On Fri, 2017-11-10 at 14:42 -0800, Deepa Dinamani wrote:
From: Arnd Bergmann email@example.com
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?
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
The CONFIG_ prefix is added by kconfig scripts and shouldn't be used in the Kconfig file.
- def_bool ARCH_HAS_64BIT_TIME
- 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
config ARCH_NO_COHERENT_DMA_MMAP bool