96 lines
2.9 KiB
Diff
96 lines
2.9 KiB
Diff
From 6a4420cb88ab99177938a2bc6e7f62e605812133 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 263/319] powerpc/pseries/iommu: Use a locallock instead
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local_irq_save()
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.103-rt42.tar.xz
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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: Steven Rostedt (VMware) <rostedt@goodmis.org>
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[Salvatore Bonaccorso: Update for context changes in 4.19.104 due to
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9ed7b9085e13 ("powerpc/pseries: Allow not having ibm,
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hypertas-functions::hcall-multi-tce for DDW")]
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---
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arch/powerpc/platforms/pseries/iommu.c | 16 ++++++++++------
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1 file changed, 10 insertions(+), 6 deletions(-)
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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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@@ -38,6 +38,7 @@
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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/locallock.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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@@ -212,6 +213,7 @@
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}
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static DEFINE_PER_CPU(__be64 *, tce_page);
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+static DEFINE_LOCAL_IRQ_LOCK(tcp_page_lock);
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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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@@ -233,7 +235,8 @@
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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(tcp_page_lock, flags);
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tcep = __this_cpu_read(tce_page);
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@@ -244,7 +247,7 @@
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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(tcp_page_lock, flags);
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return tce_build_pSeriesLP(tbl->it_index, tcenum,
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tbl->it_page_shift,
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npages, uaddr, direction, attrs);
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@@ -279,7 +282,7 @@
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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(tcp_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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@@ -450,13 +453,14 @@
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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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+ /* to protect tcep and the page behind it */
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+ local_lock_irq(tcp_page_lock);
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tcep = __this_cpu_read(tce_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(tcp_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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@@ -502,7 +506,7 @@
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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(tcp_page_lock);
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return rc;
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}
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