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author | Thomas Gleixner <tglx@linutronix.de> | 2018-09-17 14:45:38 +0200 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2018-10-04 23:00:25 +0200 |
commit | 49116f2081eeaf75316956705d46602b7eb735cc (patch) | |
tree | 4cf5dbd5a998d22d815cd61e03fa7c29c494759f /arch/x86/include/asm/vgtod.h | |
parent | 77e9c678c54f2d9214796c1c5bd0c7c7ccedd932 (diff) | |
download | linux-stable-49116f2081eeaf75316956705d46602b7eb735cc.tar.gz linux-stable-49116f2081eeaf75316956705d46602b7eb735cc.tar.bz2 linux-stable-49116f2081eeaf75316956705d46602b7eb735cc.zip |
x86/vdso: Introduce and use vgtod_ts
It's desired to support more clocks in the VDSO, e.g. CLOCK_TAI. This
results either in indirect calls due to the larger switch case, which then
requires retpolines or when the compiler is forced to avoid jump tables it
results in even more conditionals.
To avoid both variants which are bad for performance the high resolution
functions and the coarse grained functions will be collapsed into one for
each. That requires to store the clock specific base time in an array.
Introcude struct vgtod_ts for storage and convert the data store, the
update function and the individual clock functions over to use it.
The new storage does not longer use gtod_long_t for seconds depending on 32
or 64 bit compile because this needs to be the full 64bit value even for
32bit when a Y2038 function is added. No point in keeping the distinction
alive in the internal representation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Rickard <matt@softrans.com.au>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/20180917130707.324679401@linutronix.de
Diffstat (limited to 'arch/x86/include/asm/vgtod.h')
-rw-r--r-- | arch/x86/include/asm/vgtod.h | 38 |
1 files changed, 21 insertions, 17 deletions
diff --git a/arch/x86/include/asm/vgtod.h b/arch/x86/include/asm/vgtod.h index 91cad1f01027..10e534a1a51a 100644 --- a/arch/x86/include/asm/vgtod.h +++ b/arch/x86/include/asm/vgtod.h @@ -5,33 +5,37 @@ #include <linux/compiler.h> #include <linux/clocksource.h> +#include <uapi/linux/time.h> + #ifdef BUILD_VDSO32_64 typedef u64 gtod_long_t; #else typedef unsigned long gtod_long_t; #endif + +struct vgtod_ts { + u64 sec; + u64 nsec; +}; + +#define VGTOD_BASES (CLOCK_MONOTONIC_COARSE + 1) +#define VGTOD_HRES (BIT(CLOCK_REALTIME) | BIT(CLOCK_MONOTONIC)) +#define VGTOD_COARSE (BIT(CLOCK_REALTIME_COARSE) | BIT(CLOCK_MONOTONIC_COARSE)) + /* * vsyscall_gtod_data will be accessed by 32 and 64 bit code at the same time * so be carefull by modifying this structure. */ struct vsyscall_gtod_data { - unsigned int seq; - - int vclock_mode; - u64 cycle_last; - u64 mask; - u32 mult; - u32 shift; - - /* open coded 'struct timespec' */ - u64 wall_time_snsec; - gtod_long_t wall_time_sec; - gtod_long_t monotonic_time_sec; - u64 monotonic_time_snsec; - gtod_long_t wall_time_coarse_sec; - gtod_long_t wall_time_coarse_nsec; - gtod_long_t monotonic_time_coarse_sec; - gtod_long_t monotonic_time_coarse_nsec; + unsigned int seq; + + int vclock_mode; + u64 cycle_last; + u64 mask; + u32 mult; + u32 shift; + + struct vgtod_ts basetime[VGTOD_BASES]; int tz_minuteswest; int tz_dsttime; |