Messages in this thread | | | Subject | Re: [PATCH v3 2/2] powerpc/64: add stack protector support | From | Christophe LEROY <> | Date | Wed, 26 Sep 2018 09:58:30 +0200 |
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Segher, any idea about this problem ?
Christophe
Le 26/09/2018 à 09:05, Russell Currey a écrit : > On Tue, 2018-09-25 at 17:56 +0200, Christophe LEROY wrote: >> Snowpatch reports failure on pmac32_defconfig, as follows: >> >> arch/powerpc/platforms/powermac/bootx_init.o: In function `bootx_printf': >> /var/lib/jenkins-slave/workspace/snowpatch/snowpatch-linux- >> sparse/linux/arch/powerpc/platforms/powermac/bootx_init.c:88: >> undefined reference to `__stack_chk_fail_local' >> arch/powerpc/platforms/powermac/bootx_init.o: In function >> `bootx_add_display_props': >> /var/lib/jenkins-slave/workspace/snowpatch/snowpatch-linux- >> sparse/linux/arch/powerpc/platforms/powermac/bootx_init.c:211: >> undefined reference to `__stack_chk_fail_local' >> arch/powerpc/platforms/powermac/bootx_init.o: In function >> `bootx_scan_dt_build_struct': >> /var/lib/jenkins-slave/workspace/snowpatch/snowpatch-linux- >> sparse/linux/arch/powerpc/platforms/powermac/bootx_init.c:350: >> undefined reference to `__stack_chk_fail_local' >> arch/powerpc/platforms/powermac/bootx_init.o: In function `bootx_init': >> /var/lib/jenkins-slave/workspace/snowpatch/snowpatch-linux- >> sparse/linux/arch/powerpc/platforms/powermac/bootx_init.c:598: >> undefined reference to `__stack_chk_fail_local' >> ld: .tmp_vmlinux1: hidden symbol `__stack_chk_fail_local' isn't defined >> ld: final link failed: Bad value >> Makefile:1040: recipe for target 'vmlinux' failed >> make: *** [vmlinux] Error 1 >> >> I don't have this issue with GCC 8.1, bootx_init.o has references to >> __stack_chk_fail, not to __stack_chk_fail_local >> >> Looking online, it may be due to an old build and a lack of 'make >> clean', could it be the case here ? > > We do make mrproper AND clean, just to be sure :) > >> >> Otherwise, can you retry the build to see if it's happen again ? > > I've retried the build and the same thing happens. Our build environment is using > GCC 7.3 on Ubuntu 18.04. Reproduced on a different machine too, running the same > OS and compiler. > > You can see exactly what gets run here: > https://github.com/ajdlinux/openpower.xyz-snowpatch/blob/master/kernel-build-sparse.sh > > - Russell > >> >> Christophe >> >> Le 24/09/2018 à 17:15, Christophe Leroy a écrit : >>> On PPC64, as register r13 points to the paca_struct at all time, >>> this patch adds a copy of the canary there, which is copied at >>> task_switch. >>> That new canary is then used by using the following GCC options: >>> -mstack-protector-guard=tls >>> -mstack-protector-guard-reg=r13 >>> -mstack-protector-guard-offset=offsetof(struct paca_struct, canary)) >>> >>> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> >>> --- >>> arch/powerpc/Kconfig | 2 +- >>> arch/powerpc/Makefile | 8 ++++++++ >>> arch/powerpc/include/asm/paca.h | 3 +++ >>> arch/powerpc/include/asm/stackprotector.h | 3 +++ >>> arch/powerpc/kernel/asm-offsets.c | 3 +++ >>> arch/powerpc/kernel/entry_64.S | 4 ++++ >>> 6 files changed, 22 insertions(+), 1 deletion(-) >>> >>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig >>> index 3bcb05929931..602eea723624 100644 >>> --- a/arch/powerpc/Kconfig >>> +++ b/arch/powerpc/Kconfig >>> @@ -180,7 +180,7 @@ config PPC >>> select HAVE_ARCH_SECCOMP_FILTER >>> select HAVE_ARCH_TRACEHOOK >>> select HAVE_CBPF_JIT if !PPC64 >>> - select HAVE_STACKPROTECTOR if $(cc-option,-mstack-protector- >>> guard=tls) && PPC32 >>> + select HAVE_STACKPROTECTOR if $(cc-option,-mstack-protector- >>> guard=tls) >>> select HAVE_CONTEXT_TRACKING if PPC64 >>> select HAVE_DEBUG_KMEMLEAK >>> select HAVE_DEBUG_STACKOVERFLOW >>> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile >>> index 45b8eb4d8fe7..81552c7b46eb 100644 >>> --- a/arch/powerpc/Makefile >>> +++ b/arch/powerpc/Makefile >>> @@ -113,7 +113,11 @@ KBUILD_ARFLAGS += --target=elf$(BITS)-$(GNUTARGET) >>> endif >>> >>> cflags-$(CONFIG_STACKPROTECTOR) += -mstack-protector-guard=tls >>> +ifdef CONFIG_PPC64 >>> +cflags-$(CONFIG_STACKPROTECTOR) += -mstack-protector-guard-reg=r13 >>> +else >>> cflags-$(CONFIG_STACKPROTECTOR) += -mstack-protector-guard-reg=r2 >>> +endif >>> >>> LDFLAGS_vmlinux-y := -Bstatic >>> LDFLAGS_vmlinux-$(CONFIG_RELOCATABLE) := -pie >>> @@ -411,8 +415,12 @@ ifdef CONFIG_STACKPROTECTOR >>> prepare: stack_protector_prepare >>> >>> stack_protector_prepare: prepare0 >>> +ifdef CONFIG_PPC64 >>> + $(eval KBUILD_CFLAGS += -mstack-protector-guard-offset=$(shell awk '{if >>> ($$2 == "PACA_CANARY") print $$3;}' include/generated/asm-offsets.h)) >>> +else >>> $(eval KBUILD_CFLAGS += -mstack-protector-guard-offset=$(shell awk '{if >>> ($$2 == "TASK_CANARY") print $$3;}' include/generated/asm-offsets.h)) >>> endif >>> +endif >>> >>> # Use the file '.tmp_gas_check' for binutils tests, as gas won't output >>> # to stdout and these checks are run even on install targets. >>> diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h >>> index 6d6b3706232c..98d883e58945 100644 >>> --- a/arch/powerpc/include/asm/paca.h >>> +++ b/arch/powerpc/include/asm/paca.h >>> @@ -246,6 +246,9 @@ struct paca_struct { >>> struct slb_entry *mce_faulty_slbs; >>> u16 slb_save_cache_ptr; >>> #endif /* CONFIG_PPC_BOOK3S_64 */ >>> +#ifdef CONFIG_STACKPROTECTOR >>> + unsigned long canary; >>> +#endif >>> } ____cacheline_aligned; >>> >>> extern struct paca_struct **paca_ptrs; >>> diff --git a/arch/powerpc/include/asm/stackprotector.h >>> b/arch/powerpc/include/asm/stackprotector.h >>> index 263e2aab1862..e81991955c0d 100644 >>> --- a/arch/powerpc/include/asm/stackprotector.h >>> +++ b/arch/powerpc/include/asm/stackprotector.h >>> @@ -29,6 +29,9 @@ static __always_inline void boot_init_stack_canary(void) >>> canary ^= LINUX_VERSION_CODE; >>> >>> current->stack_canary = canary; >>> +#ifdef CONFIG_PPC64 >>> + get_paca()->canary = canary; >>> +#endif >>> } >>> >>> #endif /* _ASM_STACKPROTECTOR_H */ >>> diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm- >>> offsets.c >>> index a992f7a53cf3..773dee55b3f6 100644 >>> --- a/arch/powerpc/kernel/asm-offsets.c >>> +++ b/arch/powerpc/kernel/asm-offsets.c >>> @@ -81,6 +81,9 @@ int main(void) >>> OFFSET(MM, task_struct, mm); >>> #ifdef CONFIG_STACKPROTECTOR >>> OFFSET(TASK_CANARY, task_struct, stack_canary); >>> +#ifdef CONFIG_PPC64 >>> + OFFSET(PACA_CANARY, paca_struct, canary); >>> +#endif >>> #endif >>> OFFSET(MMCONTEXTID, mm_struct, context.id); >>> #ifdef CONFIG_PPC64 >>> diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S >>> index 77a888bfcb53..573fa879d785 100644 >>> --- a/arch/powerpc/kernel/entry_64.S >>> +++ b/arch/powerpc/kernel/entry_64.S >>> @@ -624,6 +624,10 @@ _GLOBAL(_switch) >>> >>> addi r6,r4,-THREAD /* Convert THREAD to 'current' */ >>> std r6,PACACURRENT(r13) /* Set new 'current' */ >>> +#if defined(CONFIG_STACKPROTECTOR) >>> + ld r6, TASK_CANARY(r6) >>> + std r6, PACA_CANARY(r13) >>> +#endif >>> >>> ld r8,KSP(r4) /* new stack pointer */ >>> #ifdef CONFIG_PPC_BOOK3S_64 >>>
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