[S390] fix system call parameter functions.
syscall_get_nr() currently returns a valid result only if the call
chain of the traced process includes do_syscall_trace_enter(). But
collect_syscall() can be called for any sleeping task, the result of
syscall_get_nr() in general is completely bogus.
To make syscall_get_nr() work for any sleeping task the traps field
in pt_regs is replace with svcnr - the system call number the process
is executing. If svcnr == 0 the process is not on a system call path.
The syscall_get_arguments and syscall_set_arguments use regs->gprs[2]
for the first system call parameter. This is incorrect since gprs[2]
may have been overwritten with the system call number if the call
chain includes do_syscall_trace_enter. Use regs->orig_gprs2 instead.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 08844fc..198ea18 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -46,7 +46,7 @@
SP_R15 = STACK_FRAME_OVERHEAD + __PT_GPRS + 60
SP_ORIG_R2 = STACK_FRAME_OVERHEAD + __PT_ORIG_GPR2
SP_ILC = STACK_FRAME_OVERHEAD + __PT_ILC
-SP_TRAP = STACK_FRAME_OVERHEAD + __PT_TRAP
+SP_SVCNR = STACK_FRAME_OVERHEAD + __PT_SVCNR
SP_SIZE = STACK_FRAME_OVERHEAD + __PT_SIZE
_TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
@@ -183,11 +183,10 @@
.macro CREATE_STACK_FRAME psworg,savearea
s %r15,BASED(.Lc_spsize) # make room for registers & psw
mvc SP_PSW(8,%r15),0(%r12) # move user PSW to stack
- la %r12,\psworg
st %r2,SP_ORIG_R2(%r15) # store original content of gpr 2
- icm %r12,12,__LC_SVC_ILC
+ icm %r12,3,__LC_SVC_ILC
stm %r0,%r11,SP_R0(%r15) # store gprs %r0-%r11 to kernel stack
- st %r12,SP_ILC(%r15)
+ st %r12,SP_SVCNR(%r15)
mvc SP_R12(16,%r15),\savearea # move %r12-%r15 to stack
la %r12,0
st %r12,__SF_BACKCHAIN(%r15) # clear back chain
@@ -264,16 +263,17 @@
#endif
sysc_do_svc:
l %r9,__LC_THREAD_INFO # load pointer to thread_info struct
- sla %r7,2 # *4 and test for svc 0
+ ltr %r7,%r7 # test for svc 0
bnz BASED(sysc_nr_ok) # svc number > 0
# svc 0: system call number in %r1
cl %r1,BASED(.Lnr_syscalls)
bnl BASED(sysc_nr_ok)
lr %r7,%r1 # copy svc number to %r7
- sla %r7,2 # *4
sysc_nr_ok:
mvc SP_ARGS(4,%r15),SP_R7(%r15)
sysc_do_restart:
+ sth %r7,SP_SVCNR(%r15)
+ sll %r7,2 # svc number *4
l %r8,BASED(.Lsysc_table)
tm __TI_flags+3(%r9),(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT)
l %r8,0(%r7,%r8) # get system call addr.
@@ -376,7 +376,6 @@
sysc_restart:
ni __TI_flags+3(%r9),255-_TIF_RESTART_SVC # clear TIF_RESTART_SVC
l %r7,SP_R2(%r15) # load new svc number
- sla %r7,2
mvc SP_R2(4,%r15),SP_ORIG_R2(%r15) # restore first argument
lm %r2,%r6,SP_R2(%r15) # load svc arguments
b BASED(sysc_do_restart) # restart svc
@@ -386,7 +385,8 @@
#
sysc_singlestep:
ni __TI_flags+3(%r9),255-_TIF_SINGLE_STEP # clear TIF_SINGLE_STEP
- mvi SP_TRAP+1(%r15),0x28 # set trap indication to pgm check
+ mvi SP_SVCNR(%r15),0xff # set trap indication to pgm check
+ mvi SP_SVCNR+1(%r15),0xff
la %r2,SP_PTREGS(%r15) # address of register-save area
l %r1,BASED(.Lhandle_per) # load adr. of per handler
la %r14,BASED(sysc_return) # load adr. of system return
@@ -407,7 +407,7 @@
bnl BASED(sysc_tracenogo)
l %r8,BASED(.Lsysc_table)
lr %r7,%r2
- sll %r7,2 # *4
+ sll %r7,2 # svc number *4
l %r8,0(%r7,%r8)
sysc_tracego:
lm %r3,%r6,SP_R3(%r15)
@@ -586,7 +586,8 @@
# per was called from kernel, must be kprobes
#
kernel_per:
- mvi SP_TRAP+1(%r15),0x28 # set trap indication to pgm check
+ mvi SP_SVCNR(%r15),0xff # set trap indication to pgm check
+ mvi SP_SVCNR+1(%r15),0xff
la %r2,SP_PTREGS(%r15) # address of register-save area
l %r1,BASED(.Lhandle_per) # load adr. of per handler
la %r14,BASED(sysc_restore)# load adr. of system return