| Message ID | 20191213003522.66450-1-brendanhiggins@google.com |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | [v1] lkdtm/bugs: fix build error in lkdtm_UNSET_SMEP | expand |
On Thu, Dec 12, 2019 at 04:35:22PM -0800, Brendan Higgins wrote: > 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 <brendanhiggins@google.com> Thanks for catching this! Is a similar marking needed for the recently added lkdtm_DOUBLE_FAULT() when using UML on 32-bit? Acked-by: Kees Cook <keescook@chromium.org> -Kees > --- > > This patch is part of my larger effort to get allyesconfig closer to > working for ARCH=um. For more information about that, checkout the cover > letter for a related patchset here: > > https://lore.kernel.org/lkml/20191211192742.95699-1-brendanhiggins@google.com/ > > --- > 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 a4fdad04809a9..6c1aab177fced 100644 > --- a/drivers/misc/lkdtm/bugs.c > +++ b/drivers/misc/lkdtm/bugs.c > @@ -278,7 +278,7 @@ 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; > -- > 2.24.1.735.g03f4e72817-goog >
diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c index a4fdad04809a9..6c1aab177fced 100644 --- a/drivers/misc/lkdtm/bugs.c +++ b/drivers/misc/lkdtm/bugs.c @@ -278,7 +278,7 @@ 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;
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 <brendanhiggins@google.com> --- This patch is part of my larger effort to get allyesconfig closer to working for ARCH=um. For more information about that, checkout the cover letter for a related patchset here: https://lore.kernel.org/lkml/20191211192742.95699-1-brendanhiggins@google.com/ --- drivers/misc/lkdtm/bugs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)