From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Thu, 7 Dec 2006 04:32:18 +0000 (-0800)
Subject: [PATCH] mm: arch do_page_fault() vs in_atomic()
X-Git-Tag: v2.6.20-rc1~145^2^2~340
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6edaf68a87d17570790fd55f0c451a29ec1d6703;p=linux-2.6

[PATCH] mm: arch do_page_fault() vs in_atomic()

In light of the recent pagefault and filemap_copy_from_user work I've gone
through all the arch pagefault handlers to make sure the inc_preempt_count()
'feature' works as expected.

Several sections of code (including the new filemap_copy_from_user) rely on
the fact that faults do not take locks under increased preempt count.

arch/x86_64 - good
arch/powerpc - good
arch/cris - fixed
arch/i386 - good
arch/parisc - fixed
arch/sh - good
arch/sparc - good
arch/s390 - good
arch/m68k - fixed
arch/ppc - good
arch/alpha - fixed
arch/mips - good
arch/sparc64 - good
arch/ia64 - good
arch/arm - fixed
arch/um - good
arch/avr32 - good
arch/h8300 - NA
arch/m32r - good
arch/v850 - good
arch/frv - fixed
arch/m68knommu - NA
arch/arm26 - fixed
arch/sh64 - fixed
arch/xtensa - good

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c
index 8871529a34..8aa9db834c 100644
--- a/arch/alpha/mm/fault.c
+++ b/arch/alpha/mm/fault.c
@@ -108,7 +108,7 @@ do_page_fault(unsigned long address, unsigned long mmcsr,
 
 	/* If we're in an interrupt context, or have no user context,
 	   we must not take the fault.  */
-	if (!mm || in_interrupt())
+	if (!mm || in_atomic())
 		goto no_context;
 
 #ifdef CONFIG_ALPHA_LARGE_VMALLOC
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index 5e658a8744..9fd6d2eafb 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -230,7 +230,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_interrupt() || !mm)
+	if (in_atomic() || !mm)
 		goto no_context;
 
 	/*
diff --git a/arch/arm26/mm/fault.c b/arch/arm26/mm/fault.c
index a1f6d8a9cc..93c0cee0fb 100644
--- a/arch/arm26/mm/fault.c
+++ b/arch/arm26/mm/fault.c
@@ -215,7 +215,7 @@ int do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_interrupt() || !mm)
+	if (in_atomic() || !mm)
 		goto no_context;
 
 	down_read(&mm->mmap_sem);
diff --git a/arch/cris/mm/fault.c b/arch/cris/mm/fault.c
index 934c51078c..c73e91f129 100644
--- a/arch/cris/mm/fault.c
+++ b/arch/cris/mm/fault.c
@@ -232,7 +232,7 @@ do_page_fault(unsigned long address, struct pt_regs *regs,
 	 * context, we must not take the fault..
 	 */
 
-	if (in_interrupt() || !mm)
+	if (in_atomic() || !mm)
 		goto no_context;
 
 	down_read(&mm->mmap_sem);
diff --git a/arch/frv/mm/fault.c b/arch/frv/mm/fault.c
index 8b3eb50c51..3f12296c36 100644
--- a/arch/frv/mm/fault.c
+++ b/arch/frv/mm/fault.c
@@ -78,7 +78,7 @@ asmlinkage void do_page_fault(int datammu, unsigned long esr0, unsigned long ear
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_interrupt() || !mm)
+	if (in_atomic() || !mm)
 		goto no_context;
 
 	down_read(&mm->mmap_sem);
diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c
index 911f2ce3f5..2adbeb16e1 100644
--- a/arch/m68k/mm/fault.c
+++ b/arch/m68k/mm/fault.c
@@ -99,7 +99,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_interrupt() || !mm)
+	if (in_atomic() || !mm)
 		goto no_context;
 
 	down_read(&mm->mmap_sem);
diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
index 64785e46f9..641f9c920e 100644
--- a/arch/parisc/mm/fault.c
+++ b/arch/parisc/mm/fault.c
@@ -152,7 +152,7 @@ void do_page_fault(struct pt_regs *regs, unsigned long code,
 	const struct exception_table_entry *fix;
 	unsigned long acc_type;
 
-	if (in_interrupt() || !mm)
+	if (in_atomic() || !mm)
 		goto no_context;
 
 	down_read(&mm->mmap_sem);
diff --git a/arch/sh64/mm/fault.c b/arch/sh64/mm/fault.c
index 8e2f6c28b7..4f72ab33bb 100644
--- a/arch/sh64/mm/fault.c
+++ b/arch/sh64/mm/fault.c
@@ -154,7 +154,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long writeaccess,
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_interrupt() || !mm)
+	if (in_atomic() || !mm)
 		goto no_context;
 
 	/* TLB misses upon some cache flushes get done under cli() */