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-rw-r--r--arch/sparc/kernel/rtrap_64.S378
1 files changed, 378 insertions, 0 deletions
diff --git a/arch/sparc/kernel/rtrap_64.S b/arch/sparc/kernel/rtrap_64.S
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+++ b/arch/sparc/kernel/rtrap_64.S
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+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * 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>
+
+#ifdef CONFIG_CONTEXT_TRACKING
+# define SCHEDULE_USER schedule_user
+#else
+# define SCHEDULE_USER schedule
+#endif
+
+ .text
+ .align 32
+__handle_preemption:
+ call SCHEDULE_USER
+661: wrpr %g0, RTRAP_PSTATE, %pstate
+ /* If userspace is using ADI, it could potentially pass
+ * a pointer with version tag embedded in it. To maintain
+ * the ADI security, we must re-enable PSTATE.mcde before
+ * we continue execution in the kernel for another thread.
+ */
+ .section .sun_m7_1insn_patch, "ax"
+ .word 661b
+ wrpr %g0, RTRAP_PSTATE|PSTATE_MCDE, %pstate
+ .previous
+ ba,pt %xcc, __handle_preemption_continue
+ wrpr %g0, RTRAP_PSTATE_IRQOFF, %pstate
+
+__handle_user_windows:
+ add %sp, PTREGS_OFF, %o0
+ call fault_in_user_windows
+661: wrpr %g0, RTRAP_PSTATE, %pstate
+ /* If userspace is using ADI, it could potentially pass
+ * a pointer with version tag embedded in it. To maintain
+ * the ADI security, we must re-enable PSTATE.mcde before
+ * we continue execution in the kernel for another thread.
+ */
+ .section .sun_m7_1insn_patch, "ax"
+ .word 661b
+ wrpr %g0, RTRAP_PSTATE|PSTATE_MCDE, %pstate
+ .previous
+ 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
+661: wrpr %g0, RTRAP_PSTATE, %pstate
+ /* If userspace is using ADI, it could potentially pass
+ * a pointer with version tag embedded in it. To maintain
+ * the ADI security, we must re-enable PSTATE.mcde before
+ * we continue execution in the kernel for another thread.
+ */
+ .section .sun_m7_1insn_patch, "ax"
+ .word 661b
+ wrpr %g0, RTRAP_PSTATE|PSTATE_MCDE, %pstate
+ .previous
+ 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
+ andn %l1, %l4, %l1
+ ba,pt %xcc, __handle_preemption_continue
+ srl %l4, 20, %l4
+
+ /* 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
+ 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.
+ */
+
+ .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
+ brz,pt %l3, 1f
+ mov %g6, %l2
+
+ /* 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
+ 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
+
+661: wrpr %l2, %g0, %canrestore
+ .section .fast_win_ctrl_1insn_patch, "ax"
+ .word 661b
+ .word 0x89880000 ! normalw
+ .previous
+
+ wrpr %l1, %g0, %wstate
+ brnz,pt %l2, user_rtt_restore
+661: wrpr %g0, %g0, %otherwin
+ .section .fast_win_ctrl_1insn_patch, "ax"
+ .word 661b
+ nop
+ .previous
+
+ 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
+ nop
+
+user_rtt_fill_fixup_dax:
+ ba,pt %xcc, user_rtt_fill_fixup_common
+ mov 1, %g3
+
+user_rtt_fill_fixup_mna:
+ ba,pt %xcc, user_rtt_fill_fixup_common
+ mov 2, %g3
+
+user_rtt_fill_fixup:
+ ba,pt %xcc, user_rtt_fill_fixup_common
+ clr %g3
+
+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]
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