Hi Linus,
The following changes since commit 9489e9dcae718d5fde988e4a684a0f55b5f94d17:
Linux 3.7-rc7 (2012-11-25 17:59:19 -0800)
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/urgent
H. Peter Anvin (2):
x86, kvm: Remove incorrect redundant assembly constraint
x86-32: Unbreak booting on some 486 clones
Vincent Palatin (1):
x86, fpu: Avoid FPU lazy restore after suspend
arch/x86/include/asm/fpu-internal.h | 15 +++++++++------
arch/x86/kernel/head_32.S | 9 +++++++--
arch/x86/kernel/smpboot.c | 5 +++++
arch/x86/kvm/emulate.c | 3 +--
4 files changed, 22 insertions(+), 10 deletions(-)
diff --git a/arch/x86/include/asm/fpu-internal.h
b/arch/x86/include/asm/fpu-internal.h
index 831dbb9..41ab26e 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -399,14 +399,17 @@ static inline void drop_init_fpu(struct task_struct *tsk)
typedef struct { int preload; } fpu_switch_t;
/*
- * FIXME! We could do a totally lazy restore, but we need to
- * add a per-cpu "this was the task that last touched the FPU
- * on this CPU" variable, and the task needs to have a "I last
- * touched the FPU on this CPU" and check them.
+ * Must be run with preemption disabled: this clears the fpu_owner_task,
+ * on this CPU.
*
- * We don't do that yet, so "fpu_lazy_restore()" always returns
- * false, but some day..
+ * This will disable any lazy FPU state restore of the current FPU state,
+ * but if the current thread owns the FPU, it will still be saved by.
*/
+static inline void __cpu_disable_lazy_restore(unsigned int cpu)
+{
+ per_cpu(fpu_owner_task, cpu) = NULL;
+}
+
static inline int fpu_lazy_restore(struct task_struct *new, unsigned int cpu)
{
return new == this_cpu_read_stable(fpu_owner_task) &&
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 957a47a..4dac2f6 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -292,8 +292,8 @@ default_entry:
* be using the global pages.
*
* NOTE! If we are on a 486 we may have no cr4 at all!
- * Specifically, cr4 exists if and only if CPUID exists,
- * which in turn exists if and only if EFLAGS.ID exists.
+ * Specifically, cr4 exists if and only if CPUID exists
+ * and has flags other than the FPU flag set.
*/
movl $X86_EFLAGS_ID,%ecx
pushl %ecx
@@ -308,6 +308,11 @@ default_entry:
testl %ecx,%eax
jz 6f # No ID flag = no CPUID = no CR4
+ movl $1,%eax
+ cpuid
+ andl $~1,%edx # Ignore CPUID.FPU
+ jz 6f # No flags or only CPUID.FPU = no CR4
+
movl pa(mmu_cr4_features),%eax
movl %eax,%cr4
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index c80a33b..f3e2ec8 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -68,6 +68,8 @@
#include <asm/mwait.h>
#include <asm/apic.h>
#include <asm/io_apic.h>
+#include <asm/i387.h>
+#include <asm/fpu-internal.h>
#include <asm/setup.h>
#include <asm/uv/uv.h>
#include <linux/mc146818rtc.h>
@@ -818,6 +820,9 @@ int __cpuinit native_cpu_up(unsigned int cpu, struct
task_struct *tidle)
per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
+ /* the FPU context is blank, nobody can own it */
+ __cpu_disable_lazy_restore(cpu);
+
err = do_boot_cpu(apicid, cpu, tidle);
if (err) {
pr_debug("do_boot_cpu failed %d\n", err);
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 39171cb..bba39bf 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -426,8 +426,7 @@ static void invalidate_registers(struct x86_emulate_ctxt
*ctxt)
_ASM_EXTABLE(1b, 3b) \
: "=m" ((ctxt)->eflags), "=&r" (_tmp), \
"+a" (*rax), "+d" (*rdx), "+qm"(_ex) \
- : "i" (EFLAGS_MASK), "m" ((ctxt)->src.val), \
- "a" (*rax), "d" (*rdx)); \
+ : "i" (EFLAGS_MASK), "m" ((ctxt)->src.val)); \
} while (0)
/* instruction has only one source operand, destination is implicit (e.g. mul,
div, imul, idiv) */
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
