Messages in this thread Patch in this message | | | From | lizf@kernel ... | Subject | [PATCH 3.4 35/92] x86/platform: Fix Geode LX timekeeping in the generic x86 build | Date | Mon, 18 Apr 2016 18:45:40 +0800 |
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From: David Woodhouse <dwmw2@infradead.org>
3.4.112-rc1 review patch. If anyone has any objections, please let me know.
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commit 03da3ff1cfcd7774c8780d2547ba0d995f7dc03d upstream.
In 2007, commit 07190a08eef36 ("Mark TSC on GeodeLX reliable") bypassed verification of the TSC on Geode LX. However, this code (now in the check_system_tsc_reliable() function in arch/x86/kernel/tsc.c) was only present if CONFIG_MGEODE_LX was set.
OpenWRT has recently started building its generic Geode target for Geode GX, not LX, to include support for additional platforms. This broke the timekeeping on LX-based devices, because the TSC wasn't marked as reliable: https://dev.openwrt.org/ticket/20531
By adding a runtime check on is_geode_lx(), we can also include the fix if CONFIG_MGEODEGX1 or CONFIG_X86_GENERIC are set, thus fixing the problem.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Andres Salomon <dilinger@queued.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Marcelo Tosatti <marcelo@kvack.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1442409003.131189.87.camel@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Zefan Li <lizefan@huawei.com> --- arch/x86/kernel/tsc.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 8652aa4..ffded61 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -18,6 +18,7 @@ #include <asm/hypervisor.h> #include <asm/nmi.h> #include <asm/x86_init.h> +#include <asm/geode.h> unsigned int __read_mostly cpu_khz; /* TSC clocks / usec, not used here */ EXPORT_SYMBOL(cpu_khz); @@ -800,15 +801,17 @@ EXPORT_SYMBOL_GPL(mark_tsc_unstable); static void __init check_system_tsc_reliable(void) { -#ifdef CONFIG_MGEODE_LX - /* RTSC counts during suspend */ +#if defined(CONFIG_MGEODEGX1) || defined(CONFIG_MGEODE_LX) || defined(CONFIG_X86_GENERIC) + if (is_geode_lx()) { + /* RTSC counts during suspend */ #define RTSC_SUSP 0x100 - unsigned long res_low, res_high; + unsigned long res_low, res_high; - rdmsr_safe(MSR_GEODE_BUSCONT_CONF0, &res_low, &res_high); - /* Geode_LX - the OLPC CPU has a very reliable TSC */ - if (res_low & RTSC_SUSP) - tsc_clocksource_reliable = 1; + rdmsr_safe(MSR_GEODE_BUSCONT_CONF0, &res_low, &res_high); + /* Geode_LX - the OLPC CPU has a very reliable TSC */ + if (res_low & RTSC_SUSP) + tsc_clocksource_reliable = 1; + } #endif if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE)) tsc_clocksource_reliable = 1; -- 1.9.1
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