From mboxrd@z Thu Jan 1 00:00:00 1970 From: jeremy.linton@arm.com (Jeremy Linton) Date: Thu, 26 Apr 2018 13:57:00 -0500 Subject: [PATCH v8 07/13] drivers: base cacheinfo: Add support for ACPI based firmware tables In-Reply-To: References: <20180425233121.13270-1-jeremy.linton@arm.com> <20180425233121.13270-8-jeremy.linton@arm.com> Message-ID: <48bd3299-a95a-8aa6-524d-b3aa01dd9ef2@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On 04/26/2018 06:05 AM, Sudeep Holla wrote: > > > On 26/04/18 00:31, Jeremy Linton wrote: >> Call ACPI cache parsing routines from base cacheinfo code if ACPI >> is enable. Also stub out cache_setup_acpi() so that individual >> architectures can enable ACPI topology parsing. >> > > [...] > >> +#ifndef CONFIG_ACPI >> +static inline int acpi_find_last_cache_level(unsigned int cpu) >> +{ >> + /* ACPI kernels should be built with PPTT support */ > > This sounds incorrect for x86. But I understand why you have it there. > Does it makes sense to change above to .. ? > > #if !defined(CONFIG_ACPI) || (defined(CONFIG_ACPI) && !(CONFIG_ACPI_PPTT)) > I'm not sure what that buys us, if anything you want more non-users of the function to be falling through to the function prototype rather than the static inline. The only place any of this matters (as long as the compiler/linker is tossing the static inline) is arm64 because its the only arch making a call to acpi_find_last_cache_level(). ACPI_PPTT is also only visible on arm64 at the moment due to being wrapped in a if ARM64 in the Kconfig Put another way, I wouldn't expect an arch to have a 'user' visible option to enable/disable parsing the PPTT. If an arch can handle ACPI/PPTT topology then I would expect it to be fixed to the CONFIG_ACPI state. What happens when acpi_find_last_cache_level() is called should only be dependent on whether ACPI is enabled, the PPTT parser itself will handle the cases of a missing table.