linux/arch/sparc/kernel/rtrap_64.S

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/*
* rtrap.S: Preparing for return from trap on Sparc V9.
*
* Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
* Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
*/
#include <asm/asi.h>
#include <asm/pstate.h>
#include <asm/ptrace.h>
#include <asm/spitfire.h>
#include <asm/head.h>
#include <asm/visasm.h>
#include <asm/processor.h>
#define RTRAP_PSTATE (PSTATE_TSO|PSTATE_PEF|PSTATE_PRIV|PSTATE_IE)
#define RTRAP_PSTATE_IRQOFF (PSTATE_TSO|PSTATE_PEF|PSTATE_PRIV)
#define RTRAP_PSTATE_AG_IRQOFF (PSTATE_TSO|PSTATE_PEF|PSTATE_PRIV|PSTATE_AG)
#ifdef CONFIG_CONTEXT_TRACKING
# define SCHEDULE_USER schedule_user
#else
# define SCHEDULE_USER schedule
#endif
.text
.align 32
__handle_preemption:
call SCHEDULE_USER
wrpr %g0, RTRAP_PSTATE, %pstate
ba,pt %xcc, __handle_preemption_continue
wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
__handle_user_windows:
call fault_in_user_windows
wrpr %g0, RTRAP_PSTATE, %pstate
ba,pt %xcc, __handle_preemption_continue
wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
__handle_userfpu:
rd %fprs, %l5
andcc %l5, FPRS_FEF, %g0
sethi %hi(TSTATE_PEF), %o0
be,a,pn %icc, __handle_userfpu_continue
andn %l1, %o0, %l1
ba,a,pt %xcc, __handle_userfpu_continue
__handle_signal:
mov %l5, %o1
add %sp, PTREGS_OFF, %o0
mov %l0, %o2
call do_notify_resume
wrpr %g0, RTRAP_PSTATE, %pstate
wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
/* Signal delivery can modify pt_regs tstate, so we must
* reload it.
*/
ldx [%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
sethi %hi(0xf << 20), %l4
and %l1, %l4, %l4
ba,pt %xcc, __handle_preemption_continue
andn %l1, %l4, %l1
/* When returning from a NMI (%pil==15) interrupt we want to
* avoid running softirqs, doing IRQ tracing, preempting, etc.
*/
.globl rtrap_nmi
rtrap_nmi: ldx [%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
sethi %hi(0xf << 20), %l4
and %l1, %l4, %l4
andn %l1, %l4, %l1
srl %l4, 20, %l4
ba,pt %xcc, rtrap_no_irq_enable
wrpr %l4, %pil
.align 64
.globl rtrap_irq, rtrap, irqsz_patchme, rtrap_xcall
rtrap_irq:
rtrap:
/* mm/ultra.S:xcall_report_regs KNOWS about this load. */
ldx [%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
rtrap_xcall:
sethi %hi(0xf << 20), %l4
and %l1, %l4, %l4
andn %l1, %l4, %l1
srl %l4, 20, %l4
#ifdef CONFIG_TRACE_IRQFLAGS
brnz,pn %l4, rtrap_no_irq_enable
nop
call trace_hardirqs_on
nop
/* Do not actually set the %pil here. We will do that
* below after we clear PSTATE_IE in the %pstate register.
* If we re-enable interrupts here, we can recurse down
* the hardirq stack potentially endlessly, causing a
* stack overflow.
*
* It is tempting to put this test and trace_hardirqs_on
* call at the 'rt_continue' label, but that will not work
* as that path hits unconditionally and we do not want to
* execute this in NMI return paths, for example.
*/
#endif
rtrap_no_irq_enable:
andcc %l1, TSTATE_PRIV, %l3
bne,pn %icc, to_kernel
nop
/* We must hold IRQs off and atomically test schedule+signal
* state, then hold them off all the way back to userspace.
* If we are returning to kernel, none of this matters. Note
* that we are disabling interrupts via PSTATE_IE, not using
* %pil.
