* to prevent leaking bits from kernel to user level.
*/
DBG_FAULT(11)
- mov r16=IA64_KR(CURRENT) // r16 = current task; 12 cycle read lat.
- mov r17=cr.iim
- mov r18=__IA64_BREAK_SYSCALL
- mov r21=ar.fpsr
- mov r29=cr.ipsr
- mov r19=b6
- mov r25=ar.unat
- mov r27=ar.rsc
- mov r26=ar.pfs
- mov r28=cr.iip
- mov r31=pr // prepare to save predicates
- mov r20=r1
- ;;
+ mov.m r16=IA64_KR(CURRENT) // M2 r16 <- current task (12 cyc)
+ mov r29=cr.ipsr // M2 (12 cyc)
+ mov r31=pr // I0 (2 cyc)
+
+ mov r17=cr.iim // M2 (2 cyc)
+ mov.m r27=ar.rsc // M2 (12 cyc)
+ mov r18=__IA64_BREAK_SYSCALL // A
+
+ mov.m ar.rsc=0 // M2
+ mov.m r21=ar.fpsr // M2 (12 cyc)
+ mov r19=b6 // I0 (2 cyc)
+ ;;
+ mov.m r23=ar.bspstore // M2 (12 cyc)
+ mov.m r24=ar.rnat // M2 (5 cyc)
+ mov.i r26=ar.pfs // I0 (2 cyc)
+
+ invala // M0|1
+ nop.m 0 // M
+ mov r20=r1 // A save r1
+
+ nop.m 0
+ movl r30=sys_call_table // X
+
+ mov r28=cr.iip // M2 (2 cyc)
+ cmp.eq p0,p7=r18,r17 // I0 is this a system call?
+(p7) br.cond.spnt non_syscall // B no ->
+ //
+ // From this point on, we are definitely on the syscall-path
+ // and we can use (non-banked) scratch registers.
+ //
+///////////////////////////////////////////////////////////////////////
+ mov r1=r16 // A move task-pointer to "addl"-addressable reg
+ mov r2=r16 // A setup r2 for ia64_syscall_setup
+ add r9=TI_FLAGS+IA64_TASK_SIZE,r16 // A r9 = ¤t_thread_info()->flags
+
adds r16=IA64_TASK_THREAD_ON_USTACK_OFFSET,r16
- cmp.eq p0,p7=r18,r17 // is this a system call? (p7 <- false, if so)
-(p7) br.cond.spnt non_syscall
+ adds r15=-1024,r15 // A subtract 1024 from syscall number
+ mov r3=NR_syscalls - 1
;;
- ld1 r17=[r16] // load current->thread.on_ustack flag
- st1 [r16]=r0 // clear current->thread.on_ustack flag
- add r1=-IA64_TASK_THREAD_ON_USTACK_OFFSET,r16 // set r1 for MINSTATE_START_SAVE_MIN_VIRT
+ ld1.bias r17=[r16] // M0|1 r17 = current->thread.on_ustack flag
+ ld4 r9=[r9] // M0|1 r9 = current_thread_info()->flags
+ extr.u r8=r29,41,2 // I0 extract ei field from cr.ipsr
+
+ shladd r30=r15,3,r30 // A r30 = sys_call_table + 8*(syscall-1024)
+ addl r22=IA64_RBS_OFFSET,r1 // A compute base of RBS
+ cmp.leu p6,p7=r15,r3 // A syscall number in range?
;;
- invala
- /* adjust return address so we skip over the break instruction: */
+ lfetch.fault.excl.nt1 [r22] // M0|1 prefetch RBS
+(p6) ld8 r30=[r30] // M0|1 load address of syscall entry point
+ tnat.nz.or p7,p0=r15 // I0 is syscall nr a NaT?
- extr.u r8=r29,41,2 // extract ei field from cr.ipsr
- ;;
- cmp.eq p6,p7=2,r8 // isr.ei==2?
- mov r2=r1 // setup r2 for ia64_syscall_setup
- ;;
-(p6) mov r8=0 // clear ei to 0
-(p6) adds r28=16,r28 // switch cr.iip to next bundle cr.ipsr.ei wrapped
-(p7) adds r8=1,r8 // increment ei to next slot
- ;;
- cmp.eq pKStk,pUStk=r0,r17 // are we in kernel mode already?
- dep r29=r8,r29,41,2 // insert new ei into cr.ipsr
+ mov.m ar.bspstore=r22 // M2 switch to kernel RBS
+ cmp.eq p8,p9=2,r8 // A isr.ei==2?
;;
- // switch from user to kernel RBS:
- MINSTATE_START_SAVE_MIN_VIRT
- br.call.sptk.many b7=ia64_syscall_setup
- ;;
- MINSTATE_END_SAVE_MIN_VIRT // switch to bank 1
- ssm psr.ic | PSR_DEFAULT_BITS
- ;;
- srlz.i // guarantee that interruption collection is on
- mov r3=NR_syscalls - 1
- ;;
-(p15) ssm psr.i // restore psr.i
- // p10==true means out registers are more than 8 or r15's Nat is true
-(p10) br.cond.spnt.many ia64_ret_from_syscall
- ;;
- movl r16=sys_call_table
+(p8) mov r8=0 // A clear ei to 0
+(p7) movl r30=sys_ni_syscall // X
- adds r15=-1024,r15 // r15 contains the syscall number---subtract 1024
- movl r2=ia64_ret_from_syscall
- ;;
- shladd r20=r15,3,r16 // r20 = sys_call_table + 8*(syscall-1024)
- cmp.leu p6,p7=r15,r3 // (syscall > 0 && syscall < 1024 + NR_syscalls) ?
