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From: Tony Lindgren <tony@atomide.com>
To: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Marc Zyngier <marc.zyngier@arm.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Christoffer Dall <christoffer.dall@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH v3 08/15] ARM: spectre-v2: harden user aborts in kernel space
Date: Fri, 25 May 2018 08:47:42 -0700	[thread overview]
Message-ID: <20180525154742.GA77025@atomide.com> (raw)
In-Reply-To: <E1fMDHD-00073Q-Ob@rmk-PC.armlinux.org.uk>

* Russell King <rmk+kernel@armlinux.org.uk> [180525 15:10]:
> +static void cpu_v7_spectre_init(void)
> +{
> +	const char *spectre_v2_method = NULL;
> +	int cpu = smp_processor_id();
> +
> +	if (per_cpu(harden_branch_predictor_fn, cpu))
> +		return;
> +
> +	switch (read_cpuid_part()) {
> +	case ARM_CPU_PART_CORTEX_A8:
> +	case ARM_CPU_PART_CORTEX_A9:
> +	case ARM_CPU_PART_CORTEX_A12:
> +	case ARM_CPU_PART_CORTEX_A17:
> +	case ARM_CPU_PART_CORTEX_A73:
> +	case ARM_CPU_PART_CORTEX_A75:
> +		per_cpu(harden_branch_predictor_fn, cpu) =
> +			harden_branch_predictor_bpiall;
> +		spectre_v2_method = "BPIALL";
> +		break;
> +
> +	case ARM_CPU_PART_CORTEX_A15:
> +	case ARM_CPU_PART_BRAHMA_B15:
> +		per_cpu(harden_branch_predictor_fn, cpu) =
> +			harden_branch_predictor_iciallu;
> +		spectre_v2_method = "ICIALLU";
> +		break;
> +	}
> +	if (spectre_v2_method)
> +		pr_info("CPU%u: Spectre v2: using %s workaround\n",
> +			smp_processor_id(), spectre_v2_method);
> +}

We can now get this with the whole series applied:

CPU0: Spectre v2: firmware did not set auxiliary control register
IBE bit, system vulnerable
CPU: Spectre v2: using ICIALLU workaround

So maybe change the wording from "using %s workaround" to
"chosen workaround %s"?

Or I guess disabling the pr_info when not functional can
be done in the later patches based on some variable set
by check_spectre_auxcr() would be doable too.

Regards,

Tony

WARNING: multiple messages have this Message-ID (diff)
From: tony@atomide.com (Tony Lindgren)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 08/15] ARM: spectre-v2: harden user aborts in kernel space
Date: Fri, 25 May 2018 08:47:42 -0700	[thread overview]
Message-ID: <20180525154742.GA77025@atomide.com> (raw)
In-Reply-To: <E1fMDHD-00073Q-Ob@rmk-PC.armlinux.org.uk>

* Russell King <rmk+kernel@armlinux.org.uk> [180525 15:10]:
> +static void cpu_v7_spectre_init(void)
> +{
> +	const char *spectre_v2_method = NULL;
> +	int cpu = smp_processor_id();
> +
> +	if (per_cpu(harden_branch_predictor_fn, cpu))
> +		return;
> +
> +	switch (read_cpuid_part()) {
> +	case ARM_CPU_PART_CORTEX_A8:
> +	case ARM_CPU_PART_CORTEX_A9:
> +	case ARM_CPU_PART_CORTEX_A12:
> +	case ARM_CPU_PART_CORTEX_A17:
> +	case ARM_CPU_PART_CORTEX_A73:
> +	case ARM_CPU_PART_CORTEX_A75:
> +		per_cpu(harden_branch_predictor_fn, cpu) =
> +			harden_branch_predictor_bpiall;
> +		spectre_v2_method = "BPIALL";
> +		break;
> +
> +	case ARM_CPU_PART_CORTEX_A15:
> +	case ARM_CPU_PART_BRAHMA_B15:
> +		per_cpu(harden_branch_predictor_fn, cpu) =
> +			harden_branch_predictor_iciallu;
> +		spectre_v2_method = "ICIALLU";
> +		break;
> +	}
> +	if (spectre_v2_method)
> +		pr_info("CPU%u: Spectre v2: using %s workaround\n",
> +			smp_processor_id(), spectre_v2_method);
> +}

We can now get this with the whole series applied:

CPU0: Spectre v2: firmware did not set auxiliary control register
IBE bit, system vulnerable
CPU: Spectre v2: using ICIALLU workaround

So maybe change the wording from "using %s workaround" to
"chosen workaround %s"?

