| Message ID | 20220908104337.11940-6-lukas.bulwahn@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Remove CONFIG_EMBEDDED | expand |
On Thu, Sep 08, 2022 at 12:43:36PM +0200, Lukas Bulwahn wrote: > Commit 6a108a14fa35 ("kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT") > introduces CONFIG_EXPERT to carry the previous intent of CONFIG_EMBEDDED > and just gives that intent a much better name. That has been clearly a good > and long overdue renaming, and it is clearly an improvement to the kernel > build configuration that has shown to help managing the kernel build > configuration in the last decade. > > However, rather than bravely and radically just deleting CONFIG_EMBEDDED, > this commit gives CONFIG_EMBEDDED a new intended semantics, but keeps it > open for future contributors to implement that intended semantics: > > A new CONFIG_EMBEDDED option is added that automatically selects > CONFIG_EXPERT when enabled and can be used in the future to isolate > options that should only be considered for embedded systems (RISC > architectures, SLOB, etc). > > Since then, this CONFIG_EMBEDDED implicitly had two purposes: > > - It can make even more options visible beyond what CONFIG_EXPERT makes > visible. In other words, it may introduce another level of enabling the > visibility of configuration options: always visible, visible with > CONFIG_EXPERT and visible with CONFIG_EMBEDDED. > > - Set certain default values of some configurations differently, > following the assumption that configuring a kernel build for an > embedded system generally starts with a different set of default values > compared to kernel builds for all other kind of systems. > > Considering the second purpose, note that already probably arguing that a > kernel build for an embedded system would choose some values differently is > already tricky: the set of embedded systems with Linux kernels is already > quite diverse. Many embedded system have powerful CPUs and it would not be > clear that all embedded systems just optimize towards one specific aspect, > e.g., a smaller kernel image size. So, it is unclear if starting with "one > set of default configuration" that is induced by CONFIG_EMBEDDED is a good > offer for developers configuring their kernels. > > Also, the differences of needed user-space features in an embedded system > compared to a non-embedded system are probably difficult or even impossible > to name in some generic way. > > So it is not surprising that in the last decade hardly anyone has > contributed changes to make something default differently in case of > CONFIG_EMBEDDED=y. > > Currently, in v6.0-rc4, SECRETMEM is the only config switched off if > CONFIG_EMBEDDED=y. > > As long as that is actually the only option that currently is selected or > deselected, it is better to just make SECRETMEM configurable at build time > by experts using menuconfig instead. > > Make SECRETMEM configurable when EXPERT is set and otherwise default to > yes. Further, SECRETMEM needs ARCH_HAS_SET_DIRECT_MAP. > > This allows us to remove CONFIG_EMBEDDED in the close future. > > Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> > --- > mm/Kconfig | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/mm/Kconfig b/mm/Kconfig > index ceec438c0741..aa154c20b129 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -1068,7 +1068,13 @@ config IO_MAPPING > bool > > config SECRETMEM > - def_bool ARCH_HAS_SET_DIRECT_MAP && !EMBEDDED > + default y > + bool "Enable memfd_secret() system call" if EXPERT > + depends on ARCH_HAS_SET_DIRECT_MAP > + help > + Enable the memfd_secret() system call with the ability to create > + memory areas visible only in the context of the owning process and > + not mapped to other processes and other kernel page tables. > > config ANON_VMA_NAME > bool "Anonymous VMA name support" > -- > 2.17.1 >
On Thu, Sep 8, 2022 at 8:24 PM Mike Rapoport <rppt@linux.ibm.com> wrote: > > On Thu, Sep 08, 2022 at 12:43:36PM +0200, Lukas Bulwahn wrote: > > Commit 6a108a14fa35 ("kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT") > > introduces CONFIG_EXPERT to carry the previous intent of CONFIG_EMBEDDED > > and just gives that intent a much better name. That has been clearly a good > > and long overdue renaming, and it is clearly an improvement to the kernel > > build configuration that has shown to help managing the kernel build > > configuration in the last decade. > > > > However, rather than bravely and radically just deleting CONFIG_EMBEDDED, > > this commit gives CONFIG_EMBEDDED a new intended semantics, but keeps it > > open for future contributors to implement that intended semantics: > > > > A new CONFIG_EMBEDDED option is added that automatically selects > > CONFIG_EXPERT when enabled and can be used in the future to isolate > > options that should only be considered for embedded systems (RISC > > architectures, SLOB, etc). > > > > Since then, this CONFIG_EMBEDDED implicitly had two purposes: > > > > - It can make even more options visible beyond what CONFIG_EXPERT makes > > visible. In other words, it may introduce another level of enabling the > > visibility of configuration options: always visible, visible with > > CONFIG_EXPERT and visible with CONFIG_EMBEDDED. > > > > - Set certain default values of some configurations differently, > > following the assumption that configuring a kernel build for an > > embedded system generally starts with a different set of default values > > compared to kernel builds for all other kind of systems. > > > > Considering the second purpose, note that already probably arguing that a > > kernel build for an embedded system would choose some values differently is > > already tricky: the set of embedded systems with