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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 10/15] xen/arm: Detect silicon revision and set cap bits accordingly
On Mon, 23 May 2016, Julien Grall wrote:
> After each CPU has been started, we iterate through a list of CPU
> errata to detect CPUs which need from hypervisor code patches.
>
> For each bug there is a function which check if that a particular CPU is
> affected. This needs to be done on every CPUs to cover heterogenous
> system properly.
>
> If a certain erratum has been detected, the capability bit will be set
> and later the call to apply_alternatives() will trigger the actual code
> patching.
>
> The code is based on the file arch/arm64/kernel/cpu_errata.c in Linux
> v4.6-rc3.
>
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
>
> ---
> Changes in v2:
> - Use XENLOG_INFO for the loglevel of the message
> ---
> xen/arch/arm/Makefile | 1 +
> xen/arch/arm/cpuerrata.c | 26 ++++++++++++++++++++++++++
> xen/arch/arm/cpufeature.c | 16 ++++++++++++++++
> xen/arch/arm/setup.c | 3 +++
> xen/arch/arm/smpboot.c | 3 +++
> xen/include/asm-arm/cpuerrata.h | 6 ++++++
> xen/include/asm-arm/cpufeature.h | 15 +++++++++++++++
> 7 files changed, 70 insertions(+)
> create mode 100644 xen/arch/arm/cpuerrata.c
> create mode 100644 xen/include/asm-arm/cpuerrata.h
>
> diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
> index 2d330aa..307578c 100644
> --- a/xen/arch/arm/Makefile
> +++ b/xen/arch/arm/Makefile
> @@ -7,6 +7,7 @@ subdir-$(CONFIG_ACPI) += acpi
> obj-$(CONFIG_ALTERNATIVE) += alternative.o
> obj-y += bootfdt.o
> obj-y += cpu.o
> +obj-y += cpuerrata.o
> obj-y += cpufeature.o
> obj-y += decode.o
> obj-y += device.o
> diff --git a/xen/arch/arm/cpuerrata.c b/xen/arch/arm/cpuerrata.c
> new file mode 100644
> index 0000000..52d39f8
> --- /dev/null
> +++ b/xen/arch/arm/cpuerrata.c
> @@ -0,0 +1,26 @@
> +#include <xen/config.h>
> +#include <asm/cpufeature.h>
> +#include <asm/cpuerrata.h>
> +
> +#define MIDR_RANGE(model, min, max) \
> + .matches = is_affected_midr_range, \
> + .midr_model = model, \
> + .midr_range_min = min, \
> + .midr_range_max = max
> +
> +static bool_t __maybe_unused
I would remove __maybe_unused given that you are going to use this
function in later patches.
> +is_affected_midr_range(const struct arm_cpu_capabilities *entry)
> +{
> + return MIDR_IS_CPU_MODEL_RANGE(boot_cpu_data.midr.bits,
> entry->midr_model,
> + entry->midr_range_min,
> + entry->midr_range_max);
> +}
> +
> +static const struct arm_cpu_capabilities arm_errata[] = {
> + {},
> +};
> +
> +void check_local_cpu_errata(void)
> +{
> + update_cpu_capabilities(arm_errata, "enabled workaround for");
> +}
update_cpu_capabilities should actually be called on arm64 only, right?
Given that runtime patching is unimplemented on arm32. I wouldn't want
to rely on the fact that we don't have any arm32 workarounds at the
moment.
> diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
> index 7a1b56b..088625b 100644
> --- a/xen/arch/arm/cpufeature.c
> +++ b/xen/arch/arm/cpufeature.c
> @@ -24,6 +24,22 @@
>
> DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
>
> +void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,
> + const char *info)
The info parameter is unnecessary.
> +{
> + int i;
> +
> + for ( i = 0; caps[i].matches; i++ )
> + {
> + if ( !caps[i].matches(&caps[i]) )
> + continue;
> +
> + if ( !cpus_have_cap(caps[i].capability) && caps[i].desc )
> + printk(XENLOG_INFO "%s: %s\n", info, caps[i].desc);
> + cpus_set_cap(caps[i].capability);
> + }
> +}
> +
> /*
> * Local variables:
> * mode: C
> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
> index c4389ef..67eb13b 100644
> --- a/xen/arch/arm/setup.c
> +++ b/xen/arch/arm/setup.c
> @@ -43,6 +43,7 @@
> #include <asm/current.h>
> #include <asm/setup.h>
> #include <asm/gic.h>
> +#include <asm/cpuerrata.h>
> #include <asm/cpufeature.h>
> #include <asm/platform.h>
> #include <asm/procinfo.h>
> @@ -171,6 +172,8 @@ static void __init processor_id(void)
> }
>
> processor_setup();
> +
> + check_local_cpu_errata();
> }
>
> void dt_unreserved_regions(paddr_t s, paddr_t e,
> diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
> index c5109bf..3f5a77b 100644
> --- a/xen/arch/arm/smpboot.c
> +++ b/xen/arch/arm/smpboot.c
> @@ -29,6 +29,7 @@
> #include <xen/timer.h>
> #include <xen/irq.h>
> #include <xen/console.h>
> +#include <asm/cpuerrata.h>
> #include <asm/gic.h>
> #include <asm/psci.h>
> #include <asm/acpi.h>
> @@ -316,6 +317,8 @@ void start_secondary(unsigned long boot_phys_offset,
> local_irq_enable();
> local_abort_enable();
>
> + check_local_cpu_errata();
> +
> printk(XENLOG_DEBUG "CPU %u booted.\n", smp_processor_id());
>
> startup_cpu_idle_loop();
> diff --git a/xen/include/asm-arm/cpuerrata.h b/xen/include/asm-arm/cpuerrata.h
> new file mode 100644
> index 0000000..8ffd7ba
> --- /dev/null
> +++ b/xen/include/asm-arm/cpuerrata.h
> @@ -0,0 +1,6 @@
> +#ifndef __ARM_CPUERRATA_H
> +#define __ARM_CPUERRATA_H
> +
> +void check_local_cpu_errata(void);
> +
> +#endif /* __ARM_CPUERRATA_H */
> diff --git a/xen/include/asm-arm/cpufeature.h
> b/xen/include/asm-arm/cpufeature.h
> index 2bebad1..fb57295 100644
> --- a/xen/include/asm-arm/cpufeature.h
> +++ b/xen/include/asm-arm/cpufeature.h
> @@ -62,6 +62,21 @@ static inline void cpus_set_cap(unsigned int num)
> __set_bit(num, cpu_hwcaps);
> }
>
> +struct arm_cpu_capabilities {
> + const char *desc;
> + u16 capability;
> + bool_t (*matches)(const struct arm_cpu_capabilities *);
> + union {
> + struct { /* To be used for eratum handling only */
> + u32 midr_model;
> + u32 midr_range_min, midr_range_max;
> + };
> + };
> +};
> +
> +void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,
> + const char *info);
> +
> #endif /* __ASSEMBLY__ */
>
> #endif
> --
> 1.9.1
>
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