Or I guess disabling the pr_info when not functional can
be done in the later patches based on some variable set
by check_spectre_auxcr() would be doable too.

Regards,

Tony

  reply	other threads:[~2018-05-25 15:47 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-25 13:59 [PATCH v3 00/15] ARM Spectre variant 2 fixes Russell King - ARM Linux
2018-05-25 13:59 ` Russell King - ARM Linux
2018-05-25 14:00 ` [PATCH v3 01/15] ARM: add more CPU part numbers for Cortex and Brahma B15 CPUs Russell King
2018-05-25 14:00   ` Russell King
2018-05-25 14:00 ` [PATCH v3 02/15] ARM: bugs: prepare processor bug infrastructure Russell King
2018-05-25 14:00   ` Russell King
2018-05-25 14:00 ` [PATCH v3 03/15] ARM: bugs: hook processor bug checking into SMP and suspend paths Russell King
2018-05-25 14:00   ` Russell King
2018-05-25 14:00 ` [PATCH v3 04/15] ARM: bugs: add support for per-processor bug checking Russell King
2018-05-25 14:00   ` Russell King
2018-05-25 14:00 ` [PATCH v3 05/15] ARM: spectre: add Kconfig symbol for CPUs vulnerable to Spectre Russell King
2018-05-25 14:00   ` Russell King
2018-05-25 14:00 ` [PATCH v3 06/15] ARM: spectre-v2: harden branch predictor on context switches Russell King
2018-05-25 14:00   ` Russell King
2018-05-25 14:00 ` [PATCH v3 07/15] ARM: spectre-v2: add Cortex A8 and A15 validation of the IBE bit Russell King
2018-05-25 14:00   ` Russell King
2018-05-25 14:01 ` [PATCH v3 08/15] ARM: spectre-v2: harden user aborts in kernel space Russell King
2018-05-25 14:01   ` Russell King
2018-05-25 15:47   ` Tony Lindgren [this message]
2018-05-25 15:47     ` Tony Lindgren
2018-05-25 15:52     ` Russell King - ARM Linux
2018-05-25 15:52       ` Russell King - ARM Linux
2018-05-25 16:01       ` Tony Lindgren
2018-05-25 16:01         ` Tony Lindgren
2018-05-25 16:15         ` Tony Lindgren
2018-05-25 16:15           ` Tony Lindgren
2018-05-25 14:01 ` [PATCH v3 09/15] ARM: spectre-v2: add firmware based hardening Russell King
2018-05-25 14:01   ` Russell King
2018-05-25 14:01 ` [PATCH v3 10/15] ARM: spectre-v2: warn about incorrect context switching functions Russell King
2018-05-25 14:01   ` Russell King
2018-05-25 14:01 ` [PATCH v3 11/15] ARM: KVM: invalidate BTB on guest exit for Cortex-A12/A17 Russell King
2018-05-25 14:01   ` Russell King
2018-05-25 14:01 ` [PATCH v3 12/15] ARM: KVM: invalidate icache on guest exit for Cortex-A15 Russell King
2018-05-25 14:01   ` Russell King
2018-05-25 14:01 ` [PATCH v3 13/15] ARM: spectre-v2: KVM: invalidate icache on guest exit for Brahma B15 Russell King
2018-05-25 14:01   ` Russell King
2018-05-25 14:01 ` [PATCH v3 14/15] ARM: KVM: Add SMCCC_ARCH_WORKAROUND_1 fast handling Russell King
2018-05-25 14:01   ` Russell King
2018-05-25 14:01 ` [PATCH v3 15/15] ARM: KVM: report support for SMCCC_ARCH_WORKAROUND_1 Russell King
2018-05-25 14:01   ` Russell King
2018-05-25 16:25 ` [PATCH v3 00/15] ARM Spectre variant 2 fixes Tony Lindgren
2018-05-25 16:25   ` Tony Lindgren

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