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-rw-r--r--arch/x86/include/asm/linkage.h16
-rw-r--r--arch/x86/kernel/cpu/amd.c52
-rw-r--r--arch/x86/kernel/cpu/intel.c25
-rw-r--r--arch/x86/kernel/ds.c3
-rw-r--r--arch/x86/kernel/setup_percpu.c73
-rw-r--r--arch/x86/kernel/smpboot.c78
-rw-r--r--arch/x86/kernel/tlb_uv.c2
-rw-r--r--arch/x86/mm/init.c2
-rw-r--r--arch/x86/mm/init_32.c23
-rw-r--r--arch/x86/mm/init_64.c8
-rw-r--r--arch/x86/mm/ioremap.c2
-rw-r--r--arch/x86/mm/kmmio.c15
-rw-r--r--arch/x86/mm/memtest.c3
13 files changed, 172 insertions, 130 deletions
diff --git a/arch/x86/include/asm/linkage.h b/arch/x86/include/asm/linkage.h
index 9320e2a8a26..a0d70b46c27 100644
--- a/arch/x86/include/asm/linkage.h
+++ b/arch/x86/include/asm/linkage.h
@@ -4,11 +4,6 @@
#undef notrace
#define notrace __attribute__((no_instrument_function))
-#ifdef CONFIG_X86_64
-#define __ALIGN .p2align 4,,15
-#define __ALIGN_STR ".p2align 4,,15"
-#endif
-
#ifdef CONFIG_X86_32
#define asmlinkage CPP_ASMLINKAGE __attribute__((regparm(0)))
/*
@@ -50,16 +45,25 @@
__asmlinkage_protect_n(ret, "g" (arg1), "g" (arg2), "g" (arg3), \
"g" (arg4), "g" (arg5), "g" (arg6))
-#endif
+#endif /* CONFIG_X86_32 */
+
+#ifdef __ASSEMBLY__
#define GLOBAL(name) \
.globl name; \
name:
+#ifdef CONFIG_X86_64
+#define __ALIGN .p2align 4,,15
+#define __ALIGN_STR ".p2align 4,,15"
+#endif
+
#ifdef CONFIG_X86_ALIGNMENT_16
#define __ALIGN .align 16,0x90
#define __ALIGN_STR ".align 16,0x90"
#endif
+#endif /* __ASSEMBLY__ */
+
#endif /* _ASM_X86_LINKAGE_H */
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 25423a5b80e..f47df59016c 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -5,6 +5,7 @@
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/apic.h>
+#include <asm/cpu.h>
#ifdef CONFIG_X86_64
# include <asm/numa_64.h>
@@ -141,6 +142,55 @@ static void __cpuinit init_amd_k6(struct cpuinfo_x86 *c)
}
}
+static void __cpuinit amd_k7_smp_check(struct cpuinfo_x86 *c)
+{
+#ifdef CONFIG_SMP
+ /* calling is from identify_secondary_cpu() ? */
+ if (c->cpu_index == boot_cpu_id)
+ return;
+
+ /*
+ * Certain Athlons might work (for various values of 'work') in SMP
+ * but they are not certified as MP capable.
+ */
+ /* Athlon 660/661 is valid. */
+ if ((c->x86_model == 6) && ((c->x86_mask == 0) ||
+ (c->x86_mask == 1)))
+ goto valid_k7;
+
+ /* Duron 670 is valid */
+ if ((c->x86_model == 7) && (c->x86_mask == 0))
+ goto valid_k7;
+
+ /*
+ * Athlon 662, Duron 671, and Athlon >model 7 have capability
+ * bit. It's worth noting that the A5 stepping (662) of some
+ * Athlon XP's have the MP bit set.
+ * See http://www.heise.de/newsticker/data/jow-18.10.01-000 for
+ * more.
