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-rw-r--r--Documentation/kdump/kdump.txt24
1 files changed, 13 insertions, 11 deletions
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index 79775a4130b5..2fedc081b4c8 100644
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -30,6 +30,10 @@ On x86 machines, the first 640 KB of physical memory is needed to boot,
30regardless of where the kernel loads. Therefore, kexec backs up this 30regardless of where the kernel loads. Therefore, kexec backs up this
31region just before rebooting into the dump-capture kernel. 31region just before rebooting into the dump-capture kernel.
32 32
33Similarly on PPC64 machines first 32KB of physical memory is needed for
34booting regardless of where the kernel is loaded and to support 64K page
35size kexec backs up the first 64KB memory.
36
33All of the necessary information about the system kernel's core image is 37All of the necessary information about the system kernel's core image is
34encoded in the ELF format, and stored in a reserved area of memory 38encoded in the ELF format, and stored in a reserved area of memory
35before a crash. The physical address of the start of the ELF header is 39before a crash. The physical address of the start of the ELF header is
@@ -224,7 +228,7 @@ Dump-capture kernel config options (Arch Dependent, x86_64)
224Dump-capture kernel config options (Arch Dependent, ppc64) 228Dump-capture kernel config options (Arch Dependent, ppc64)
225---------------------------------------------------------- 229----------------------------------------------------------
226 230
227- Make and install the kernel and its modules. DO NOT add this kernel 231* Make and install the kernel and its modules. DO NOT add this kernel
228 to the boot loader configuration files. 232 to the boot loader configuration files.
229 233
230Dump-capture kernel config options (Arch Dependent, ia64) 234Dump-capture kernel config options (Arch Dependent, ia64)
@@ -251,8 +255,8 @@ Dump-capture kernel config options (Arch Dependent, ia64)
251Boot into System Kernel 255Boot into System Kernel
252======================= 256=======================
253 257
2541) Make and install the kernel and its modules. Update the boot loader 2581) Update the boot loader (such as grub, yaboot, or lilo) configuration
255 (such as grub, yaboot, or lilo) configuration files as necessary. 259 files as necessary.
256 260
2572) Boot the system kernel with the boot parameter "crashkernel=Y@X", 2612) Boot the system kernel with the boot parameter "crashkernel=Y@X",
258 where Y specifies how much memory to reserve for the dump-capture kernel 262 where Y specifies how much memory to reserve for the dump-capture kernel
@@ -356,10 +360,11 @@ If die() is called, and it happens to be a thread with pid 0 or 1, or die()
356is called inside interrupt context or die() is called and panic_on_oops is set, 360is called inside interrupt context or die() is called and panic_on_oops is set,
357the system will boot into the dump-capture kernel. 361the system will boot into the dump-capture kernel.
358 362
359On powererpc systems when a soft-reset is generated, die() is called by all cpus and the system will boot into the dump-capture kernel. 363On powererpc systems when a soft-reset is generated, die() is called by all cpus
364and the system will boot into the dump-capture kernel.
360 365
361For testing purposes, you can trigger a crash by using "ALT-SysRq-c", 366For testing purposes, you can trigger a crash by using "ALT-SysRq-c",
362"echo c > /proc/sysrq-trigger or write a module to force the panic. 367"echo c > /proc/sysrq-trigger" or write a module to force the panic.
363 368
364Write Out the Dump File 369Write Out the Dump File
365======================= 370=======================
@@ -410,12 +415,9 @@ format. Crash is available on Dave Anderson's site at the following URL:
410To Do 415To Do
411===== 416=====
412 417
4131) Provide a kernel pages filtering mechanism, so core file size is not 4181) Provide relocatable kernels for all architectures to help in maintaining
414 extreme on systems with huge memory banks. 419 multiple kernels for crash_dump, and the same kernel as the system kernel
415 420 can be used to capture the dump.
4162) Relocatable kernel can help in maintaining multiple kernels for
417 crash_dump, and the same kernel as the system kernel can be used to
418 capture the dump.
419 421
420 422
421Contact 423Contact