Hi Ard, On 9/23/19 5:41 PM, Ard Biesheuvel wrote: > On Fri, 20 Sep 2019 at 18:33, Vincenzo Frascino > <vincenzo.frasc...@arm.com> wrote: >> >> Hi Will, >> >> thank you for reporting this. >> >> On 20/09/2019 15:27, Will Deacon wrote: >>> Hi Vincenzo, >>> >>> I've been running into a few issues with the COMPAT vDSO. Please could >>> you have a look? >>> >> >> I will be at Linux Recipes next week. I will look at this with priority when >> I >> come back. >> > > Hi all, > > I noticed another issue: I build out of tree, and the VDSO gets > rebuilt every time I build the kernel, even if I haven't made any > changes to the source tree at all. > > Could you please look into that as well? (once you get around to it) >
I am happy to have a look at this once back from Kernel Recipes next week. In the meantime may I ask for some more details? Could be useful to have a set of commands and a log that shows the problem, in this way I will be sure to be looking at the same issue. > Thanks, > Ard. > > >>> If I do the following: >>> >>> $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig >>> [...] >>> $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- menuconfig >>> [set CONFIG_CROSS_COMPILE_COMPAT_VDSO="arm-linux-gnueabihf-"] >>> $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- >>> >>> Then I see the following warning: >>> >>> arch/arm64/Makefile:62: CROSS_COMPILE_COMPAT not defined or empty, the >>> compat vDSO will not be built >>> >>> even though the compat vDSO *has* been built: >>> >>> $ file arch/arm64/kernel/vdso32/vdso.so >>> arch/arm64/kernel/vdso32/vdso.so: ELF 32-bit LSB pie executable, ARM, EABI5 >>> version 1 (SYSV), dynamically linked, >>> BuildID[sha1]=c67f6c786f2d2d6f86c71f708595594aa25247f6, stripped >>> >>> However, I also get some warnings because arm64 headers are being included >>> in the compat vDSO build: >>> >>> In file included from ./arch/arm64/include/asm/thread_info.h:17:0, >>> from ./include/linux/thread_info.h:38, >>> from ./arch/arm64/include/asm/preempt.h:5, >>> from ./include/linux/preempt.h:78, >>> from ./include/linux/spinlock.h:51, >>> from ./include/linux/seqlock.h:36, >>> from ./include/linux/time.h:6, >>> from >>> /usr/local/google/home/willdeacon/work/linux/lib/vdso/gettimeofday.c:7, >>> from <command-line>:0: >>> ./arch/arm64/include/asm/memory.h: In function ‘__tag_set’: >>> ./arch/arm64/include/asm/memory.h:233:15: warning: cast from pointer to >>> integer of different size [-Wpointer-to-int-cast] >>> u64 __addr = (u64)addr & ~__tag_shifted(0xff); >>> ^ >>> In file included from ./arch/arm64/include/asm/pgtable-hwdef.h:8:0, >>> from ./arch/arm64/include/asm/processor.h:34, >>> from ./arch/arm64/include/asm/elf.h:118, >>> from ./include/linux/elf.h:5, >>> from ./include/linux/elfnote.h:62, >>> from arch/arm64/kernel/vdso32/note.c:11: >>> ./arch/arm64/include/asm/memory.h: In function ‘__tag_set’: >>> ./arch/arm64/include/asm/memory.h:233:15: warning: cast from pointer to >>> integer of different size [-Wpointer-to-int-cast] >>> u64 __addr = (u64)addr & ~__tag_shifted(0xff); >>> ^ >>> Worse, if your compat binutils isn't up-to-date, you'll actually run into >>> a build failure: >>> >>> /tmp/ccFCrjUg.s:80: Error: invalid barrier type -- `dmb ishld' >>> /tmp/ccFCrjUg.s:124: Error: invalid barrier type -- `dmb ishld' >>> >>> There also appears to be a problem getting the toolchain prefix from >>> Kconfig. >>> If, for example, I do: >>> >>> $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig >>> [...] >>> $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- menuconfig >>> [set CONFIG_CROSS_COMPILE_COMPAT_VDSO="vincenzo"] >>> $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- >>> arch/arm64/Makefile:64: *** vincenzogcc not found, check >>> CROSS_COMPILE_COMPAT. Stop. >>> $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- menuconfig >>> [set CONFIG_CROSS_COMPILE_COMPAT_VDSO="arm-linux-gnueabihf-"] >>> $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- >>> arch/arm64/Makefile:64: *** vincenzogcc not found, check >>> CROSS_COMPILE_COMPAT. Stop. >>> $ grep CONFIG_CROSS_COMPILE_COMPAT_VDSO .config >>> CONFIG_CROSS_COMPILE_COMPAT_VDSO="arm-linux-gnueabihf-" >>> >>> which is irritating, because it seems to force a 'mrproper' if you don't >>> get the prefix right first time. >>> >>> Cheers, >>> >>> Will >>> >> >> -- >> Regards, >> Vincenzo -- Regards, Vincenzo
