wireguard-linux/arch/mips/vdso/Makefile, branch jd/unified-crypt-queue

MIPS: vdso: Wrap -mexplicit-relocs in cc-option

2020-02-19T18:30:10Z

Clang does not support this option and errors out: clang-11: error: unknown argument: '-mexplicit-relocs' Clang does not appear to need this flag like GCC does because the jalr check that was added in commit 976c23af3ee5 ("mips: vdso: add build time check that no 'jalr t9' calls left") passes just fine with $ make ARCH=mips CC=clang CROSS_COMPILE=mipsel-linux-gnu- malta_defconfig arch/mips/vdso/ even before commit d3f703c4359f ("mips: vdso: fix 'jalr t9' crash in vdso code"). -mrelax-pic-calls has been supported since clang 9, which is the earliest version that could build a working MIPS kernel, and it is the default for clang so just leave it be. Fixes: d3f703c4359f ("mips: vdso: fix 'jalr t9' crash in vdso code") Link: https://github.com/ClangBuiltLinux/linux/issues/890 Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Tested-by: Nick Desaulniers Signed-off-by: Paul Burton Cc: Ralf Baechle Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: clang-built-linux@googlegroups.com

mips: vdso: add build time check that no 'jalr t9' calls left

2020-02-15T20:44:03Z

vdso shared object cannot have GOT based PIC 'jalr t9' calls because nobody set GOT table in vdso. Contributing into vdso .o files are compiled in PIC mode and as result for internal static functions calls compiler will generate 'jalr t9' instructions. Those are supposed to be converted into PC relative 'bal' calls by linker when relocation are processed. Mips global GOT entries do have dynamic relocations and they will be caught by cmd_vdso_check Makefile rule. Static PIC calls go through mips local GOT entries that do not have dynamic relocations. For those 'jalr t9' calls could be present but without dynamic relocations and they need to be converted to 'bal' calls by linker. Add additional build time check to make sure that no 'jalr t9' slip through because of some toolchain misconfiguration that prevents 'jalr t9' to 'bal' conversion. Signed-off-by: Victor Kamensky Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: Ralf Baechle Cc: James Hogan Cc: Vincenzo Frascino Cc: bruce.ashfield@gmail.com Cc: richard.purdie@linuxfoundation.org

MIPS: Disable VDSO time functionality on microMIPS

2020-02-15T20:44:03Z

A check we're about to add to pick up on function calls that depend on bogus use of the GOT in the VDSO picked up on instances of such function calls in microMIPS builds. Since the code appears genuinely problematic, and given the relatively small amount of use & testing that microMIPS sees, go ahead & disable the VDSO for microMIPS builds. Signed-off-by: Paul Burton

mips: vdso: fix 'jalr t9' crash in vdso code

2020-02-15T19:04:05Z

Observed that when kernel is built with Yocto mips64-poky-linux-gcc, and mips64-poky-linux-gnun32-gcc toolchain, resulting vdso contains 'jalr t9' instructions in its code and since in vdso case nobody sets GOT table code crashes when instruction reached. On other hand observed that when kernel is built mips-poky-linux-gcc toolchain, the same 'jalr t9' instruction are replaced with PC relative function calls using 'bal' instructions. The difference boils down to -mrelax-pic-calls and -mexplicit-relocs gcc options that gets different default values depending on gcc target triplets and corresponding binutils. -mrelax-pic-calls got enabled by default only in mips-poky-linux-gcc case. MIPS binutils ld relies on R_MIPS_JALR relocation to convert 'jalr t9' into 'bal' and such relocation is generated only if -mrelax-pic-calls option is on. Please note 'jalr t9' conversion to 'bal' can happen only to static functions. These static PIC calls use mips local GOT entries that are supposed to be filled with start of DSO value by run-time linker (missing in VDSO case) and they do not have dynamic relocations. Global mips GOT entries must have dynamic relocations and they should be prevented by cmd_vdso_check Makefile rule. Solution call out -mrelax-pic-calls and -mexplicit-relocs options explicitly while compiling MIPS vdso code. That would get correct and consistent between different toolchains behaviour. Reported-by: Bruce Ashfield Signed-off-by: Victor Kamensky Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: Ralf Baechle Cc: James Hogan Cc: Vincenzo Frascino Cc: richard.purdie@linuxfoundation.org

kbuild: rename hostprogs-y/always to hostprogs/always-y

2020-02-03T16:53:07Z

In old days, the "host-progs" syntax was used for specifying host programs. It was renamed to the current "hostprogs-y" in 2004. It is typically useful in scripts/Makefile because it allows Kbuild to selectively compile host programs based on the kernel configuration. This commit renames like follows: always -> always-y hostprogs-y -> hostprogs So, scripts/Makefile will look like this: always-$(CONFIG_BUILD_BIN2C) += ... always-$(CONFIG_KALLSYMS) += ... ... hostprogs := $(always-y) $(always-m) I think this makes more sense because a host program is always a host program, irrespective of the kernel configuration. We want to specify which ones to compile by CONFIG options, so always-y will be handier. The "always", "hostprogs-y", "hostprogs-m" will be kept for backward compatibility for a while. Signed-off-by: Masahiro Yamada

