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Message-Id: <1456212255-23959-11-git-send-email-mcgrof@kernel.org>
Date:	Mon, 22 Feb 2016 23:24:14 -0800
From:	"Luis R. Rodriguez" <mcgrof@...nel.org>
To:	bp@...en8.de, hpa@...or.com, tglx@...utronix.de, mingo@...hat.com,
	rusty@...tcorp.com.au
Cc:	x86@...nel.org, linux-kernel@...r.kernel.org, luto@...capital.net,
	boris.ostrovsky@...cle.com, david.vrabel@...rix.com,
	konrad.wilk@...cle.com, xen-devel@...ts.xensource.com,
	lguest@...ts.ozlabs.org, "Luis R. Rodriguez" <mcgrof@...nel.org>
Subject: [PATCH v3 10/11] x86/rtc: replace paravirt rtc check with x86 specific solution

We have 4 types of x86 platforms that disable RTC:

  * Intel MID
  * Lguest - uses paravirt
  * Xen dom-U - uses paravirt
  * x86 on legacy systems annotated with an ACPI legacy flag

We can consolidate all of these into a platform specific solution.

Signed-off-by: Luis R. Rodriguez <mcgrof@...nel.org>
---
 arch/x86/include/asm/paravirt.h         |  6 ------
 arch/x86/include/asm/paravirt_types.h   |  5 -----
 arch/x86/include/asm/processor.h        |  1 -
 arch/x86/include/asm/x86_init.h         | 12 ++++++++++++
 arch/x86/kernel/acpi/boot.c             |  4 ++++
 arch/x86/kernel/rtc.c                   | 15 ++-------------
 arch/x86/lguest/boot.c                  |  2 +-
 arch/x86/platform/intel-mid/intel-mid.c |  3 +++
 arch/x86/xen/enlighten.c                |  3 ---
 arch/x86/xen/time.c                     |  4 +++-
 10 files changed, 25 insertions(+), 30 deletions(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index f6192502149e..c261402340e3 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -19,12 +19,6 @@ static inline int paravirt_enabled(void)
 	return pv_info.paravirt_enabled;
 }
 
-static inline int paravirt_has_feature(unsigned int feature)
-{
-	WARN_ON_ONCE(!pv_info.paravirt_enabled);
-	return (pv_info.features & feature);
-}
-
 static inline void load_sp0(struct tss_struct *tss,
 			     struct thread_struct *thread)
 {
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 77db5616a473..2489d6a08e89 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -70,14 +70,9 @@ struct pv_info {
 #endif
 
 	int paravirt_enabled;
-	unsigned int features;	  /* valid only if paravirt_enabled is set */
 	const char *name;
 };
 
-#define paravirt_has(x) paravirt_has_feature(PV_SUPPORTED_##x)
-/* Supported features */
-#define PV_SUPPORTED_RTC        (1<<0)
-
 struct pv_init_ops {
 	/*
 	 * Patch may replace one of the defined code sequences with
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 20c11d1aa4cc..10f3614265c1 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -472,7 +472,6 @@ static inline unsigned long current_top_of_stack(void)
 #else
 #define __cpuid			native_cpuid
 #define paravirt_enabled()	0
-#define paravirt_has(x) 	0
 
 static inline void load_sp0(struct tss_struct *tss,
 			    struct thread_struct *thread)
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index 1ae89a2721d6..0ef697e46f6e 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -1,6 +1,7 @@
 #ifndef _ASM_X86_PLATFORM_H
 #define _ASM_X86_PLATFORM_H
 
+#include <linux/bitops.h>
 #include <asm/bootparam.h>
 
 struct mpc_bus;
@@ -116,6 +117,7 @@ struct x86_init_pci {
 /**
  * struct x86_init_ops - functions for platform specific setup
  *
+ * @platform_flags:		bitmask of enum x86_platform_flags.
  */
 struct x86_init_ops {
 	struct x86_init_resources	resources;
@@ -126,6 +128,7 @@ struct x86_init_ops {
 	struct x86_init_timers		timers;
 	struct x86_init_iommu		iommu;
 	struct x86_init_pci		pci;
+	u64 platform_flags;
 };
 
 /**
@@ -142,6 +145,15 @@ struct x86_cpuinit_ops {
 struct timespec;
 
 /**
+ * enum x86_platform_flags - x86 platform flags
+ *
+ * X86_PLATFORM_NO_RTC: set when platform has no CMOS real-time clock present
+ */
+enum x86_platform_flags {
+	X86_PLATFORM_NO_RTC	= BIT(0),
+};
+
+/**
  * struct x86_platform_ops - platform specific runtime functions
  * @calibrate_tsc:		calibrate TSC
  * @get_wallclock:		get time from HW clock like RTC etc.
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index e75907601a41..d156f6cd2be3 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -913,6 +913,10 @@ late_initcall(hpet_insert_resource);
 
 static int __init acpi_parse_fadt(struct acpi_table_header *table)
 {
+	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
+		pr_debug("ACPI: not registering RTC platform device\n");
+		x86_init.platform_flags |= X86_PLATFORM_NO_RTC;
+	}
 
