The HPET is so amazingly slow that this is barely a win. It adds
complexity, and it scares me a tiny bit to map a piece of crappy
hardware where every userspace program can poke at it (even if said
poking is read-only). Let's just remove it.
This is probably a tiny speedup on kvmclock systems.
Signed-off-by: Andy Lutomirski <l...@amacapital.net>
---
arch/x86/include/asm/clocksource.h | 3 +--
arch/x86/include/asm/fixmap.h | 1 -
arch/x86/kernel/hpet.c | 7 -------
arch/x86/kvm/trace.h | 4 ++--
arch/x86/vdso/vclock_gettime.c | 8 --------
5 files changed, 3 insertions(+), 20 deletions(-)
diff --git a/arch/x86/include/asm/clocksource.h
b/arch/x86/include/asm/clocksource.h
index 16a57f4..00d2e6f 100644
--- a/arch/x86/include/asm/clocksource.h
+++ b/arch/x86/include/asm/clocksource.h
@@ -7,8 +7,7 @@
#define VCLOCK_NONE 0 /* No vDSO clock available. */
#define VCLOCK_TSC 1 /* vDSO should use vread_tsc. */
-#define VCLOCK_HPET 2 /* vDSO should use vread_hpet. */
-#define VCLOCK_PVCLOCK 3 /* vDSO should use vread_pvclock. */
+#define VCLOCK_PVCLOCK 2 /* vDSO should use vread_pvclock. */
struct arch_clocksource_data {
int vclock_mode;
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index 7252cd3..a1c741c 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -80,7 +80,6 @@ enum fixed_addresses {
VSYSCALL_FIRST_PAGE = VSYSCALL_LAST_PAGE
+ ((VSYSCALL_END-VSYSCALL_START) >> PAGE_SHIFT) - 1,
VVAR_PAGE,
- VSYSCALL_HPET,
#ifdef CONFIG_PARAVIRT_CLOCK
PVCLOCK_FIXMAP_BEGIN,
PVCLOCK_FIXMAP_END = PVCLOCK_FIXMAP_BEGIN+PVCLOCK_VSYSCALL_NR_PAGES-1,
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index da85a8e..b578e07 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -12,7 +12,6 @@
#include <linux/pm.h>
#include <linux/io.h>
-#include <asm/fixmap.h>
#include <asm/hpet.h>
#include <asm/time.h>
@@ -74,9 +73,6 @@ static inline void hpet_writel(unsigned int d, unsigned int a)
static inline void hpet_set_mapping(void)
{
hpet_virt_address = ioremap_nocache(hpet_address, HPET_MMAP_SIZE);
-#ifdef CONFIG_X86_64
- __set_fixmap(VSYSCALL_HPET, hpet_address, PAGE_KERNEL_VVAR_NOCACHE);
-#endif
}
static inline void hpet_clear_mapping(void)
@@ -752,9 +748,6 @@ static struct clocksource clocksource_hpet = {
.mask = HPET_MASK,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.resume = hpet_resume_counter,
-#ifdef CONFIG_X86_64
- .archdata = { .vclock_mode = VCLOCK_HPET },
-#endif
};
static int hpet_clocksource_register(void)
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 545245d..02d1a84 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -781,8 +781,8 @@ TRACE_EVENT(kvm_write_tsc_offset,
#define host_clocks \
{VCLOCK_NONE, "none"}, \
- {VCLOCK_TSC, "tsc"}, \
- {VCLOCK_HPET, "hpet"} \
+ {VCLOCK_TSC, "tsc"}
+
TRACE_EVENT(kvm_update_master_clock,
TP_PROTO(bool use_master_clock, unsigned int host_clock, bool
offset_matched),
diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index eb5d7a5..3095446 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -19,7 +19,6 @@
#include <asm/fixmap.h>
#include <asm/vgtod.h>
#include <asm/timex.h>
-#include <asm/hpet.h>
#include <asm/unistd.h>
#include <asm/io.h>
#include <asm/pvclock.h>
@@ -58,11 +57,6 @@ notrace static cycle_t vread_tsc(void)
return last;
}
-static notrace cycle_t vread_hpet(void)
-{
- return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) +
HPET_COUNTER);
-}
-
#ifdef CONFIG_PARAVIRT_CLOCK
static notrace const struct pvclock_vsyscall_time_info *get_pvti(int cpu)
@@ -157,8 +151,6 @@ notrace static inline u64 vgetsns(int *mode)
cycles_t cycles;
if (gtod->clock.vclock_mode == VCLOCK_TSC)
cycles = vread_tsc();
- else if (gtod->clock.vclock_mode == VCLOCK_HPET)
- cycles = vread_hpet();
#ifdef CONFIG_PARAVIRT_CLOCK
else if (gtod->clock.vclock_mode == VCLOCK_PVCLOCK)
cycles = vread_pvclock(mode);
--
1.8.5.3
--
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