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s390/vdso: Introduce and use struct stack_frame_vdso_wrapper

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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: aa44433ac4 ("s390: add USER_STACKTRACE support")
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
This commit is contained in:
Heiko Carstens
2024-04-29 14:28:47 +02:00
committed by Alexander Gordeev
parent cd58109283
commit be72ea09c1
3 changed files with 17 additions and 10 deletions
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5
arch/s390/include/asm/stacktrace.h
View File

@@ -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,

4
arch/s390/kernel/asm-offsets.c
View File

@@ -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);

18
arch/s390/kernel/vdso64/vdso_user_wrapper.S
View File

@@ -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