From: Mika Westerberg <mika.westerberg@iki.fi>
Date: Tue, 13 Apr 2010 06:01:46 +0000 (+0100)
Subject: ARM: 6052/1: kdump: make kexec work in interrupt context
X-Git-Tag: firefly_0821_release~10292
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=4d473cae1c0768d01a31580510d8729d983c2b8c;p=firefly-linux-kernel-4.4.55.git

ARM: 6052/1: kdump: make kexec work in interrupt context

When crash happens in interrupt context there is no userspace context.
We always use current->active_mm in those cases.

Signed-off-by: Mika Westerberg <ext-mika.1.westerberg@nokia.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index ea67be0223ac..c2f22eaa388e 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -1050,10 +1050,12 @@ void setup_mm_for_reboot(char mode)
 	pgd_t *pgd;
 	int i;
 
-	if (current->mm && current->mm->pgd)
-		pgd = current->mm->pgd;
-	else
-		pgd = init_mm.pgd;
+	/*
+	 * We need to access to user-mode page tables here. For kernel threads
+	 * we don't have any user-mode mappings so we use the context that we
+	 * "borrowed".
+	 */
+	pgd = current->active_mm->pgd;
 
 	base_pmdval = PMD_SECT_AP_WRITE | PMD_SECT_AP_READ | PMD_TYPE_SECT;
 	if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())