Le 18/02/2019 à 10:27, Michael Ellerman a écrit :
Christophe Leroy <christophe.le...@c-s.fr> writes:
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?
It's gone. Hope the new approach is more clear. It's now in a dedicated
patch.
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 += $(DISABLE_LATENT_ENTROPY_PLUGIN)
-DDISABLE_BRANCH_PROFILING
Why do we need to disable branch profiling now?
Recommended by Andrey, see https://patchwork.ozlabs.org/patch/1023887/
Maybe it should be only when KASAN is active ? For prom_init it should
probably be all the time, for the others I don't know. Can't remember
why I did it that way.
I'd probably be happier if all the CFLAGS changes were done in a leadup
patch to make them more obvious.
Oops, I forgot to read your mail entirely before sending out v6. Indeed
I only read first part. Anyway, that's probably not the last run.
diff --git a/arch/powerpc/kernel/prom_init_check.sh
b/arch/powerpc/kernel/prom_init_check.sh
index 667df97d2595..da6bb16e0876 100644
--- a/arch/powerpc/kernel/prom_init_check.sh
+++ b/arch/powerpc/kernel/prom_init_check.sh
@@ -16,8 +16,16 @@
# If you really need to reference something from prom_init.o add
# it to the list below:
+grep CONFIG_KASAN=y .config >/dev/null
Just to be safe "^CONFIG_KASAN=y$" ?
ok
+if [ $? -eq 0 ]
+then
+ MEMFCT="__memcpy __memset"
+else
+ MEMFCT="memcpy memset"
+fi
MEM_FUNCS ?
Yes, I change it now before I forget.
diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index 3bf9fc6fd36c..ce8d4a9f810a 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -8,6 +8,14 @@ ccflags-$(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.
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?
map_kernel_page() in pgtable_32.c does exactly the same.
pud_offset() and pmd_offset() are no-ops and only serve as type
modifiers, so pmd will get the value returned by pgd_offset_k() which
should always be valid unless init_mm->pgd is bad.
Christophe
cheers
