42 lines
1.4 KiB
Diff
42 lines
1.4 KiB
Diff
From 91021aa7ea1469d0b3127e68d177e0ad58a7eda3 Mon Sep 17 00:00:00 2001
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From: David Hildenbrand <dahi@linux.vnet.ibm.com>
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Date: Mon, 11 May 2015 17:52:10 +0200
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Subject: [PATCH 05/14] mips: kmap_coherent relies on disabled preemption
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.0/patches-4.0.4-rt1.tar.xz
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k(un)map_coherent relies on pagefault_disable() to also disable
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preemption.
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Let's make this explicit, to prepare for pagefault_disable() not
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touching preemption anymore.
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This patch is based on a patch by Yang Shi on the -rt tree:
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"k{un}map_coherent are just called when cpu_has_dc_aliases == 1 with VIPT
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cache. However, actually, the most modern MIPS processors have PIPT dcache
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without dcache alias issue. In such case, k{un}map_atomic will be called
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with preempt enabled."
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Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
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---
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arch/mips/mm/init.c | 2 ++
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1 file changed, 2 insertions(+)
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--- a/arch/mips/mm/init.c
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+++ b/arch/mips/mm/init.c
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@@ -90,6 +90,7 @@ static void *__kmap_pgprot(struct page *
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BUG_ON(Page_dcache_dirty(page));
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+ preempt_disable();
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pagefault_disable();
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idx = (addr >> PAGE_SHIFT) & (FIX_N_COLOURS - 1);
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idx += in_interrupt() ? FIX_N_COLOURS : 0;
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@@ -147,6 +148,7 @@ void kunmap_coherent(void)
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write_c0_entryhi(old_ctx);
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local_irq_restore(flags);
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pagefault_enable();
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+ preempt_enable();
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}
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void copy_user_highpage(struct page *to, struct page *from,
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