From 59da21398e680e8100625d689c8bebee6a139e93 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Thu, 27 Nov 2008 11:05:55 +0100 Subject: [PATCH] [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 --- arch/s390/include/asm/ptrace.h | 2 +- arch/s390/include/asm/syscall.h | 28 ++++++++++++++++------------ arch/s390/kernel/asm-offsets.c | 2 +- arch/s390/kernel/compat_signal.c | 2 +- arch/s390/kernel/entry.S | 21 +++++++++++---------- arch/s390/kernel/entry64.S | 23 ++++++++++------------- arch/s390/kernel/ptrace.c | 2 +- arch/s390/kernel/signal.c | 6 +++--- 8 files changed, 44 insertions(+), 42 deletions(-) diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h index a7226f8143f..fb0ca4796d3 100644 --- a/arch/s390/include/asm/ptrace.h +++ b/arch/s390/include/asm/ptrace.h @@ -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 diff --git a/arch/s390/include/asm/syscall.h b/arch/s390/include/asm/syscall.h index 6e623971fbb..2429b87eb28 100644 --- a/arch/s390/include/asm/syscall.h +++ b/arch/s390/include/asm/syscall.h @@ -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, ®s->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(®s->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 */ diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c index fa28ecae636..3d144e6020c 100644 --- a/arch/s390/kernel/asm-offsets.c +++ b/arch/s390/kernel/asm-offsets.c @@ -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)); diff --git a/arch/s390/kernel/compat_signal.c b/arch/s390/kernel/compat_signal.c index c7f02e777af..b537cb0e9b5 100644 --- a/arch/s390/kernel/compat_signal.c +++ b/arch/s390/kernel/compat_signal.c @@ -340,7 +340,7 @@ static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs) return err; restore_fp_regs(¤t->thread.fp_regs); - regs->trap = -1; /* disable syscall checks */ + regs->svcnr = 0; /* disable syscall checks */ return 0; } diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 08844fc24a2..198ea18a534 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -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 diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S index 41aca06682a..89c121ae633 100644 --- a/arch/s390/kernel/entry64.S +++ b/arch/s390/kernel/entry64.S @@ -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 diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c index 1f31be1ecc4..38ff2bce120 100644 --- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -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; } diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c index 4f7fc3059a8..8e6812a2267 100644 --- a/arch/s390/kernel/signal.c +++ b/arch/s390/kernel/signal.c @@ -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(¤t->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 = ¤t->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 -- 2.41.1