[PATCH] x86/speculation: Clean up various Spectre related details

[Ingo Molnar]

* David Woodhouse <dwmw@xxxxxxxxxxxx> wrote:

> +	/*
> +	 * Retpoline means the kernel is safe because it has no indirect
> +	 * branches. But firmware isn't, so use IBRS to protect that.
> +	 */
> +	if (boot_cpu_has(X86_FEATURE_IBRS)) {
> +		setup_force_cpu_cap(X86_FEATURE_USE_IBRS_FW);
> +		pr_info("Enabling Restricted Speculation for firmware calls\n");
> +	}

I have changed this text to say:

		pr_info("Spectre mitigation: Restricting branch speculation (enabling IBRS) for firmware calls\n");

In fact while at it I found and improved a few other details as well, such as:

 	 * Retpoline means the kernel is safe because it has no indirect
-	 * branches. But firmware isn't, so use IBRS to protect that.
+	 * branches. But we don't know whether the firmware is safe, so
+	 * use IBRS to protect against that:

most Spectre related messages are now harmonized:

arch/x86/kernel/cpu/bugs.c:             pr_info("Spectre mitigation: Filling RSB on context switch\n");
arch/x86/kernel/cpu/bugs.c:             pr_info("Spectre mitigation: Enabling Indirect Branch Prediction Barrier (IBPB)\n");
arch/x86/kernel/cpu/bugs.c:             pr_info("Spectre mitigation: Restricting branch speculation (enabling IBRS) for firmware calls\n");

Find the full patch below.

Thanks,

	Ingo

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