+ */
+ if (((c->x86_model == 6) && (c->x86_mask >= 2)) ||
+ ((c->x86_model == 7) && (c->x86_mask >= 1)) ||
+ (c->x86_model > 7))
+ if (cpu_has_mp)
+ goto valid_k7;
+
+ /* If we get here, not a certified SMP capable AMD system. */
+
+ /*
+ * Don't taint if we are running SMP kernel on a single non-MP
+ * approved Athlon
+ */
+ WARN_ONCE(1, "WARNING: This combination of AMD"
+ "processors is not suitable for SMP.\n");
+ if (!test_taint(TAINT_UNSAFE_SMP))
+ add_taint(TAINT_UNSAFE_SMP);
+
+valid_k7:
+ ;
+#endif
+}
+
static void __cpuinit init_amd_k7(struct cpuinfo_x86 *c)
{
u32 l, h;
@@ -175,6 +225,8 @@ static void __cpuinit init_amd_k7(struct cpuinfo_x86 *c)
}
set_cpu_cap(c, X86_FEATURE_K7);
+
+ amd_k7_smp_check(c);
}
#endif
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 25c559ba8d5..191117f1ad5 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -13,6 +13,7 @@
#include <asm/uaccess.h>
#include <asm/ds.h>
#include <asm/bugs.h>
+#include <asm/cpu.h>
#ifdef CONFIG_X86_64
#include <asm/topology.h>
@@ -110,6 +111,28 @@ static void __cpuinit trap_init_f00f_bug(void)
}
#endif
+static void __cpuinit intel_smp_check(struct cpuinfo_x86 *c)
+{
+#ifdef CONFIG_SMP
+ /* calling is from identify_secondary_cpu() ? */
+ if (c->cpu_index == boot_cpu_id)
+ return;
+
+ /*
+ * Mask B, Pentium, but not Pentium MMX
+ */
+ if (c->x86 == 5 &&
+ c->x86_mask >= 1 && c->x86_mask <= 4 &&
+ c->x86_model <= 3) {
+ /*
+ * Remember we have B step Pentia with bugs
+ */
+ WARN_ONCE(1, "WARNING: SMP operation may be unreliable"
+ "with B stepping processors.\n");
+ }
+#endif
+}
+
static void __cpuinit intel_workarounds(struct cpuinfo_x86 *c)
{
unsigned long lo, hi;
@@ -186,6 +209,8 @@ static void __cpuinit intel_workarounds(struct cpuinfo_x86 *c)
#ifdef CONFIG_X86_NUMAQ
numaq_tsc_disable();
#endif
+
+ intel_smp_check(c);
}
#else
static void __cpuinit intel_workarounds(struct cpuinfo_x86 *c)
diff --git a/arch/x86/kernel/ds.c b/arch/x86/kernel/ds.c
index 169a120587b..87b67e3a765 100644
--- a/arch/x86/kernel/ds.c
+++ b/arch/x86/kernel/ds.c
@@ -729,7 +729,7 @@ struct pebs_tracer *ds_request_pebs(struct task_struct *task,
spin_unlock_irqrestore(&ds_lock, irq);
- ds_write_config(tracer->ds.context, &tracer->trace.ds, ds_bts);
+ ds_write_config(tracer->ds.context, &tracer->trace.ds, ds_pebs);
ds_resume_pebs(tracer);
return tracer;
@@ -1029,5 +1029,4 @@ void ds_copy_thread(struct task_struct *tsk, struct task_struct *father)
void ds_exit_thread(struct task_struct *tsk)
{
- WARN_ON(tsk->thread.ds_ctx);
}
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index c29f301d388..efa615f2bf4 100644
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -42,6 +42,19 @@ unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = {
};
EXPORT_SYMBOL(__per_cpu_offset);
+/*
+ * On x86_64 symbols referenced from code should be reachable using
+ * 32bit relocations. Reserve space for static percpu variables in
+ * modules so that they are always served from the first chunk which
+ * is located at the percpu segment base. On x86_32, anything can
+ * address anywhere. No need to reserve space in the first chunk.
