diff options
| -rw-r--r-- | arch/m68k/kernel/signal.c | 173 |
1 files changed, 61 insertions, 112 deletions
diff --git a/arch/m68k/kernel/signal.c b/arch/m68k/kernel/signal.c index 16ea319d1ed..d5f4a82515f 100644 --- a/arch/m68k/kernel/signal.c +++ b/arch/m68k/kernel/signal.c @@ -286,36 +286,10 @@ out: return err; } -static inline int -restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __user *fp, - int *pd0) +static int mangle_kernel_stack(struct pt_regs *regs, int formatvec, + void __user *fp) { - int fsize, formatvec; - struct sigcontext context; - int err; - - /* Always make any pending restarted system calls return -EINTR */ - current_thread_info()->restart_block.fn = do_no_restart_syscall; - - /* get previous context */ - if (copy_from_user(&context, usc, sizeof(context))) - goto badframe; - - /* restore passed registers */ - regs->d1 = context.sc_d1; - regs->a0 = context.sc_a0; - regs->a1 = context.sc_a1; - regs->sr = (regs->sr & 0xff00) | (context.sc_sr & 0xff); - regs->pc = context.sc_pc; - regs->orig_d0 = -1; /* disable syscall checks */ - wrusp(context.sc_usp); - formatvec = context.sc_formatvec; - regs->format = formatvec >> 12; - regs->vector = formatvec & 0xfff; - - err = restore_fpu_state(&context); - - fsize = frame_extra_sizes[regs->format]; + int fsize = frame_extra_sizes[formatvec >> 12]; if (fsize < 0) { /* * user process trying to return with weird frame format @@ -323,16 +297,22 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __u #ifdef DEBUG printk("user process returning with weird frame format\n"); #endif - goto badframe; + return 1; } + if (!fsize) { + regs->format = formatvec >> 12; + regs->vector = formatvec & 0xfff; + } else { + struct switch_stack *sw = (struct switch_stack *)regs - 1; + unsigned long buf[fsize / 2]; /* yes, twice as much */ - /* OK. Make room on the supervisor stack for the extra junk, - * if necessary. - */ + /* that'll make sure that expansion won't crap over data */ + if (copy_from_user(buf + fsize / 4, fp, fsize)) + return 1; - if (fsize) { - struct switch_stack *sw = (struct switch_stack *)regs - 1; - regs->d0 = context.sc_d0; + /* point of no return */ + regs->format = formatvec >> 12; + regs->vector = formatvec & 0xfff; #define frame_offset (sizeof(struct pt_regs)+sizeof(struct switch_stack)) __asm__ __volatile__ (" movel %0,%/a0\n\t" @@ -344,30 +324,50 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __u " lea %/sp@(%c3),%/a0\n\t" /* add offset of fmt */ " lsrl #2,%1\n\t" " subql #1,%1\n\t" - "2: movesl %4@+,%2\n\t" - "3: movel %2,%/a0@+\n\t" + /* copy to the gap we'd made */ + "2: movel %4@+,%/a0@+\n\t" " dbra %1,2b\n\t" " bral ret_from_signal\n" - "4:\n" - ".section __ex_table,\"a\"\n" - " .align 4\n" - " .long 2b,4b\n" - " .long 3b,4b\n" - ".previous" : /* no outputs, it doesn't ever return */ : "a" (sw), "d" (fsize), "d" (frame_offset/4-1), - "n" (frame_offset), "a" (fp) + "n" (frame_offset), "a" (buf + fsize/4) : "a0"); #undef frame_offset - /* - * If we ever get here an exception occurred while - * building the above stack-frame. - */ - goto badframe; } + return 0; +} - *pd0 = context.sc_d0; - return err; +static inline int +restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __user *fp) +{ + int formatvec; + struct sigcontext context; + int err; + + /* Always make any pending restarted system calls return -EINTR */ + current_thread_info()->restart_block.fn = do_no_restart_syscall; + + /* get previous context */ + if (copy_from_user(&context, usc, sizeof(context))) + goto badframe; + + /* restore passed registers */ + regs->d0 = context.sc_d0; + regs->d1 = context.sc_d1; + regs->a0 = context.sc_a0; + regs->a1 = context.sc_a1; + regs->sr = (regs->sr & 0xff00) | (context.sc_sr & 0xff); + regs->pc = context.sc_pc; + regs->orig_d0 = -1; /* disable syscall checks */ + wrusp(context.sc_usp); + formatvec = context.sc_formatvec; + + err = restore_fpu_state(&context); + + if (err || mangle_kernel_stack(regs, formatvec, fp)) + goto badframe; + + return 0; badframe: return 1; @@ -375,9 +375,9 @@ badframe: static inline int rt_restore_ucontext(struct pt_regs *regs, struct switch_stack *sw, - struct ucontext __user *uc, int *pd0) + struct ucontext __user *uc) { - int fsize, temp; + int temp; greg_t __user *gregs = uc->uc_mcontext.gregs; unsigned long usp; int err; @@ -411,65 +411,16 @@ rt_restore_ucontext(struct pt_regs *regs, struct switch_stack *sw, regs->sr = (regs->sr & 0xff00) | (temp & 0xff); regs->orig_d0 = -1; /* disable syscall checks */ err |= __get_user(temp, &uc->uc_formatvec); - regs->format = temp >> 12; - regs->vector = temp & 0xfff; err |= rt_restore_fpu_state(uc); - if (do_sigaltstack(&uc->uc_stack, NULL, usp) == -EFAULT) + if (err || do_sigaltstack(&uc->uc_stack, NULL, usp) == -EFAULT) goto badframe; - fsize = frame_extra_sizes[regs->format]; - if (fsize < 0) { - /* - * user process trying to return with weird frame format - */ -#ifdef DEBUG - printk("user process returning with weird frame format\n"); -#endif + if (mangle_kernel_stack(regs, temp, &uc->uc_extra)) goto badframe; - } - /* OK. Make room on the supervisor stack for the extra junk, - * if necessary. - */ - - if (fsize) { -#define frame_offset (sizeof(struct pt_regs)+sizeof(struct switch_stack)) - __asm__ __volatile__ - (" movel %0,%/a0\n\t" - " subl %1,%/a0\n\t" /* make room on stack */ - " movel %/a0,%/sp\n\t" /* set stack pointer */ - /* move switch_stack and pt_regs */ - "1: movel %0@+,%/a0@+\n\t" - " dbra %2,1b\n\t" - " lea %/sp@(%c3),%/a0\n\t" /* add offset of fmt */ - " lsrl #2,%1\n\t" - " subql #1,%1\n\t" - "2: movesl %4@+,%2\n\t" - "3: movel %2,%/a0@+\n\t" - " dbra %1,2b\n\t" - " bral ret_from_signal\n" - "4:\n" - ".section __ex_table,\"a\"\n" - " .align 4\n" - " .long 2b,4b\n" - " .long 3b,4b\n" - ".previous" - : /* no outputs, it doesn't ever return */ - : "a" (sw), "d" (fsize), "d" (frame_offset/4-1), - "n" (frame_offset), "a" (&uc->uc_extra) - : "a0"); -#undef frame_offset - /* - * If we ever get here an exception occurred while - * building the above stack-frame. - */ - goto badframe; - } - - *pd0 = regs->d0; - return err; + return 0; badframe: return 1; @@ -482,7 +433,6 @@ asmlinkage int do_sigreturn(unsigned long __unused) unsigned long usp = rdusp(); struct sigframe __user *frame = (struct sigframe __user *)(usp - 4); sigset_t set; - int d0; if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) goto badframe; @@ -496,9 +446,9 @@ asmlinkage int do_sigreturn(unsigned long __unused) current->blocked = set; recalc_sigpending(); - if (restore_sigcontext(regs, &frame->sc, frame + 1, &d0)) + if (restore_sigcontext(regs, &frame->sc, frame + 1)) goto badframe; - return d0; + return regs->d0; badframe: force_sig(SIGSEGV, current); @@ -512,7 +462,6 @@ asmlinkage int do_rt_sigreturn(unsigned long __unused) unsigned long usp = rdusp(); struct rt_sigframe __user *frame = (struct rt_sigframe __user *)(usp - 4); sigset_t set; - int d0; if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) goto badframe; @@ -523,9 +472,9 @@ asmlinkage int do_rt_sigreturn(unsigned long __unused) current->blocked = set; recalc_sigpending(); - if (rt_restore_ucontext(regs, sw, &frame->uc, &d0)) + if (rt_restore_ucontext(regs, sw, &frame->uc)) goto badframe; - return d0; + return regs->d0; badframe: force_sig(SIGSEGV, current); |