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Date: Sun, 26 Jul 2020 21:31:30 -0700
From: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
To: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...e.de>,
Andy Lutomirski <luto@...nel.org>, x86@...nel.org
Cc: Dave Hansen <dave.hansen@...el.com>,
Tony Luck <tony.luck@...el.com>,
Cathy Zhang <cathy.zhang@...el.com>,
Fenghua Yu <fenghua.yu@...el.com>,
"H. Peter Anvin" <hpa@...or.com>,
Kyung Min Park <kyung.min.park@...el.com>,
"Peter Zijlstra (Intel)" <peterz@...radead.org>,
"Ravi V. Shankar" <ravi.v.shankar@...el.com>,
Sean Christopherson <sean.j.christopherson@...el.com>,
linux-kernel@...r.kernel.org,
Ricardo Neri <ricardo.neri@...el.com>,
Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Dimitri Sivanich <sivanich@....com>, linux-edac@...r.kernel.org
Subject: [PATCH 2/4] x86/cpu: Relocate sync_core() to sync_core.h
Having sync_core() in processor.h is problematic since it is not possible
to check for hardware capabilities via the *cpu_has() family of macros.
The latter needs the definitions in processor.h.
It also looks more intuitive to relocate the function to sync_core.h.
This changeset does not make changes in functionality.
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Cathy Zhang <cathy.zhang@...el.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Dimitri Sivanich <sivanich@....com>
Cc: Fenghua Yu <fenghua.yu@...el.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Kyung Min Park <kyung.min.park@...el.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: "Ravi V. Shankar" <ravi.v.shankar@...el.com>
Cc: Sean Christopherson <sean.j.christopherson@...el.com>
Cc: linux-edac@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Reviewed-by: Tony Luck <tony.luck@...el.com>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
---
---
arch/x86/include/asm/processor.h | 64 -----------------------------
arch/x86/include/asm/sync_core.h | 64 +++++++++++++++++++++++++++++
arch/x86/kernel/alternative.c | 1 +
arch/x86/kernel/cpu/mce/core.c | 1 +
drivers/misc/sgi-gru/grufault.c | 1 +
drivers/misc/sgi-gru/gruhandles.c | 1 +
drivers/misc/sgi-gru/grukservices.c | 1 +
7 files changed, 69 insertions(+), 64 deletions(-)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 2a1f7e1d7151..97143d87994c 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -676,70 +676,6 @@ static inline unsigned int cpuid_edx(unsigned int op)
return edx;
}
-/*
- * This function forces the icache and prefetched instruction stream to
- * catch up with reality in two very specific cases:
- *
- * a) Text was modified using one virtual address and is about to be executed
- * from the same physical page at a different virtual address.
- *
- * b) Text was modified on a different CPU, may subsequently be
- * executed on this CPU, and you want to make sure the new version
- * gets executed. This generally means you're calling this in a IPI.
- *
- * If you're calling this for a different reason, you're probably doing
- * it wrong.
- */
-static inline void sync_core(void)
-{
- /*
- * There are quite a few ways to do this. IRET-to-self is nice
- * because it works on every CPU, at any CPL (so it's compatible
- * with paravirtualization), and it never exits to a hypervisor.
- * The only down sides are that it's a bit slow (it seems to be
- * a bit more than 2x slower than the fastest options) and that
- * it unmasks NMIs. The "push %cs" is needed because, in
- * paravirtual environments, __KERNEL_CS may not be a valid CS
- * value when we do IRET directly.
- *
- * In case NMI unmasking or performance ever becomes a problem,
- * the next best option appears to be MOV-to-CR2 and an
- * unconditional jump. That sequence also works on all CPUs,
- * but it will fault at CPL3 (i.e. Xen PV).
- *
- * CPUID is the conventional way, but it's nasty: it doesn't
- * exist on some 486-like CPUs, and it usually exits to a
- * hypervisor.
- *
- * Like all of Linux's memory ordering operations, this is a
- * compiler barrier as well.
- */
-#ifdef CONFIG_X86_32
- asm volatile (
- "pushfl\n\t"
- "pushl %%cs\n\t"
- "pushl $1f\n\t"
- "iret\n\t"
- "1:"
- : ASM_CALL_CONSTRAINT : : "memory");
-#else
- unsigned int tmp;
-
- asm volatile (
- "mov %%ss, %0\n\t"
- "pushq %q0\n\t"
- "pushq %%rsp\n\t"
- "addq $8, (%%rsp)\n\t"
- "pushfq\n\t"
- "mov %%cs, %0\n\t"
- "pushq %q0\n\t"
- "pushq $1f\n\t"
- "iretq\n\t"
- "1:"
- : "=&r" (tmp), ASM_CALL_CONSTRAINT : : "cc", "memory");
-#endif
-}
-
extern void select_idle_routine(const struct cpuinfo_x86 *c);
extern void amd_e400_c1e_apic_setup(void);
diff --git a/arch/x86/include/asm/sync_core.h b/arch/x86/include/asm/sync_core.h
index c67caafd3381..9c5573f2c333 100644
--- a/arch/x86/include/asm/sync_core.h
+++ b/arch/x86/include/asm/sync_core.h
@@ -6,6 +6,70 @@
#include <asm/processor.h>
#include <asm/cpufeature.h>
+/*
+ * This function forces the icache and prefetched instruction stream to
+ * catch up with reality in two very specific cases:
+ *
+ * a) Text was modified using one virtual address and is about to be executed
+ * from the same physical page at a different virtual address.