- mov rp=r2 // set the real return addr
+(p8) adds r28=16,r28 // A switch cr.iip to next bundle
+(p9) adds r8=1,r8 // A increment ei to next slot
+ nop.i 0
;;
-(p6) ld8 r20=[r20] // load address of syscall entry point
-(p7) movl r20=sys_ni_syscall
- add r2=TI_FLAGS+IA64_TASK_SIZE,r13
- ;;
- ld4 r2=[r2] // r2 = current_thread_info()->flags
- ;;
- and r2=_TIF_SYSCALL_TRACEAUDIT,r2 // mask trace or audit
+ mov.m r25=ar.unat // M2 (5 cyc)
+ dep r29=r8,r29,41,2 // I0 insert new ei into cr.ipsr
+ adds r15=1024,r15 // A restore original syscall number
+ //
+ // If any of the above loads miss in L1D, we'll stall here until
+ // the data arrives.
+ //
+///////////////////////////////////////////////////////////////////////
+ st1 [r16]=r0 // M2|3 clear current->thread.on_ustack flag
+ mov b6=r30 // I0 setup syscall handler branch reg early
+ cmp.eq pKStk,pUStk=r0,r17 // A were we on kernel stacks already?
+
+ and r9=_TIF_SYSCALL_TRACEAUDIT,r9 // A mask trace or audit
+ mov r18=ar.bsp // M2 (12 cyc)
+(pKStk) br.cond.spnt .break_fixup // B we're already in kernel-mode -- fix up RBS
+ ;;
+.back_from_break_fixup:
+(pUStk) addl r1=IA64_STK_OFFSET-IA64_PT_REGS_SIZE,r1 // A compute base of memory stack
+ cmp.eq p14,p0=r9,r0 // A are syscalls being traced/audited?
+ br.call.sptk.many b7=ia64_syscall_setup // B
+1:
+ mov ar.rsc=0x3 // M2 set eager mode, pl 0, LE, loadrs=0
+ nop 0
+ bsw.1 // B (6 cyc) regs are saved, switch to bank 1
;;
- cmp.eq p8,p0=r2,r0
- mov b6=r20
+
+ ssm psr.ic | PSR_DEFAULT_BITS // M2 now it's safe to re-enable intr.-collection
+ movl r3=ia64_ret_from_syscall // X
;;
-(p8) br.call.sptk.many b6=b6 // ignore this return addr
- br.cond.sptk ia64_trace_syscall
+
+ srlz.i // M0 ensure interruption collection is on
+ mov rp=r3 // I0 set the real return addr
+(p10) br.cond.spnt.many ia64_ret_from_syscall // B return if bad call-frame or r15 is a NaT
+
+(p15) ssm psr.i // M2 restore psr.i
+(p14) br.call.sptk.many b6=b6 // B invoke syscall-handker (ignore return addr)
+ br.cond.spnt.many ia64_trace_syscall // B do syscall-tracing thingamagic
// NOT REACHED
+///////////////////////////////////////////////////////////////////////
+ // On entry, we optimistically assumed that we're coming from user-space.
+ // For the rare cases where a system-call is done from within the kernel,
+ // we fix things up at this point:
+.break_fixup:
+ add r1=-IA64_PT_REGS_SIZE,sp // A allocate space for pt_regs structure
+ mov ar.rnat=r24 // M2 restore kernel's AR.RNAT
+ ;;
+ mov ar.bspstore=r23 // M2 restore kernel's AR.BSPSTORE
+ br.cond.sptk .back_from_break_fixup
END(break_fault)
.org ia64_ivt+0x3000
* - r31: saved pr
* - b0: original contents (to be saved)
* On exit:
- * - executing on bank 1 registers
- * - psr.ic enabled, interrupts restored
* - p10: TRUE if syscall is invoked with more than 8 out
* registers or r15's Nat is true
* - r1: kernel's gp
* - r8: -EINVAL if p10 is true
* - r12: points to kernel stack
* - r13: points to current task
+ * - r14: preserved (same as on entry)
+ * - p13: preserved
* - p15: TRUE if interrupts need to be re-enabled
* - ar.fpsr: set to kernel settings
+ * - b6: preserved (same as on entry)
*/
GLOBAL_ENTRY(ia64_syscall_setup)
#if PT(B6) != 0
(p13) mov in5=-1
;;
st8 [r16]=r21,PT(R8)-PT(AR_FPSR) // save ar.fpsr
- tnat.nz p14,p0=in6
+ tnat.nz p13,p0=in6
cmp.lt p10,p9=r11,r8 // frame size can't be more than local+8
;;
mov r8=1
movl r1=__gp // establish kernel global pointer
;;
st8 [r16]=r8 // ensure pt_regs.r8 != 0 (see handle_syscall_error)
-(p14) mov in6=-1
+(p13) mov in6=-1
(p8) mov in7=-1
cmp.eq pSys,pNonSys=r0,r0 // set pSys=1, pNonSys=0
FAULT(17)
ENTRY(non_syscall)
+ mov ar.rsc=r27 // restore ar.rsc before SAVE_MIN_WITH_COVER
+ ;;
SAVE_MIN_WITH_COVER
// There is no particular reason for this code to be here, other than that
projects / linux-2.6 / commitdiff