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authorRussell King <rmk@dyn-67.arm.linux.org.uk>2008-12-15 22:13:26 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2008-12-15 22:13:26 +0000
commit7e1548a597ef7e26d5d62f8be3be6da9e101b26c (patch)
treefe6cbf4d9a3c1afdba04fb276fef0f932403727c /arch/arm/mm/alignment.c
parent1f7f569c0ae6e619504095eabf796edd712d943d (diff)
parent2619bc327417f549f1c89d5ef9b4a4aa768f41a2 (diff)
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Merge branch 'omap3-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6 into devel
Diffstat (limited to 'arch/arm/mm/alignment.c')
-rw-r--r--arch/arm/mm/alignment.c26
1 files changed, 23 insertions, 3 deletions
diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c
index c5a57fbf095d..3a398befed41 100644
--- a/arch/arm/mm/alignment.c
+++ b/arch/arm/mm/alignment.c
@@ -71,6 +71,10 @@ static unsigned long ai_dword;
static unsigned long ai_multi;
static int ai_usermode;
+#define UM_WARN (1 << 0)
+#define UM_FIXUP (1 << 1)
+#define UM_SIGNAL (1 << 2)
+
#ifdef CONFIG_PROC_FS
static const char *usermode_action[] = {
"ignored",
@@ -755,7 +759,7 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
user:
ai_user += 1;
- if (ai_usermode & 1)
+ if (ai_usermode & UM_WARN)
printk("Alignment trap: %s (%d) PC=0x%08lx Instr=0x%0*lx "
"Address=0x%08lx FSR 0x%03x\n", current->comm,
task_pid_nr(current), instrptr,
@@ -763,10 +767,10 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
thumb_mode(regs) ? tinstr : instr,
addr, fsr);
- if (ai_usermode & 2)
+ if (ai_usermode & UM_FIXUP)
goto fixup;
- if (ai_usermode & 4)
+ if (ai_usermode & UM_SIGNAL)
force_sig(SIGBUS, current);
else
set_cr(cr_no_alignment);
@@ -797,6 +801,22 @@ static int __init alignment_init(void)
res->write_proc = proc_alignment_write;
#endif
+ /*
+ * ARMv6 and later CPUs can perform unaligned accesses for
+ * most single load and store instructions up to word size.
+ * LDM, STM, LDRD and STRD still need to be handled.
+ *
+ * Ignoring the alignment fault is not an option on these
+ * CPUs since we spin re-faulting the instruction without
+ * making any progress.
+ */
+ if (cpu_architecture() >= CPU_ARCH_ARMv6 && (cr_alignment & CR_U)) {
+ cr_alignment &= ~CR_A;
+ cr_no_alignment &= ~CR_A;
+ set_cr(cr_alignment);
+ ai_usermode = UM_FIXUP;
+ }
+
hook_fault_code(1, do_alignment, SIGILL, "alignment exception");
hook_fault_code(3, do_alignment, SIGILL, "alignment exception");