Linux kernels is already > > quite diverse. Many embedded system have powerful CPUs and it would not be > > clear that all embedded systems just optimize towards one specific aspect, > > e.g., a smaller kernel image size. So, it is unclear if starting with "one > > set of default configuration" that is induced by CONFIG_EMBEDDED is a good > > offer for developers configuring their kernels. > > > > Also, the differences of needed user-space features in an embedded system > > compared to a non-embedded system are probably difficult or even impossible > > to name in some generic way. > > > > So it is not surprising that in the last decade hardly anyone has > > contributed changes to make something default differently in case of > > CONFIG_EMBEDDED=y. > > > > Currently, in v6.0-rc4, SECRETMEM is the only config switched off if > > CONFIG_EMBEDDED=y. > > > > As long as that is actually the only option that currently is selected or > > deselected, it is better to just make SECRETMEM configurable at build time > > by experts using menuconfig instead. > > > > Make SECRETMEM configurable when EXPERT is set and otherwise default to > > yes. Further, SECRETMEM needs ARCH_HAS_SET_DIRECT_MAP. > > > > This allows us to remove CONFIG_EMBEDDED in the close future. > > > > Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> > > Acked-by: Mike Rapoport <rppt@linux.ibm.com> > > > --- > > mm/Kconfig | 8 +++++++- > > 1 file changed, 7 insertions(+), 1 deletion(-) > > > > diff --git a/mm/Kconfig b/mm/Kconfig > > index ceec438c0741..aa154c20b129 100644 > > --- a/mm/Kconfig > > +++ b/mm/Kconfig > > @@ -1068,7 +1068,13 @@ config IO_MAPPING > > bool > > > > config SECRETMEM > > - def_bool ARCH_HAS_SET_DIRECT_MAP && !EMBEDDED > > + default y > > + bool "Enable memfd_secret() system call" if EXPERT > > + depends on ARCH_HAS_SET_DIRECT_MAP > > + help > > + Enable the memfd_secret() system call with the ability to create > > + memory areas visible only in the context of the owning process and > > + not mapped to other processes and other kernel page tables. > > > > config ANON_VMA_NAME > > bool "Anonymous VMA name support" > > -- > > 2.17.1 > > > > -- > Sincerely yours, > Mike. Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
diff --git a/mm/Kconfig b/mm/Kconfig index ceec438c0741..aa154c20b129 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -1068,7 +1068,13 @@ config IO_MAPPING bool config SECRETMEM - def_bool ARCH_HAS_SET_DIRECT_MAP && !EMBEDDED + default y + bool "Enable memfd_secret() system call" if EXPERT + depends on ARCH_HAS_SET_DIRECT_MAP + help + Enable the memfd_secret() system call with the ability to create + memory areas visible only in the context of the owning process and + not mapped to other processes and other kernel page tables. config ANON_VMA_NAME bool "Anonymous VMA name support"
Commit 6a108a14fa35 ("kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT") introduces CONFIG_EXPERT to carry the previous intent of CONFIG_EMBEDDED and just gives that intent a much better name. That has been clearly a good and long overdue renaming, and it is clearly an improvement to the kernel build configuration that has shown to help managing the kernel build configuration in the last decade. However, rather than bravely and radically just deleting CONFIG_EMBEDDED, this commit gives CONFIG_EMBEDDED a new intended semantics, but keeps it open for future contributors to implement that intended semantics: A new CONFIG_EMBEDDED option is added that automatically selects CONFIG_EXPERT when enabled and can be used in the future to isolate options that should only be considered for embedded systems (RISC architectures, SLOB, etc). Since then, this CONFIG_EMBEDDED implicitly had two purposes: - It can make even more options visible beyond what CONFIG_EXPERT makes visible. In other words, it may introduce another level of enabling the visibility of configuration options: always visible, visible with CONFIG_EXPERT and visible with CONFIG_EMBEDDED. - Set certain default values of some configurations differently, following the assumption that configuring a kernel build for an embedded system generally starts with a different set of default values compared to kernel builds for all other kind of systems. Considering the second purpose, note that already probably arguing that a kernel build for an embedded system would choose some values differently is already tricky: the set of embedded systems with Linux kernels is already quite diverse. Many embedded system have powerful CPUs and it would not be clear that all embedded systems just optimize towards one specific aspect, e.g., a smaller kernel image size. So, it is unclear if starting with "one set of default configuration" that is induced by CONFIG_EMBEDDED is a good offer for developers configuring their kernels. Also, the differences of needed user-space features in an embedded system compared to a non-embedded system are probably difficult or even impossible to name in some generic way. So it is not surprising that in the last decade hardly anyone has contributed changes to make something default differently in case of CONFIG_EMBEDDED=y. Currently, in v6.0-rc4, SECRETMEM is the only config switched off if CONFIG_EMBEDDED=y. As long as that is actually the only option that currently is selected or deselected, it is better to just make SECRETMEM configurable at build time by experts using menuconfig instead. Make SECRETMEM configurable when EXPERT is set and otherwise default to yes. Further, SECRETMEM needs ARCH_HAS_SET_DIRECT_MAP. This allows us to remove CONFIG_EMBEDDED in the close future. Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> --- mm/Kconfig | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)