powerpc/fadump: Update fadump documentation

With the unnecessary restriction to reserve memory for fadump at the
top of RAM forgone, update the documentation accordingly.

Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Hari Bathini 2017-03-17 02:35:42 +05:30 committed by Michael Ellerman
parent f6e6bedb77
commit bc183779de

View File

@ -105,21 +105,21 @@ memory is held.
If there is no waiting dump data, then only the memory required
to hold CPU state, HPTE region, boot memory dump and elfcore
header, is reserved at the top of memory (see Fig. 1). This area
is *not* released: this region will be kept permanently reserved,
so that it can act as a receptacle for a copy of the boot memory
content in addition to CPU state and HPTE region, in the case a
crash does occur.
header, is usually reserved at an offset greater than boot memory
size (see Fig. 1). This area is *not* released: this region will
be kept permanently reserved, so that it can act as a receptacle
for a copy of the boot memory content in addition to CPU state
and HPTE region, in the case a crash does occur.
o Memory Reservation during first kernel
Low memory Top of memory
Low memory Top of memory
0 boot memory size |
| | |<--Reserved dump area -->|
V V | Permanent Reservation V
+-----------+----------/ /----------+---+----+-----------+----+
| | |CPU|HPTE| DUMP |ELF |
+-----------+----------/ /----------+---+----+-----------+----+
| | |<--Reserved dump area -->| |
V V | Permanent Reservation | V
+-----------+----------/ /---+---+----+-----------+----+------+
| | |CPU|HPTE| DUMP |ELF | |
+-----------+----------/ /---+---+----+-----------+----+------+
| ^
| |
\ /
@ -135,12 +135,12 @@ crash does occur.
0 boot memory size |
| |<------------- Reserved dump area ----------- -->|
V V V
+-----------+----------/ /----------+---+----+-----------+----+
| | |CPU|HPTE| DUMP |ELF |
+-----------+----------/ /----------+---+----+-----------+----+
| |
V V
Used by second /proc/vmcore
+-----------+----------/ /---+---+----+-----------+----+------+
| | |CPU|HPTE| DUMP |ELF | |
+-----------+----------/ /---+---+----+-----------+----+------+
| |
V V
Used by second /proc/vmcore
kernel to boot
Fig. 2