Commit 3e4a12a1 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'gcc-plugins-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux 

Pull gcc plugin updates from Kees Cook:
 "Primarily improvements to STACKLEAK from Alexander Popov, along with
  some additional cleanups.

    - Update URLs for HTTPS scheme where available (Alexander A. Klimov)

   - Improve STACKLEAK code generation on x86 (Alexander Popov)"

* tag 'gcc-plugins-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  gcc-plugins: Replace HTTP links with HTTPS ones
  gcc-plugins/stackleak: Add 'verbose' plugin parameter
  gcc-plugins/stackleak: Use asm instrumentation to avoid useless register saving
  ARM: vdso: Don't use gcc plugins for building vgettimeofday.c
  gcc-plugins/stackleak: Don't instrument itself
parents 19a93823 496b24ec

arch/arm/vdso/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -29,7 +29,7 @@ CPPFLAGS_vdso.lds += -P -C -U$(ARCH) 
CFLAGS_REMOVE_vdso.o = -pg



# Force -O2 to avoid libgcc dependencies

CFLAGS_REMOVE_vgettimeofday.o = -pg -Os

CFLAGS_REMOVE_vgettimeofday.o = -pg -Os $(GCC_PLUGINS_CFLAGS)

ifeq ($(c-gettimeofday-y),)

CFLAGS_vgettimeofday.o = -O2

else

include/linux/compiler_attributes.h

+13 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
# define __GCC4_has_attribute___copy__                0

# define __GCC4_has_attribute___designated_init__     0

# define __GCC4_has_attribute___externally_visible__  1

# define __GCC4_has_attribute___no_caller_saved_registers__ 0

# define __GCC4_has_attribute___noclone__             1

# define __GCC4_has_attribute___nonstring__           0

# define __GCC4_has_attribute___no_sanitize_address__ (__GNUC_MINOR__ >= 8)
@@ -176,6 +177,18 @@ 
 */

#define __mode(x)                       __attribute__((__mode__(x)))



/*

 * Optional: only supported since gcc >= 7

 *

 *   gcc: https://gcc.gnu.org/onlinedocs/gcc/x86-Function-Attributes.html#index-no_005fcaller_005fsaved_005fregisters-function-attribute_002c-x86

 * clang: https://clang.llvm.org/docs/AttributeReference.html#no-caller-saved-registers

 */

#if __has_attribute(__no_caller_saved_registers__)

# define __no_caller_saved_registers	__attribute__((__no_caller_saved_registers__))

#else

# define __no_caller_saved_registers

#endif



/*

 * Optional: not supported by clang

 *

kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -125,6 +125,7 @@ obj-$(CONFIG_WATCH_QUEUE) += watch_queue.o 


obj-$(CONFIG_SYSCTL_KUNIT_TEST) += sysctl-test.o



CFLAGS_stackleak.o += $(DISABLE_STACKLEAK_PLUGIN)

obj-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak.o

KASAN_SANITIZE_stackleak.o := n

KCSAN_SANITIZE_stackleak.o := n

kernel/stackleak.c

+4 −12
Original line number Diff line number Diff line
@@ -104,19 +104,9 @@ asmlinkage void notrace stackleak_erase(void) 
}

NOKPROBE_SYMBOL(stackleak_erase);



void __used notrace stackleak_track_stack(void)

void __used __no_caller_saved_registers notrace stackleak_track_stack(void)

{

	/*

	 * N.B. stackleak_erase() fills the kernel stack with the poison value,

	 * which has the register width. That code assumes that the value

	 * of 'lowest_stack' is aligned on the register width boundary.

	 *

	 * That is true for x86 and x86_64 because of the kernel stack

	 * alignment on these platforms (for details, see 'cc_stack_align' in

	 * arch/x86/Makefile). Take care of that when you port STACKLEAK to

	 * new platforms.

	 */

	unsigned long sp = (unsigned long)&sp;

	unsigned long sp = current_stack_pointer;



	/*

	 * Having CONFIG_STACKLEAK_TRACK_MIN_SIZE larger than
@@ -125,6 +115,8 @@ void __used notrace stackleak_track_stack(void) 
	 */

	BUILD_BUG_ON(CONFIG_STACKLEAK_TRACK_MIN_SIZE > STACKLEAK_SEARCH_DEPTH);



	/* 'lowest_stack' should be aligned on the register width boundary */

	sp = ALIGN(sp, sizeof(unsigned long));

	if (sp < current->lowest_stack &&

	    sp >= (unsigned long)task_stack_page(current) +

						sizeof(unsigned long)) {

scripts/Makefile.gcc-plugins

+2 −0
Original line number Diff line number Diff line
@@ -33,6 +33,8 @@ gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ 
		+= -DSTACKLEAK_PLUGIN

gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK)		\

		+= -fplugin-arg-stackleak_plugin-track-min-size=$(CONFIG_STACKLEAK_TRACK_MIN_SIZE)

gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK)		\

		+= -fplugin-arg-stackleak_plugin-arch=$(SRCARCH)

ifdef CONFIG_GCC_PLUGIN_STACKLEAK

    DISABLE_STACKLEAK_PLUGIN += -fplugin-arg-stackleak_plugin-disable

endif

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