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MIPS: kexec: Add crashkernel=YM handling

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When the kernel crashkernel parameter is specified with just a size,
we are supposed to allocate a region from RAM to store the crashkernel.
However, MIPS merely reserves physical address zero with no checking
that there is even RAM there.

Fix this by lifting similar code from x86, importing it to MIPS with the
MIPS specific parameters added. In the absence of any platform specific
information, we allocate the crashkernel region from the first 512MB of
physical memory (limited to CKSEG0 or KSEG0 address range).

When X is not specified, crash_base defaults to 0 (crashkernel=YM@XM).

E.g. without this patch:

The environment as follows:
[    0.000000] MIPS: machine is loongson,loongson64c-4core-ls7a
...
[    0.000000] Kernel command line: root=/dev/sda2 crashkernel=96M ...

The warning as follows:
[    0.000000] Invalid memory region reserved for crash kernel

And the iomem as follows:
00200000-0effffff : System RAM
  00200000-00b47f87 : Kernel code
  00b47f88-00dfffff : Kernel data
  00e60000-01f73c7f : Kernel bss
1a000000-1bffffff : pci@1a000000
...

With this patch:

After increasing crash_base <= 0 handling.

And the iomem as follows:
00200000-0effffff : System RAM
  00200000-00b47f87 : Kernel code
  00b47f88-00dfffff : Kernel data
  00e60000-01f73c7f : Kernel bss
  04000000-09ffffff : Crash kernel
1a000000-1bffffff : pci@1a000000
...

Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
This commit is contained in:
Youling Tang 2020-09-19 09:55:46 +08:00 committed by Thomas Bogendoerfer
parent 5fa1f7680f
commit 2626239614
1 changed files with 21 additions and 3 deletions
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24
arch/mips/kernel/setup.c
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@ -477,6 +477,11 @@ early_param("elfcorehdr", early_parse_elfcorehdr);
#endif
#ifdef CONFIG_KEXEC
/* 64M alignment for crash kernel regions */
#define CRASH_ALIGN SZ_64M
#define CRASH_ADDR_MAX SZ_512M
static void __init mips_parse_crashkernel(void)
{
unsigned long long total_mem;
@ -489,9 +494,22 @@ static void __init mips_parse_crashkernel(void)
if (ret != 0 || crash_size <= 0)
return;
if (!memblock_find_in_range(crash_base, crash_base + crash_size, crash_size, 1)) {
pr_warn("Invalid memory region reserved for crash kernel\n");
return;
if (crash_base <= 0) {
crash_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_MAX,
crash_size, CRASH_ALIGN);
if (!crash_base) {
pr_warn("crashkernel reservation failed - No suitable area found.\n");
return;
}
} else {
unsigned long long start;
start = memblock_find_in_range(crash_base, crash_base + crash_size,
crash_size, 1);
if (start != crash_base) {
pr_warn("Invalid memory region reserved for crash kernel\n");
return;
}
}
crashk_res.start = crash_base;