mirror of
https://github.com/torvalds/linux.git
synced 2024-11-07 04:32:03 +00:00
3705ff6da5
There is a subtle race in the CPU hotplug code, where a CPU which has been offlined can online itself before being requested, which results in things going astray on the next online/offline cycle. What happens in the normal online/offline/online cycle is: CPU0 CPU3 requests boot of CPU3 pen_release = 3 flush cache line checks pen_release, reads 3 starts boot pen_release = -1 ... requests CPU3 offline ... ... dies ... checks pen_release, reads -1 requests boot of CPU3 pen_release = 3 flush cache line checks pen_release, reads 3 starts boot pen_release = -1 However, as the write of -1 of pen_release is not fully flushed back to memory, and the checking of pen_release is done with caches disabled, this allows CPU3 the opportunity to read the old value of pen_release: CPU0 CPU3 requests boot of CPU3 pen_release = 3 flush cache line checks pen_release, reads 3 starts boot pen_release = -1 ... requests CPU3 offline ... ... dies ... checks pen_release, reads 3 starts boot pen_release = -1 requests boot of CPU3 pen_release = 3 flush cache line Fix this by grouping the write of pen_release along with its cache line flushing code to ensure that any update to pen_release is always pushed out to physical memory. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> |
||
|---|---|---|
| .. | ||
| include/mach | ||
| board-mop500-regulators.c | ||
| board-mop500-sdi.c | ||
| board-mop500.c | ||
| board-mop500.h | ||
| board-u5500.c | ||
| clock.c | ||
| clock.h | ||
| cpu-db5500.c | ||
| cpu-db8500.c | ||
| cpu.c | ||
| devices-db5500.c | ||
| devices-db8500.c | ||
| devices.c | ||
| headsmp.S | ||
| hotplug.c | ||
| Kconfig | ||
| localtimer.c | ||
| Makefile | ||
| Makefile.boot | ||
| mbox.c | ||
| modem_irq.c | ||
| pins-db5500.h | ||
| pins-db8500.h | ||
| platsmp.c | ||
| prcmu.c | ||
| ste-dma40-db5500.h | ||
| ste-dma40-db8500.h | ||