Commit be72ea09 authored by Heiko Carstens's avatar Heiko Carstens Committed by Alexander Gordeev
Browse files

s390/vdso: Introduce and use struct stack_frame_vdso_wrapper 



Introduce and use struct stack_frame_vdso_wrapper within vdso user wrapper
code.  With this structure it is possible to automatically generate an
asm-offset define which can be used to save and restore the return address
of the calling function.

Also use STACK_FRAME_USER_OVERHEAD instead of STACK_FRAME_OVERHEAD to
document that the code works with user space stack frames with the standard
stack frame layout.

Fixes: aa44433a ("s390: add USER_STACKTRACE support")
Reviewed-by: default avatarJens Remus <jremus@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
parent cd581092

arch/s390/include/asm/stacktrace.h

+5 −0
Original line number Diff line number Diff line
@@ -13,6 +13,11 @@ struct stack_frame_user { 
	unsigned long empty2[4];

};



struct stack_frame_vdso_wrapper {

	struct stack_frame_user sf;

	unsigned long return_address;

};



struct perf_callchain_entry_ctx;



void arch_stack_walk_user_common(stack_trace_consume_fn consume_entry, void *cookie,

arch/s390/kernel/asm-offsets.c

+4 −0
Original line number Diff line number Diff line
@@ -66,6 +66,10 @@ int main(void) 
	OFFSET(__SF_SIE_CONTROL_PHYS, stack_frame, sie_control_block_phys);

	DEFINE(STACK_FRAME_OVERHEAD, sizeof(struct stack_frame));

	BLANK();

	DEFINE(STACK_FRAME_USER_OVERHEAD, sizeof(struct stack_frame_user));

	OFFSET(__SFVDSO_RETURN_ADDRESS, stack_frame_vdso_wrapper, return_address);

	DEFINE(STACK_FRAME_VDSO_OVERHEAD, sizeof(struct stack_frame_vdso_wrapper));

	BLANK();

	/* idle data offsets */

	OFFSET(__CLOCK_IDLE_ENTER, s390_idle_data, clock_idle_enter);

	OFFSET(__TIMER_IDLE_ENTER, s390_idle_data, timer_idle_enter);

arch/s390/kernel/vdso64/vdso_user_wrapper.S

+8 −10
Original line number Diff line number Diff line
@@ -6,8 +6,6 @@ 
#include <asm/dwarf.h>

#include <asm/ptrace.h>



#define WRAPPER_FRAME_SIZE (STACK_FRAME_OVERHEAD+8)



/*

 * Older glibc version called vdso without allocating a stackframe. This wrapper

 * is just used to allocate a stackframe. See
@@ -20,16 +18,16 @@ 
	__ALIGN

__kernel_\func:

	CFI_STARTPROC

	aghi	%r15,-WRAPPER_FRAME_SIZE

	CFI_DEF_CFA_OFFSET (STACK_FRAME_OVERHEAD + WRAPPER_FRAME_SIZE)

	CFI_VAL_OFFSET 15, -STACK_FRAME_OVERHEAD

	stg	%r14,STACK_FRAME_OVERHEAD(%r15)

	CFI_REL_OFFSET 14, STACK_FRAME_OVERHEAD

	aghi	%r15,-STACK_FRAME_VDSO_OVERHEAD

	CFI_DEF_CFA_OFFSET (STACK_FRAME_USER_OVERHEAD + STACK_FRAME_VDSO_OVERHEAD)

	CFI_VAL_OFFSET 15,-STACK_FRAME_USER_OVERHEAD

	stg	%r14,__SFVDSO_RETURN_ADDRESS(%r15)

	CFI_REL_OFFSET 14,__SFVDSO_RETURN_ADDRESS

	brasl	%r14,__s390_vdso_\func

	lg	%r14,STACK_FRAME_OVERHEAD(%r15)

	lg	%r14,__SFVDSO_RETURN_ADDRESS(%r15)

	CFI_RESTORE 14

	aghi	%r15,WRAPPER_FRAME_SIZE

	CFI_DEF_CFA_OFFSET STACK_FRAME_OVERHEAD

	aghi	%r15,STACK_FRAME_VDSO_OVERHEAD

	CFI_DEF_CFA_OFFSET STACK_FRAME_USER_OVERHEAD

	CFI_RESTORE 15

	br	%r14

	CFI_ENDPROC