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* [PATCH] ARM: Implement Clang's SLS mitigation
@ 2021-02-12  5:14 Jian Cai
  2021-02-12  5:55 ` Nathan Chancellor
  0 siblings, 1 reply; 29+ messages in thread
From: Jian Cai @ 2021-02-12  5:14 UTC (permalink / raw)
  Cc: ndesaulniers, manojgupta, llozano, clang-built-linux, Jian Cai,
	Russell King, Catalin Marinas, Will Deacon, James Morris,
	Serge E. Hallyn, Nathan Chancellor, Arnd Bergmann,
	Masahiro Yamada, Kees Cook, Ard Biesheuvel, Daniel Palmer,
	Andreas Färber, linux-arm-kernel, linux-kernel,
	linux-security-module

This patch adds a config CONFIG_HARDEN_SLS_ALL that can be used to turn
on -mharden-sls=all, which mitigates the straight-line speculation
vulnerability, or more commonly known as Spectre, Meldown.

Notice -mharden-sls= has other options as below, and this config turns
on the strongest option.

all: enable all mitigations against Straight Line Speculation that are implemented.
none: disable all mitigations against Straight Line Speculation.
retbr: enable the mitigation against Straight Line Speculation for RET and BR instructions.
blr: enable the mitigation against Straight Line Speculation for BLR instructions.

Link: https://reviews.llvm.org/D93221
Link: https://reviews.llvm.org/D81404
Link: https://developer.arm.com/support/arm-security-updates/speculative-processor-vulnerability/downloads/straight-line-speculation
Link: https://crbug.com/1171521

Suggested-by: Manoj Gupta <manojgupta@google.com>
Signed-off-by: Jian Cai <jiancai@google.com>
---
 arch/arm/Makefile          |  4 ++++
 arch/arm64/Makefile        |  5 +++++
 security/Kconfig.hardening | 11 +++++++++++
 3 files changed, 20 insertions(+)

diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 4aaec9599e8a..11d89ef32da9 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -48,6 +48,10 @@ CHECKFLAGS	+= -D__ARMEL__
 KBUILD_LDFLAGS	+= -EL
 endif
 
+ifeq ($(CONFIG_HARDEN_SLS_ALL), y)
+KBUILD_CFLAGS  += -mharden-sls=all
+endif
+
 #
 # The Scalar Replacement of Aggregates (SRA) optimization pass in GCC 4.9 and
 # later may result in code being generated that handles signed short and signed
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 90309208bb28..8fd0ccd87eca 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -34,6 +34,11 @@ $(warning LSE atomics not supported by binutils)
   endif
 endif
 
+ifeq ($(CONFIG_HARDEN_SLS_ALL), y)
+KBUILD_CFLAGS  += -mharden-sls=all
+endif
+
+
 cc_has_k_constraint := $(call try-run,echo				\
 	'int main(void) {						\
 		asm volatile("and w0, w0, %w0" :: "K" (4294967295));	\
diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening
index 269967c4fc1b..d83c406c81a3 100644
--- a/security/Kconfig.hardening
+++ b/security/Kconfig.hardening
@@ -121,6 +121,17 @@ choice
 
 endchoice
 
+
+config CC_HAS_HARDEN_SLS_ALL
+	def_bool $(cc-option,-mharden-sls=all)
+
+	config HARDEN_SLS_ALL
+               bool "enable SLS vulnerability hardening"
+               depends on CC_HAS_HARDEN_SLS_ALL
+               help
+                 Enables straight-line speculation vulnerability hardening
+		 at highest level.
+
 config GCC_PLUGIN_STRUCTLEAK_VERBOSE
 	bool "Report forcefully initialized variables"
 	depends on GCC_PLUGIN_STRUCTLEAK
-- 
2.30.0.478.g8a0d178c01-goog


^ permalink raw reply related	[flat|nested] 29+ messages in thread

end of thread, other threads:[~2021-03-25 14:02 UTC | newest]

Thread overview: 29+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-12  5:14 [PATCH] ARM: Implement Clang's SLS mitigation Jian Cai
2021-02-12  5:55 ` Nathan Chancellor
2021-02-12 10:41   ` David Laight
2021-02-12 19:52     ` [PATCH v2] " Jian Cai
2021-02-17  9:49       ` Will Deacon
2021-02-17 11:05         ` David Laight
2021-03-25 14:01         ` Linus Walleij
2021-02-17 18:20       ` Nick Desaulniers
2021-02-19 20:18       ` [PATCH v3] ARM: Implement " Jian Cai
2021-02-19 20:30         ` Nathan Chancellor
2021-02-19 23:08         ` [PATCH v4] " Jian Cai
2021-02-21 10:13           ` Russell King - ARM Linux admin
2021-02-22 11:58           ` Will Deacon
2021-02-22 21:50             ` Jian Cai
2021-02-23 10:04               ` Will Deacon
2021-03-03 15:18                 ` Linus Walleij
2021-03-03 15:29                   ` David Laight
2021-03-03 15:31                     ` Linus Walleij
2021-02-23  2:31           ` [PATCH v5] " Jian Cai
2021-02-23  2:35             ` Jian Cai
2021-03-03 15:04               ` Linus Walleij
2021-03-04 23:22                 ` Jian Cai
2021-03-06 12:25                   ` Linus Walleij
2021-03-10  4:43                     ` Jian Cai
2021-03-22 11:45                       ` Linus Walleij
2021-03-23 22:39                         ` Jian Cai
2021-03-05  0:53               ` [PATCH v6] " Jian Cai
2021-03-05  9:52                 ` Will Deacon
2021-03-06 12:27                   ` Linus Walleij

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