| Message ID | 20171110224259.15930-6-deepa.kernel@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | None | expand |
On Fri, 2017-11-10 at 14:42 -0800, Deepa Dinamani wrote: > From: Arnd Bergmann <arnd@arndb.de> > > 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 <arnd@arndb.de> > Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> > --- > 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.
On Fri, Dec 8, 2017 at 8:53 AM, Ben Hutchings <ben.hutchings@codethink.co.uk> wrote: > On Fri, 2017-11-10 at 14:42 -0800, Deepa Dinamani wrote: >> From: Arnd Bergmann <arnd@arndb.de> >> >> 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? This was already discussed on the review and we have an updated version: https://lkml.org/lkml/2017/11/27/938 >> Signed-off-by: Arnd Bergmann <arnd@arndb.de> >> Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> >> --- >> 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. Yes, this was a typo and was fixed by the next revision which has already been posted: https://lkml.org/lkml/2017/11/27/938 -Deepa
On Fri, 2017-12-08 at 09:01 -0800, Deepa Dinamani wrote: > On Fri, Dec 8, 2017 at 8:53 AM, Ben Hutchings > > <ben.hutchings@codethink.co.uk> wrote: > > On Fri, 2017-11-10 at 14:42 -0800, Deepa Dinamani wrote: > > > From: Arnd Bergmann <arnd@arndb.de> > > > > > > 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? > > This was already discussed on the review and we have an updated version: > > https://lkml.org/lkml/2017/11/27/938 Sorry, I'll move on to reviewing that. Ben. -- Ben Hutchings Software Developer, Codethink Ltd.
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 + 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