 #ifdef CONFIG_X86_PM_TIMER
 	/* detect the location of the ACPI PM Timer */
diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c
index 4af8d063fb36..5f95e42ecc68 100644
--- a/arch/x86/kernel/rtc.c
+++ b/arch/x86/kernel/rtc.c
@@ -14,6 +14,7 @@
 #include <asm/time.h>
 #include <asm/intel-mid.h>
 #include <asm/rtc.h>
+#include <asm/setup.h>
 
 #ifdef CONFIG_X86_32
 /*
@@ -188,19 +189,7 @@ static __init int add_rtc_cmos(void)
 	if (of_have_populated_dt())
 		return 0;
 
-	/* Intel MID platforms don't have ioport rtc */
-	if (intel_mid_identify_cpu())
-		return -ENODEV;
-
-#ifdef CONFIG_ACPI
-	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
-		/* This warning can likely go away again in a year or two. */
-		pr_info("ACPI: not registering RTC platform device\n");
-		return -ENODEV;
-	}
-#endif
-
-	if (paravirt_enabled() && !paravirt_has(RTC))
+	if (x86_init.platform_flags & X86_PLATFORM_NO_RTC)
 		return -ENODEV;
 
 	platform_device_register(&rtc_device);
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index 4ba229ac3f4f..a85add6ce776 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -1414,7 +1414,6 @@ __init void lguest_init(void)
 	pv_info.kernel_rpl = 1;
 	/* Everyone except Xen runs with this set. */
 	pv_info.shared_kernel_pmd = 1;
-	pv_info.features = 0;
 
 	/*
 	 * We set up all the lguest overrides for sensitive operations.  These
@@ -1482,6 +1481,7 @@ __init void lguest_init(void)
 	x86_init.resources.memory_setup = lguest_memory_setup;
 	x86_init.irqs.intr_init = lguest_init_IRQ;
 	x86_init.timers.timer_init = lguest_time_init;
+	x86_init.platform_flags |= X86_PLATFORM_NO_RTC;
 	x86_platform.calibrate_tsc = lguest_tsc_khz;
 	x86_platform.get_wallclock =  lguest_get_wallclock;
 
diff --git a/arch/x86/platform/intel-mid/intel-mid.c b/arch/x86/platform/intel-mid/intel-mid.c
index 90bb997ed0a2..17953abcea52 100644
--- a/arch/x86/platform/intel-mid/intel-mid.c
+++ b/arch/x86/platform/intel-mid/intel-mid.c
@@ -175,6 +175,9 @@ void __init x86_intel_mid_early_setup(void)
 	x86_init.timers.timer_init = intel_mid_time_init;
 	x86_init.timers.setup_percpu_clockev = x86_init_noop;
 
+	/* Intel MID platforms don't have ioport rtc */
+	x86_init.platform_flags |= X86_PLATFORM_NO_RTC;
+
 	x86_init.irqs.pre_vector_init = x86_init_noop;
 
 	x86_init.oem.arch_setup = intel_mid_arch_setup;
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 5b3f1c763806..5c06169bce27 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1192,7 +1192,6 @@ static const struct pv_info xen_info __initconst = {
 #ifdef CONFIG_X86_64
 	.extra_user_64bit_cs = FLAT_USER_CS64,
 #endif
-	.features = 0,
 	.name = "Xen",
 };
 
@@ -1526,8 +1525,6 @@ asmlinkage __visible void __init xen_start_kernel(void)
 
 	/* Install Xen paravirt ops */
 	pv_info = xen_info;
-	if (xen_initial_domain())
-		pv_info.features |= PV_SUPPORTED_RTC;
 	pv_init_ops = xen_init_ops;
 	if (!xen_pvh_domain()) {
 		pv_cpu_ops = xen_cpu_ops;
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index a0a4e554c6f1..fbfcb01015f0 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -446,8 +446,10 @@ void __init xen_init_time_ops(void)
 	x86_platform.calibrate_tsc = xen_tsc_khz;
 	x86_platform.get_wallclock = xen_get_wallclock;
 	/* Dom0 uses the native method to set the hardware RTC. */
-	if (!xen_initial_domain())
+	if (!xen_initial_domain()) {
+		x86_init.platform_flags |= X86_PLATFORM_NO_RTC;
 		x86_platform.set_wallclock = xen_set_wallclock;
+	}
 }
 
 #ifdef CONFIG_XEN_PVHVM
-- 
2.7.0

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