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* MIPS: VDSO: Use same -m%-float cflag as the kernel properPaul Burton2019-09-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 0648e50e548d881d025b9419a1a168753c8e2bf7 upstream. The MIPS VDSO build currently doesn't provide the -msoft-float flag to the compiler as the kernel proper does. This results in an attempt to use the compiler's default floating point configuration, which can be problematic in cases where this is incompatible with the target CPU's -march= flag. For example decstation_defconfig fails to build using toolchains in which gcc was configured --with-fp-32=xx with the following error: LDS arch/mips/vdso/vdso.lds cc1: error: '-march=r3000' requires '-mfp32' make[2]: *** [scripts/Makefile.build:379: arch/mips/vdso/vdso.lds] Error 1 The kernel proper avoids this error because we build with the -msoft-float compiler flag, rather than using the compiler's default. Pass this flag through to the VDSO build so that it too becomes agnostic to the toolchain's floating point configuration. Note that this is filtered out from KBUILD_CFLAGS rather than simply always using -msoft-float such that if we switch the kernel to use -mno-float in the future the VDSO will automatically inherit the change. The VDSO doesn't actually include any floating point code, and its .MIPS.abiflags section is already manually generated to specify that it's compatible with any floating point ABI. As such this change should have no effect on the resulting VDSO, apart from fixing the build failure for affected toolchains. Signed-off-by: Paul Burton <paul.burton@mips.com> Reported-by: Kevin Hilman <khilman@baylibre.com> Reported-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Kevin Hilman <khilman@baylibre.com> References: https://lore.kernel.org/linux-mips/1477843551-21813-1-git-send-email-linux@roeck-us.net/ References: https://kernelci.org/build/id/5c4e4ae059b5142a249ad004/logs/ Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Cc: Maciej W. Rozycki <macro@linux-mips.org> Cc: linux-mips@vger.kernel.org Cc: stable@vger.kernel.org # v4.4+ Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* MIPS: VDSO: Prevent use of smp_processor_id()Paul Burton2019-09-21
| | | | | | | | | | | | | | | | | | | | | | | commit 351fdddd366245c0fb4636f32edfb4198c8d6b8c upstream. VDSO code should not be using smp_processor_id(), since it is executed in user mode. Introduce a VDSO-specific path which will cause a compile-time or link-time error (depending upon support for __compiletime_error) if the VDSO ever incorrectly attempts to use smp_processor_id(). [Matt Redfearn <matt.redfearn@imgtec.com>: Move before change to smp_processor_id in series] Signed-off-by: Paul Burton <paul.burton@mips.com> Signed-off-by: Matt Redfearn <matt.redfearn@mips.com> Patchwork: https://patchwork.linux-mips.org/patch/17932/ Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* MIPS: VDSO: Include $(ccflags-vdso) in o32,n32 .lds buildsPaul Burton2019-02-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 67fc5dc8a541e8f458d7f08bf88ff55933bf9f9d upstream. When generating vdso-o32.lds & vdso-n32.lds for use with programs running as compat ABIs under 64b kernels, we previously haven't included the compiler flags that are supposedly common to all ABIs - ie. those in the ccflags-vdso variable. This is problematic in cases where we need to provide the -m%-float flag in order to ensure that we don't attempt to use a floating point ABI that's incompatible with the target CPU & ABI. For example a toolchain using current gcc trunk configured --with-fp-32=xx fails to build a 64r6el_defconfig kernel with the following error: cc1: error: '-march=mips1' requires '-mfp32' make[2]: *** [arch/mips/vdso/Makefile:135: arch/mips/vdso/vdso-o32.lds] Error 1 Include $(ccflags-vdso) for the compat VDSO .lds builds, just as it is included for the native VDSO .lds & when compiling objects for the compat VDSOs. This ensures we consistently provide the -msoft-float flag amongst others, avoiding the problem by ensuring we're agnostic to the toolchain defaults. Signed-off-by: Paul Burton <paul.burton@mips.com> Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Cc: linux-mips@vger.kernel.org Cc: Kevin Hilman <khilman@baylibre.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Maciej W . Rozycki <macro@linux-mips.org> Cc: stable@vger.kernel.org # v4.4+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* MIPS: Fix -mabi=64 build of vdso.ldsJames Hogan2016-10-28
| | | | | | | | | | | | | | | | | | | | | | | | commit 034827c727f7f3946a18355b63995b402c226c82 upstream. The native ABI vDSO linker script vdso.lds is built by preprocessing vdso.lds.S, with the native -mabi flag passed in to get the correct ABI definitions. Unfortunately however certain toolchains choke on -mabi=64 without a corresponding compatible -march flag, for example: cc1: error: ‘-march=mips32r2’ is not compatible with the selected ABI scripts/Makefile.build:338: recipe for target 'arch/mips/vdso/vdso.lds' failed Fix this by including ccflags-vdso in the KBUILD_CPPFLAGS for vdso.lds, which includes the appropriate -march flag. Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Signed-off-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: Maciej W. Rozycki <macro@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14368/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* MIPS: VDSO: Build with `-fno-strict-aliasing'Maciej W. Rozycki2016-06-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 94cc36b84acc29f543b48bc5ed786011b112a666 upstream. Avoid an aliasing issue causing a build error in VDSO: In file included from include/linux/srcu.h:34:0, from include/linux/notifier.h:15, from ./arch/mips/include/asm/uprobes.h:9, from include/linux/uprobes.h:61, from include/linux/mm_types.h:13, from ./arch/mips/include/asm/vdso.h:14, from arch/mips/vdso/vdso.h:27, from arch/mips/vdso/gettimeofday.c:11: include/linux/workqueue.h: In function 'work_static': include/linux/workqueue.h:186:2: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] return *work_data_bits(work) & WORK_STRUCT_STATIC; ^ cc1: all warnings being treated as errors make[2]: *** [arch/mips/vdso/gettimeofday.o] Error 1 with a CONFIG_DEBUG_OBJECTS_WORK configuration and GCC 5.2.0. Include `-fno-strict-aliasing' along with compiler options used, as required for kernel code, fixing a problem present since the introduction of VDSO with commit ebb5e78cc634 ("MIPS: Initial implementation of a VDSO"). Thanks to Tejun for diagnosing this properly! Signed-off-by: Maciej W. Rozycki <macro@imgtec.com> Reviewed-by: James Hogan <james.hogan@imgtec.com> Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Cc: Tejun Heo <tj@kernel.org> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13357/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* MIPS: Build microMIPS VDSO for microMIPS kernelsJames Hogan2016-06-07
| | | | | | | | | | | | | | | | | commit bb93078e655be1e24d68f28f2756676e62c037ce upstream. MicroMIPS kernels may be expected to run on microMIPS only cores which don't support the normal MIPS instruction set, so be sure to pass the -mmicromips flag through to the VDSO cflags. Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13349/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* MIPS: VDSO: Fix build error with binutils 2.24 and earlierGuenter Roeck2015-12-29
| | | | | | | | | | | | | | | | | | | | | | Commit 2a037f310bab ("MIPS: VDSO: Fix build error") tries to fix a build error seen with binutils 2.24 and earlier. However, the fix does not work, and again results in the already known build errors if the kernel is built with an earlier version of binutils. CC arch/mips/vdso/gettimeofday.o /tmp/ccnOVbHT.s: Assembler messages: /tmp/ccnOVbHT.s:50: Error: can't resolve `_start' {*UND* section} - `L0 {.text section} /tmp/ccnOVbHT.s:374: Error: can't resolve `_start' {*UND* section} - `L0 {.text section} scripts/Makefile.build:258: recipe for target 'arch/mips/vdso/gettimeofday.o' failed make[2]: *** [arch/mips/vdso/gettimeofday.o] Error 1 Fixes: 2a037f310bab ("MIPS: VDSO: Fix build error") Cc: Qais Yousef <qais.yousef@imgtec.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/11926/ Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: VDSO: Fix build errorQais Yousef2015-12-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") introduced a build error. For MIPS VDSO to be compiled it requires binutils version 2.25 or above but the check in the Makefile had inverted logic causing it to be compiled in if binutils is below 2.25. This fixes the following compilation error: CC arch/mips/vdso/gettimeofday.o /tmp/ccsExcUd.s: Assembler messages: /tmp/ccsExcUd.s:62: Error: can't resolve `_start' {*UND* section} - `L0' {.text section} /tmp/ccsExcUd.s:467: Error: can't resolve `_start' {*UND* section} - `L0' {.text section} make[2]: *** [arch/mips/vdso/gettimeofday.o] Error 1 make[1]: *** [arch/mips/vdso] Error 2 make: *** [arch/mips] Error 2 [ralf@linux-mips: Fixed Sergei's complaint on the formatting of the cited commit and generally reformatted the log message.] Signed-off-by: Qais Yousef <qais.yousef@imgtec.com> Cc: alex@alex-smith.me.uk Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/11745/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: Initial implementation of a VDSOAlex Smith2015-11-11
Add an initial implementation of a proper (i.e. an ELF shared library) VDSO. With this commit it does not export any symbols, it only replaces the current signal return trampoline page. A later commit will add user implementations of gettimeofday()/clock_gettime(). To support both new toolchains and old ones which don't generate ABI flags section, we define its content manually and then use a tool (genvdso) to patch up the section to have the correct name and type. genvdso also extracts symbol offsets ({,rt_}sigreturn) needed by the kernel, and generates a C file containing a "struct mips_vdso_image" containing both the VDSO data and these offsets. This C file is compiled into the kernel. On 64-bit kernels we require a different VDSO for each supported ABI, so we may build up to 3 different VDSOs. The VDSO to use is selected by the mips_abi structure. A kernel/user shared data page is created and mapped below the VDSO image. This is currently empty, but will be used by the user time function implementations which are added later. [markos.chandras@imgtec.com: - Add more comments - Move abi detection in genvdso.h since it's the get_symbol function that needs it. - Add an R6 specific way to calculate the base address of VDSO in order to avoid the branch instruction which affects performance. - Do not patch .gnu.attributes since it's not needed for dynamic linking. - Simplify Makefile a little bit. - checkpatch fixes - Restrict VDSO support for binutils < 2.25 for pre-R6 - Include atomic64.h for O32 variant on MIPS64] Signed-off-by: Alex Smith <alex.smith@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Cc: Matthew Fortune <matthew.fortune@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/11337/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>