[tip:perf/x86] x86: Clean up cr4 manipulation

From: tip-bot for Andy Lutomirski
Date: Wed Feb 04 2015 - 09:42:31 EST

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Commit-ID: 375074cc736ab1d89a708c0a8d7baa4a70d5d476
Gitweb: http://git.kernel.org/tip/375074cc736ab1d89a708c0a8d7baa4a70d5d476
Author: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
AuthorDate: Fri, 24 Oct 2014 15:58:07 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 4 Feb 2015 12:10:41 +0100

x86: Clean up cr4 manipulation

CR4 manipulation was split, seemingly at random, between direct
(write_cr4) and using a helper (set/clear_in_cr4). Unfortunately,
the set_in_cr4 and clear_in_cr4 helpers also poke at the boot code,
which only a small subset of users actually wanted.

This patch replaces all cr4 access in functions that don't leave cr4
exactly the way they found it with new helpers cr4_set_bits,
cr4_clear_bits, and cr4_set_bits_and_update_boot.

Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Vince Weaver <vince@xxxxxxxxxx>
Cc: "hillf.zj" <hillf.zj@xxxxxxxxxxxxxxx>
Cc: Valdis Kletnieks <Valdis.Kletnieks@xxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/495a10bdc9e67016b8fd3945700d46cfd5c12c2f.1414190806.git.luto@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/processor.h | 33 --------------------------------
arch/x86/include/asm/tlbflush.h | 37 ++++++++++++++++++++++++++++++++++++
arch/x86/include/asm/virtext.h | 3 ++-
arch/x86/kernel/cpu/common.c | 10 +++++-----
arch/x86/kernel/cpu/mcheck/mce.c | 3 ++-
arch/x86/kernel/cpu/mcheck/p5.c | 3 ++-
arch/x86/kernel/cpu/mcheck/winchip.c | 3 ++-
arch/x86/kernel/cpu/perf_event.c | 7 ++++---
arch/x86/kernel/i387.c | 3 ++-
arch/x86/kernel/process.c | 5 +++--
arch/x86/kernel/xsave.c | 3 ++-
arch/x86/kvm/vmx.c | 4 ++--
arch/x86/mm/init.c | 4 ++--
arch/x86/xen/enlighten.c | 4 ++--
drivers/lguest/x86/core.c | 5 +++--
15 files changed, 70 insertions(+), 57 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index a092a0c..ec1c935 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -579,39 +579,6 @@ static inline void load_sp0(struct tss_struct *tss,
#define set_iopl_mask native_set_iopl_mask
#endif /* CONFIG_PARAVIRT */

-/*
- * Save the cr4 feature set we're using (ie
- * Pentium 4MB enable and PPro Global page
- * enable), so that any CPU's that boot up
- * after us can get the correct flags.
- */
-extern unsigned long mmu_cr4_features;
-extern u32 *trampoline_cr4_features;
-
-static inline void set_in_cr4(unsigned long mask)
-{
- unsigned long cr4;
-
- mmu_cr4_features |= mask;
- if (trampoline_cr4_features)
- *trampoline_cr4_features = mmu_cr4_features;
- cr4 = read_cr4();
- cr4 |= mask;
- write_cr4(cr4);
-}
-
-static inline void clear_in_cr4(unsigned long mask)
-{
- unsigned long cr4;
-
- mmu_cr4_features &= ~mask;
- if (trampoline_cr4_features)
- *trampoline_cr4_features = mmu_cr4_features;
- cr4 = read_cr4();
- cr4 &= ~mask;
- write_cr4(cr4);
-}
-
typedef struct {
unsigned long seg;
} mm_segment_t;
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index 04905bf..fc0c4bc 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -15,6 +15,43 @@
#define __flush_tlb_single(addr) __native_flush_tlb_single(addr)
#endif

