118 lines
3.7 KiB
Diff
118 lines
3.7 KiB
Diff
From 568f517f60a2278ce951e4c406c2b1a23b023276 Mon Sep 17 00:00:00 2001
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Tue, 26 Mar 2019 18:31:54 +0100
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Subject: [PATCH 46/62] powerpc/pseries/iommu: Use a locallock instead
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local_irq_save()
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The locallock protects the per-CPU variable tce_page. The function
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attempts to allocate memory while tce_page is protected (by disabling
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interrupts).
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Use local_irq_save() instead of local_irq_disable().
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Cc: stable-rt@vger.kernel.org
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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arch/powerpc/platforms/pseries/iommu.c | 31 +++++++++++++++++---------
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1 file changed, 20 insertions(+), 11 deletions(-)
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diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
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index 97b026130c71..01b3d19be382 100644
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--- a/arch/powerpc/platforms/pseries/iommu.c
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+++ b/arch/powerpc/platforms/pseries/iommu.c
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@@ -24,6 +24,7 @@
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#include <linux/of.h>
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#include <linux/iommu.h>
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#include <linux/rculist.h>
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+#include <linux/local_lock.h>
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#include <asm/io.h>
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#include <asm/prom.h>
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#include <asm/rtas.h>
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@@ -200,7 +201,13 @@ static int tce_build_pSeriesLP(unsigned long liobn, long tcenum, long tceshift,
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return ret;
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}
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-static DEFINE_PER_CPU(__be64 *, tce_page);
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+struct tce_page {
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+ __be64 * page;
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+ local_lock_t lock;
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+};
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+static DEFINE_PER_CPU(struct tce_page, tce_page) = {
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+ .lock = INIT_LOCAL_LOCK(lock),
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+};
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static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
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long npages, unsigned long uaddr,
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@@ -223,9 +230,10 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
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direction, attrs);
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}
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- local_irq_save(flags); /* to protect tcep and the page behind it */
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+ /* to protect tcep and the page behind it */
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+ local_lock_irqsave(&tce_page.lock, flags);
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- tcep = __this_cpu_read(tce_page);
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+ tcep = __this_cpu_read(tce_page.page);
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/* This is safe to do since interrupts are off when we're called
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* from iommu_alloc{,_sg}()
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@@ -234,12 +242,12 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
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tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
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/* If allocation fails, fall back to the loop implementation */
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if (!tcep) {
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- local_irq_restore(flags);
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+ local_unlock_irqrestore(&tce_page.lock, flags);
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return tce_build_pSeriesLP(tbl->it_index, tcenum,
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tceshift,
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npages, uaddr, direction, attrs);
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}
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- __this_cpu_write(tce_page, tcep);
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+ __this_cpu_write(tce_page.page, tcep);
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}
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rpn = __pa(uaddr) >> tceshift;
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@@ -269,7 +277,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
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tcenum += limit;
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} while (npages > 0 && !rc);
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- local_irq_restore(flags);
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+ local_unlock_irqrestore(&tce_page.lock, flags);
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if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) {
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ret = (int)rc;
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@@ -454,16 +462,17 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
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DMA_BIDIRECTIONAL, 0);
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}
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- local_irq_disable(); /* to protect tcep and the page behind it */
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- tcep = __this_cpu_read(tce_page);
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+ /* to protect tcep and the page behind it */
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+ local_lock_irq(&tce_page.lock);
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+ tcep = __this_cpu_read(tce_page.page);
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if (!tcep) {
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tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
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if (!tcep) {
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- local_irq_enable();
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+ local_unlock_irq(&tce_page.lock);
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return -ENOMEM;
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}
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- __this_cpu_write(tce_page, tcep);
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+ __this_cpu_write(tce_page.page, tcep);
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}
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proto_tce = TCE_PCI_READ | TCE_PCI_WRITE;
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@@ -506,7 +515,7 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
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/* error cleanup: caller will clear whole range */
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- local_irq_enable();
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+ local_unlock_irq(&tce_page.lock);
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return rc;
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}
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--
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2.43.0
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