56fb4df6da
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>
347 lines
9.4 KiB
ArmAsm
347 lines
9.4 KiB
ArmAsm
/* $Id: rtrap.S,v 1.61 2002/02/09 19:49:31 davem Exp $
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* rtrap.S: Preparing for return from trap on Sparc V9.
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*
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* Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
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* Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
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*/
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#include <linux/config.h>
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#include <asm/asi.h>
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#include <asm/pstate.h>
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#include <asm/ptrace.h>
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#include <asm/spitfire.h>
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#include <asm/head.h>
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#include <asm/visasm.h>
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#include <asm/processor.h>
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#define RTRAP_PSTATE (PSTATE_RMO|PSTATE_PEF|PSTATE_PRIV|PSTATE_IE)
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#define RTRAP_PSTATE_IRQOFF (PSTATE_RMO|PSTATE_PEF|PSTATE_PRIV)
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#define RTRAP_PSTATE_AG_IRQOFF (PSTATE_RMO|PSTATE_PEF|PSTATE_PRIV|PSTATE_AG)
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/* Register %l6 keeps track of whether we are returning
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* from a system call or not. It is cleared if we call
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* do_notify_resume, and it must not be otherwise modified
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* until we fully commit to returning to userspace.
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*/
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.text
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.align 32
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__handle_softirq:
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call do_softirq
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nop
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ba,a,pt %xcc, __handle_softirq_continue
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nop
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__handle_preemption:
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call schedule
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wrpr %g0, RTRAP_PSTATE, %pstate
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ba,pt %xcc, __handle_preemption_continue
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wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
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__handle_user_windows:
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call fault_in_user_windows
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wrpr %g0, RTRAP_PSTATE, %pstate
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wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
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/* Redo sched+sig checks */
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ldx [%g6 + TI_FLAGS], %l0
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andcc %l0, _TIF_NEED_RESCHED, %g0
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be,pt %xcc, 1f
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nop
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call schedule
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wrpr %g0, RTRAP_PSTATE, %pstate
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wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
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ldx [%g6 + TI_FLAGS], %l0
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1: andcc %l0, (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK), %g0
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be,pt %xcc, __handle_user_windows_continue
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nop
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mov %l5, %o1
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mov %l6, %o2
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add %sp, PTREGS_OFF, %o0
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mov %l0, %o3
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call do_notify_resume
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wrpr %g0, RTRAP_PSTATE, %pstate
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wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
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clr %l6
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/* Signal delivery can modify pt_regs tstate, so we must
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* reload it.
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*/
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ldx [%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
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sethi %hi(0xf << 20), %l4
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and %l1, %l4, %l4
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ba,pt %xcc, __handle_user_windows_continue
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andn %l1, %l4, %l1
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__handle_perfctrs:
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call update_perfctrs
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wrpr %g0, RTRAP_PSTATE, %pstate
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wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
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ldub [%g6 + TI_WSAVED], %o2
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brz,pt %o2, 1f
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nop
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/* Redo userwin+sched+sig checks */
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call fault_in_user_windows
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wrpr %g0, RTRAP_PSTATE, %pstate
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wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
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ldx [%g6 + TI_FLAGS], %l0
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andcc %l0, _TIF_NEED_RESCHED, %g0
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be,pt %xcc, 1f
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nop
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call schedule
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wrpr %g0, RTRAP_PSTATE, %pstate
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wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
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ldx [%g6 + TI_FLAGS], %l0
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1: andcc %l0, (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK), %g0
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be,pt %xcc, __handle_perfctrs_continue
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sethi %hi(TSTATE_PEF), %o0
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mov %l5, %o1
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mov %l6, %o2
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add %sp, PTREGS_OFF, %o0
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mov %l0, %o3
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call do_notify_resume
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wrpr %g0, RTRAP_PSTATE, %pstate
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wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
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clr %l6
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/* Signal delivery can modify pt_regs tstate, so we must
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* reload it.
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*/
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ldx [%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
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sethi %hi(0xf << 20), %l4
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and %l1, %l4, %l4
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andn %l1, %l4, %l1
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ba,pt %xcc, __handle_perfctrs_continue
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sethi %hi(TSTATE_PEF), %o0
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__handle_userfpu:
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rd %fprs, %l5
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andcc %l5, FPRS_FEF, %g0
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sethi %hi(TSTATE_PEF), %o0
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be,a,pn %icc, __handle_userfpu_continue
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andn %l1, %o0, %l1
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ba,a,pt %xcc, __handle_userfpu_continue
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__handle_signal:
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mov %l5, %o1
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mov %l6, %o2
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add %sp, PTREGS_OFF, %o0
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mov %l0, %o3
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call do_notify_resume
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wrpr %g0, RTRAP_PSTATE, %pstate
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wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
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clr %l6
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/* Signal delivery can modify pt_regs tstate, so we must
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* reload it.
