diff options
Diffstat (limited to 'features/rt/powerpc-pseries-iommu-Use-a-locallock-instead-local_.patch')
| -rw-r--r-- | features/rt/powerpc-pseries-iommu-Use-a-locallock-instead-local_.patch | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/features/rt/powerpc-pseries-iommu-Use-a-locallock-instead-local_.patch b/features/rt/powerpc-pseries-iommu-Use-a-locallock-instead-local_.patch new file mode 100644 index 00000000..d3850690 --- /dev/null +++ b/features/rt/powerpc-pseries-iommu-Use-a-locallock-instead-local_.patch @@ -0,0 +1,116 @@ +From 4478a8edce91a9ecc083e0a1c892bc61e03debb5 Mon Sep 17 00:00:00 2001 +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Tue, 26 Mar 2019 18:31:54 +0100 +Subject: [PATCH 181/191] powerpc/pseries/iommu: Use a locallock instead + local_irq_save() + +The locallock protects the per-CPU variable tce_page. The function +attempts to allocate memory while tce_page is protected (by disabling +interrupts). + +Use local_irq_save() instead of local_irq_disable(). + +Cc: stable-rt@vger.kernel.org +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + arch/powerpc/platforms/pseries/iommu.c | 31 +++++++++++++++++--------- + 1 file changed, 20 insertions(+), 11 deletions(-) + +diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c +index 9fc5217f0c8e..4fdb9370b913 100644 +--- a/arch/powerpc/platforms/pseries/iommu.c ++++ b/arch/powerpc/platforms/pseries/iommu.c +@@ -24,6 +24,7 @@ + #include <linux/of.h> + #include <linux/iommu.h> + #include <linux/rculist.h> ++#include <linux/local_lock.h> + #include <asm/io.h> + #include <asm/prom.h> + #include <asm/rtas.h> +@@ -190,7 +191,13 @@ static int tce_build_pSeriesLP(unsigned long liobn, long tcenum, long tceshift, + return ret; + } + +-static DEFINE_PER_CPU(__be64 *, tce_page); ++struct tce_page { ++ __be64 * page; ++ local_lock_t lock; ++}; ++static DEFINE_PER_CPU(struct tce_page, tce_page) = { ++ .lock = INIT_LOCAL_LOCK(lock), ++}; + + static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, + long npages, unsigned long uaddr, +@@ -212,9 +219,10 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, + direction, attrs); + } + +- local_irq_save(flags); /* to protect tcep and the page behind it */ ++ /* to protect tcep and the page behind it */ ++ local_lock_irqsave(&tce_page.lock, flags); + +- tcep = __this_cpu_read(tce_page); ++ tcep = __this_cpu_read(tce_page.page); + + /* This is safe to do since interrupts are off when we're called + * from iommu_alloc{,_sg}() +@@ -223,12 +231,12 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, + tcep = (__be64 *)__get_free_page(GFP_ATOMIC); + /* If allocation fails, fall back to the loop implementation */ + if (!tcep) { +- local_irq_restore(flags); ++ local_unlock_irqrestore(&tce_page.lock, flags); + return tce_build_pSeriesLP(tbl->it_index, tcenum, + tbl->it_page_shift, + npages, uaddr, direction, attrs); + } +- __this_cpu_write(tce_page, tcep); ++ __this_cpu_write(tce_page.page, tcep); + } + + rpn = __pa(uaddr) >> TCE_SHIFT; +@@ -258,7 +266,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, + tcenum += limit; + } while (npages > 0 && !rc); + +- local_irq_restore(flags); ++ local_unlock_irqrestore(&tce_page.lock, flags); + + if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) { + ret = (int)rc; +@@ -429,16 +437,17 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn, + DMA_BIDIRECTIONAL, 0); + } + +- local_irq_disable(); /* to protect tcep and the page behind it */ +- tcep = __this_cpu_read(tce_page); ++ /* to protect tcep and the page behind it */ ++ local_lock_irq(&tce_page.lock); ++ tcep = __this_cpu_read(tce_page.page); + + if (!tcep) { + tcep = (__be64 *)__get_free_page(GFP_ATOMIC); + if (!tcep) { +- local_irq_enable(); ++ local_unlock_irq(&tce_page.lock); + return -ENOMEM; + } +- __this_cpu_write(tce_page, tcep); ++ __this_cpu_write(tce_page.page, tcep); + } + + proto_tce = TCE_PCI_READ | TCE_PCI_WRITE; +@@ -481,7 +490,7 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn, + + /* error cleanup: caller will clear whole range */ + +- local_irq_enable(); ++ local_unlock_irq(&tce_page.lock); + return rc; + } + +-- +2.19.1 + |