*
* If we do not do this, there is a window where we would do
* the tests, later the signal/resched event arrives but we do
* not process it since we are still in kernel mode. It would
* take until the next local IRQ before the signal/resched
* event would be handled.
*
* This also means that if we have to deal with user
* windows, we have to redo all of these sched+signal checks
* with IRQs disabled.
*/
to_user: wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
wrpr 0, %pil
__handle_preemption_continue:
ldx [%g6 + TI_FLAGS], %l0
sethi %hi(_TIF_USER_WORK_MASK), %o0
or %o0, %lo(_TIF_USER_WORK_MASK), %o0
andcc %l0, %o0, %g0
sethi %hi(TSTATE_PEF), %o0
be,pt %xcc, user_nowork
andcc %l1, %o0, %g0
andcc %l0, _TIF_NEED_RESCHED, %g0
bne,pn %xcc, __handle_preemption
andcc %l0, _TIF_DO_NOTIFY_RESUME_MASK, %g0
bne,pn %xcc, __handle_signal
ldub [%g6 + TI_WSAVED], %o2
brnz,pn %o2, __handle_user_windows
nop
sethi %hi(TSTATE_PEF), %o0
andcc %l1, %o0, %g0
/* This fpdepth clear is necessary for non-syscall rtraps only */
user_nowork:
bne,pn %xcc, __handle_userfpu
stb %g0, [%g6 + TI_FPDEPTH]
__handle_userfpu_continue:
rt_continue: ldx [%sp + PTREGS_OFF + PT_V9_G1], %g1
ldx [%sp + PTREGS_OFF + PT_V9_G2], %g2
ldx [%sp + PTREGS_OFF + PT_V9_G3], %g3
ldx [%sp + PTREGS_OFF + PT_V9_G4], %g4
ldx [%sp + PTREGS_OFF + PT_V9_G5], %g5
[SPARC64]: Elminate all usage of hard-coded trap globals. UltraSPARC has special sets of global registers which are switched to for certain trap types. There is one set for MMU related traps, one set of Interrupt Vector processing, and another set (called the Alternate globals) for all other trap types. For what seems like forever we've hard coded the values in some of these trap registers. Some examples include: 1) Interrupt Vector global %g6 holds current processors interrupt work struct where received interrupts are managed for IRQ handler dispatch. 2) MMU global %g7 holds the base of the page tables of the currently active address space. 3) Alternate global %g6 held the current_thread_info() value. Such hardcoding has resulted in some serious issues in many areas. There are some code sequences where having another register available would help clean up the implementation. Taking traps such as cross-calls from the OBP firmware requires some trick code sequences wherein we have to save away and restore all of the special sets of global registers when we enter/exit OBP. We were also using the IMMU TSB register on SMP to hold the per-cpu area base address, which doesn't work any longer now that we actually use the TSB facility of the cpu. The implementation is pretty straight forward. One tricky bit is getting the current processor ID as that is different on different cpu variants. We use a stub with a fancy calling convention which we patch at boot time. The calling convention is that the stub is branched to and the (PC - 4) to return to is in register %g1. The cpu number is left in %g6. This stub can be invoked by using the __GET_CPUID macro. We use an array of per-cpu trap state to store the current thread and physical address of the current address space's page tables. The TRAP_LOAD_THREAD_REG loads %g6 