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Diffstat (limited to 'Documentation/filesystems/pstore.rst')
| -rw-r--r-- | Documentation/filesystems/pstore.rst | 74 |
1 files changed, 37 insertions, 37 deletions
diff --git a/Documentation/filesystems/pstore.rst b/Documentation/filesystems/pstore.rst index 22e89b3f1f..b8c2cb825c 100644 --- a/Documentation/filesystems/pstore.rst +++ b/Documentation/filesystems/pstore.rst @@ -1,17 +1,17 @@ .. index:: pstore (filesystem) -pstore filesystem with RAM backend (RAMOOPS) -============================================ +*pstore* filesystem with RAM backend (RAMOOPS) +============================================== -Barebox supports the pstore filesystem known from the kernel. The main backend +Barebox supports the *pstore* filesystem known from the kernel. The main backend implementation is RAM. All other backends are currently not implemented by Barebox. -pstore is a filesystem to store kernel log or kernel panic messages. These +*pstore* is a filesystem to store kernel log or kernel panic messages. These messages are stored by the kernel in a specified RAM area which is never overwritten by any user. This data can be accessed after a reboot through -/pstore in Barebox or the kernel. The pstore filesystem is automatically mounted -at boot: +``/pstore`` in Barebox or the kernel. The *pstore* filesystem is automatically +mounted at boot: .. code-block:: none @@ -19,7 +19,7 @@ at boot: none on /dev type devfs none on /pstore type pstore -pstore may add additional warnings during boot due to wrong ECCs (no data +*pstore* may add additional warnings during boot due to wrong ECCs (no data written): .. code-block:: none @@ -40,44 +40,44 @@ written): pstore: Registered ramoops as persistent store backend ramoops: attached 0x200000@0x1fdf4000, ecc: 16/0 -To use pstore/RAMOOPS both Barebox and Kernel have to be compiled with pstore +To use *pstore/RAMOOPS* both Barebox and Kernel have to be compiled with *pstore* and RAM backend support. The kernel receives the parameters describing the -layout over the kernel command line. These parameters are automatically -generated by Barebox. You can change these parameters in Barebox menuconfig. The -RAMOOPS parameters for the Kernel are stored in the variable -global.linux.bootargs.ramoops. +layout via devicetree or - as a fallback - over the kernel command line. +To ensure both worlds are using the same memory layout, the required +configuration data for the kernel is generated on-the-fly prior booting a kernel. +For the devicetree use case Barebox adapts the kernel's devicetree, for the +kernel command line fallback the variable ``global.linux.bootargs.ramoops`` is +created and its content used to build the kernel command line. -To see where the RAMOOPS area is located, you can execute iomem in Barebox. The -RAMOOPS area is listed as 'persistent ram': +You can adapt the *pstore* parameters in Barebox menuconfig. + +To see where the RAMOOPS area is located, you can execute the ``iomem`` command +in the Barebox shell. The RAMOOPS area is listed as 'persistent ram': .. code-block:: none 0x10000000 - 0x1fffffff (size 0x10000000) ram0 - 0x17e7c0c0 - 0x1fcf817f (size 0x07e7c0c0) malloc space - 0x1fcf8180 - 0x1fcfffff (size 0x00007e80) board data - 0x1fd00000 - 0x1fd6eeff (size 0x0006ef00) barebox - 0x1fd6ef00 - 0x1fd88dff (size 0x00019f00) barebox data - 0x1fd88e00 - 0x1fd8c3db (size 0x000035dc) bss - 0x1fdf4000 - 0x1fe13fff (size 0x00020000) persistent ram - 0x1fe14000 - 0x1fe33fff (size 0x00020000) persistent ram - 0x1fe34000 - 0x1fe53fff (size 0x00020000) persistent ram - 0x1fe54000 - 0x1fe73fff (size 0x00020000) persistent ram - 0x1fe74000 - 0x1fe93fff (size 0x00020000) persistent ram - 0x1fe94000 - 0x1feb3fff (size 0x00020000) persistent ram - 0x1feb4000 - 0x1fed3fff (size 0x00020000) persistent ram - 0x1fed4000 - 0x1fef3fff (size 0x00020000) persistent ram - 0x1fef4000 - 0x1ff13fff (size 0x00020000) persistent ram - 0x1ff14000 - 0x1ff33fff (size 0x00020000) persistent ram - 0x1ff34000 - 0x1ff53fff (size 0x00020000) persistent ram - 0x1ff54000 - 0x1ff73fff (size 0x00020000) persistent ram - 0x1ff74000 - 0x1ff93fff (size 0x00020000) persistent ram - 0x1ff94000 - 0x1ffb3fff (size 0x00020000) persistent ram - 0x1ffb4000 - 0x1ffd3fff (size 0x00020000) persistent ram - 0x1ffd4000 - 0x1fff3fff (size 0x00020000) persistent ram - 0x1fff4000 - 0x1fff7fff (size 0x00004000) ttb - 0x1fff8000 - 0x1fffffff (size 0x00008000) stack + 0x247f59c0 - 0x2fbf59bf (size 0x0b400000) malloc space + 0x2fbf59c0 - 0x2fbffffe (size 0x0000a63f) board data + 0x2fc00000 - 0x2fc8619f (size 0x000861a0) barebox + 0x2fc861a0 - 0x2fca35ef (size 0x0001d450) barebox data + 0x2fca35f0 - 0x2fca9007 (size 0x00005a18) bss + 0x2fdd4000 - 0x2fdf3fff (size 0x00020000) ramoops:dump(0/4) + 0x2fdf4000 - 0x2fe13fff (size 0x00020000) ramoops:dump(1/4) + 0x2fe14000 - 0x2fe33fff (size 0x00020000) ramoops:dump(2/4) + 0x2fe34000 - 0x2fe53fff (size 0x00020000) ramoops:dump(3/4) + 0x2fe54000 - 0x2fe73fff (size 0x00020000) ramoops:dump(4/4) + 0x2fe74000 - 0x2fe93fff (size 0x00020000) ramoops:console + 0x2fe94000 - 0x2feb3fff (size 0x00020000) ramoops:ftrace + 0x2feb4000 - 0x2fed3fff (size 0x00020000) ramoops:pmsg + 0x2fee4000 - 0x2fee7fff (size 0x00004000) ttb + 0x2fee8000 - 0x2feeffff (size 0x00008000) stack All pstore files that could be found are added to the /pstore directory. This is a read-only filesystem. If you disable the Kconfig option FS_PSTORE_RAMOOPS_RO, the RAMOOPS area is reset and its ECC recalculated. But that does not allow any writes from Barebox into that area. + +If the menu entry ``FS_PSTORE_CONSOLE`` is enabled, Barebox itself will add all +its own console output to the *ramoops:console* part, which enables the regular +userland later on to have access to the bootloaders output. |