Le 30/03/2022 à 13:24, Joel Stanley a écrit : > Currently the boot wrapper lacks a -mcpu option, so it will be built for > the toolchain's default cpu. This is a problem if the toolchain defaults > to a cpu with newer instructions. > > We could wire in TARGET_CPU but instead use the oldest supported option > so the wrapper runs anywhere. > > The GCC documentation stays that -mcpu=powerpc64le will give us a > generic 64 bit powerpc machine: > > -mcpu=powerpc, -mcpu=powerpc64, and -mcpu=powerpc64le specify pure > 32-bit PowerPC (either endian), 64-bit big endian PowerPC and 64-bit > little endian PowerPC architecture machine types, with an appropriate, > generic processor model assumed for scheduling purposes. > > So do that for each of the three machines. > > This bug was found when building the kernel with a toolchain that > defaulted to powre10, resulting in a pcrel enabled wrapper which fails > to link: > > arch/powerpc/boot/wrapper.a(crt0.o): in function `p_base': > (.text+0x150): call to `platform_init' lacks nop, can't restore toc; (toc > save/adjust stub) > (.text+0x154): call to `start' lacks nop, can't restore toc; (toc > save/adjust stub) > powerpc64le-buildroot-linux-gnu-ld: final link failed: bad value > > Even with tha bug worked around the resulting kernel would crash on a > power9 box: > > $ qemu-system-ppc64 -nographic -nodefaults -M powernv9 -kernel > arch/powerpc/boot/zImage.epapr -serial mon:stdio > [ 7.069331356,5] INIT: Starting kernel at 0x20010020, fdt at 0x3068c628 > 25694 bytes > [ 7.130374661,3] *********************************************** > [ 7.131072886,3] Fatal Exception 0xe40 at 00000000200101e4 MSR > 9000000000000001 > [ 7.131290613,3] CFAR : 000000002001027c MSR : 9000000000000001 > [ 7.131433759,3] SRR0 : 0000000020010050 SRR1 : 9000000000000001 > [ 7.131577775,3] HSRR0: 00000000200101e4 HSRR1: 9000000000000001 > [ 7.131733687,3] DSISR: 00000000 DAR : 0000000000000000 > [ 7.131905162,3] LR : 0000000020010280 CTR : 0000000000000000 > [ 7.132068356,3] CR : 44002004 XER : 00000000 > > Link: https://github.com/linuxppc/issues/issues/400 > Signed-off-by: Joel Stanley <j...@jms.id.au> > --- > Tested: > > - ppc64le_defconfig > - pseries and powernv qemu, for power8, power9, power10 cpus > - buildroot compiler that defaults to -mcpu=power10 (gcc 10.3.0, ld 2.36.1) > - RHEL9 cross compilers (gcc 11.2.1-1, ld 2.35.2-17.el9) > > All decompressed and made it into the kernel ok. > > ppc64_defconfig did not work, as we've got a regression when the wrapper > is built for big endian. It hasn't worked for zImage.pseries for a long > time (at least v4.14), and broke some time between v5.4 and v5.17 for > zImage.epapr. > > arch/powerpc/boot/Makefile | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile > index 9993c6256ad2..1f5cc401bfc0 100644 > --- a/arch/powerpc/boot/Makefile > +++ b/arch/powerpc/boot/Makefile > @@ -38,9 +38,13 @@ BOOTCFLAGS := -Wall -Wundef -Wstrict-prototypes > -Wno-trigraphs \ > $(LINUXINCLUDE) > > ifdef CONFIG_PPC64_BOOT_WRAPPER > -BOOTCFLAGS += -m64 > +ifdef CONFIG_CPU_LITTLE_ENDIAN > +BOOTCFLAGS += -m64 -mcpu=powerpc64le > else > -BOOTCFLAGS += -m32 > +BOOTCFLAGS += -m64 -mcpu=powerpc64 > +endif > +else > +BOOTCFLAGS += -m32 -mcpu=powerpc
How does that interracts with the following lines ? Isn't it an issue to have two -mcpu ? arch/powerpc/boot/Makefile:$(obj)/4xx.o: BOOTCFLAGS += -mcpu=405 arch/powerpc/boot/Makefile:$(obj)/ebony.o: BOOTCFLAGS += -mcpu=440 arch/powerpc/boot/Makefile:$(obj)/cuboot-hotfoot.o: BOOTCFLAGS += -mcpu=405 arch/powerpc/boot/Makefile:$(obj)/cuboot-taishan.o: BOOTCFLAGS += -mcpu=440 arch/powerpc/boot/Makefile:$(obj)/cuboot-katmai.o: BOOTCFLAGS += -mcpu=440 arch/powerpc/boot/Makefile:$(obj)/cuboot-acadia.o: BOOTCFLAGS += -mcpu=405 arch/powerpc/boot/Makefile:$(obj)/treeboot-iss4xx.o: BOOTCFLAGS += -mcpu=405 arch/powerpc/boot/Makefile:$(obj)/treeboot-currituck.o: BOOTCFLAGS += -mcpu=405 arch/powerpc/boot/Makefile:$(obj)/treeboot-akebono.o: BOOTCFLAGS += -mcpu=405 > endif > > BOOTCFLAGS += -isystem $(shell $(BOOTCC) -print-file-name=include)