+ */
+#ifdef CONFIG_X86_64
+#define PERCPU_FIRST_CHUNK_RESERVE PERCPU_MODULE_RESERVE
+#else
+#define PERCPU_FIRST_CHUNK_RESERVE 0
+#endif
+
/**
* pcpu_need_numa - determine percpu allocation needs to consider NUMA
*
@@ -141,7 +154,7 @@ static ssize_t __init setup_pcpu_remap(size_t static_size)
{
static struct vm_struct vm;
pg_data_t *last;
- size_t ptrs_size;
+ size_t ptrs_size, dyn_size;
unsigned int cpu;
ssize_t ret;
@@ -169,12 +182,14 @@ proceed:
* Currently supports only single page. Supporting multiple
* pages won't be too difficult if it ever becomes necessary.
*/
- pcpur_size = PFN_ALIGN(static_size + PERCPU_DYNAMIC_RESERVE);
+ pcpur_size = PFN_ALIGN(static_size + PERCPU_MODULE_RESERVE +
+ PERCPU_DYNAMIC_RESERVE);
if (pcpur_size > PMD_SIZE) {
pr_warning("PERCPU: static data is larger than large page, "
"can't use large page\n");
return -EINVAL;
}
+ dyn_size = pcpur_size - static_size - PERCPU_FIRST_CHUNK_RESERVE;
/* allocate pointer array and alloc large pages */
ptrs_size = PFN_ALIGN(num_possible_cpus() * sizeof(pcpur_ptrs[0]));
@@ -217,8 +232,9 @@ proceed:
pr_info("PERCPU: Remapped at %p with large pages, static data "
"%zu bytes\n", vm.addr, static_size);
- ret = pcpu_setup_first_chunk(pcpur_get_page, static_size, PMD_SIZE,
- pcpur_size - static_size, vm.addr, NULL);
+ ret = pcpu_setup_first_chunk(pcpur_get_page, static_size,
+ PERCPU_FIRST_CHUNK_RESERVE,
+ PMD_SIZE, dyn_size, vm.addr, NULL);
goto out_free_ar;
enomem:
@@ -241,24 +257,31 @@ static ssize_t __init setup_pcpu_remap(size_t static_size)
* Embedding allocator
*
* The first chunk is sized to just contain the static area plus
- * PERCPU_DYNAMIC_RESERVE and allocated as a contiguous area using
- * bootmem allocator and used as-is without being mapped into vmalloc
- * area. This enables the first chunk to piggy back on the linear
- * physical PMD mapping and doesn't add any additional pressure to
- * TLB.
+ * module and dynamic reserves, and allocated as a contiguous area
+ * using bootmem allocator and used as-is without being mapped into
+ * vmalloc area. This enables the first chunk to piggy back on the
+ * linear physical PMD mapping and doesn't add any additional pressure
+ * to TLB. Note that if the needed size is smaller than the minimum
+ * unit size, the leftover is returned to the bootmem allocator.
*/
static void *pcpue_ptr __initdata;
+static size_t pcpue_size __initdata;
static size_t pcpue_unit_size __initdata;
static struct page * __init pcpue_get_page(unsigned int cpu, int pageno)
{
- return virt_to_page(pcpue_ptr + cpu * pcpue_unit_size
- + ((size_t)pageno << PAGE_SHIFT));
+ size_t off = (size_t)pageno << PAGE_SHIFT;
+
+ if (off >= pcpue_size)
+ return NULL;
+
+ return virt_to_page(pcpue_ptr + cpu * pcpue_unit_size + off);
}
static ssize_t __init setup_pcpu_embed(size_t static_size)
{
unsigned int cpu;
+ size_t dyn_size;
/*