MIPS: vdso: Define BUILD_VDSO32 when building a 32bit kernel

2020-01-16T20:24:25Z

The confinement of the 32bit specific VDSO functions missed to define BUILD_VDSO32 when building a 32bit MIPS kernel: arch/mips/vdso/vgettimeofday.c: In function __vdso_clock_gettime: arch/mips/vdso/vgettimeofday.c:17:9: error: implicit declaration of function __cvdso_clock_gettime32 arch/mips/vdso/vgettimeofday.c: In function __vdso_clock_getres: arch/mips/vdso/vgettimeofday.c:39:9: error: implicit declaration of function __cvdso_clock_getres_time32 Force the define for 32bit builds in the VDSO Makefile. Fixes: bf279849ad59 ("lib/vdso: Build 32 bit specific functions in the right context") Reported-by: kbuild test robot Signed-off-by: Thomas Gleixner Acked-by: Paul Burton Link: https://lore.kernel.org/r/87d0bjfaqa.fsf@nanos.tec.linutronix.de

MIPS: allow building with kcov coverage

2019-11-11T18:46:53Z

Add ARCH_HAS_KCOV and HAVE_GCC_PLUGINS to MIPS config. Disable instrumentation of vdso to avoid build failure. Signed-off-by: Alexey Khoroshilov Signed-off-by: Paul Burton Cc: Ralf Baechle Cc: James Hogan Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org

MIPS: Disable Loongson MMI instructions for kernel build

2019-10-10T18:58:52Z

GCC 9.x automatically enables support for Loongson MMI instructions when using some -march= flags, and then errors out when -msoft-float is specified with: cc1: error: ‘-mloongson-mmi’ must be used with ‘-mhard-float’ The kernel shouldn't be using these MMI instructions anyway, just as it doesn't use floating point instructions. Explicitly disable them in order to fix the build with GCC 9.x. Signed-off-by: Paul Burton Fixes: 3702bba5eb4f ("MIPS: Loongson: Add GCC 4.4 support for Loongson2E") Fixes: 6f7a251a259e ("MIPS: Loongson: Add basic Loongson 2F support") Fixes: 5188129b8c9f ("MIPS: Loongson-3: Improve -march option and move it to Platform") Cc: Huacai Chen Cc: Jiaxun Yang Cc: stable@vger.kernel.org # v2.6.32+ Cc: linux-mips@vger.kernel.org

MIPS: VDSO: Fix build for binutils < 2.25

2019-10-02T21:07:32Z

Versions of binutils prior to 2.25 are unable to link our VDSO due to an unsupported R_MIPS_PC32 relocation generated by the ".word _start - ." line of the inline asm in get_vdso_base(). As such, the intent is that when building with binutils older than 2.25 we don't build code for gettimeofday() & friends in the VDSO that rely upon get_vdso_base(). Commit 24640f233b46 ("mips: Add support for generic vDSO") converted us to using generic VDSO infrastructure, and as part of that the gettimeofday() functionality moved to a new vgettimeofday.c file. The check for binutils < 2.25 wasn't updated to handle this new filename, and so it continues trying to remove the old unused filename from the build. The end result is that we try to include the gettimeofday() code in builds that will fail to link. Fix this by updating the binutils < 2.25 case to remove vgettimeofday.c from obj-vdso-y, rather than gettimeofday.c. Signed-off-by: Paul Burton Fixes: 24640f233b46 ("mips: Add support for generic vDSO") Cc: Vincenzo Frascino Cc: linux-mips@vger.kernel.org

mips: vdso: Fix flip/flop vdso building bug

2019-07-26T23:43:38Z

Running "make" on an already compiled kernel tree will rebuild the vdso library even if this has not been modified. $ make GEN Makefile Using linux as source for kernel CALL linux/scripts/atomic/check-atomics.sh CALL linux/scripts/checksyscalls.sh :1511:2: warning: #warning syscall clone3 not implemented [-Wcpp] CHK include/generated/compile.h VDSO arch/mips/vdso/vdso.so.dbg.raw OBJCOPY arch/mips/vdso/vdso.so.raw GENVDSO arch/mips/vdso/vdso-image.c CC arch/mips/vdso/vdso-image.o AR arch/mips/vdso/built-in.a AR arch/mips/built-in.a CHK include/generated/autoksyms.h GEN .version CHK include/generated/compile.h UPD include/generated/compile.h CC init/version.o AR init/built-in.a LD vmlinux.o MODPOST vmlinux.o MODINFO modules.builtin.modinfo KSYM .tmp_kallsyms1.o KSYM .tmp_kallsyms2.o LD vmlinux SORTEX vmlinux SYSMAP System.map Building modules, stage 2. ITS arch/mips/boot/vmlinux.gz.its OBJCOPY arch/mips/boot/vmlinux.bin MODPOST 7 modules GZIP arch/mips/boot/vmlinux.bin.gz ITB arch/mips/boot/vmlinux.gz.itb The issue is generated by the fact that "if_changed" is called twice in a single target. Fix the build bug merging the two commands into a single function. Signed-off-by: Vincenzo Frascino Signed-off-by: Paul Burton