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[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>
This commit is contained in:
Martin Schwidefsky 2008-11-27 11:05:55 +01:00
parent ed313489ba
commit 59da21398e
8 changed files with 44 additions and 42 deletions
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2
arch/s390/include/asm/ptrace.h
View File

@ -321,8 +321,8 @@ struct pt_regs
psw_t psw;
unsigned long gprs[NUM_GPRS];
unsigned long orig_gpr2;
unsigned short svcnr;
unsigned short ilc;
unsigned short trap;
};
#endif

28
arch/s390/include/asm/syscall.h
View File

@ -17,9 +17,7 @@
static inline long syscall_get_nr(struct task_struct *task,
struct pt_regs *regs)
{
if (regs->trap != __LC_SVC_OLD_PSW)
return -1;
return regs->gprs[2];
return regs->svcnr ? regs->svcnr : -1;
}
static inline void syscall_rollback(struct task_struct *task,
@ -52,18 +50,20 @@ static inline void syscall_get_arguments(struct task_struct *task,
unsigned int i, unsigned int n,
unsigned long *args)
{
unsigned long mask = -1UL;
BUG_ON(i + n > 6);
#ifdef CONFIG_COMPAT
if (test_tsk_thread_flag(task, TIF_31BIT)) {
if (i + n == 6)
args[--n] = (u32) regs->args[0];
while (n-- > 0)
args[n] = (u32) regs->gprs[2 + i + n];
}
if (test_tsk_thread_flag(task, TIF_31BIT))
mask = 0xffffffff;
#endif
if (i + n == 6)
args[--n] = regs->args[0];
memcpy(args, &regs->gprs[2 + i], n * sizeof(args[0]));
args[--n] = regs->args[0] & mask;
while (n-- > 0)
if (i + n > 0)
args[n] = regs->gprs[2 + i + n] & mask;
if (i == 0)
args[0] = regs->orig_gpr2 & mask;
}
static inline void syscall_set_arguments(struct task_struct *task,
@ -74,7 +74,11 @@ static inline void syscall_set_arguments(struct task_struct *task,
BUG_ON(i + n > 6);
if (i + n == 6)
regs->args[0] = args[--n];
memcpy(&regs->gprs[2 + i], args, n * sizeof(args[0]));
while (n-- > 0)
if (i + n > 0)
regs->gprs[2 + i + n] = args[n];
if (i == 0)
regs->orig_gpr2 = args[0];
}
#endif /* _ASM_SYSCALL_H */

2
arch/s390/kernel/asm-offsets.c
View File

@ -32,7 +32,7 @@ int main(void)
DEFINE(__PT_GPRS, offsetof(struct pt_regs, gprs));
DEFINE(__PT_ORIG_GPR2, offsetof(struct pt_regs, orig_gpr2));
DEFINE(__PT_ILC, offsetof(struct pt_regs, ilc));
DEFINE(__PT_TRAP, offsetof(struct pt_regs, trap));
DEFINE(__PT_SVCNR, offsetof(struct pt_regs, svcnr));
DEFINE(__PT_SIZE, sizeof(struct pt_regs));
BLANK();
DEFINE(__SF_BACKCHAIN, offsetof(struct stack_frame, back_chain));

2
arch/s390/kernel/compat_signal.c
View File

@ -340,7 +340,7 @@ static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
return err;
restore_fp_regs(&current->thread.fp_regs);
regs->trap = -1; /* disable syscall checks */
regs->svcnr = 0; /* disable syscall checks */
return 0;
}

21
arch/s390/kernel/entry.S
View File

@ -46,7 +46,7 @@ SP_R14 = STACK_FRAME_OVERHEAD + __PT_GPRS + 56
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 @@ STACK_SIZE = 1 << STACK_SHIFT
.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 @@ sysc_update:
#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_notify_resume:
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_restart:
#
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 @@ sysc_tracesys:
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 @@ pgm_svcper:
# 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

23
arch/s390/kernel/entry64.S
View File

@ -46,7 +46,7 @@ SP_R14 = STACK_FRAME_OVERHEAD + __PT_GPRS + 112
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 @@ _TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
.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 @@ sysc_update:
#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_notify_resume:
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 @@ sysc_restart:
# _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 @@ sysc_tracesys:
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 @@ pgm_svcper:
# 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

2
arch/s390/kernel/ptrace.c
View File

@ -657,7 +657,7 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
* debugger stored an invalid system call number. Skip
* the system call and the system call restart handling.
*/
regs->trap = -1;
regs->svcnr = 0;
ret = -1;
}

6
arch/s390/kernel/signal.c
View File

@ -160,7 +160,7 @@ static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
current->thread.fp_regs.fpc &= FPC_VALID_MASK;
restore_fp_regs(&current->thread.fp_regs);
regs->trap = -1; /* disable syscall checks */
regs->svcnr = 0; /* disable syscall checks */
return 0;
}
@ -445,7 +445,7 @@ void do_signal(struct pt_regs *regs)
oldset = &current->blocked;
/* Are we from a system call? */
if (regs->trap == __LC_SVC_OLD_PSW) {
if (regs->svcnr) {
continue_addr = regs->psw.addr;
restart_addr = continue_addr - regs->ilc;
retval = regs->gprs[2];
@ -462,7 +462,7 @@ void do_signal(struct pt_regs *regs)
case -ERESTART_RESTARTBLOCK:
regs->gprs[2] = -EINTR;
}
regs->trap = -1; /* Don't deal with this again. */
regs->svcnr = 0; /* Don't deal with this again. */
}
/* Get signal to deliver. When running under ptrace, at this point