scripts/runqemu: fix qemumips qemumips64 memory detection kernel panic

$ runqemu qemumips64 core-image-minimal nographic qemuparams="-m 512"
...
[    0.000000] Call Trace:
[    0.000000] [<ffffffff801268c0>] clear_page+0x0/0x128
[    0.000000] [<ffffffff80238158>] get_page_from_freelist+0xab8/0xc00
[    0.000000] [<ffffffff80238964>] __alloc_pages_nodemask+0xdc/0xf68
[    0.000000] [<ffffffff80239808>] __get_free_pages+0x18/0x70
[    0.000000] [<ffffffff80122a4c>] setup_zero_pages+0x1c/0xb8
[    0.000000] [<ffffffff80c7c998>] mem_init+0x54/0xa0
[    0.000000] [<ffffffff80c74904>] start_kernel+0x204/0x4d8
[    0.000000] [<ffffffff8091dfb0>] kernel_entry+0x0/0x40
[    0.000000] Code: 02002025  1000f8d9  8e634d7c <34860f80> cc9e0000
cc9e0020  cc9e0040  cc9e0060  cc9e0080
[    0.000000]
[    0.000000] ---[ end trace 0000000000000000 ]---
[    0.000000] Kernel panic - not syncing: Attempted to kill the idle task!
[    0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task!
...

OE uses qemumips to simulate a Malta board by default.

As upstream qemu introduced:
https://git.qemu.org/?p=qemu.git;a=commit;h=94c2b6aff43cdfcfdfb552773a6b6b973a72ef0b

The Malta board can support up to 2GiB of RAM which should
be able to boot a Linux kernel built with CONFIG_HIGHMEM
enabled and passing "-m 2048" to QEMU and appending the
following kernel parameters:
...
mem=256M@0x0 mem=256M@0x90000000 mem=1536M@0x20000000
...

But the following commit in kernel broke above mem=X@Y setting
which added the memory as reserved memory area.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=73fbc1eba7ffa3bf0ad12486232a8a1edb4e4411
...
commit 73fbc1eba7ffa3bf0ad12486232a8a1edb4e4411
Author: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Date:   Wed Nov 23 14:43:49 2016 +0100

    MIPS: fix mem=X@Y commandline processing
...

So remove `mem=*' to disable user-defined physical RAM map
which let kernel itself caculates memory ranges.

Author: Hongxu Jia <hongxu.jia@windriver.com>
[ Merge the two fixes for qemumips32 and qemumips64 into one patch,
  and make it support all mips cases ]
(From OE-Core rev: 0220cb34a91658ecc3782ec1a4700dcb5ece37d8)

Signed-off-by: He Zhe <zhe.he@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/scripts/runqemu b/scripts/runqemu
index de42d0f323..73d7d5818b 100755
--- a/scripts/runqemu
+++ b/scripts/runqemu
@@ -668,7 +668,10 @@ class BaseConfig(object):
             logger.info('QB_MEM is not set, use 512M by default')
             self.set('QB_MEM', '-m 512')
 
-        self.kernel_cmdline_script += ' mem=%s' % self.get('QB_MEM').replace('-m','').strip() + 'M'
+        mach = self.get('MACHINE')
+        if not mach.startswith('qemumips'):
+            self.kernel_cmdline_script += ' mem=%s' % self.get('QB_MEM').replace('-m','').strip() + 'M'
+
         self.qemu_opt_script += ' %s' % self.get('QB_MEM')
 
     def check_tcpserial(self):