+/* Set in this cpu's CR4. */
+static inline void cr4_set_bits(unsigned long mask)
+{
+ unsigned long cr4;
+
+ cr4 = read_cr4();
+ cr4 |= mask;
+ write_cr4(cr4);
+}
+
+/* Clear in this cpu's CR4. */
+static inline void cr4_clear_bits(unsigned long mask)
+{
+ unsigned long cr4;
+
+ cr4 = read_cr4();
+ cr4 &= ~mask;
+ write_cr4(cr4);
+}
+
+/*
+ * Save some of cr4 feature set we're using (e.g. Pentium 4MB
+ * enable and PPro Global page enable), so that any CPU's that boot
+ * up after us can get the correct flags. This should only be used
+ * during boot on the boot cpu.
+ */
+extern unsigned long mmu_cr4_features;
+extern u32 *trampoline_cr4_features;
+
+static inline void cr4_set_bits_and_update_boot(unsigned long mask)
+{
+ mmu_cr4_features |= mask;
+ if (trampoline_cr4_features)
+ *trampoline_cr4_features = mmu_cr4_features;
+ cr4_set_bits(mask);
+}
+
static inline void __native_flush_tlb(void)
{
native_write_cr3(native_read_cr3());
diff --git a/arch/x86/include/asm/virtext.h b/arch/x86/include/asm/virtext.h
index 5da71c2..f41e19c 100644
--- a/arch/x86/include/asm/virtext.h
+++ b/arch/x86/include/asm/virtext.h
@@ -19,6 +19,7 @@

#include <asm/vmx.h>
#include <asm/svm.h>
+#include <asm/tlbflush.h>

/*
* VMX functions:
@@ -40,7 +41,7 @@ static inline int cpu_has_vmx(void)
static inline void cpu_vmxoff(void)
{
asm volatile (ASM_VMX_VMXOFF : : : "cc");
- write_cr4(read_cr4() & ~X86_CR4_VMXE);
+ cr4_clear_bits(X86_CR4_VMXE);
}

static inline int cpu_vmx_enabled(void)
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index c604965..9d8fc49 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -278,7 +278,7 @@ __setup("nosmep", setup_disable_smep);
static __always_inline void setup_smep(struct cpuinfo_x86 *c)
{
if (cpu_has(c, X86_FEATURE_SMEP))
- set_in_cr4(X86_CR4_SMEP);
+ cr4_set_bits(X86_CR4_SMEP);
}

static __init int setup_disable_smap(char *arg)
@@ -298,9 +298,9 @@ static __always_inline void setup_smap(struct cpuinfo_x86 *c)

if (cpu_has(c, X86_FEATURE_SMAP)) {
#ifdef CONFIG_X86_SMAP
- set_in_cr4(X86_CR4_SMAP);
+ cr4_set_bits(X86_CR4_SMAP);
#else
- clear_in_cr4(X86_CR4_SMAP);
+ cr4_clear_bits(X86_CR4_SMAP);
#endif
}
}
@@ -1312,7 +1312,7 @@ void cpu_init(void)

pr_debug("Initializing CPU#%d\n", cpu);

- clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
+ cr4_clear_bits(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);

/*
* Initialize the per-CPU GDT with the boot GDT,
@@ -1393,7 +1393,7 @@ void cpu_init(void)
printk(KERN_INFO "Initializing CPU#%d\n", cpu);

if (cpu_feature_enabled(X86_FEATURE_VME) || cpu_has_tsc || cpu_has_de)
- clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
+ cr4_clear_bits(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);

load_current_idt();
switch_to_new_gdt(cpu);
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index d231799..15ad3ed 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -44,6 +44,7 @@

#include <asm/processor.h>
#include <asm/traps.h>
+#include <asm/tlbflush.h>
#include <asm/mce.h>
#include <asm/msr.h>

@@ -1449,7 +1450,7 @@ static void __mcheck_cpu_init_generic(void)
bitmap_fill(all_banks, MAX_NR_BANKS);
machine_check_poll(MCP_UC | m_fl, &all_banks);

