etrap_64.S

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * etrap.S: Preparing for entry into the kernel on Sparc V9.
 *
 * Copyright (C) 1996, 1997 David S. Miller ([email protected])
 * Copyright (C) 1997, 1998, 1999 Jakub Jelinek ([email protected])
 */


#include <asm/asi.h>
#include <asm/pstate.h>
#include <asm/ptrace.h>
#include <asm/page.h>
#include <asm/spitfire.h>
#include <asm/head.h>
#include <asm/processor.h>
#include <asm/mmu.h>

#define		TASK_REGOFF		(THREAD_SIZE-TRACEREG_SZ-STACKFRAME_SZ)
#define		ETRAP_PSTATE1		(PSTATE_TSO | PSTATE_PRIV)
#define		ETRAP_PSTATE2		\
		(PSTATE_TSO | PSTATE_PEF | PSTATE_PRIV | PSTATE_IE)

/*
 * On entry, %g7 is return address - 0x4.
 * %g4 and %g5 will be preserved %l4 and %l5 respectively.
 */

		.text		
		.align	64
		.globl	etrap_syscall, etrap, etrap_irq, etraptl1
etrap:		rdpr	%pil, %g2
etrap_irq:	clr	%g3
etrap_syscall:	TRAP_LOAD_THREAD_REG(%g6, %g1)
		rdpr	%tstate, %g1
		or	%g1, %g3, %g1
		sllx	%g2, 20, %g3
		andcc	%g1, TSTATE_PRIV, %g0
		or	%g1, %g3, %g1
		bne,pn	%xcc, 1f
		 sub	%sp, STACKFRAME_SZ+TRACEREG_SZ-STACK_BIAS, %g2
661:		wrpr	%g0, 7, %cleanwin
		.section .fast_win_ctrl_1insn_patch, "ax"
		.word	661b
		.word	0x85880000	! allclean
		.previous

		sethi	%hi(TASK_REGOFF), %g2
		sethi	%hi(TSTATE_PEF), %g3
		or	%g2, %lo(TASK_REGOFF), %g2
		and	%g1, %g3, %g3
		brnz,pn	%g3, 1f
		 add	%g6, %g2, %g2
		wr	%g0, 0, %fprs
1:		rdpr	%tpc, %g3

		stx	%g1, [%g2 + STACKFRAME_SZ + PT_V9_TSTATE]
		rdpr	%tnpc, %g1
		stx	%g3, [%g2 + STACKFRAME_SZ + PT_V9_TPC]
		rd	%y, %g3
		stx	%g1, [%g2 + STACKFRAME_SZ + PT_V9_TNPC]
		rdpr	%tt, %g1
		st	%g3, [%g2 + STACKFRAME_SZ + PT_V9_Y]
		sethi	%hi(PT_REGS_MAGIC), %g3
		or	%g3, %g1, %g1
		st	%g1, [%g2 + STACKFRAME_SZ + PT_V9_MAGIC]

		rdpr	%cansave, %g1
		brnz,pt %g1, etrap_save
		 nop

		rdpr	%cwp, %g1
		add	%g1, 2, %g1
		wrpr	%g1, %cwp
		be,pt	%xcc, etrap_user_spill
		 mov	ASI_AIUP, %g3

		rdpr	%otherwin, %g3
		brz	%g3, etrap_kernel_spill
		 mov	ASI_AIUS, %g3

etrap_user_spill:

		wr	%g3, 0x0, %asi
		ldx	[%g6 + TI_FLAGS], %g3
		and	%g3, _TIF_32BIT, %g3
		brnz,pt	%g3, etrap_user_spill_32bit
		 nop
		ba,a,pt	%xcc, etrap_user_spill_64bit

etrap_save:	save	%g2, -STACK_BIAS, %sp
		mov	%g6, %l6

		bne,pn	%xcc, 3f
		 mov	PRIMARY_CONTEXT, %l4
661:		rdpr	%canrestore, %g3
		.section .fast_win_ctrl_1insn_patch, "ax"
		.word	661b
		nop
		.previous

		rdpr	%wstate, %g2
661:		wrpr	%g0, 0, %canrestore
		.section .fast_win_ctrl_1insn_patch, "ax"
		.word	661b
		nop
		.previous
		sll	%g2, 3, %g2

		/* Set TI_SYS_FPDEPTH to 1 and clear TI_SYS_NOERROR.  */
		mov	1, %l5
		sth	%l5, [%l6 + TI_SYS_NOERROR]

661:		wrpr	%g3, 0, %otherwin
		.section .fast_win_ctrl_1insn_patch, "ax"
		.word	661b
		.word	0x87880000	! otherw
		.previous

		wrpr	%g2, 0, %wstate
		sethi	%hi(sparc64_kern_pri_context), %g2
		ldx	[%g2 + %lo(sparc64_kern_pri_context)], %g3

661:		stxa	%g3, [%l4] ASI_DMMU
		.section .sun4v_1insn_patch, "ax"
		.word	661b
		stxa	%g3, [%l4] ASI_MMU
		.previous

		sethi	%hi(KERNBASE), %l4
		flush	%l4
		mov	ASI_AIUS, %l7
2:		mov	%g4, %l4
		mov	%g5, %l5
		add	%g7, 4, %l2

