From 9e62f296dbaeb9a007e9b2ba82be231c5d679d22 Mon Sep 17 00:00:00 2001 From: Brendan Higgins Date: Thu, 12 Dec 2019 16:35:22 -0800 Subject: [PATCH] lkdtm/bugs: fix build error in lkdtm_UNSET_SMEP MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit 0e31e3573f0cd94d7b821117db854187ffc85765 ] When building ARCH=um with CONFIG_UML_X86=y and CONFIG_64BIT=y we get the build errors: drivers/misc/lkdtm/bugs.c: In function ‘lkdtm_UNSET_SMEP’: drivers/misc/lkdtm/bugs.c:288:8: error: implicit declaration of function ‘native_read_cr4’ [-Werror=implicit-function-declaration] cr4 = native_read_cr4(); ^~~~~~~~~~~~~~~ drivers/misc/lkdtm/bugs.c:290:13: error: ‘X86_CR4_SMEP’ undeclared (first use in this function); did you mean ‘X86_FEATURE_SMEP’? if ((cr4 & X86_CR4_SMEP) != X86_CR4_SMEP) { ^~~~~~~~~~~~ X86_FEATURE_SMEP drivers/misc/lkdtm/bugs.c:290:13: note: each undeclared identifier is reported only once for each function it appears in drivers/misc/lkdtm/bugs.c:297:2: error: implicit declaration of function ‘native_write_cr4’; did you mean ‘direct_write_cr4’? [-Werror=implicit-function-declaration] native_write_cr4(cr4); ^~~~~~~~~~~~~~~~ direct_write_cr4 So specify that this block of code should only build when CONFIG_X86_64=y *AND* CONFIG_UML is unset. Signed-off-by: Brendan Higgins Acked-by: Kees Cook Link: https://lore.kernel.org/r/20191213003522.66450-1-brendanhiggins@google.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/misc/lkdtm/bugs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c index 7284a22b1a09..4d5a512769e9 100644 --- a/drivers/misc/lkdtm/bugs.c +++ b/drivers/misc/lkdtm/bugs.c @@ -274,7 +274,7 @@ void lkdtm_STACK_GUARD_PAGE_TRAILING(void) void lkdtm_UNSET_SMEP(void) { -#ifdef CONFIG_X86_64 +#if IS_ENABLED(CONFIG_X86_64) && !IS_ENABLED(CONFIG_UML) #define MOV_CR4_DEPTH 64 void (*direct_write_cr4)(unsigned long val); unsigned char *insn;