| Message ID | 20190115210729.6014-1-yann.morin.1998@free.fr |
|---|---|
| State | Accepted |
| Commit | fc8a5f56b99164219c51d4f0e297dcf726a81bfc |
| Headers | show |
| Series | [v2] infra/pkg-cmake: use an obviously-invalid value for CMAKE_SYSTEM_VERSION | expand |
On 15/01/2019 22:07, Yann E. MORIN wrote: > Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr> > Cc: Arnout Vandecappelle <arnout@mind.be> > Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com> > Cc: Samuel Martin <s.martin49@gmail.com> > Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be> > > --- > Changes v1 -> v2: > - directly hard-code the condtant in toolchainfile.cmake.in (Thomas) > > Arnout, despite the change, I kept your acked-by tag; I believe that was > appropriate, as you explained why you acked it, and that condition has > not changed. I hope that is OK. Absolutely. Regards, Arnout
>>>>> "Yann" == Yann E MORIN <yann.morin.1998@free.fr> writes: > In 36568732e4, we expanded toolchain.cmake to also define the value for > CMAKE_SYSTEM_VERSION, as the cmake documentation states that it must be > manually defined when doing cross-compilation [0]: > When the CMAKE_SYSTEM_NAME variable is set explicitly to enable > cross compiling then the value of CMAKE_SYSTEM_VERSION must also > be set explicitly to specify the target system version. > However, the fix in 36568732e4 uses the version of the kernel headers, > assuming that would be the oldest kernel we could run on. Yet, this is > not the case, because glibc (for example) has fallbacks to support > running on kernels older than the headers it was built against. > The cmake official wiki [1] additionally states: > * CMAKE_SYSTEM_VERSION : optional, version of your target system, not > used very much. > Folllowed a little bit below, by: > * CMAKE_TOOLCHAIN_FILE : absolute or relative path to a cmake script > which sets up all the toolchain related variables mentioned above > For instance for crosscompiling from Linux to Embedded Linux on PowerPC > this file could look like this: > # this one is important > SET(CMAKE_SYSTEM_NAME Linux) > #this one not so much > SET(CMAKE_SYSTEM_VERSION 1) > [...] > Furthermore, using the kernel headers version can be a bit misleading (as > it really looks like is is the correct version to use when it is not), > while it is obvious that 1 is not really the output of `uname -r` and > thus is definitely not misleading. > Finally, random searches [2] about CMAKE_SYSTEM_VERSION, mostly only > turns up issues related with Windows, Mac-OS, and to a lesser extent, > Android (where it is forcibly set to 1), with issues realted to running > under just Linux (as opposed to Adnroid) mostly non-existent. > Consequently, we revert to using the value that is suggested in the > cmake WiKi, i.e. 1, and which is basically what we also used as a > workaround in the azure-iot-sdk-c paclkage up until d300b1d3b1. > A case were we will need to have a real kernel version, is if we one day > have a cmake-based pacakge that builds and installs a kernel module [3], > because it will need the _running_ kernel version to install it in > /lib/modules/VERSION/, but in that case it will anyway most probably > not be the headers version. > [0] https://cmake.org/cmake/help/v3.8/variable/CMAKE_SYSTEM_VERSION.html > [1] https://gitlab.kitware.com/cmake/community/wikis/doc/cmake/CrossCompiling > [2] https://duckduckgo.com/?q=CMAKE_SYSTEM_VERSION > [3] https://stackoverflow.com/questions/38205745/cmake-system-version-not-updated-for-new-kernel > Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr> > Cc: Arnout Vandecappelle <arnout@mind.be> > Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com> > Cc: Samuel Martin <s.martin49@gmail.com> > Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be> > --- > Changes v1 -> v2: > - directly hard-code the condtant in toolchainfile.cmake.in (Thomas) Committed, thanks.
