diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 363e348bff9b93598587710de952a22c89f12bbe..da0e0773ca96d8107b3b72bfbf59a390085beee0 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -594,6 +594,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
is selected automatically. Check
Documentation/kdump/kdump.txt for further details.
+ crashkernel_low=size[KMG]
+ [KNL, x86] parts under 4G.
+
crashkernel=range1:size1[,range2:size2,...][@offset]
[KNL] Same as above, but depends on the memory
in the running system. The syntax of range is
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 4778ddeedc8aef6c1e01c17b14fff44645ab609d..5dc47c3e537b62f5d5af814bbaacf0a6b93cc581 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -508,8 +508,44 @@ static void __init memblock_x86_reserve_range_setup_data(void)
# define CRASH_KERNEL_ADDR_MAX MAXMEM
#endif
+static void __init reserve_crashkernel_low(void)
+{
+#ifdef CONFIG_X86_64
+ const unsigned long long alignment = 16<<20; /* 16M */
+ unsigned long long low_base = 0, low_size = 0;
+ unsigned long total_low_mem;
+ unsigned long long base;
+ int ret;
+
+ total_low_mem = memblock_mem_size(1UL<<(32-PAGE_SHIFT));
+ ret = parse_crashkernel_low(boot_command_line, total_low_mem,
+ &low_size, &base);
+ if (ret != 0 || low_size <= 0)
+ return;
+
+ low_base = memblock_find_in_range(low_size, (1ULL<<32),
+ low_size, alignment);
+
+ if (!low_base) {
+ pr_info("crashkernel low reservation failed - No suitable area found.\n");
+
+ return;
+ }
+
+ memblock_reserve(low_base, low_size);
+ pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (System low RAM: %ldMB)\n",
+ (unsigned long)(low_size >> 20),
+ (unsigned long)(low_base >> 20),
+ (unsigned long)(total_low_mem >> 20));
+ crashk_low_res.start = low_base;
+ crashk_low_res.end = low_base + low_size - 1;
+ insert_resource(&iomem_resource, &crashk_low_res);
+#endif
+}
+
static void __init reserve_crashkernel(void)
{
+ const unsigned long long alignment = 16<<20; /* 16M */
unsigned long long total_mem;
unsigned long long crash_size, crash_base;
int ret;
@@ -523,8 +559,6 @@ static void __init reserve_crashkernel(void)
/* 0 means: find the address automatically */
if (crash_base <= 0) {
- const unsigned long long alignment = 16<<20; /* 16M */
-
/*
* kexec want bzImage is below CRASH_KERNEL_ADDR_MAX
*/
@@ -535,6 +569,7 @@ static void __init reserve_crashkernel(void)
pr_info("crashkernel reservation failed - No suitable area found.\n");
return;
}
+
} else {
unsigned long long start;
@@ -556,6 +591,9 @@ static void __init reserve_crashkernel(void)
crashk_res.start = crash_base;
crashk_res.end = crash_base + crash_size - 1;
insert_resource(&iomem_resource, &crashk_res);
+
+ if (crash_base >= (1ULL<<32))
+ reserve_crashkernel_low();
}
#else
static void __init reserve_crashkernel(void)
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index d0b8458a703a25503bcfe75f39ef804f36636aea..d2e6927bbaae1eb65b5b1dd2575643a5562e329a 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -191,6 +191,7 @@ extern struct kimage *kexec_crash_image;
/* Location of a reserved region to hold the crash kernel.
*/
extern struct resource crashk_res;
+extern struct resource crashk_low_res;
typedef u32 note_buf_t[KEXEC_NOTE_BYTES/4];
extern note_buf_t __percpu *crash_notes;
extern u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4];
@@ -199,6 +200,8 @@ extern size_t vmcoreinfo_max_size;
int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,
unsigned long long *crash_size, unsigned long long *crash_base);
+int parse_crashkernel_low(char *cmdline, unsigned long long system_ram,
+ unsigned long long *crash_size, unsigned long long *crash_base);
int crash_shrink_memory(unsigned long new_size);
size_t crash_get_memory_size(void);
void crash_free_reserved_phys_range(unsigned long begin, unsigned long end);
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 5e4bd7864c5dedf836a7c85cc1ed8e3c4e31e6cb..2436ffcec91f0de58543e259c3dac620a26da36b 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -54,6 +54,12 @@ struct resource crashk_res = {
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_MEM
};
+struct resource crashk_low_res = {
+ .name = "Crash kernel low",
+ .start = 0,
+ .end = 0,
+ .flags = IORESOURCE_BUSY | IORESOURCE_MEM
+};
int kexec_should_crash(struct task_struct *p)
{
@@ -1369,10 +1375,11 @@ static int __init parse_crashkernel_simple(char *cmdline,
* That function is the entry point for command line parsing and should be
* called from the arch-specific code.
*/
-int __init parse_crashkernel(char *cmdline,
+static int __init __parse_crashkernel(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
- unsigned long long *crash_base)
+ unsigned long long *crash_base,
+ const char *name)
{
char *p = cmdline, *ck_cmdline = NULL;
char *first_colon, *first_space;
@@ -1382,16 +1389,16 @@ int __init parse_crashkernel(char *cmdline,
*crash_base = 0;
/* find crashkernel and use the last one if there are more */
- p = strstr(p, "crashkernel=");
+ p = strstr(p, name);
while (p) {
ck_cmdline = p;
- p = strstr(p+1, "crashkernel=");
+ p = strstr(p+1, name);
}
if (!ck_cmdline)
return -EINVAL;
- ck_cmdline += 12; /* strlen("crashkernel=") */
+ ck_cmdline += strlen(name);
/*
* if the commandline contains a ':', then that's the extended
@@ -1409,6 +1416,23 @@ int __init parse_crashkernel(char *cmdline,
return 0;
}
+int __init parse_crashkernel(char *cmdline,
+ unsigned long long system_ram,
+ unsigned long long *crash_size,
+ unsigned long long *crash_base)
+{
+ return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
+ "crashkernel=");
+}
+
+int __init parse_crashkernel_low(char *cmdline,
+ unsigned long long system_ram,
+ unsigned long long *crash_size,
+ unsigned long long *crash_base)
+{
+ return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
+ "crashkernel_low=");
+}
static void update_vmcoreinfo_note(void)
{