On 11/30/2013 10:59 PM, Aaro Koskinen wrote: > Hi, > > On Sun, Nov 24, 2013 at 01:05:18PM +0200, Aaro Koskinen wrote: >> With 3.13-rc1 the boot hangs early when initrd/cramfs is used. I bisected >> this to commit f9a7febd82f413b9c8bafd40145bc398b7eb619f (MIPS: Fix start >> of free memory when using initrd). >> >> I'm loading cramfs initrd on my WRT54GL router (16 MB memory) to >> 0x80400000. The kernel command line is: >> console=ttyS0,115200 rd_start=0x80400000 rd_size=5181440 root=/dev/ram init=/init >> >> With 3.13-rc1 it hangs with below output. With the above commit reverted, >> the board boots fine. >> >> Starting program at 0x80231cb0 >> [ 0.000000] Linux version 3.13.0-rc1-wrt54gl-los.git-6e483b8-dirty (aaro@blackmetal) (gcc version 4.8.2 (GCC) ) #13 Sun Nov 24 12:54:47 EET 2013 >> [ 0.000000] bootconsole [early0] enabled >> [ 0.000000] CPU0 revision is: 00029008 (Broadcom BMIPS3300) >> [ 0.000000] bcm47xx: using ssb bus >> [ 0.000000] ssb: Found chip with id 0x5352, rev 0x00 and package 0x02 >> [ 0.000000] ssb: Sonics Silicon Backplane found at address 0x18000000 >> [ 0.000000] Determined physical RAM map: >> [ 0.000000] memory: 01000000 @ 00000000 (usable) >> [ 0.000000] Initial ramdisk at: 0x80400000 (5181440 bytes) >> [ 0.000000] Zone ranges: >> [ 0.000000] Normal [mem 0x00000000-0x00ffffff] >> [ 0.000000] Movable zone start for each node >> [ 0.000000] Early memory node ranges >> [ 0.000000] node 0: [mem 0x00000000-0x00ffffff] >> [ 0.000000] Primary instruction cache 16kB, VIPT, 2-way, linesize 16 bytes. >> [ 0.000000] Primary data cache 8kB, 2-way, VIPT, no aliases, linesize 16 bytes > > It seems the commit itself is OK, but it just exposes some limitation or > "feature" when running Linux on WRT54GL. It seems some areas of memory > cannot be used by Linux. > > The hang seems to happen in memset() called by alloc_bootmem_bdata(). It's > trying to zero 8 pages starting from address 0x80301000. This seems to > be perfectly valid and I have no idea why it hangs, but this area seems > to be used by CFE code earlier during the boot: > > Total memory: 16384 KBytes > > Total memory used by CFE: 0x80300000 - 0x803A39B0 (670128) > > Kernel works if I blacklist this area using command line: > > mem=3M@0 mem=12M@0x400000 > > [...] > > [ 0.000000] Determined physical RAM map: > [ 0.000000] memory: 01000000 @ 00000000 (usable) > [ 0.000000] User-defined physical RAM map: > [ 0.000000] memory: 00300000 @ 00000000 (usable) > [ 0.000000] memory: 00c00000 @ 00400000 (usable) > [ 0.000000] Initial ramdisk at: 0x80400000 (5181440 bytes) > > And the rest of the boot is now fine. > > A. kernel 3.13 uses CFE for early printks and the kernel use CFE's memory. I send patches to remove usage of CFE for the boot console some time ago. Please thy these patches: https://patchwork.linux-mips.org/patch/5888/ https://patchwork.linux-mips.org/patch/5889/ Hauke