+ *
+ * b) Text was modified on a different CPU, may subsequently be
+ * executed on this CPU, and you want to make sure the new version
+ * gets executed. This generally means you're calling this in a IPI.
+ *
+ * If you're calling this for a different reason, you're probably doing
+ * it wrong.
+ */
+static inline void sync_core(void)
+{
+ /*
+ * There are quite a few ways to do this. IRET-to-self is nice
+ * because it works on every CPU, at any CPL (so it's compatible
+ * with paravirtualization), and it never exits to a hypervisor.
+ * The only down sides are that it's a bit slow (it seems to be
+ * a bit more than 2x slower than the fastest options) and that
+ * it unmasks NMIs. The "push %cs" is needed because, in
+ * paravirtual environments, __KERNEL_CS may not be a valid CS
+ * value when we do IRET directly.
+ *
+ * In case NMI unmasking or performance ever becomes a problem,
+ * the next best option appears to be MOV-to-CR2 and an
+ * unconditional jump. That sequence also works on all CPUs,
+ * but it will fault at CPL3 (i.e. Xen PV).
+ *
+ * CPUID is the conventional way, but it's nasty: it doesn't
+ * exist on some 486-like CPUs, and it usually exits to a
+ * hypervisor.
+ *
+ * Like all of Linux's memory ordering operations, this is a
+ * compiler barrier as well.
+ */
+#ifdef CONFIG_X86_32
+ asm volatile (
+ "pushfl\n\t"
+ "pushl %%cs\n\t"
+ "pushl $1f\n\t"
+ "iret\n\t"
+ "1:"
+ : ASM_CALL_CONSTRAINT : : "memory");
+#else
+ unsigned int tmp;
+
+ asm volatile (
+ "mov %%ss, %0\n\t"
+ "pushq %q0\n\t"
+ "pushq %%rsp\n\t"
+ "addq $8, (%%rsp)\n\t"
+ "pushfq\n\t"
+ "mov %%cs, %0\n\t"
+ "pushq %q0\n\t"
+ "pushq $1f\n\t"
+ "iretq\n\t"
+ "1:"
+ : "=&r" (tmp), ASM_CALL_CONSTRAINT : : "cc", "memory");
+#endif
+}
+
/*
* Ensure that a core serializing instruction is issued before returning
* to user-mode. x86 implements return to user-space through sysexit,
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 20e07feb4064..3abc1316f91b 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -16,6 +16,7 @@
#include <linux/kprobes.h>
#include <linux/mmu_context.h>
#include <linux/bsearch.h>
+#include <linux/sync_core.h>
#include <asm/text-patching.h>
#include <asm/alternative.h>
#include <asm/sections.h>
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 1a0139d9a34b..e76c1ddd35e7 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -42,6 +42,7 @@
#include <linux/export.h>
#include <linux/jump_label.h>
#include <linux/set_memory.h>
+#include <linux/sync_core.h>
#include <linux/task_work.h>
#include <linux/hardirq.h>
diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
index b1521112dbbd..723825524ea0 100644
--- a/drivers/misc/sgi-gru/grufault.c
+++ b/drivers/misc/sgi-gru/grufault.c
@@ -20,6 +20,7 @@
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/security.h>
+#include <linux/sync_core.h>
#include <linux/prefetch.h>
#include "gru.h"
#include "grutables.h"
diff --git a/drivers/misc/sgi-gru/gruhandles.c b/drivers/misc/sgi-gru/gruhandles.c
index f7224f90f413..1d75d5e540bc 100644
--- a/drivers/misc/sgi-gru/gruhandles.c
+++ b/drivers/misc/sgi-gru/gruhandles.c
@@ -16,6 +16,7 @@
#define GRU_OPERATION_TIMEOUT (((cycles_t) local_cpu_data->itc_freq)*10)
#define CLKS2NSEC(c) ((c) *1000000000 / local_cpu_data->itc_freq)
#else
+#include <linux/sync_core.h>
#include <asm/tsc.h>
#define GRU_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000)
#define CLKS2NSEC(c) ((c) * 1000000 / tsc_khz)
diff --git a/drivers/misc/sgi-gru/grukservices.c b/drivers/misc/sgi-gru/grukservices.c
index 0197441a1eae..f6e600bfac5d 100644
--- a/drivers/misc/sgi-gru/grukservices.c
+++ b/drivers/misc/sgi-gru/grukservices.c
@@ -16,6 +16,7 @@
#include <linux/miscdevice.h>
#include <linux/proc_fs.h>
#include <linux/interrupt.h>
+#include <linux/sync_core.h>
#include <linux/uaccess.h>
#include <linux/delay.h>
#include <linux/export.h>
--
2.17.1
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