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From 1ada8088b43e71f7da2b9032172dad4841d4a9be Mon Sep 17 00:00:00 2001
From: Kevin Hao <kexin.hao@windriver.com>
Date: Tue, 2 Mar 2010 16:51:57 -0500
Subject: [PATCH] powerpc: Replace kmap_atomic with kmap in pte_offset_map
commit 1268870be30e4571b0e007c986231c434c3b4912 in tip.
The pte_offset_map/pte_offset_map_nested use kmap_atomic to get the
virtual address for the pte table, but kmap_atomic will disable preempt.
Hence there will be call trace if we acquire a spin lock after invoking
pte_offset_map/pte_offset_map_nested in preempt-rt. To fix it, I've
replaced kmap_atomic with kmap in these macros.
Signed-off-by: Kevin Hao <kexin.hao@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
LKML-Reference: <ffaf532c138188b526a8c623ed3c7f5067da6d68.1267566249.git.paul.gortmaker@windriver.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/powerpc/include/asm/pgtable-ppc32.h | 12 ++++++++++++
1 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/pgtable-ppc32.h b/arch/powerpc/include/asm/pgtable-ppc32.h
index 55646ad..a838099 100644
--- a/arch/powerpc/include/asm/pgtable-ppc32.h
+++ b/arch/powerpc/include/asm/pgtable-ppc32.h
@@ -307,6 +307,17 @@ static inline void __ptep_set_access_flags(pte_t *ptep, pte_t entry)
(((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
#define pte_offset_kernel(dir, addr) \
((pte_t *) pmd_page_vaddr(*(dir)) + pte_index(addr))
+#ifdef CONFIG_PREEMPT_RT
+#define pte_offset_map(dir, addr) \
+ ((pte_t *) kmap(pmd_page(*(dir))) + pte_index(addr))
+#define pte_offset_map_nested(dir, addr) \
+ ((pte_t *) kmap(pmd_page(*(dir))) + pte_index(addr))
+
+#define pte_unmap(pte) \
+ kunmap((struct page *)_ALIGN_DOWN((unsigned int)pte, PAGE_SIZE))
+#define pte_unmap_nested(pte) \
+ kunmap((struct page *)_ALIGN_DOWN((unsigned int)pte, PAGE_SIZE))
+#else
#define pte_offset_map(dir, addr) \
((pte_t *) kmap_atomic(pmd_page(*(dir)), KM_PTE0) + pte_index(addr))
#define pte_offset_map_nested(dir, addr) \
@@ -314,6 +325,7 @@ static inline void __ptep_set_access_flags(pte_t *ptep, pte_t entry)
#define pte_unmap(pte) kunmap_atomic(pte, KM_PTE0)
#define pte_unmap_nested(pte) kunmap_atomic(pte, KM_PTE1)
+#endif
/*
* Encode and decode a swap entry.
--
1.7.0.4
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