queue-4.19/x86-mm-mem_encrypt-disable-all-instrumentation-for-e.patch

   1 From 47337ab9b2cf39e134f41a50608957307301ec07 Mon Sep 17 00:00:00 2001
   2 From: Gary Hook <Gary.Hook@amd.com>
   3 Date: Mon, 29 Apr 2019 22:22:58 +0000
   4 Subject: x86/mm/mem_encrypt: Disable all instrumentation for early SME setup
   5
   6 [ Upstream commit b51ce3744f115850166f3d6c292b9c8cb849ad4f ]
   7
   8 Enablement of AMD's Secure Memory Encryption feature is determined very
   9 early after start_kernel() is entered. Part of this procedure involves
  10 scanning the command line for the parameter 'mem_encrypt'.
  11
  12 To determine intended state, the function sme_enable() uses library
  13 functions cmdline_find_option() and strncmp(). Their use occurs early
  14 enough such that it cannot be assumed that any instrumentation subsystem
  15 is initialized.
  16
  17 For example, making calls to a KASAN-instrumented function before KASAN
  18 is set up will result in the use of uninitialized memory and a boot
  19 failure.
  20
  21 When AMD's SME support is enabled, conditionally disable instrumentation
  22 of these dependent functions in lib/string.c and arch/x86/lib/cmdline.c.
  23
  24  [ bp: Get rid of intermediary nostackp var and cleanup whitespace. ]
  25
  26 Fixes: aca20d546214 ("x86/mm: Add support to make use of Secure Memory Encryption")
  27 Reported-by: Li RongQing <lirongqing@baidu.com>
  28 Signed-off-by: Gary R Hook <gary.hook@amd.com>
  29 Signed-off-by: Borislav Petkov <bp@suse.de>
  30 Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
  31 Cc: Andrew Morton <akpm@linux-foundation.org>
  32 Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
  33 Cc: Boris Brezillon <bbrezillon@kernel.org>
  34 Cc: Coly Li <colyli@suse.de>
  35 Cc: "dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>
  36 Cc: "H. Peter Anvin" <hpa@zytor.com>
  37 Cc: Ingo Molnar <mingo@redhat.com>
  38 Cc: Kees Cook <keescook@chromium.org>
  39 Cc: Kent Overstreet <kent.overstreet@gmail.com>
  40 Cc: "luto@kernel.org" <luto@kernel.org>
  41 Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
  42 Cc: Matthew Wilcox <willy@infradead.org>
  43 Cc: "mingo@redhat.com" <mingo@redhat.com>
  44 Cc: "peterz@infradead.org" <peterz@infradead.org>
  45 Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
  46 Cc: Thomas Gleixner <tglx@linutronix.de>
  47 Cc: x86-ml <x86@kernel.org>
  48 Link: https://lkml.kernel.org/r/155657657552.7116.18363762932464011367.stgit@sosrh3.amd.com
  49 Signed-off-by: Sasha Levin <sashal@kernel.org>
  50 ---
  51  arch/x86/lib/Makefile | 12 ++++++++++++
  52  lib/Makefile          | 11 +++++++++++
  53  2 files changed, 23 insertions(+)
  54
  55 diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
  56 index 25a972c61b0ae..3c19d60316a88 100644
  57 --- a/arch/x86/lib/Makefile
  58 +++ b/arch/x86/lib/Makefile
  59 @@ -6,6 +6,18 @@
  60  # Produces uninteresting flaky coverage.
  61  KCOV_INSTRUMENT_delay.o        := n
  62
  63 +# Early boot use of cmdline; don't instrument it
  64 +ifdef CONFIG_AMD_MEM_ENCRYPT
  65 +KCOV_INSTRUMENT_cmdline.o := n
  66 +KASAN_SANITIZE_cmdline.o  := n
  67 +
  68 +ifdef CONFIG_FUNCTION_TRACER
  69 +CFLAGS_REMOVE_cmdline.o = -pg
  70 +endif
  71 +
  72 +CFLAGS_cmdline.o := $(call cc-option, -fno-stack-protector)
  73 +endif
  74 +
  75  inat_tables_script = $(srctree)/arch/x86/tools/gen-insn-attr-x86.awk
  76  inat_tables_maps = $(srctree)/arch/x86/lib/x86-opcode-map.txt
  77  quiet_cmd_inat_tables = GEN     $@
  78 diff --git a/lib/Makefile b/lib/Makefile
  79 index 4238764468109..0ab808318202c 100644
  80 --- a/lib/Makefile
  81 +++ b/lib/Makefile
  82 @@ -17,6 +17,17 @@ KCOV_INSTRUMENT_list_debug.o := n
  83  KCOV_INSTRUMENT_debugobjects.o := n
  84  KCOV_INSTRUMENT_dynamic_debug.o := n
  85
  86 +# Early boot use of cmdline, don't instrument it
  87 +ifdef CONFIG_AMD_MEM_ENCRYPT
  88 +KASAN_SANITIZE_string.o := n
  89 +
  90 +ifdef CONFIG_FUNCTION_TRACER
  91 +CFLAGS_REMOVE_string.o = -pg
  92 +endif
  93 +
  94 +CFLAGS_string.o := $(call cc-option, -fno-stack-protector)
  95 +endif
  96 +
  97  lib-y := ctype.o string.o vsprintf.o cmdline.o \
  98          rbtree.o radix-tree.o timerqueue.o\
  99          idr.o int_sqrt.o extable.o \
 100 --
 101 2.20.1
 102