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authorLuis R. Rodriguez <mcgrof@kernel.org>2016-04-13 17:04:34 -0700
committerIngo Molnar <mingo@kernel.org>2016-04-22 10:29:01 +0200
commit8d152e7a5c7537b18b4e9e0eb96f549b016636dc (patch)
treede956f52ec790f8ff066dc78c192e3dd8da70a3b /arch/x86/xen
parent907bb655797427cc6498045d6977e77f8363fff7 (diff)
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x86/rtc: Replace paravirt rtc check with platform legacy quirk
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 legacy quirk set early in boot through i386_start_kernel() and through x86_64_start_reservations(). This deals with the RTC quirks which we can rely on through the hardware subarch, the ACPI check can be dealt with separately. For Xen things are bit more complex given that the @X86_SUBARCH_XEN x86_hardware_subarch is shared on for Xen which uses the PV path for both domU and dom0. Since the semantics for differentiating between the two are Xen specific we provide a platform helper to help override default legacy features -- x86_platform.set_legacy_features(). Use of this helper is highly discouraged, its only purpose should be to account for the lack of semantics available within your given x86_hardware_subarch. As per 0-day, this bumps the vmlinux size using i386-tinyconfig as follows: TOTAL TEXT init.text x86_early_init_platform_quirks() +70 +62 +62 +43 Only 8 bytes overhead total, as the main increase in size is all removed via __init. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Reviewed-by: Juergen Gross <jgross@suse.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: andrew.cooper3@citrix.com Cc: andriy.shevchenko@linux.intel.com Cc: bigeasy@linutronix.de Cc: boris.ostrovsky@oracle.com Cc: david.vrabel@citrix.com Cc: ffainelli@freebox.fr Cc: george.dunlap@citrix.com Cc: glin@suse.com Cc: jlee@suse.com Cc: josh@joshtriplett.org Cc: julien.grall@linaro.org Cc: konrad.wilk@oracle.com Cc: kozerkov@parallels.com Cc: lenb@kernel.org Cc: lguest@lists.ozlabs.org Cc: linux-acpi@vger.kernel.org Cc: lv.zheng@intel.com Cc: matt@codeblueprint.co.uk Cc: mbizon@freebox.fr Cc: rjw@rjwysocki.net Cc: robert.moore@intel.com Cc: rusty@rustcorp.com.au Cc: tiwai@suse.de Cc: toshi.kani@hp.com Cc: xen-devel@lists.xensource.com Link: http://lkml.kernel.org/r/1460592286-300-5-git-send-email-mcgrof@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/xen')
-rw-r--r--arch/x86/xen/enlighten.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 61f4d9f67f60..752029d571bf 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1193,7 +1193,6 @@ static const struct pv_info xen_info __initconst = {
#ifdef CONFIG_X86_64
.extra_user_64bit_cs = FLAT_USER_CS64,
#endif
- .features = 0,
.name = "Xen",
};
@@ -1506,6 +1505,11 @@ static void __init xen_pvh_early_guest_init(void)
}
#endif /* CONFIG_XEN_PVH */
+static void __init xen_dom0_set_legacy_features(void)
+{
+ x86_platform.legacy.rtc = 1;
+}
+
/* First C function to be called on Xen boot */
asmlinkage __visible void __init xen_start_kernel(void)
{
@@ -1527,8 +1531,6 @@ 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;
@@ -1688,6 +1690,8 @@ asmlinkage __visible void __init xen_start_kernel(void)
.u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS,
};
+ x86_platform.set_legacy_features =
+ xen_dom0_set_legacy_features;
xen_init_vga(info, xen_start_info->console.dom0.info_size);
xen_start_info->console.domU.mfn = 0;
xen_start_info->console.domU.evtchn = 0;
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