- set_in_cr4(X86_CR4_MCE);
+ cr4_set_bits(X86_CR4_MCE);

rdmsrl(MSR_IA32_MCG_CAP, cap);
if (cap & MCG_CTL_P)
diff --git a/arch/x86/kernel/cpu/mcheck/p5.c b/arch/x86/kernel/cpu/mcheck/p5.c
index ec2663a..737b0ad 100644
--- a/arch/x86/kernel/cpu/mcheck/p5.c
+++ b/arch/x86/kernel/cpu/mcheck/p5.c
@@ -9,6 +9,7 @@

#include <asm/processor.h>
#include <asm/traps.h>
+#include <asm/tlbflush.h>
#include <asm/mce.h>
#include <asm/msr.h>

@@ -65,7 +66,7 @@ void intel_p5_mcheck_init(struct cpuinfo_x86 *c)
"Intel old style machine check architecture supported.\n");

/* Enable MCE: */
- set_in_cr4(X86_CR4_MCE);
+ cr4_set_bits(X86_CR4_MCE);
printk(KERN_INFO
"Intel old style machine check reporting enabled on CPU#%d.\n",
smp_processor_id());
diff --git a/arch/x86/kernel/cpu/mcheck/winchip.c b/arch/x86/kernel/cpu/mcheck/winchip.c
index bd5d46a..44f1382 100644
--- a/arch/x86/kernel/cpu/mcheck/winchip.c
+++ b/arch/x86/kernel/cpu/mcheck/winchip.c
@@ -8,6 +8,7 @@

#include <asm/processor.h>
#include <asm/traps.h>
+#include <asm/tlbflush.h>
#include <asm/mce.h>
#include <asm/msr.h>

@@ -36,7 +37,7 @@ void winchip_mcheck_init(struct cpuinfo_x86 *c)
lo &= ~(1<<4); /* Enable MCE */
wrmsr(MSR_IDT_FCR1, lo, hi);

- set_in_cr4(X86_CR4_MCE);
+ cr4_set_bits(X86_CR4_MCE);

printk(KERN_INFO
"Winchip machine check reporting enabled on CPU#0.\n");
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 143e5f5..6b5acd5 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -31,6 +31,7 @@
#include <asm/nmi.h>
#include <asm/smp.h>
#include <asm/alternative.h>
+#include <asm/tlbflush.h>
#include <asm/timer.h>
#include <asm/desc.h>
#include <asm/ldt.h>
@@ -1328,7 +1329,7 @@ x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)

case CPU_STARTING:
if (x86_pmu.attr_rdpmc)
- set_in_cr4(X86_CR4_PCE);
+ cr4_set_bits(X86_CR4_PCE);
if (x86_pmu.cpu_starting)
x86_pmu.cpu_starting(cpu);
break;
@@ -1834,9 +1835,9 @@ static void change_rdpmc(void *info)
bool enable = !!(unsigned long)info;

if (enable)
- set_in_cr4(X86_CR4_PCE);
+ cr4_set_bits(X86_CR4_PCE);
else
- clear_in_cr4(X86_CR4_PCE);
+ cr4_clear_bits(X86_CR4_PCE);
}

static ssize_t set_attr_rdpmc(struct device *cdev,
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index a9a4229..87727b0 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -13,6 +13,7 @@
#include <asm/sigcontext.h>
#include <asm/processor.h>
#include <asm/math_emu.h>
+#include <asm/tlbflush.h>
#include <asm/uaccess.h>
#include <asm/ptrace.h>
#include <asm/i387.h>
@@ -180,7 +181,7 @@ void fpu_init(void)
if (cpu_has_xmm)
cr4_mask |= X86_CR4_OSXMMEXCPT;
if (cr4_mask)
- set_in_cr4(cr4_mask);
+ cr4_set_bits(cr4_mask);

cr0 = read_cr0();
cr0 &= ~(X86_CR0_TS|X86_CR0_EM); /* clear TS and EM */
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index e127dda..046e2d6 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -28,6 +28,7 @@
#include <asm/fpu-internal.h>
#include <asm/debugreg.h>
#include <asm/nmi.h>
+#include <asm/tlbflush.h>

