[ Upstream commit b51ce3744f115850166f3d6c292b9c8cb849ad4f ]
Enablement of AMD's Secure Memory Encryption feature is determined very early after start_kernel() is entered. Part of this procedure involves scanning the command line for the parameter 'mem_encrypt'.
To determine intended state, the function sme_enable() uses library functions cmdline_find_option() and strncmp(). Their use occurs early enough such that it cannot be assumed that any instrumentation subsystem is initialized.
For example, making calls to a KASAN-instrumented function before KASAN is set up will result in the use of uninitialized memory and a boot failure.
When AMD's SME support is enabled, conditionally disable instrumentation of these dependent functions in lib/string.c and arch/x86/lib/cmdline.c.
[ bp: Get rid of intermediary nostackp var and cleanup whitespace. ]
Fixes: aca20d546214 ("x86/mm: Add support to make use of Secure Memory Encryption") Reported-by: Li RongQing lirongqing@baidu.com Signed-off-by: Gary R Hook gary.hook@amd.com Signed-off-by: Borislav Petkov bp@suse.de Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Andrew Morton akpm@linux-foundation.org Cc: Andy Shevchenko andriy.shevchenko@linux.intel.com Cc: Boris Brezillon bbrezillon@kernel.org Cc: Coly Li colyli@suse.de Cc: "dave.hansen@linux.intel.com" dave.hansen@linux.intel.com Cc: "H. Peter Anvin" hpa@zytor.com Cc: Ingo Molnar mingo@redhat.com Cc: Kees Cook keescook@chromium.org Cc: Kent Overstreet kent.overstreet@gmail.com Cc: "luto@kernel.org" luto@kernel.org Cc: Masahiro Yamada yamada.masahiro@socionext.com Cc: Matthew Wilcox willy@infradead.org Cc: "mingo@redhat.com" mingo@redhat.com Cc: "peterz@infradead.org" peterz@infradead.org Cc: Sebastian Andrzej Siewior bigeasy@linutronix.de Cc: Thomas Gleixner tglx@linutronix.de Cc: x86-ml x86@kernel.org Link: https://lkml.kernel.org/r/155657657552.7116.18363762932464011367.stgit@sosrh... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/lib/Makefile | 12 ++++++++++++ lib/Makefile | 11 +++++++++++ 2 files changed, 23 insertions(+)
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index 25a972c61b0ae..3c19d60316a88 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -6,6 +6,18 @@ # Produces uninteresting flaky coverage. KCOV_INSTRUMENT_delay.o := n
+# Early boot use of cmdline; don't instrument it +ifdef CONFIG_AMD_MEM_ENCRYPT +KCOV_INSTRUMENT_cmdline.o := n +KASAN_SANITIZE_cmdline.o := n + +ifdef CONFIG_FUNCTION_TRACER +CFLAGS_REMOVE_cmdline.o = -pg +endif + +CFLAGS_cmdline.o := $(call cc-option, -fno-stack-protector) +endif + inat_tables_script = $(srctree)/arch/x86/tools/gen-insn-attr-x86.awk inat_tables_maps = $(srctree)/arch/x86/lib/x86-opcode-map.txt quiet_cmd_inat_tables = GEN $@ diff --git a/lib/Makefile b/lib/Makefile index 4238764468109..0ab808318202c 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -17,6 +17,17 @@ KCOV_INSTRUMENT_list_debug.o := n KCOV_INSTRUMENT_debugobjects.o := n KCOV_INSTRUMENT_dynamic_debug.o := n
+# Early boot use of cmdline, don't instrument it +ifdef CONFIG_AMD_MEM_ENCRYPT +KASAN_SANITIZE_string.o := n + +ifdef CONFIG_FUNCTION_TRACER +CFLAGS_REMOVE_string.o = -pg +endif + +CFLAGS_string.o := $(call cc-option, -fno-stack-protector) +endif + lib-y := ctype.o string.o vsprintf.o cmdline.o \ rbtree.o radix-tree.o timerqueue.o\ idr.o int_sqrt.o extable.o \