aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--arch/arm/include/asm/smp_plat.h16
-rw-r--r--arch/arm/kernel/smp.c7
-rw-r--r--arch/arm/mm/mmu.c37
3 files changed, 50 insertions, 10 deletions
diff --git a/arch/arm/include/asm/smp_plat.h b/arch/arm/include/asm/smp_plat.h
new file mode 100644
index 00000000000..59303e20084
--- /dev/null
+++ b/arch/arm/include/asm/smp_plat.h
@@ -0,0 +1,16 @@
+/*
+ * ARM specific SMP header, this contains our implementation
+ * details.
+ */
+#ifndef __ASMARM_SMP_PLAT_H
+#define __ASMARM_SMP_PLAT_H
+
+#include <asm/cputype.h>
+
+/* all SMP configurations have the extended CPUID registers */
+static inline int tlb_ops_need_broadcast(void)
+{
+ return ((read_cpuid_ext(CPUID_EXT_MMFR3) >> 12) & 0xf) < 2;
+}
+
+#endif
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index e0d32770bb3..9d015ee5747 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -36,6 +36,7 @@
#include <asm/tlbflush.h>
#include <asm/ptrace.h>
#include <asm/localtimer.h>
+#include <asm/smp_plat.h>
/*
* as from 2.5, kernels no longer have an init_tasks structure
@@ -586,12 +587,6 @@ struct tlb_args {
unsigned long ta_end;
};
-/* all SMP configurations have the extended CPUID registers */
-static inline int tlb_ops_need_broadcast(void)
-{
- return ((read_cpuid_ext(CPUID_EXT_MMFR3) >> 12) & 0xf) < 2;
-}
-
static inline void ipi_flush_tlb_all(void *ignored)
{
local_flush_tlb_all();
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index ce551ec2cb2..02243eeccf5 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -21,6 +21,7 @@
#include <asm/cachetype.h>
#include <asm/setup.h>
#include <asm/sizes.h>
+#include <asm/smp_plat.h>
#include <asm/tlb.h>
#include <asm/highmem.h>
@@ -709,10 +710,6 @@ static void __init sanity_check_meminfo(void)
if (meminfo.nr_banks >= NR_BANKS) {
printk(KERN_CRIT "NR_BANKS too low, "
"ignoring high memory\n");
- } else if (cache_is_vipt_aliasing()) {
- printk(KERN_CRIT "HIGHMEM is not yet supported "
- "with VIPT aliasing cache, "
- "ignoring high memory\n");
} else {
memmove(bank + 1, bank,
(meminfo.nr_banks - i) * sizeof(*bank));
@@ -756,6 +753,38 @@ static void __init sanity_check_meminfo(void)
#endif
j++;
}
+#ifdef CONFIG_HIGHMEM
+ if (highmem) {
+ const char *reason = NULL;
+
+ if (cache_is_vipt_aliasing()) {
+ /*
+ * Interactions between kmap and other mappings
+ * make highmem support with aliasing VIPT caches
+ * rather difficult.
+ */
+ reason = "with VIPT aliasing cache";
+#ifdef CONFIG_SMP
+ } else if (tlb_ops_need_broadcast()) {
+ /*
+ * kmap_high needs to occasionally flush TLB entries,
+ * however, if the TLB entries need to be broadcast
+ * we may deadlock:
+ * kmap_high(irqs off)->flush_all_zero_pkmaps->
+ * flush_tlb_kernel_range->smp_call_function_many
+ * (must not be called with irqs off)
+ */
+ reason = "without hardware TLB ops broadcasting";
+#endif
+ }
+ if (reason) {
+ printk(KERN_CRIT "HIGHMEM is not supported %s, ignoring high memory\n",
+ reason);
+ while (j > 0 && meminfo.bank[j - 1].highmem)
+ j--;
+ }
+ }
+#endif
meminfo.nr_banks = j;
}