/*
* per-CPU TSS segments. Threads are completely 'soft' on Linux,
@@ -141,7 +142,7 @@ void flush_thread(void)

static void hard_disable_TSC(void)
{
- write_cr4(read_cr4() | X86_CR4_TSD);
+ cr4_set_bits(X86_CR4_TSD);
}

void disable_TSC(void)
@@ -158,7 +159,7 @@ void disable_TSC(void)

static void hard_enable_TSC(void)
{
- write_cr4(read_cr4() & ~X86_CR4_TSD);
+ cr4_clear_bits(X86_CR4_TSD);
}

static void enable_TSC(void)
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index 0de1fae..34f66e5 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -12,6 +12,7 @@
#include <asm/i387.h>
#include <asm/fpu-internal.h>
#include <asm/sigframe.h>
+#include <asm/tlbflush.h>
#include <asm/xcr.h>

/*
@@ -453,7 +454,7 @@ static void prepare_fx_sw_frame(void)
*/
static inline void xstate_enable(void)
{
- set_in_cr4(X86_CR4_OSXSAVE);
+ cr4_set_bits(X86_CR4_OSXSAVE);
xsetbv(XCR_XFEATURE_ENABLED_MASK, pcntxt_mask);
}

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d4c58d8..db77537 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2812,7 +2812,7 @@ static int hardware_enable(void)
/* enable and lock */
wrmsrl(MSR_IA32_FEATURE_CONTROL, old | test_bits);
}
- write_cr4(read_cr4() | X86_CR4_VMXE); /* FIXME: not cpu hotplug safe */
+ cr4_set_bits(X86_CR4_VMXE);

if (vmm_exclusive) {
kvm_cpu_vmxon(phys_addr);
@@ -2849,7 +2849,7 @@ static void hardware_disable(void)
vmclear_local_loaded_vmcss();
kvm_cpu_vmxoff();
}
- write_cr4(read_cr4() & ~X86_CR4_VMXE);
+ cr4_clear_bits(X86_CR4_VMXE);
}

static __init int adjust_vmx_controls(u32 ctl_min, u32 ctl_opt,
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 079c3b6..d4eddbd 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -173,11 +173,11 @@ static void __init probe_page_size_mask(void)

/* Enable PSE if available */
if (cpu_has_pse)
- set_in_cr4(X86_CR4_PSE);
+ cr4_set_bits_and_update_boot(X86_CR4_PSE);

/* Enable PGE if available */
if (cpu_has_pge) {
- set_in_cr4(X86_CR4_PGE);
+ cr4_set_bits_and_update_boot(X86_CR4_PGE);
__supported_pte_mask |= _PAGE_GLOBAL;
}
}
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 78a881b..bd8b845 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1494,10 +1494,10 @@ static void xen_pvh_set_cr_flags(int cpu)
* set them here. For all, OSFXSR OSXMMEXCPT are set in fpu_init.
*/
if (cpu_has_pse)
- set_in_cr4(X86_CR4_PSE);
+ cr4_set_bits_and_update_boot(X86_CR4_PSE);

if (cpu_has_pge)
- set_in_cr4(X86_CR4_PGE);
+ cr4_set_bits_and_update_boot(X86_CR4_PGE);
}

/*
diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c
index 922a1ac..6adfd7b 100644
--- a/drivers/lguest/x86/core.c
+++ b/drivers/lguest/x86/core.c
@@ -47,6 +47,7 @@
#include <asm/lguest.h>
#include <asm/uaccess.h>
#include <asm/i387.h>
+#include <asm/tlbflush.h>
#include "../lg.h"

static int cpu_had_pge;
@@ -452,9 +453,9 @@ void lguest_arch_handle_trap(struct lg_cpu *cpu)
static void adjust_pge(void *on)
{
if (on)
- write_cr4(read_cr4() | X86_CR4_PGE);
+ cr4_set_bits(X86_CR4_PGE);
else
- write_cr4(read_cr4() & ~X86_CR4_PGE);
+ cr4_clear_bits(X86_CR4_PGE);
}

/*H:020
--
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Next message: tip-bot for Davidlohr Bueso: "[tip:locking/core] locking/mutex: Explicitly mark task as running after wakeup"
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