diff options
Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/powerpc_pseries_iommu__Use_a_locallock_instead_local_irq_save.patch | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/debian/patches-rt/powerpc_pseries_iommu__Use_a_locallock_instead_local_irq_save.patch b/debian/patches-rt/powerpc_pseries_iommu__Use_a_locallock_instead_local_irq_save.patch new file mode 100644 index 000000000..f20adf29e --- /dev/null +++ b/debian/patches-rt/powerpc_pseries_iommu__Use_a_locallock_instead_local_irq_save.patch @@ -0,0 +1,115 @@ +Subject: powerpc/pseries/iommu: Use a locallock instead local_irq_save() +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Tue Mar 26 18:31:54 2019 +0100 +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> + +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> +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> + + +--- + arch/powerpc/platforms/pseries/iommu.c | 31 ++++++++++++++++++++----------- + 1 file changed, 20 insertions(+), 11 deletions(-) +--- +--- a/arch/powerpc/platforms/pseries/iommu.c ++++ b/arch/powerpc/platforms/pseries/iommu.c +@@ -25,6 +25,7 @@ + #include <linux/of_address.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> +@@ -206,7 +207,13 @@ static int tce_build_pSeriesLP(unsigned + 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, +@@ -229,9 +236,10 @@ static int tce_buildmulti_pSeriesLP(stru + 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}() +@@ -240,12 +248,12 @@ static int tce_buildmulti_pSeriesLP(stru + 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, + tceshift, + npages, uaddr, direction, attrs); + } +- __this_cpu_write(tce_page, tcep); ++ __this_cpu_write(tce_page.page, tcep); + } + + rpn = __pa(uaddr) >> tceshift; +@@ -275,7 +283,7 @@ static int tce_buildmulti_pSeriesLP(stru + 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; +@@ -459,16 +467,17 @@ static int tce_setrange_multi_pSeriesLP( + 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; +@@ -511,7 +520,7 @@ static int tce_setrange_multi_pSeriesLP( + + /* error cleanup: caller will clear whole range */ + +- local_irq_enable(); ++ local_unlock_irq(&tce_page.lock); + return rc; + } + |