| Message ID | 1474533318-7796-4-git-send-email-oss@buserror.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
It helps to add the appropriate people to your email if you want to get a change into the kernel. Will has had to point this message out to me. On Thu, Sep 22, 2016 at 03:35:18AM -0500, Scott Wood wrote: > Instead of comparing the name to a magic string, use archdata to > explicitly communicate whether the arch timer is suitable for > direct vdso access. > > Signed-off-by: Scott Wood <oss@buserror.net> > Acked-by: Will Deacon <will.deacon@arm.com> > --- > arch/arm/Kconfig | 1 + > arch/arm/include/asm/clocksource.h | 8 ++++++++ > arch/arm/kernel/vdso.c | 2 +- > arch/arm64/Kconfig | 1 + > arch/arm64/include/asm/clocksource.h | 8 ++++++++ > arch/arm64/kernel/vdso.c | 2 +- > drivers/clocksource/arm_arch_timer.c | 11 +++-------- > 7 files changed, 23 insertions(+), 10 deletions(-) > create mode 100644 arch/arm/include/asm/clocksource.h > create mode 100644 arch/arm64/include/asm/clocksource.h > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index a9c4e48..b2113c2 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -1,6 +1,7 @@ > config ARM > bool > default y > + select ARCH_CLOCKSOURCE_DATA > select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE > select ARCH_HAS_DEVMEM_IS_ALLOWED > select ARCH_HAS_ELF_RANDOMIZE > diff --git a/arch/arm/include/asm/clocksource.h b/arch/arm/include/asm/clocksource.h > new file mode 100644 > index 0000000..0b350a7 > --- /dev/null > +++ b/arch/arm/include/asm/clocksource.h > @@ -0,0 +1,8 @@ > +#ifndef _ASM_CLOCKSOURCE_H > +#define _ASM_CLOCKSOURCE_H > + > +struct arch_clocksource_data { > + bool vdso_direct; /* Usable for direct VDSO access? */ > +}; > + > +#endif > diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c > index 994e971..a0affd1 100644 > --- a/arch/arm/kernel/vdso.c > +++ b/arch/arm/kernel/vdso.c > @@ -270,7 +270,7 @@ static bool tk_is_cntvct(const struct timekeeper *tk) > if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER)) > return false; > > - if (strcmp(tk->tkr_mono.clock->name, "arch_sys_counter") != 0) > + if (!tk->tkr_mono.clock->archdata.vdso_direct) > return false; > > return true; For the ARM bits: Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
On 22/09/16 09:35, Scott Wood wrote: > Instead of comparing the name to a magic string, use archdata to > explicitly communicate whether the arch timer is suitable for > direct vdso access. > > Signed-off-by: Scott Wood <oss@buserror.net> > Acked-by: Will Deacon <will.deacon@arm.com> > --- > arch/arm/Kconfig | 1 + > arch/arm/include/asm/clocksource.h | 8 ++++++++ > arch/arm/kernel/vdso.c | 2 +- > arch/arm64/Kconfig | 1 + > arch/arm64/include/asm/clocksource.h | 8 ++++++++ > arch/arm64/kernel/vdso.c | 2 +- > drivers/clocksource/arm_arch_timer.c | 11 +++-------- > 7 files changed, 23 insertions(+), 10 deletions(-) > create mode 100644 arch/arm/include/asm/clocksource.h > create mode 100644 arch/arm64/include/asm/clocksource.h Acked-by: Marc Zyngier <marc.zyngier@arm.com> M.
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index a9c4e48..b2113c2 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1,6 +1,7 @@ config ARM bool default y + select ARCH_CLOCKSOURCE_DATA select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE select ARCH_HAS_DEVMEM_IS_ALLOWED select ARCH_HAS_ELF_RANDOMIZE diff --git a/arch/arm/include/asm/clocksource.h b/arch/arm/include/asm/clocksource.h new file mode 100644 index 0000000..0b350a7 --- /dev/null +++ b/arch/arm/include/asm/clocksource.h @@ -0,0 +1,8 @@ +#ifndef _ASM_CLOCKSOURCE_H +#define _ASM_CLOCKSOURCE_H + +struct arch_clocksource_data { + bool vdso_direct; /* Usable for direct VDSO access? */ +}; + +#endif diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c index 994e971..a0affd1 100644 --- a/arch/arm/kernel/vdso.c +++ b/arch/arm/kernel/vdso.c @@ -270,7 +270,7 @@ static bool tk_is_cntvct(const struct timekeeper *tk) if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER)) return false; - if (strcmp(tk->tkr_mono.clock->name, "arch_sys_counter") != 0) + if (!tk->tkr_mono.clock->archdata.vdso_direct) return false; return true; diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 0e11c8a..8f868ec 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -4,6 +4,7 @@ config ARM64 select ACPI_GENERIC_GSI if ACPI select ACPI_REDUCED_HARDWARE_ONLY if ACPI select ACPI_MCFG if ACPI + select ARCH_CLOCKSOURCE_DATA select ARCH_HAS_DEVMEM_IS_ALLOWED select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE diff --git a/arch/arm64/include/asm/clocksource.h b/arch/arm64/include/asm/clocksource.h new file mode 100644 index 0000000..0b350a7 --- /dev/null +++ b/arch/arm64/include/asm/clocksource.h @@ -0,0 +1,8 @@ +#ifndef _ASM_CLOCKSOURCE_H +#define _ASM_CLOCKSOURCE_H + +struct arch_clocksource_data { + bool vdso_direct; /* Usable for direct VDSO access? */ +}; + +#endif diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index 6225612..a2c2478 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -201,7 +201,7 @@ up_fail: */ void update_vsyscall(struct timekeeper *tk) { - u32 use_syscall = strcmp(tk->tkr_mono.clock->name, "arch_sys_counter"); + u32 use_syscall = !tk->tkr_mono.clock->archdata.vdso_direct; ++vdso_data->tb_seq_count; smp_wmb(); diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index eb5fb41..73c487d 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -602,23 +602,18 @@ static void __init arch_counter_register(unsigned type) else arch_timer_read_counter = arch_counter_get_cntpct; + clocksource_counter.archdata.vdso_direct = true; + #ifdef CONFIG_FSL_ERRATUM_A008585 /* * Don't use the vdso fastpath if errata require using * the out-of-line counter accessor. */ if (static_branch_unlikely(&arch_timer_read_ool_enabled)) - clocksource_counter.name = "arch_sys_counter_ool"; + clocksource_counter.archdata.vdso_direct = false; #endif } else { arch_timer_read_counter = arch_counter_get_cntvct_mem; - - /* If the clocksource name is "arch_sys_counter" the - * VDSO will attempt to read the CP15-based counter. - * Ensure this does not happen when CP15-based - * counter is not available. - */ - clocksource_counter.name = "arch_mem_counter"; } start_count = arch_timer_read_counter();