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*/
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ldx [%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
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sethi %hi(0xf << 20), %l4
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and %l1, %l4, %l4
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ba,pt %xcc, __handle_signal_continue
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andn %l1, %l4, %l1
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.align 64
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.globl rtrap_irq, rtrap_clr_l6, rtrap, irqsz_patchme, rtrap_xcall
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rtrap_irq:
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rtrap_clr_l6: clr %l6
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rtrap:
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#ifndef CONFIG_SMP
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sethi %hi(per_cpu____cpu_data), %l0
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lduw [%l0 + %lo(per_cpu____cpu_data)], %l1
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#else
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sethi %hi(per_cpu____cpu_data), %l0
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or %l0, %lo(per_cpu____cpu_data), %l0
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lduw [%l0 + %g5], %l1
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#endif
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cmp %l1, 0
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/* mm/ultra.S:xcall_report_regs KNOWS about this load. */
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bne,pn %icc, __handle_softirq
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ldx [%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
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__handle_softirq_continue:
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rtrap_xcall:
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sethi %hi(0xf << 20), %l4
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andcc %l1, TSTATE_PRIV, %l3
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and %l1, %l4, %l4
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bne,pn %icc, to_kernel
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andn %l1, %l4, %l1
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/* We must hold IRQs off and atomically test schedule+signal
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* state, then hold them off all the way back to userspace.
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* If we are returning to kernel, none of this matters.
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*
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* If we do not do this, there is a window where we would do
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* the tests, later the signal/resched event arrives but we do
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* not process it since we are still in kernel mode. It would
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* take until the next local IRQ before the signal/resched
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* event would be handled.
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*
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* This also means that if we have to deal with performance
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* counters or user windows, we have to redo all of these
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* sched+signal checks with IRQs disabled.
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*/
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to_user: wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
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wrpr 0, %pil
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__handle_preemption_continue:
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ldx [%g6 + TI_FLAGS], %l0
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sethi %hi(_TIF_USER_WORK_MASK), %o0
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or %o0, %lo(_TIF_USER_WORK_MASK), %o0
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andcc %l0, %o0, %g0
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sethi %hi(TSTATE_PEF), %o0
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be,pt %xcc, user_nowork
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andcc %l1, %o0, %g0
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andcc %l0, _TIF_NEED_RESCHED, %g0
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bne,pn %xcc, __handle_preemption
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andcc %l0, (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK), %g0
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bne,pn %xcc, __handle_signal
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__handle_signal_continue:
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ldub [%g6 + TI_WSAVED], %o2
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brnz,pn %o2, __handle_user_windows
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nop
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__handle_user_windows_continue:
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ldx [%g6 + TI_FLAGS], %l5
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andcc %l5, _TIF_PERFCTR, %g0
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sethi %hi(TSTATE_PEF), %o0
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bne,pn %xcc, __handle_perfctrs
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__handle_perfctrs_continue:
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andcc %l1, %o0, %g0
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/* This fpdepth clear is necessary for non-syscall rtraps only */
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user_nowork:
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bne,pn %xcc, __handle_userfpu
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stb %g0, [%g6 + TI_FPDEPTH]
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__handle_userfpu_continue:
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rt_continue: ldx [%sp + PTREGS_OFF + PT_V9_G1], %g1
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ldx [%sp + PTREGS_OFF + PT_V9_G2], %g2
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ldx [%sp + PTREGS_OFF + PT_V9_G3], %g3
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ldx [%sp + PTREGS_OFF + PT_V9_G4], %g4
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ldx [%sp + PTREGS_OFF + PT_V9_G5], %g5
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brz,pt %l3, 1f
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nop
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/* Must do this before thread reg is clobbered below. */
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LOAD_PER_CPU_BASE(%g6, %g7)
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1:
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ldx [%sp + PTREGS_OFF + PT_V9_G6], %g6
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ldx [%sp + PTREGS_OFF + PT_V9_G7], %g7
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wrpr %g0, RTRAP_PSTATE_AG_IRQOFF, %pstate
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ldx [%sp + PTREGS_OFF + PT_V9_I0], %i0
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ldx [%sp + PTREGS_OFF + PT_V9_I1], %i1
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ldx [%sp + PTREGS_OFF + PT_V9_I2], %i2