>>>>> "Yann" == Yann E MORIN <yann.morin.1998@free.fr> writes: > In 36568732e4, we expanded toolchain.cmake to also define the value for > CMAKE_SYSTEM_VERSION, as the cmake documentation states that it must be > manually defined when doing cross-compilation [0]: > When the CMAKE_SYSTEM_NAME variable is set explicitly to enable > cross compiling then the value of CMAKE_SYSTEM_VERSION must also > be set explicitly to specify the target system version. > However, the fix in 36568732e4 uses the version of the kernel headers, > assuming that would be the oldest kernel we could run on. Yet, this is > not the case, because glibc (for example) has fallbacks to support > running on kernels older than the headers it was built against. > The cmake official wiki [1] additionally states: > * CMAKE_SYSTEM_VERSION : optional, version of your target system, not > used very much. > Folllowed a little bit below, by: > * CMAKE_TOOLCHAIN_FILE : absolute or relative path to a cmake script > which sets up all the toolchain related variables mentioned above > For instance for crosscompiling from Linux to Embedded Linux on PowerPC > this file could look like this: > # this one is important > SET(CMAKE_SYSTEM_NAME Linux) > #this one not so much > SET(CMAKE_SYSTEM_VERSION 1) > [...] > Furthermore, using the kernel headers version can be a bit misleading (as > it really looks like is is the correct version to use when it is not), > while it is obvious that 1 is not really the output of `uname -r` and > thus is definitely not misleading. > Finally, random searches [2] about CMAKE_SYSTEM_VERSION, mostly only > turns up issues related with Windows, Mac-OS, and to a lesser extent, > Android (where it is forcibly set to 1), with issues realted to running > under just Linux (as opposed to Adnroid) mostly non-existent. > Consequently, we revert to using the value that is suggested in the > cmake WiKi, i.e. 1, and which is basically what we also used as a > workaround in the azure-iot-sdk-c paclkage up until d300b1d3b1. > A case were we will need to have a real kernel version, is if we one day > have a cmake-based pacakge that builds and installs a kernel module [3], > because it will need the _running_ kernel version to install it in > /lib/modules/VERSION/, but in that case it will anyway most probably > not be the headers version. > [0] https://cmake.org/cmake/help/v3.8/variable/CMAKE_SYSTEM_VERSION.html > [1] https://gitlab.kitware.com/cmake/community/wikis/doc/cmake/CrossCompiling > [2] https://duckduckgo.com/?q=CMAKE_SYSTEM_VERSION > [3] https://stackoverflow.com/questions/38205745/cmake-system-version-not-updated-for-new-kernel > Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr> > Cc: Arnout Vandecappelle <arnout@mind.be> > Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com> > Cc: Samuel Martin <s.martin49@gmail.com> > Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be> > --- > Changes v1 -> v2: > - directly hard-code the condtant in toolchainfile.cmake.in (Thomas) > Arnout, despite the change, I kept your acked-by tag; I believe that was > appropriate, as you explained why you acked it, and that condition has > not changed. I hope that is OK. Committed to 2018.02.x and 2018.11.x, thanks.
