Re: [PATCH v5 3/3] powerpc/32: Add KASAN support
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2019-02-18 09:27:53
Also in:
linux-mm, lkml
Christophe Leroy [off-list ref] writes:
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diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h index e0637730a8e7..dba2c1038363 100644 --- a/arch/powerpc/include/asm/ppc_asm.h +++ b/arch/powerpc/include/asm/ppc_asm.h@@ -251,6 +251,10 @@ GLUE(.,name): #define _GLOBAL_TOC(name) _GLOBAL(name) +#define KASAN_OVERRIDE(x, y) \ + .weak x; \ + .set x, y +
Can you add a comment describing what that does and why?
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diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index 879b36602748..fc4c42262694 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile@@ -16,8 +16,9 @@ CFLAGS_prom_init.o += -fPIC CFLAGS_btext.o += -fPIC endif -CFLAGS_cputable.o += $(DISABLE_LATENT_ENTROPY_PLUGIN) -CFLAGS_prom_init.o += $(DISABLE_LATENT_ENTROPY_PLUGIN) +CFLAGS_early_32.o += -DDISABLE_BRANCH_PROFILING +CFLAGS_cputable.o += $(DISABLE_LATENT_ENTROPY_PLUGIN) -DDISABLE_BRANCH_PROFILING +CFLAGS_prom_init.o += $(DISABLE_LATENT_ENTROPY_PLUGIN) -DDISABLE_BRANCH_PROFILING
Why do we need to disable branch profiling now? I'd probably be happier if all the CFLAGS changes were done in a leadup patch to make them more obvious.
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diff --git a/arch/powerpc/kernel/prom_init_check.sh b/arch/powerpc/kernel/prom_init_check.sh index 667df97d2595..da6bb16e0876 100644 --- a/arch/powerpc/kernel/prom_init_check.sh +++ b/arch/powerpc/kernel/prom_init_check.sh@@ -16,8 +16,16 @@ # If you really need to reference something from prom_init.o add # it to the list below: +grep CONFIG_KASAN=y .config >/dev/null
Just to be safe "^CONFIG_KASAN=y$" ?
+if [ $? -eq 0 ] +then + MEMFCT="__memcpy __memset" +else + MEMFCT="memcpy memset" +fi
MEM_FUNCS ?
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diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile index 3bf9fc6fd36c..ce8d4a9f810a 100644 --- a/arch/powerpc/lib/Makefile +++ b/arch/powerpc/lib/Makefile@@ -8,6 +8,14 @@ ccflags-$(CONFIG_PPC64) := $(NO_MINIMAL_TOC) CFLAGS_REMOVE_code-patching.o = $(CC_FLAGS_FTRACE) CFLAGS_REMOVE_feature-fixups.o = $(CC_FLAGS_FTRACE) +KASAN_SANITIZE_code-patching.o := n +KASAN_SANITIZE_feature-fixups.o := n + +ifdef CONFIG_KASAN +CFLAGS_code-patching.o += -DDISABLE_BRANCH_PROFILING +CFLAGS_feature-fixups.o += -DDISABLE_BRANCH_PROFILING +endif
There's that branch profiling again, though here it's only if KASAN is enabled.
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diff --git a/arch/powerpc/mm/kasan_init.c b/arch/powerpc/mm/kasan_init.c new file mode 100644 index 000000000000..bd8e0a263e12 --- /dev/null +++ b/arch/powerpc/mm/kasan_init.c@@ -0,0 +1,114 @@ +// SPDX-License-Identifier: GPL-2.0 + +#define DISABLE_BRANCH_PROFILING + +#include <linux/kasan.h> +#include <linux/printk.h> +#include <linux/memblock.h> +#include <linux/sched/task.h> +#include <asm/pgalloc.h> + +void __init kasan_early_init(void) +{ + unsigned long addr = KASAN_SHADOW_START; + unsigned long end = KASAN_SHADOW_END; + unsigned long next; + pmd_t *pmd = pmd_offset(pud_offset(pgd_offset_k(addr), addr), addr);
Can none of those fail? cheers