with the current thread from this table, it uses __GET_CPUID and also clobbers %g1. TRAP_LOAD_IRQ_WORK is used by the interrupt vector processing to load the current processor's IRQ software state into %g6. It also uses __GET_CPUID and clobbers %g1. Finally, TRAP_LOAD_PGD_PHYS loads the physical address base of the current address space's page tables into %g7, it clobbers %g1 and uses __GET_CPUID. Many refinements are possible, as well as some tuning, with this stuff in place. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-27 07:24:22 +00:00
brz,pt %l3, 1f
mov %g6, %l2
[SPARC64]: Elminate all usage of hard-coded trap globals. UltraSPARC has special sets of global registers which are switched to for certain trap types. There is one set for MMU related traps, one set of Interrupt Vector processing, and another set (called the Alternate globals) for all other trap types. For what seems like forever we've hard coded the values in some of these trap registers. Some examples include: 1) Interrupt Vector global %g6 holds current processors interrupt work struct where received interrupts are managed for IRQ handler dispatch. 2) MMU global %g7 holds the base of the page tables of the currently active address space. 3) Alternate global %g6 held the current_thread_info() value. Such hardcoding has resulted in some serious issues in many areas. There are some code sequences where having another register available would help clean up the implementation. Taking traps such as cross-calls from the OBP firmware requires some trick code sequences wherein we have to save away and restore all of the special sets of global registers when we enter/exit OBP. We were also using the IMMU TSB register on SMP to hold the per-cpu area base address, which doesn't work any longer now that we actually use the TSB facility of the cpu. The implementation is pretty straight forward. One tricky bit is getting the current processor ID as that is different on different cpu variants. We use a stub with a fancy calling convention which we patch at boot time. The calling convention is that the stub is branched to and the (PC - 4) to return to is in register %g1. The cpu number is left in %g6. This stub can be invoked by using the __GET_CPUID macro. We use an array of per-cpu trap state to store the current thread and physical address of the current address space's page tables. The TRAP_LOAD_THREAD_REG loads %g6 with the current thread from this table, it uses __GET_CPUID and also clobbers %g1. TRAP_LOAD_IRQ_WORK is used by the interrupt vector processing to load the current processor's IRQ software state into %g6. It also uses __GET_CPUID and clobbers %g1. Finally, TRAP_LOAD_PGD_PHYS loads the physical address base of the current address space's page tables into %g7, it clobbers %g1 and uses __GET_CPUID. Many refinements are possible, as well as some tuning, with this stuff in place. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-27 07:24:22 +00:00
/* Must do this before thread reg is clobbered below. */
LOAD_PER_CPU_BASE(%g5, %g6, %i0, %i1, %i2)
1:
ldx [%sp + PTREGS_OFF + PT_V9_G6], %g6
ldx [%sp + PTREGS_OFF + PT_V9_G7], %g7
