[PATCH 6/8] arm64: kdump: use generic interface to simplify crashkernel reservation

Baoquan He
2023-08-27T10:12:36Z

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

1) Provide CRASH_ALIGN, CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX and
DEFAULT_CRASH_KERNEL_LOW_SIZE in <asm/kexec.h>;

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

3) Add ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION Kconfig in
arch/arm64/Kconfig.

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

Signed-off-by: Baoquan He <bhe@redhat.com>
---
arch/arm64/Kconfig | 3 +
arch/arm64/include/asm/kexec.h | 5 ++
arch/arm64/mm/init.c | 140 ++-------------------------------
3 files changed, 16 insertions(+), 132 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index a2511b30d0f6..6739e7b456b9 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1481,6 +1481,9 @@ config KEXEC_FILE
for kernel and initramfs as opposed to list of segments as
accepted by previous system call.

+config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
+ def_bool CRASH_CORE
+
config KEXEC_SIG
bool "Verify kernel signature during kexec_file_load() syscall"
depends on KEXEC_FILE
diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 9ac9572a3bbe..442fc13588a2 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -132,4 +132,9 @@ extern int load_other_segments(struct kimage *image,

#endif /* __ASSEMBLY__ */

+/* Current arm64 boot protocol requires 2MB alignment */
+#define CRASH_ALIGN SZ_2M
+
+#define CRASH_ADDR_LOW_MAX arm64_dma_phys_limit
+#define CRASH_ADDR_HIGH_MAX (PHYS_MASK + 1)
#endif
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 36967b82c150..2e63954a2574 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -64,149 +64,25 @@ EXPORT_SYMBOL(memstart_addr);
*/
phys_addr_t __ro_after_init arm64_dma_phys_limit;

-/* Current arm64 boot protocol requires 2MB alignment */
-#define CRASH_ALIGN SZ_2M
-
-#define CRASH_ADDR_LOW_MAX arm64_dma_phys_limit
-#define CRASH_ADDR_HIGH_MAX (PHYS_MASK + 1)
-#define CRASH_HIGH_SEARCH_BASE SZ_4G
-
-#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, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
- 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%08llx - 0x%08llx (%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;
- insert_resource(&iomem_resource, &crashk_low_res);
-
- return 0;
-}
-
-/*
- * reserve_crashkernel() - reserves memory for crash kernel
- *
- * This function reserves memory area given in "crashkernel=" kernel command
- * 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_low_size = 0, search_base = 0;
- unsigned long long crash_max = CRASH_ADDR_LOW_MAX;
+ 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;

if (!IS_ENABLED(CONFIG_KEXEC_CORE))
return;

- /* crashkernel=X[@offset] */
ret = parse_crashkernel(cmdline, memblock_phys_mem_size(),
- &crash_size, &crash_base, NULL, NULL);
- if (ret == -ENOENT) {
- ret = parse_crashkernel_high(cmdline, 0, &crash_size, &crash_base);
- if (ret || !crash_size)
- return;
-
- /*
- * crashkernel=Y,low can be specified or not, but invalid value
- * is not allowed.
- */
- 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_base = CRASH_HIGH_SEARCH_BASE;
- crash_max = CRASH_ADDR_HIGH_MAX;
- high = true;
- } else if (ret || !crash_size) {
- /* The specified value is invalid */
+ &crash_size, &crash_base,
+ &low_size, &high);
+ if (ret)
return;
- }
-
- crash_size = PAGE_ALIGN(crash_size);
-
- /* User specifies base address explicitly. */
- if (crash_base) {
- fixed_base = true;
- search_base = crash_base;
- crash_max = crash_base + crash_size;
- }
-
-retry:
- crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
- search_base, crash_max);
- if (!crash_base) {
- /*
- * For crashkernel=size[KMG]@offset[KMG], print out failure
- * message if can't reserve the specified region.
- */
- if (fixed_base) {
- pr_warn("crashkernel reservation failed - memory is in use.\n");
- return;
- }
-
- /*
- * 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.
- */
- if (!high && crash_max == CRASH_ADDR_LOW_MAX) {
- crash_max = CRASH_ADDR_HIGH_MAX;
- search_base = CRASH_ADDR_LOW_MAX;
- crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
- goto retry;
- }
-
- /*
- * For crashkernel=size[KMG],high, if the first attempt was
- * for high memory, fall back to low memory.
- */
- if (high && crash_max == CRASH_ADDR_HIGH_MAX) {
- crash_max = CRASH_ADDR_LOW_MAX;
- search_base = 0;
- goto retry;
- }
- pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
- crash_size);
- return;
- }
-
- if ((crash_base >= CRASH_ADDR_LOW_MAX) && 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);
-
- /*
- * The crashkernel memory will be removed from the kernel linear
- * map. Inform kmemleak so that it won't try to access it.
- */
- kmemleak_ignore_phys(crash_base);
- if (crashk_low_res.end)
- kmemleak_ignore_phys(crashk_low_res.start);

- crashk_res.start = crash_base;
- crashk_res.end = crash_base + crash_size - 1;
- insert_resource(&iomem_resource, &crashk_res);
+ reserve_crashkernel_generic(cmdline, crash_size, crash_base,
+ low_size, high);
}

/*
@@ -454,7 +330,7 @@ void __init bootmem_init(void)
* request_standard_resources() depends on crashkernel's memory being
* reserved, so do it here.
*/
- reserve_crashkernel();
+ arch_reserve_crashkernel();

memblock_dump_all();