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ldx [%sp + PTREGS_OFF + PT_V9_I3], %i3
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ldx [%sp + PTREGS_OFF + PT_V9_I4], %i4
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ldx [%sp + PTREGS_OFF + PT_V9_I5], %i5
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ldx [%sp + PTREGS_OFF + PT_V9_I6], %i6
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ldx [%sp + PTREGS_OFF + PT_V9_I7], %i7
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ldx [%sp + PTREGS_OFF + PT_V9_TPC], %l2
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ldx [%sp + PTREGS_OFF + PT_V9_TNPC], %o2
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ld [%sp + PTREGS_OFF + PT_V9_Y], %o3
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wr %o3, %g0, %y
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srl %l4, 20, %l4
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wrpr %l4, 0x0, %pil
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wrpr %g0, 0x1, %tl
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wrpr %l1, %g0, %tstate
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wrpr %l2, %g0, %tpc
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wrpr %o2, %g0, %tnpc
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brnz,pn %l3, kern_rtt
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mov PRIMARY_CONTEXT, %l7
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ldxa [%l7 + %l7] ASI_DMMU, %l0
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sethi %hi(sparc64_kern_pri_nuc_bits), %l1
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ldx [%l1 + %lo(sparc64_kern_pri_nuc_bits)], %l1
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or %l0, %l1, %l0
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stxa %l0, [%l7] ASI_DMMU
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flush %g6
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rdpr %wstate, %l1
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rdpr %otherwin, %l2
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srl %l1, 3, %l1
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wrpr %l2, %g0, %canrestore
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wrpr %l1, %g0, %wstate
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wrpr %g0, %g0, %otherwin
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restore
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rdpr %canrestore, %g1
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wrpr %g1, 0x0, %cleanwin
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retry
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nop
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kern_rtt: restore
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retry
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to_kernel:
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#ifdef CONFIG_PREEMPT
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ldsw [%g6 + TI_PRE_COUNT], %l5
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brnz %l5, kern_fpucheck
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ldx [%g6 + TI_FLAGS], %l5
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andcc %l5, _TIF_NEED_RESCHED, %g0
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be,pt %xcc, kern_fpucheck
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srl %l4, 20, %l5
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cmp %l5, 0
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bne,pn %xcc, kern_fpucheck
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sethi %hi(PREEMPT_ACTIVE), %l6
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stw %l6, [%g6 + TI_PRE_COUNT]
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call schedule
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nop
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ba,pt %xcc, rtrap
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stw %g0, [%g6 + TI_PRE_COUNT]
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#endif
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kern_fpucheck: ldub [%g6 + TI_FPDEPTH], %l5
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brz,pt %l5, rt_continue
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srl %l5, 1, %o0
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add %g6, TI_FPSAVED, %l6
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ldub [%l6 + %o0], %l2
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sub %l5, 2, %l5
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add %g6, TI_GSR, %o1
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andcc %l2, (FPRS_FEF|FPRS_DU), %g0
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be,pt %icc, 2f
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and %l2, FPRS_DL, %l6
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andcc %l2, FPRS_FEF, %g0
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be,pn %icc, 5f
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sll %o0, 3, %o5
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rd %fprs, %g1
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wr %g1, FPRS_FEF, %fprs
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ldx [%o1 + %o5], %g1
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add %g6, TI_XFSR, %o1
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sll %o0, 8, %o2
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add %g6, TI_FPREGS, %o3
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brz,pn %l6, 1f
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add %g6, TI_FPREGS+0x40, %o4
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membar #Sync
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ldda [%o3 + %o2] ASI_BLK_P, %f0
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ldda [%o4 + %o2] ASI_BLK_P, %f16
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membar #Sync
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1: andcc %l2, FPRS_DU, %g0
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be,pn %icc, 1f
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wr %g1, 0, %gsr
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add %o2, 0x80, %o2
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membar #Sync
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ldda [%o3 + %o2] ASI_BLK_P, %f32
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ldda [%o4 + %o2] ASI_BLK_P, %f48
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1: membar #Sync
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ldx [%o1 + %o5], %fsr
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2: stb %l5, [%g6 + TI_FPDEPTH]
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ba,pt %xcc, rt_continue
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nop
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5: wr %g0, FPRS_FEF, %fprs
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sll %o0, 8, %o2
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add %g6, TI_FPREGS+0x80, %o3
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add %g6, TI_FPREGS+0xc0, %o4
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membar #Sync
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ldda [%o3 + %o2] ASI_BLK_P, %f32
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ldda [%o4 + %o2] ASI_BLK_P, %f48
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membar #Sync
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wr %g0, FPRS_DU, %fprs
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ba,pt %xcc, rt_continue
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stb %l5, [%g6 + TI_FPDEPTH]
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