summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorGary Hook <Gary.Hook@amd.com>2019-04-29 22:22:58 +0000
committerBorislav Petkov <bp@suse.de>2019-04-30 17:59:08 +0200
commitb51ce3744f115850166f3d6c292b9c8cb849ad4f (patch)
tree884ff05efc8c3fb97041f6fcaca61c834c2f9b7c
parent0d02113b31b2017dd349ec9df2314e798a90fa6e (diff)
x86/mm/mem_encrypt: Disable all instrumentation for early SME setup
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@sosrh3.amd.com
-rw-r--r--arch/x86/lib/Makefile12
-rw-r--r--lib/Makefile11
2 files changed, 23 insertions, 0 deletions
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 140e61843a07..3cb3af51ec89 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 3b08673e8881..18c2be516ab4 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 xarray.o \
idr.o int_sqrt.o extable.o \