/* Normal globals are restored, go to trap globals. */
661: wrpr %g0, RTRAP_PSTATE_AG_IRQOFF, %pstate
nop
.section .sun4v_2insn_patch, "ax"
.word 661b
wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
SET_GL(1)
.previous
mov %l2, %g6
ldx [%sp + PTREGS_OFF + PT_V9_I0], %i0
ldx [%sp + PTREGS_OFF + PT_V9_I1], %i1
ldx [%sp + PTREGS_OFF + PT_V9_I2], %i2
ldx [%sp + PTREGS_OFF + PT_V9_I3], %i3
ldx [%sp + PTREGS_OFF + PT_V9_I4], %i4
ldx [%sp + PTREGS_OFF + PT_V9_I5], %i5
ldx [%sp + PTREGS_OFF + PT_V9_I6], %i6
ldx [%sp + PTREGS_OFF + PT_V9_I7], %i7
ldx [%sp + PTREGS_OFF + PT_V9_TPC], %l2
ldx [%sp + PTREGS_OFF + PT_V9_TNPC], %o2
ld [%sp + PTREGS_OFF + PT_V9_Y], %o3
wr %o3, %g0, %y
wrpr %l4, 0x0, %pil
wrpr %g0, 0x1, %tl
sparc: Fix debugger syscall restart interactions. So, forever, we've had this ptrace_signal_deliver implementation which tries to handle all of the nasties that can occur when the debugger looks at a process about to take a signal. It's meant to address all of these issues inside of the kernel so that the debugger need not be mindful of such things. Problem is, this doesn't work. The idea was that we should do the syscall restart business first, so that the debugger captures that state. Otherwise, if the debugger for example saves the child's state, makes the child execute something else, then restores the saved state, we won't handle the syscall restart properly because we lose the "we're in a syscall" state. The code here worked for most cases, but if the debugger actually passes the signal through to the child unaltered, it's possible that we would do a syscall restart when we shouldn't have. In particular this breaks the case of debugging a process under a gdb which is being debugged by yet another gdb. gdb uses sigsuspend to wait for SIGCHLD of the inferior, but if gdb itself is being debugged by a top-level gdb we get a ptrace_stop(). The top-level gdb does a PTRACE_CONT with SIGCHLD to let the inferior gdb see the signal. But ptrace_signal_deliver() assumed the debugger would cancel out the signal and therefore did a syscall restart, because the return error was ERESTARTNOHAND. Fix this by simply making ptrace_signal_deliver() a nop, and providing a way for the debugger to control system call restarting properly: 1) Report a "in syscall" software bit in regs->{tstate,psr}. It is set early on in trap entry to a system call and is fully visible to the debugger via ptrace() and regsets. 2) Test this bit right before doing a syscall restart. We have to do a final recheck right after get_signal_to_deliver() in case the debugger cleared the bit during ptrace_stop(). 3) Clear the bit in trap return so we don't accidently try to set that bit in the real register. As a result we also get a ptrace_{is,clear}_syscall() for sparc32 just like sparc64 has. M68K has this same exact bug, and is now the only other user of the ptrace_signal_deliver hook. It needs to be fixed in the same exact way as sparc. Signed-off-by: David S. Miller <davem@davemloft.net>
2008-05-11 09:07:19 +00:00
andn %l1, TSTATE_SYSCALL, %l1
wrpr %l1, %g0, %tstate
wrpr %l2, %g0, %tpc
wrpr %o2, %g0, %tnpc
brnz,pn %l3, kern_rtt
mov PRIMARY_CONTEXT, %l7
