Re: [PATCH v9 14/21] ACPI / processor: Make it possible to get CPU hardware ID via GICC

From: Catalin Marinas <catalin.marinas@arm.com>
To: Hanjun Guo <guohanjun@huawei.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Hanjun Guo <hanjun.guo@linaro.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Ashwin Chaugule <ashwinc@codeaurora.org>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
	Robert Richter <rric@kernel.org>,
	Graeme Gregory <graeme.gregory@linaro.org>,
	Arnd Bergmann <arnd@arndb.de>,
	linux-acpi@vger.kernel.org, Marc Zyngier <marc.zyngier@arm.com>,
	Timur Tabi <timur@codeaurora.org>,
	linaro-acpi@lists.linaro.org, Will Deacon <will.deacon@arm.com>,
	linux-kernel@vger.kernel.org,
	Grant Likely <grant.likely@linaro.org>,
	Mark Brown <broonie@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	suravee.suthikulpanit@amd.com,
	Sudeep Holla <Sudeep.Holla@arm.com>,
	Olof Johansson <olof@lixom.net>, Jon Masters <jcm@redhat.com>
Subject: Re: [PATCH v9 14/21] ACPI / processor: Make it possible to get CPU hardware ID via GICC
Date: Thu, 5 Mar 2015 11:27:08 +0000	[thread overview]
Message-ID: <20150305112707.GB7712@e104818-lin.cambridge.arm.com> (raw)
In-Reply-To: <54F80DC9.3090808@huawei.com>

On Thu, Mar 05, 2015 at 04:03:21PM +0800, Hanjun Guo wrote:
> On 2015/3/5 6:46, Rafael J. Wysocki wrote:
> > IMO, you really need to define phys_cpuid_t in a common place or people will
> > forget that it may be 64-bit, because they'll only be looking at their arch.
> 
> Since x86 and ARM64 are using different types for phys_cpuid_t, we need to
> introduce something like following if define it in common place:
> 
> in linux/acpi.h,
> 
> #if defined(CONFIG_X86) || defined(CONFIG_IA64)
> typedef u32 phys_cpuid_t;
> #define PHYS_CPUID_INVALID (phys_cpuid_t)(-1)
> #else if defined(CONFIG_ARM64)
> typedef u64 phys_cpuid_t;
> #define PHYS_CPUID_INVALID INVALID_HWID
> #endif
> 
> I think it's awful, did I miss something?

I also think that's awful. I'm rather in favour of a per-arch
phys_cpuid_t.

-- 
Catalin