		/* Go to trap time globals so we can save them.  */
661:		wrpr	%g0, ETRAP_PSTATE1, %pstate
		.section .sun4v_1insn_patch, "ax"
		.word	661b
		SET_GL(0)
		.previous

		stx	%g1, [%sp + PTREGS_OFF + PT_V9_G1]
		stx	%g2, [%sp + PTREGS_OFF + PT_V9_G2]
		sllx	%l7, 24, %l7
		stx	%g3, [%sp + PTREGS_OFF + PT_V9_G3]
		rdpr	%cwp, %l0
		stx	%g4, [%sp + PTREGS_OFF + PT_V9_G4]
		stx	%g5, [%sp + PTREGS_OFF + PT_V9_G5]
		stx	%g6, [%sp + PTREGS_OFF + PT_V9_G6]
		stx	%g7, [%sp + PTREGS_OFF + PT_V9_G7]
		or	%l7, %l0, %l7
661:		sethi	%hi(TSTATE_TSO | TSTATE_PEF), %l0
		/* If userspace is using ADI, it could potentially pass
		 * a pointer with version tag embedded in it. To maintain
		 * the ADI security, we must enable PSTATE.mcde. Userspace
		 * would have already set TTE.mcd in an earlier call to
		 * kernel and set the version tag for the address being
		 * dereferenced. Setting PSTATE.mcde would ensure any
		 * access to userspace data through a system call honors
		 * ADI and does not allow a rogue app to bypass ADI by
		 * using system calls. Setting PSTATE.mcde only affects
		 * accesses to virtual addresses that have TTE.mcd set.
		 * Set PMCDPER to ensure any exceptions caused by ADI
		 * version tag mismatch are exposed before system call
		 * returns to userspace. Setting PMCDPER affects only
		 * writes to virtual addresses that have TTE.mcd set and
		 * have a version tag set as well.
		 */
		.section .sun_m7_1insn_patch, "ax"
		.word	661b
		sethi	%hi(TSTATE_TSO | TSTATE_PEF | TSTATE_MCDE), %l0
		.previous
661:		nop
		.section .sun_m7_1insn_patch, "ax"
		.word	661b
		.word 0xaf902001	/* wrpr %g0, 1, %pmcdper */
		.previous
		or	%l7, %l0, %l7
		wrpr	%l2, %tnpc
		wrpr	%l7, (TSTATE_PRIV | TSTATE_IE), %tstate
		stx	%i0, [%sp + PTREGS_OFF + PT_V9_I0]
		stx	%i1, [%sp + PTREGS_OFF + PT_V9_I1]
		stx	%i2, [%sp + PTREGS_OFF + PT_V9_I2]
		stx	%i3, [%sp + PTREGS_OFF + PT_V9_I3]
		stx	%i4, [%sp + PTREGS_OFF + PT_V9_I4]
		stx	%i5, [%sp + PTREGS_OFF + PT_V9_I5]
		stx	%i6, [%sp + PTREGS_OFF + PT_V9_I6]
		mov	%l6, %g6
		stx	%i7, [%sp + PTREGS_OFF + PT_V9_I7]
		LOAD_PER_CPU_BASE(%g5, %g6, %g4, %g3, %l1)
		ldx	[%g6 + TI_TASK], %g4
		done

3:		mov	ASI_P, %l7
		ldub	[%l6 + TI_FPDEPTH], %l5
		add	%l6, TI_FPSAVED + 1, %l4
		srl	%l5, 1, %l3
		add	%l5, 2, %l5

		/* Set TI_SYS_FPDEPTH to %l5 and clear TI_SYS_NOERROR.  */
		sth	%l5, [%l6 + TI_SYS_NOERROR]
		ba,pt	%xcc, 2b
		 stb	%g0, [%l4 + %l3]
		nop

etraptl1:	/* Save tstate/tpc/tnpc of TL 1-->4 and the tl register itself.
		 * We place this right after pt_regs on the trap stack.
		 * The layout is:
		 *	0x00	TL1's TSTATE
		 *	0x08	TL1's TPC
		 *	0x10	TL1's TNPC
		 *	0x18	TL1's TT
		 *	 ...
		 *	0x58	TL4's TT
		 *	0x60	TL
		 */
		TRAP_LOAD_THREAD_REG(%g6, %g1)
		sub	%sp, ((4 * 8) * 4) + 8, %g2
		rdpr	%tl, %g1

		wrpr	%g0, 1, %tl
		rdpr	%tstate, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x00]
		rdpr	%tpc, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x08]
		rdpr	%tnpc, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x10]
		rdpr	%tt, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x18]

		wrpr	%g0, 2, %tl
		rdpr	%tstate, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x20]
		rdpr	%tpc, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x28]
		rdpr	%tnpc, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x30]
		rdpr	%tt, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x38]

		sethi	%hi(is_sun4v), %g3
		lduw	[%g3 + %lo(is_sun4v)], %g3
		brnz,pn	%g3, finish_tl1_capture
		 nop

		wrpr	%g0, 3, %tl
		rdpr	%tstate, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x40]
		rdpr	%tpc, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x48]
		rdpr	%tnpc, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x50]
		rdpr	%tt, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x58]

		wrpr	%g0, 4, %tl
		rdpr	%tstate, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x60]
		rdpr	%tpc, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x68]
		rdpr	%tnpc, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x70]
		rdpr	%tt, %g3
		stx	%g3, [%g2 + STACK_BIAS + 0x78]

		stx	%g1, [%g2 + STACK_BIAS + 0x80]

finish_tl1_capture:
		wrpr	%g0, 1, %tl
661:		nop
		.section .sun4v_1insn_patch, "ax"
		.word	661b
		SET_GL(1)
		.previous

		rdpr	%tstate, %g1
		sub	%g2, STACKFRAME_SZ + TRACEREG_SZ - STACK_BIAS, %g2
		ba,pt	%xcc, 1b
		 andcc	%g1, TSTATE_PRIV, %g0

#undef TASK_REGOFF
#undef ETRAP_PSTATE1