Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 67e68bde authored by Tejun Heo's avatar Tejun Heo
Browse files

x86: update canary handling during switch 



Impact: cleanup

In switch_to(), instead of taking offset to irq_stack_union.stack,
make it a proper percpu access using __percpu_arg() and per_cpu_var().

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 8f5d36ed

arch/x86/include/asm/system.h

+9 −6
Original line number Original line Diff line number Diff line
@@ -89,13 +89,15 @@ do { \ 
#ifdef CONFIG_CC_STACKPROTECTOR

#ifdef CONFIG_CC_STACKPROTECTOR

#define __switch_canary							  \

#define __switch_canary							  \

	"movq %P[task_canary](%%rsi),%%r8\n\t"				  \

	"movq %P[task_canary](%%rsi),%%r8\n\t"				  \

	"movq %%r8,%%gs:%P[gs_canary]\n\t"

	"movq %%r8,"__percpu_arg([gs_canary])"\n\t"

#define __switch_canary_param						  \

#define __switch_canary_oparam						  \

	, [task_canary] "i" (offsetof(struct task_struct, stack_canary))  \

	, [gs_canary] "=m" (per_cpu_var(irq_stack_union.stack_canary))

	, [gs_canary] "i" (offsetof(union irq_stack_union, stack_canary))

#define __switch_canary_iparam						  \

	, [task_canary] "i" (offsetof(struct task_struct, stack_canary))

#else	/* CC_STACKPROTECTOR */

#else	/* CC_STACKPROTECTOR */

#define __switch_canary

#define __switch_canary

#define __switch_canary_param

#define __switch_canary_oparam

#define __switch_canary_iparam

#endif	/* CC_STACKPROTECTOR */

#endif	/* CC_STACKPROTECTOR */





/* Save restore flags to clear handle leaking NT */

/* Save restore flags to clear handle leaking NT */
@@ -114,13 +116,14 @@ do { \ 
	     "jc   ret_from_fork\n\t"					  \

	     "jc   ret_from_fork\n\t"					  \

	     RESTORE_CONTEXT						  \

	     RESTORE_CONTEXT						  \

	     : "=a" (last)					  	  \

	     : "=a" (last)					  	  \

	       __switch_canary_oparam					  \

	     : [next] "S" (next), [prev] "D" (prev),			  \

	     : [next] "S" (next), [prev] "D" (prev),			  \

	       [threadrsp] "i" (offsetof(struct task_struct, thread.sp)), \

	       [threadrsp] "i" (offsetof(struct task_struct, thread.sp)), \

	       [ti_flags] "i" (offsetof(struct thread_info, flags)),	  \

	       [ti_flags] "i" (offsetof(struct thread_info, flags)),	  \

	       [tif_fork] "i" (TIF_FORK),			  	  \

	       [tif_fork] "i" (TIF_FORK),			  	  \

	       [thread_info] "i" (offsetof(struct task_struct, stack)),   \

	       [thread_info] "i" (offsetof(struct task_struct, stack)),   \

	       [current_task] "m" (per_cpu_var(current_task))		  \

	       [current_task] "m" (per_cpu_var(current_task))		  \

	       __switch_canary_param					  \

	       __switch_canary_iparam					  \

	     : "memory", "cc" __EXTRA_CLOBBER)

	     : "memory", "cc" __EXTRA_CLOBBER)

#endif

#endif