On Fri, 2017-11-10 at 14:42 -0800, Deepa Dinamani wrote:
> From: Arnd Bergmann <[email protected]>
>
> There are a total of 53 system calls (aside from ioctl) that pass a time_t
> or derived data structure as an argument, and in order to extend time_t
> to 64-bit, we have to replace them with new system calls and keep providing
> backwards compatibility.
>
> To avoid adding completely new and untested code for this purpose, we
> introduce a new CONFIG_64BIT_TIME symbol. Every architecture that supports
> new 64 bit time_t syscalls enables this config via ARCH_HAS_64BIT_TIME.
>
> After this is done for all architectures, the CONFIG_64BIT_TIME symbol
> can be made a user-selected option, to enable users to build a kernel
> that only provides y2038-safe system calls by making 32 time_t syscalls
> conditionally included based on the above config.
I don't understand why we would want to change the semantics of
CONFIG_64BIT_TIME symbol from "enable 64-bit time support" to "disable
32-bit time support".
Why not add two config symbols:
config 32BIT_TIME
def_bool COMPAT || !64BIT
config 64BIT_TIME
def_bool ARCH_HAS_64BIT_TIME
and then make 32BIT_TIME user-configurable later?
> Signed-off-by: Arnd Bergmann <[email protected]>
> Signed-off-by: Deepa Dinamani <[email protected]>
> ---
> arch/Kconfig | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 8911ff37335a..3266ac1a4ff7 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -875,6 +875,17 @@ config OLD_SIGACTION
> config COMPAT_OLD_SIGACTION
> bool
>
> +config ARCH_HAS_64BIT_TIME
> + def_bool n
> +
> +config CONFIG_64BIT_TIME
The CONFIG_ prefix is added by kconfig scripts and shouldn't be used in
the Kconfig file.
Ben.
> + def_bool ARCH_HAS_64BIT_TIME
> + help
> + This should be selected by all architectures that need to support
> + new system calls with a 64-bit time_t. This is relevant on all 32-bit
> + architectures, and 64-bit architectures as part of compat syscall
> + handling.
> +
> config ARCH_NO_COHERENT_DMA_MMAP
> bool
>
--
Ben Hutchings
Software Developer, Codethink Ltd.
