From: Anton Blanchard Date: Sun, 3 Jun 2012 19:42:13 +0000 (+0000) Subject: powerpc/pseries: Disable interrupts around IOMMU percpu data accesses X-Git-Tag: firefly_0821_release~3680^2~2388^2~56 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=c1703e85a7b20ffcefd5360e2542460737ecc15c;p=firefly-linux-kernel-4.4.55.git powerpc/pseries: Disable interrupts around IOMMU percpu data accesses tce_buildmulti_pSeriesLP uses a per cpu page to communicate with the hypervisor. We currently rely on the IOMMU table spinlock but subsequent patches will be removing that so disable interrupts around all accesses of tce_page. Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt --- diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c index d5d1dd58ca74..07c09cbbfb19 100644 --- a/arch/powerpc/platforms/pseries/iommu.c +++ b/arch/powerpc/platforms/pseries/iommu.c @@ -192,12 +192,15 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, long l, limit; long tcenum_start = tcenum, npages_start = npages; int ret = 0; + unsigned long flags; if (npages == 1) { return tce_build_pSeriesLP(tbl, tcenum, npages, uaddr, direction, attrs); } + local_irq_save(flags); /* to protect tcep and the page behind it */ + tcep = __get_cpu_var(tce_page); /* This is safe to do since interrupts are off when we're called @@ -207,6 +210,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, tcep = (u64 *)__get_free_page(GFP_ATOMIC); /* If allocation fails, fall back to the loop implementation */ if (!tcep) { + local_irq_restore(flags); return tce_build_pSeriesLP(tbl, tcenum, npages, uaddr, direction, attrs); } @@ -240,6 +244,8 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, tcenum += limit; } while (npages > 0 && !rc); + local_irq_restore(flags); + if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) { ret = (int)rc; tce_freemulti_pSeriesLP(tbl, tcenum_start,