| From 47337ab9b2cf39e134f41a50608957307301ec07 Mon Sep 17 00:00:00 2001 |
| From: Gary Hook <Gary.Hook@amd.com> |
| Date: Mon, 29 Apr 2019 22:22:58 +0000 |
| Subject: x86/mm/mem_encrypt: Disable all instrumentation for early SME setup |
| |
| [ 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@sosrh3.amd.com |
| 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 \ |
| -- |
| 2.20.1 |
| |