Hi Baoquan,
On 04/28/2015 06:19 PM, Baoquan He wrote:
+#ifdef CONFIG_CRASH_DUMP
+/*
+ * reserve_elfcorehdr() - reserves memory for elf core header
+ *
+ * This function reserves memory area given in "elfcorehdr=" kernel command
+ * line parameter. The memory reserved is used by a dump capture kernel to
+ * identify the memory used by primary kernel.
+ */
Hi AKASHI,
May I know why elfcorehdr need be reserved separately but not locate a
memory region in crashkernel reserved region like all other ARCHs? Is
there any special reason?
I don't get your point, but arm as well as arm64 locates elfcorehdr
in a crash kernel's memory region.
See kexec/arch/arm{,64}/crashdump-arm{,64}.c in kexec-tools.
And this region is reserved at boot time *on crash kernel* because we don't want
to corrupt it accidentally.
(After Mark's comment, we might better remove the mmu mapping for this region,
too.)
Make sense?
-Takahiro AKASHI
Thanks
Baoquan
+static void __init reserve_elfcorehdr(void)
+{
+ if (!elfcorehdr_size)
+ return;
+
+ if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) {
+ pr_warn("elfcorehdr reservation failed - memory is in use
(0x%llx)\n",
+ elfcorehdr_addr);
+ return;
+ }
+
+ if (memblock_reserve(elfcorehdr_addr, elfcorehdr_size)) {
+ pr_warn("elfcorehdr reservation failed - out of memory\n");
+ return;
+ }
+
+ pr_info("Reserving %lldKB of memory at %lldMB for elfcorehdr\n",
+ elfcorehdr_size >> 10, elfcorehdr_addr >> 20);
+}
+#endif /* CONFIG_CRASH_DUMP */
/*
* Return the maximum physical address for ZONE_DMA (DMA_BIT_MASK(32)). It
* currently assumes that for memory starting above 4G, 32-bit devices will
@@ -170,6 +247,13 @@ void __init arm64_memblock_init(void)
memblock_reserve(__virt_to_phys(initrd_start), initrd_end -
initrd_start);
#endif
+#ifdef CONFIG_KEXEC
+ reserve_crashkernel(memory_limit);
+#endif
+#ifdef CONFIG_CRASH_DUMP
+ reserve_elfcorehdr();
+#endif
+
early_init_fdt_scan_reserved_mem();
/* 4GB maximum for 32-bit only capable devices */
--
1.7.9.5
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