[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/entry64.S b/arch/s390/kernel/entry64.S
index 41aca06..89c121a 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -46,7 +46,7 @@
SP_R15 = STACK_FRAME_OVERHEAD + __PT_GPRS + 120
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
STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
@@ -171,11 +171,10 @@
.macro CREATE_STACK_FRAME psworg,savearea
aghi %r15,-SP_SIZE # make room for registers & psw
mvc SP_PSW(16,%r15),0(%r12) # move user PSW to stack
- la %r12,\psworg
stg %r2,SP_ORIG_R2(%r15) # store original content of gpr 2
- icm %r12,12,__LC_SVC_ILC
+ icm %r12,3,__LC_SVC_ILC
stmg %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(32,%r15),\savearea # move %r12-%r15 to stack
la %r12,0
stg %r12,__SF_BACKCHAIN(%r15)
@@ -250,16 +249,17 @@
#endif
sysc_do_svc:
lg %r9,__LC_THREAD_INFO # load pointer to thread_info struct
- slag %r7,%r7,2 # *4 and test for svc 0
+ ltgr %r7,%r7 # test for svc 0
jnz sysc_nr_ok
# svc 0: system call number in %r1
cl %r1,BASED(.Lnr_syscalls)
jnl sysc_nr_ok
lgfr %r7,%r1 # clear high word in r1
- slag %r7,%r7,2 # svc 0: system call number in %r1
sysc_nr_ok:
mvc SP_ARGS(8,%r15),SP_R7(%r15)
sysc_do_restart:
+ sth %r7,SP_SVCNR(%r15)
+ sllg %r7,%r7,2 # svc number * 4
larl %r10,sys_call_table
#ifdef CONFIG_COMPAT
tm __TI_flags+5(%r9),(_TIF_31BIT>>16) # running in 31 bit mode ?
@@ -363,7 +363,6 @@
sysc_restart:
ni __TI_flags+7(%r9),255-_TIF_RESTART_SVC # clear TIF_RESTART_SVC
lg %r7,SP_R2(%r15) # load new svc number
- slag %r7,%r7,2 # *4
mvc SP_R2(8,%r15),SP_ORIG_R2(%r15) # restore first argument
lmg %r2,%r6,SP_R2(%r15) # load svc arguments
j sysc_do_restart # restart svc
@@ -372,9 +371,8 @@
# _TIF_SINGLE_STEP is set, call do_single_step
#
sysc_singlestep:
- ni __TI_flags+7(%r9),255-_TIF_SINGLE_STEP # clear TIF_SINGLE_STEP
- lhi %r0,__LC_PGM_OLD_PSW
- sth %r0,SP_TRAP(%r15) # set trap indication to pgm check
+ ni __TI_flags+7(%r9),255-_TIF_SINGLE_STEP # clear TIF_SINGLE_STEP
+ xc SP_SVCNR(2,%r15),SP_SVCNR(%r15) # clear svc number
la %r2,SP_PTREGS(%r15) # address of register-save area
larl %r14,sysc_return # load adr. of system return
jg do_single_step # branch to do_sigtrap
@@ -392,7 +390,7 @@
lghi %r0,NR_syscalls
clgr %r0,%r2
jnh sysc_tracenogo
- slag %r7,%r2,2 # *4
+ sllg %r7,%r2,2 # svc number *4
lgf %r8,0(%r7,%r10)
sysc_tracego:
lmg %r3,%r6,SP_R3(%r15)
@@ -567,8 +565,7 @@
# per was called from kernel, must be kprobes
#
kernel_per:
- lhi %r0,__LC_PGM_OLD_PSW
- sth %r0,SP_TRAP(%r15) # set trap indication to pgm check
+ xc SP_SVCNR(2,%r15),SP_SVCNR(%r15) # clear svc number
la %r2,SP_PTREGS(%r15) # address of register-save area
larl %r14,sysc_restore # load adr. of system ret, no work
jg do_single_step # branch to do_single_step