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@@ -0,0 +1,61 @@
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+From: David Woodhouse <[email protected]>
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+Date: Thu, 17 Sep 2015 10:16:54 +0100
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+Subject: [PATCH] x86/platform: Fix Geode LX timekeeping in the generic x86
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+ build
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+
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+In 2007, commit 07190a08eef36 ("Mark TSC on GeodeLX reliable")
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+bypassed verification of the TSC on Geode LX. However, this code
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+(now in the check_system_tsc_reliable() function in
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+arch/x86/kernel/tsc.c) was only present if CONFIG_MGEODE_LX was
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+set.
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+
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+OpenWRT has recently started building its generic Geode target
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+for Geode GX, not LX, to include support for additional
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+platforms. This broke the timekeeping on LX-based devices,
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+because the TSC wasn't marked as reliable:
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+https://dev.openwrt.org/ticket/20531
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+
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+By adding a runtime check on is_geode_lx(), we can also include
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+the fix if CONFIG_MGEODEGX1 or CONFIG_X86_GENERIC are set, thus
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+fixing the problem.
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+
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+Signed-off-by: David Woodhouse <[email protected]>
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+Signed-off-by: Ingo Molnar <[email protected]>
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+Closes #20531
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+---
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+
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+--- a/arch/x86/kernel/tsc.c
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++++ b/arch/x86/kernel/tsc.c
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+@@ -21,6 +21,7 @@
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+ #include <asm/hypervisor.h>
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+ #include <asm/nmi.h>
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+ #include <asm/x86_init.h>
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++#include <asm/geode.h>
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+
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+ unsigned int __read_mostly cpu_khz; /* TSC clocks / usec, not used here */
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+ EXPORT_SYMBOL(cpu_khz);
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+@@ -1004,15 +1005,17 @@ EXPORT_SYMBOL_GPL(mark_tsc_unstable);
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+
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+ static void __init check_system_tsc_reliable(void)
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+ {
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+-#ifdef CONFIG_MGEODE_LX
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+- /* RTSC counts during suspend */
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++#if defined(CONFIG_MGEODEGX1) || defined(CONFIG_MGEODE_LX) || defined(CONFIG_X86_GENERIC)
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++ if (is_geode_lx()) {
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++ /* RTSC counts during suspend */
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+ #define RTSC_SUSP 0x100
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+- unsigned long res_low, res_high;
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++ unsigned long res_low, res_high;
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+
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+- rdmsr_safe(MSR_GEODE_BUSCONT_CONF0, &res_low, &res_high);
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+- /* Geode_LX - the OLPC CPU has a very reliable TSC */
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+- if (res_low & RTSC_SUSP)
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+- tsc_clocksource_reliable = 1;
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++ rdmsr_safe(MSR_GEODE_BUSCONT_CONF0, &res_low, &res_high);
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++ /* Geode_LX - the OLPC CPU has a very reliable TSC */
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++ if (res_low & RTSC_SUSP)
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++ tsc_clocksource_reliable = 1;
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++ }
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+ #endif
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+ if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE))
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+ tsc_clocksource_reliable = 1;
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Felix Fietkau