* If large page isn't supported, there's no benefit in doing
@@ -269,25 +292,32 @@ static ssize_t __init setup_pcpu_embed(size_t static_size)
return -EINVAL;
/* allocate and copy */
- pcpue_unit_size = PFN_ALIGN(static_size + PERCPU_DYNAMIC_RESERVE);
- pcpue_unit_size = max_t(size_t, pcpue_unit_size, PCPU_MIN_UNIT_SIZE);
+ pcpue_size = PFN_ALIGN(static_size + PERCPU_MODULE_RESERVE +
+ PERCPU_DYNAMIC_RESERVE);
+ pcpue_unit_size = max_t(size_t, pcpue_size, PCPU_MIN_UNIT_SIZE);
+ dyn_size = pcpue_size - static_size - PERCPU_FIRST_CHUNK_RESERVE;
+
pcpue_ptr = pcpu_alloc_bootmem(0, num_possible_cpus() * pcpue_unit_size,
PAGE_SIZE);
if (!pcpue_ptr)
return -ENOMEM;
- for_each_possible_cpu(cpu)
- memcpy(pcpue_ptr + cpu * pcpue_unit_size, __per_cpu_load,
- static_size);
+ for_each_possible_cpu(cpu) {
+ void *ptr = pcpue_ptr + cpu * pcpue_unit_size;
+
+ free_bootmem(__pa(ptr + pcpue_size),
+ pcpue_unit_size - pcpue_size);
+ memcpy(ptr, __per_cpu_load, static_size);
+ }
/* we're ready, commit */
pr_info("PERCPU: Embedded %zu pages at %p, static data %zu bytes\n",
- pcpue_unit_size >> PAGE_SHIFT, pcpue_ptr, static_size);
+ pcpue_size >> PAGE_SHIFT, pcpue_ptr, static_size);
return pcpu_setup_first_chunk(pcpue_get_page, static_size,
- pcpue_unit_size,
- pcpue_unit_size - static_size, pcpue_ptr,
- NULL);
+ PERCPU_FIRST_CHUNK_RESERVE,
+ pcpue_unit_size, dyn_size,
+ pcpue_ptr, NULL);
}
/*
@@ -344,7 +374,8 @@ static ssize_t __init setup_pcpu_4k(size_t static_size)
pr_info("PERCPU: Allocated %d 4k pages, static data %zu bytes\n",
pcpu4k_nr_static_pages, static_size);
- ret = pcpu_setup_first_chunk(pcpu4k_get_page, static_size, 0, 0, NULL,
+ ret = pcpu_setup_first_chunk(pcpu4k_get_page, static_size,
+ PERCPU_FIRST_CHUNK_RESERVE, -1, -1, NULL,
pcpu4k_populate_pte);
goto out_free_ar;
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 249334f5080..ef7d10170c3 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -114,10 +114,6 @@ EXPORT_PER_CPU_SYMBOL(cpu_info);
atomic_t init_deasserted;
-
-/* Set if we find a B stepping CPU */
-static int __cpuinitdata smp_b_stepping;
-
#if defined(CONFIG_NUMA) && defined(CONFIG_X86_32)
/* which logical CPUs are on which nodes */
@@ -271,8 +267,6 @@ static void __cpuinit smp_callin(void)
cpumask_set_cpu(cpuid, cpu_callin_mask);
}
-static int __cpuinitdata unsafe_smp;
-
/*
* Activate a secondary processor.
*/
@@ -340,76 +334,6 @@ notrace static void __cpuinit start_secondary(void *unused)
cpu_idle();
}
-static void __cpuinit smp_apply_quirks(struct cpuinfo_x86 *c)
-{
- /*
- * Mask B, Pentium, but not Pentium MMX
- */
- if (c->x86_vendor == X86_VENDOR_INTEL &&
- c->x86 == 5 &&
- c->x86_mask >= 1 && c->x86_mask <= 4 &&
- c->x86_model <= 3)
- /*
- * Remember we have B step Pentia with bugs
- */
- smp_b_stepping = 1;
-
- /*
- * Certain Athlons might work (for various values of 'work') in SMP
- * but they are not certified as MP capable.
