */
- search_start = (unsigned long)dma32_phys_limit;
- search_end = memblock_end_of_DRAM();
- crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
- }
-
- crash_base = memblock_phys_alloc_range(crash_size, PMD_SIZE,
- search_start, search_end);
- if (crash_base == 0) {
- pr_warn("crashkernel: couldn't allocate %lldKB\n",
- crash_size >> 10);
- return;
- }
- }
-
- if ((crash_base >= dma32_phys_limit) && crash_low_size &&
- reserve_crashkernel_low(crash_low_size)) {
- memblock_phys_free(crash_base, crash_size);
- return;
- }
-
- pr_info("crashkernel: reserved 0x%016llx - 0x%016llx (%lld MB)\n",
- crash_base, crash_base + crash_size, crash_size >> 20);
- crashk_res.start = crash_base;
- crashk_res.end = crash_base + crash_size - 1;
+ reserve_crashkernel_generic(cmdline, crash_size, crash_base,
+ low_size, high);
}
void __init paging_init(void)
@@ -1495,7 +1376,7 @@ void __init misc_mem_init(void)
arch_numa_init();
sparse_init();
zone_sizes_init();
- reserve_crashkernel();
+ arch_reserve_crashkernel();
memblock_dump_all();
}