diff --git a/package/pkg-cmake.mk b/package/pkg-cmake.mk index dd048b0949..51a1929ebb 100644 --- a/package/pkg-cmake.mk +++ b/package/pkg-cmake.mk @@ -264,7 +264,6 @@ define TOOLCHAIN_CMAKE_INSTALL_FILES -e 's#@@TARGET_CC@@#$(subst $(HOST_DIR)/,,$(call qstrip,$(TARGET_CC)))#' \ -e 's#@@TARGET_CXX@@#$(subst $(HOST_DIR)/,,$(call qstrip,$(TARGET_CXX)))#' \ -e 's#@@TARGET_FC@@#$(subst $(HOST_DIR)/,,$(call qstrip,$(TARGET_FC)))#' \ - -e 's#@@CMAKE_SYSTEM_VERSION@@#$(call qstrip,$(BR2_TOOLCHAIN_HEADERS_AT_LEAST))#' \ -e 's#@@CMAKE_SYSTEM_PROCESSOR@@#$(call qstrip,$(CMAKE_SYSTEM_PROCESSOR))#' \ -e 's#@@TOOLCHAIN_HAS_FORTRAN@@#$(if $(BR2_TOOLCHAIN_HAS_FORTRAN),1,0)#' \ -e 's#@@CMAKE_BUILD_TYPE@@#$(if $(BR2_ENABLE_DEBUG),Debug,Release)#' \ diff --git a/support/misc/toolchainfile.cmake.in b/support/misc/toolchainfile.cmake.in index 276b36629f..b25031a656 100644 --- a/support/misc/toolchainfile.cmake.in +++ b/support/misc/toolchainfile.cmake.in @@ -15,7 +15,7 @@ string(REPLACE "/share/buildroot" "" RELOCATED_HOST_DIR ${CMAKE_CURRENT_LIST_DIR list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_LIST_DIR}) set(CMAKE_SYSTEM_NAME Buildroot) -set(CMAKE_SYSTEM_VERSION @@CMAKE_SYSTEM_VERSION@@) +set(CMAKE_SYSTEM_VERSION 1) set(CMAKE_SYSTEM_PROCESSOR @@CMAKE_SYSTEM_PROCESSOR@@) # Set the {C,CXX}FLAGS appended by CMake depending on the build type
In 36568732e4, we expanded toolchain.cmake to also define the value for CMAKE_SYSTEM_VERSION, as the cmake documentation states that it must be manually defined when doing cross-compilation [0]: When the CMAKE_SYSTEM_NAME variable is set explicitly to enable cross compiling then the value of CMAKE_SYSTEM_VERSION must also be set explicitly to specify the target system version. However, the fix in 36568732e4 uses the version of the kernel headers, assuming that would be the oldest kernel we could run on. Yet, this is not the case, because glibc (for example) has fallbacks to support running on kernels older than the headers it was built against. The cmake official wiki [1] additionally states: * CMAKE_SYSTEM_VERSION : optional, version of your target system, not used very much. Folllowed a little bit below, by: * CMAKE_TOOLCHAIN_FILE : absolute or relative path to a cmake script which sets up all the toolchain related variables mentioned above For instance for crosscompiling from Linux to Embedded Linux on PowerPC this file could look like this: # this one is important SET(CMAKE_SYSTEM_NAME Linux) #this one not so much SET(CMAKE_SYSTEM_VERSION 1) [...] Furthermore, using the kernel headers version can be a bit misleading (as it really looks like is is the correct version to use when it is not), while it is obvious that 1 is not really the output of `uname -r` and thus is definitely not misleading. Finally, random searches [2] about CMAKE_SYSTEM_VERSION, mostly only turns up issues related with Windows, Mac-OS, and to a lesser extent, Android (where it is forcibly set to 1), with issues realted to running under just Linux (as opposed to Adnroid) mostly non-existent. Consequently, we revert to using the value that is suggested in the cmake WiKi, i.e. 1, and which is basically what we also used as a workaround in the azure-iot-sdk-c paclkage up until d300b1d3b1. A case were we will need to have a real kernel version, is if we one day have a cmake-based pacakge that builds and installs a kernel module [3], because it will need the _running_ kernel version to install it in /lib/modules/VERSION/, but in that case it will anyway most probably not be the headers version. [0] https://cmake.org/cmake/help/v3.8/variable/CMAKE_SYSTEM_VERSION.html [1] https://gitlab.kitware.com/cmake/community/wikis/doc/cmake/CrossCompiling [2] https://duckduckgo.com/?q=CMAKE_SYSTEM_VERSION [3] https://stackoverflow.com/questions/38205745/cmake-system-version-not-updated-for-new-kernel Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr> Cc: Arnout Vandecappelle <arnout@mind.be> Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Cc: Samuel Martin <s.martin49@gmail.com> Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be> --- Changes v1 -> v2: - directly hard-code the condtant in toolchainfile.cmake.in (Thomas) Arnout, despite the change, I kept your acked-by tag; I believe that was appropriate, as you explained why you acked it, and that condition has not changed. I hope that is OK. --- package/pkg-cmake.mk | 1 - support/misc/toolchainfile.cmake.in | 2 +- 2 files changed, 1 insertion(+), 2 deletions(-)