661: ldxa [%l7 + %l7] ASI_DMMU, %l0
.section .sun4v_1insn_patch, "ax"
.word 661b
ldxa [%l7 + %l7] ASI_MMU, %l0
.previous
sethi %hi(sparc64_kern_pri_nuc_bits), %l1
ldx [%l1 + %lo(sparc64_kern_pri_nuc_bits)], %l1
or %l0, %l1, %l0
661: stxa %l0, [%l7] ASI_DMMU
.section .sun4v_1insn_patch, "ax"
.word 661b
stxa %l0, [%l7] ASI_MMU
.previous
sethi %hi(KERNBASE), %l7
flush %l7
rdpr %wstate, %l1
rdpr %otherwin, %l2
srl %l1, 3, %l1
wrpr %l2, %g0, %canrestore
wrpr %l1, %g0, %wstate
brnz,pt %l2, user_rtt_restore
wrpr %g0, %g0, %otherwin
ldx [%g6 + TI_FLAGS], %g3
wr %g0, ASI_AIUP, %asi
rdpr %cwp, %g1
andcc %g3, _TIF_32BIT, %g0
sub %g1, 1, %g1
bne,pt %xcc, user_rtt_fill_32bit
wrpr %g1, %cwp
ba,a,pt %xcc, user_rtt_fill_64bit
user_rtt_fill_fixup:
rdpr %cwp, %g1
add %g1, 1, %g1
wrpr %g1, 0x0, %cwp
rdpr %wstate, %g2
sll %g2, 3, %g2
wrpr %g2, 0x0, %wstate
/* We know %canrestore and %otherwin are both zero. */
sethi %hi(sparc64_kern_pri_context), %g2
ldx [%g2 + %lo(sparc64_kern_pri_context)], %g2
mov PRIMARY_CONTEXT, %g1
661: stxa %g2, [%g1] ASI_DMMU
.section .sun4v_1insn_patch, "ax"
.word 661b
stxa %g2, [%g1] ASI_MMU
.previous
sethi %hi(KERNBASE), %g1
flush %g1
or %g4, FAULT_CODE_WINFIXUP, %g4
stb %g4, [%g6 + TI_FAULT_CODE]
stx %g5, [%g6 + TI_FAULT_ADDR]
mov %g6, %l1
wrpr %g0, 0x0, %tl
661: nop
.section .sun4v_1insn_patch, "ax"
.word 661b
SET_GL(0)
.previous
wrpr %g0, RTRAP_PSTATE, %pstate
mov %l1, %g6
ldx [%g6 + TI_TASK], %g4
LOAD_PER_CPU_BASE(%g5, %g6, %g1, %g2, %g3)
call do_sparc64_fault
add %sp, PTREGS_OFF, %o0
ba,pt %xcc, rtrap
nop
user_rtt_pre_restore:
add %g1, 1, %g1
wrpr %g1, 0x0, %cwp
user_rtt_restore:
restore
rdpr %canrestore, %g1
wrpr %g1, 0x0, %cleanwin
retry
nop
kern_rtt: rdpr %canrestore, %g1
brz,pn %g1, kern_rtt_fill
nop
kern_rtt_restore:
stw %g0, [%sp + PTREGS_OFF + PT_V9_MAGIC]
restore
retry
to_kernel:
#ifdef CONFIG_PREEMPT
ldsw [%g6 + TI_PRE_COUNT], %l5
brnz %l5, kern_fpucheck
ldx [%g6 + TI_FLAGS], %l5
andcc %l5, _TIF_NEED_RESCHED, %g0
be,pt %xcc, kern_fpucheck
nop
cmp %l4, 0
bne,pn %xcc, kern_fpucheck
nop
call preempt_schedule_irq
nop
ba,pt %xcc, rtrap
#endif
kern_fpucheck: ldub [%g6 + TI_FPDEPTH], %l5
brz,pt %l5, rt_continue
srl %l5, 1, %o0
add %g6, TI_FPSAVED, %l6
ldub [%l6 + %o0], %l2
sub %l5, 2, %l5
add %g6, TI_GSR, %o1
andcc %l2, (FPRS_FEF|FPRS_DU), %g0
be,pt %icc, 2f
and %l2, FPRS_DL, %l6
andcc %l2, FPRS_FEF, %g0
be,pn %icc, 5f
sll %o0, 3, %o5
rd %fprs, %g1
wr %g1, FPRS_FEF, %fprs
ldx [%o1 + %o5], %g1
add %g6, TI_XFSR, %o1
sll %o0, 8, %o2
add %g6, TI_FPREGS, %o3
brz,pn %l6, 1f
add %g6, TI_FPREGS+0x40, %o4
membar #Sync
ldda [%o3 + %o2] ASI_BLK_P, %f0
ldda [%o4 + %o2] ASI_BLK_P, %f16
membar #Sync
1: andcc %l2, FPRS_DU, %g0
be,pn %icc, 1f
wr %g1, 0, %gsr
add %o2, 0x80, %o2
membar #Sync
ldda [%o3 + %o2] ASI_BLK_P, %f32
ldda [%o4 + %o2] ASI_BLK_P, %f48
1: membar #Sync
ldx [%o1 + %o5], %fsr
2: stb %l5, [%g6 + TI_FPDEPTH]
ba,pt %xcc, rt_continue
nop
5: wr %g0, FPRS_FEF, %fprs
sll %o0, 8, %o2
add %g6, TI_FPREGS+0x80, %o3
add %g6, TI_FPREGS+0xc0, %o4
membar #Sync
ldda [%o3 + %o2] ASI_BLK_P, %f32
ldda [%o4 + %o2] ASI_BLK_P, %f48
membar #Sync
wr %g0, FPRS_DU, %fprs
ba,pt %xcc, rt_continue
stb %l5, [%g6 + TI_FPDEPTH]