- */
- if ((c->x86_vendor == X86_VENDOR_AMD) && (c->x86 == 6)) {
-
- if (num_possible_cpus() == 1)
- goto valid_k7;
-
- /* Athlon 660/661 is valid. */
- if ((c->x86_model == 6) && ((c->x86_mask == 0) ||
- (c->x86_mask == 1)))
- goto valid_k7;
-
- /* Duron 670 is valid */
- if ((c->x86_model == 7) && (c->x86_mask == 0))
- goto valid_k7;
-
- /*
- * Athlon 662, Duron 671, and Athlon >model 7 have capability
- * bit. It's worth noting that the A5 stepping (662) of some
- * Athlon XP's have the MP bit set.
- * See http://www.heise.de/newsticker/data/jow-18.10.01-000 for
- * more.
- */
- if (((c->x86_model == 6) && (c->x86_mask >= 2)) ||
- ((c->x86_model == 7) && (c->x86_mask >= 1)) ||
- (c->x86_model > 7))
- if (cpu_has_mp)
- goto valid_k7;
-
- /* If we get here, not a certified SMP capable AMD system. */
- unsafe_smp = 1;
- }
-
-valid_k7:
- ;
-}
-
-static void __cpuinit smp_checks(void)
-{
- if (smp_b_stepping)
- printk(KERN_WARNING "WARNING: SMP operation may be unreliable"
- "with B stepping processors.\n");
-
- /*
- * Don't taint if we are running SMP kernel on a single non-MP
- * approved Athlon
- */
- if (unsafe_smp && num_online_cpus() > 1) {
- printk(KERN_INFO "WARNING: This combination of AMD"
- "processors is not suitable for SMP.\n");
- add_taint(TAINT_UNSAFE_SMP);
- }
-}
-
/*
* The bootstrap kernel entry code has set these up. Save them for
* a given CPU
@@ -423,7 +347,6 @@ void __cpuinit smp_store_cpu_info(int id)
c->cpu_index = id;
if (id != 0)
identify_secondary_cpu(c);
- smp_apply_quirks(c);
}
@@ -1193,7 +1116,6 @@ void __init native_smp_cpus_done(unsigned int max_cpus)
pr_debug("Boot done.\n");
impress_friends();
- smp_checks();
#ifdef CONFIG_X86_IO_APIC
setup_ioapic_dest();
#endif
diff --git a/arch/x86/kernel/tlb_uv.c b/arch/x86/kernel/tlb_uv.c
index f04549afcfe..d038b9c45cf 100644
--- a/arch/x86/kernel/tlb_uv.c
+++ b/arch/x86/kernel/tlb_uv.c
@@ -314,8 +314,6 @@ const struct cpumask *uv_flush_tlb_others(const struct cpumask *cpumask,
int locals = 0;
struct bau_desc *bau_desc;
- WARN_ON(!in_atomic());
-
cpumask_andnot(flush_mask, cpumask, cpumask_of(cpu));
uv_cpu = uv_blade_processor_id();
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 6d63e3d1253..15219e0d124 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -134,8 +134,8 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
{
unsigned long page_size_mask = 0;
unsigned long start_pfn, end_pfn;
+ unsigned long ret = 0;
unsigned long pos;
- unsigned long ret;
struct map_range mr[NR_RANGE_MR];
int nr_range, i;
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 2966c6b8d30..db81e9a8556 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -806,11 +806,6 @@ static unsigned long __init setup_node_bootmem(int nodeid,
{
unsigned long bootmap_size;
- if (start_pfn > max_low_pfn)
- return bootmap;
- if (end_pfn > max_low_pfn)
- end_pfn = max_low_pfn;
-
/* don't touch min_low_pfn */
bootmap_size = init_bootmem_node(NODE_DATA(nodeid),
bootmap >> PAGE_SHIFT,
@@ -843,13 +838,23 @@ void __init setup_bootmem_allocator(void)
max_pfn_mapped<<PAGE_SHIFT);
printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);
+ for_each_online_node(nodeid) {
