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) 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
