diff options
| author | Miao Yan <yanmiaobest@gmail.com> | 2015-07-27 19:16:07 +0800 |
|---|---|---|
| committer | Simon Glass <sjg@chromium.org> | 2015-08-05 08:42:38 -0600 |
| commit | 417576c2f1f2c5392cd69ef3ed33668cc9900e6e (patch) | |
| tree | 6888f7074c19e8bee629877c3d359de082a03830 /doc | |
| parent | 947eb4396dfe11e89f0d3cafe755b395c6c0a8a2 (diff) | |
| download | blackbird-obmc-uboot-417576c2f1f2c5392cd69ef3ed33668cc9900e6e.tar.gz blackbird-obmc-uboot-417576c2f1f2c5392cd69ef3ed33668cc9900e6e.zip | |
x86: Add a 'pause' instruction in __udelay() for QEMU target
When running SMP configuration on QEMU (tcg mode, no kvm), there is
a busy loop in start_aps(), calling udelay(), that waits for APs to
show up online. However, there is a chance that VCPU1 will be timeout
waiting, IOW the secondary VCPUs haven't started their execution yet.
This patch adds a 'pause' instruction in __udelay() only for QEMU
target, to give other VCPUs a chance to run. When QEMU sees the
'pause' instruction, it will yeild the execution to other CPUs.
Signed-off-by: Miao Yan <yanmiaobest@gmail.com>
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'doc')
0 files changed, 0 insertions, 0 deletions