+ unsigned long start_pfn, end_pfn;
+
#ifdef CONFIG_NEED_MULTIPLE_NODES
- for_each_online_node(nodeid)
- bootmap = setup_node_bootmem(nodeid, node_start_pfn[nodeid],
- node_end_pfn[nodeid], bootmap);
+ start_pfn = node_start_pfn[nodeid];
+ end_pfn = node_end_pfn[nodeid];
+ if (start_pfn > max_low_pfn)
+ continue;
+ if (end_pfn > max_low_pfn)
+ end_pfn = max_low_pfn;
#else
- bootmap = setup_node_bootmem(0, 0, max_low_pfn, bootmap);
+ start_pfn = 0;
+ end_pfn = max_low_pfn;
#endif
+ bootmap = setup_node_bootmem(nodeid, start_pfn, end_pfn,
+ bootmap);
+ }
after_bootmem = 1;
}
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 8a853bc3b28..54efa57d1c0 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -85,7 +85,7 @@ early_param("gbpages", parse_direct_gbpages_on);
pteval_t __supported_pte_mask __read_mostly = ~_PAGE_IOMAP;
EXPORT_SYMBOL_GPL(__supported_pte_mask);
-static int do_not_nx __cpuinitdata;
+static int disable_nx __cpuinitdata;
/*
* noexec=on|off
@@ -100,9 +100,9 @@ static int __init nonx_setup(char *str)
return -EINVAL;
if (!strncmp(str, "on", 2)) {
__supported_pte_mask |= _PAGE_NX;
- do_not_nx = 0;
+ disable_nx = 0;
} else if (!strncmp(str, "off", 3)) {
- do_not_nx = 1;
+ disable_nx = 1;
__supported_pte_mask &= ~_PAGE_NX;
}
return 0;
@@ -114,7 +114,7 @@ void __cpuinit check_efer(void)
unsigned long efer;
rdmsrl(MSR_EFER, efer);
- if (!(efer & EFER_NX) || do_not_nx)
+ if (!(efer & EFER_NX) || disable_nx)
__supported_pte_mask &= ~_PAGE_NX;
}
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 96786ef2c9a..aca924a30ee 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -87,6 +87,8 @@ bool __virt_addr_valid(unsigned long x)
return false;
if (__vmalloc_start_set && is_vmalloc_addr((void *) x))
return false;
+ if (x >= FIXADDR_START)
+ return false;
return pfn_valid((x - PAGE_OFFSET) >> PAGE_SHIFT);
}
EXPORT_SYMBOL(__virt_addr_valid);
diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c
index 9f205030d9a..6a518dd08a3 100644
--- a/arch/x86/mm/kmmio.c
+++ b/arch/x86/mm/kmmio.c
@@ -451,23 +451,24 @@ static void rcu_free_kmmio_fault_pages(struct rcu_head *head)
static void remove_kmmio_fault_pages(struct rcu_head *head)
{
- struct kmmio_delayed_release *dr = container_of(
- head,
- struct kmmio_delayed_release,
- rcu);
+ struct kmmio_delayed_release *dr =
+ container_of(head, struct kmmio_delayed_release, rcu);
struct kmmio_fault_page *p = dr->release_list;
struct kmmio_fault_page **prevp = &dr->release_list;
unsigned long flags;
+
spin_lock_irqsave(&kmmio_lock, flags);
while (p) {
- if (!p->count)
+ if (!p->count) {
list_del_rcu(&p->list);
- else
+ prevp = &p->release_next;
+ } else {
*prevp = p->release_next;
- prevp = &p->release_next;
+ }
p = p->release_next;
}
spin_unlock_irqrestore(&kmmio_lock, flags);
+
/* This is the real RCU destroy call. */
call_rcu(&dr->rcu, rcu_free_kmmio_fault_pages);
}
diff --git a/arch/x86/mm/memtest.c b/arch/x86/mm/memtest.c
index 0bcd7883d03..605c8be0621 100644
--- a/arch/x86/mm/memtest.c
+++ b/arch/x86/mm/memtest.c
@@ -100,6 +100,9 @@ static int __init parse_memtest(char *arg)
{
if (arg)
memtest_pattern = simple_strtoul(arg, NULL, 0);
+ else
+ memtest_pattern = ARRAY_SIZE(patterns);
+
return 0;
}