mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-16 14:06:48 +07:00
b86fb88855
This patch implements a fast entry for syscalls. Syscalls don't have to preserve non volatile registers except LR. This patch then implement a fast entry for syscalls, where volatile registers get clobbered. As this entry is dedicated to syscall it always sets MSR_EE and warns in case MSR_EE was previously off It also assumes that the call is always from user, system calls are unexpected from kernel. The overall series improves null_syscall selftest by 12,5% on an 83xx and by 17% on a 8xx. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
204 lines
4.9 KiB
C
204 lines
4.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __HEAD_32_H__
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#define __HEAD_32_H__
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#include <asm/ptrace.h> /* for STACK_FRAME_REGS_MARKER */
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/*
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* MSR_KERNEL is > 0x8000 on 4xx/Book-E since it include MSR_CE.
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*/
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.macro __LOAD_MSR_KERNEL r, x
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.if \x >= 0x8000
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lis \r, (\x)@h
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ori \r, \r, (\x)@l
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.else
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li \r, (\x)
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.endif
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.endm
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#define LOAD_MSR_KERNEL(r, x) __LOAD_MSR_KERNEL r, x
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/*
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* Exception entry code. This code runs with address translation
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* turned off, i.e. using physical addresses.
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* We assume sprg3 has the physical address of the current
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* task's thread_struct.
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*/
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.macro EXCEPTION_PROLOG
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mtspr SPRN_SPRG_SCRATCH0,r10
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mtspr SPRN_SPRG_SCRATCH1,r11
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mfcr r10
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EXCEPTION_PROLOG_1
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EXCEPTION_PROLOG_2
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.endm
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.macro EXCEPTION_PROLOG_1
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mfspr r11,SPRN_SRR1 /* check whether user or kernel */
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andi. r11,r11,MSR_PR
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tophys(r11,r1) /* use tophys(r1) if kernel */
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beq 1f
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mfspr r11,SPRN_SPRG_THREAD
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lwz r11,TASK_STACK-THREAD(r11)
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addi r11,r11,THREAD_SIZE
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tophys(r11,r11)
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1: subi r11,r11,INT_FRAME_SIZE /* alloc exc. frame */
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.endm
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.macro EXCEPTION_PROLOG_2
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stw r10,_CCR(r11) /* save registers */
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stw r12,GPR12(r11)
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stw r9,GPR9(r11)
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mfspr r10,SPRN_SPRG_SCRATCH0
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stw r10,GPR10(r11)
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mfspr r12,SPRN_SPRG_SCRATCH1
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stw r12,GPR11(r11)
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mflr r10
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stw r10,_LINK(r11)
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mfspr r12,SPRN_SRR0
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mfspr r9,SPRN_SRR1
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stw r1,GPR1(r11)
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stw r1,0(r11)
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tovirt(r1,r11) /* set new kernel sp */
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#ifdef CONFIG_40x
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rlwinm r9,r9,0,14,12 /* clear MSR_WE (necessary?) */
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#else
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li r10,MSR_KERNEL & ~(MSR_IR|MSR_DR) /* can take exceptions */
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MTMSRD(r10) /* (except for mach check in rtas) */
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#endif
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stw r0,GPR0(r11)
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lis r10,STACK_FRAME_REGS_MARKER@ha /* exception frame marker */
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addi r10,r10,STACK_FRAME_REGS_MARKER@l
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stw r10,8(r11)
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SAVE_4GPRS(3, r11)
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SAVE_2GPRS(7, r11)
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.endm
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.macro SYSCALL_ENTRY trapno
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mfspr r12,SPRN_SPRG_THREAD
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mfcr r10
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lwz r11,TASK_STACK-THREAD(r12)
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mflr r9
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addi r11,r11,THREAD_SIZE - INT_FRAME_SIZE
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rlwinm r10,r10,0,4,2 /* Clear SO bit in CR */
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tophys(r11,r11)
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stw r10,_CCR(r11) /* save registers */
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mfspr r10,SPRN_SRR0
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stw r9,_LINK(r11)
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mfspr r9,SPRN_SRR1
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stw r1,GPR1(r11)
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stw r1,0(r11)
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tovirt(r1,r11) /* set new kernel sp */
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stw r10,_NIP(r11)
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#ifdef CONFIG_40x
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rlwinm r9,r9,0,14,12 /* clear MSR_WE (necessary?) */
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#else
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LOAD_MSR_KERNEL(r10, MSR_KERNEL & ~(MSR_IR|MSR_DR)) /* can take exceptions */
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MTMSRD(r10) /* (except for mach check in rtas) */
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#endif
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lis r10,STACK_FRAME_REGS_MARKER@ha /* exception frame marker */
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stw r2,GPR2(r11)
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addi r10,r10,STACK_FRAME_REGS_MARKER@l
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stw r9,_MSR(r11)
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li r2, \trapno + 1
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stw r10,8(r11)
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stw r2,_TRAP(r11)
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SAVE_GPR(0, r11)
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SAVE_4GPRS(3, r11)
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SAVE_2GPRS(7, r11)
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addi r11,r1,STACK_FRAME_OVERHEAD
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addi r2,r12,-THREAD
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stw r11,PT_REGS(r12)
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#if defined(CONFIG_40x)
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/* Check to see if the dbcr0 register is set up to debug. Use the
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internal debug mode bit to do this. */
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lwz r12,THREAD_DBCR0(r12)
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andis. r12,r12,DBCR0_IDM@h
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#endif
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ACCOUNT_CPU_USER_ENTRY(r2, r11, r12)
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#if defined(CONFIG_40x)
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beq+ 3f
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/* From user and task is ptraced - load up global dbcr0 */
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li r12,-1 /* clear all pending debug events */
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mtspr SPRN_DBSR,r12
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lis r11,global_dbcr0@ha
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tophys(r11,r11)
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addi r11,r11,global_dbcr0@l
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lwz r12,0(r11)
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mtspr SPRN_DBCR0,r12
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lwz r12,4(r11)
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addi r12,r12,-1
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stw r12,4(r11)
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#endif
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3:
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tovirt(r2, r2) /* set r2 to current */
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lis r11, transfer_to_syscall@h
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ori r11, r11, transfer_to_syscall@l
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#ifdef CONFIG_TRACE_IRQFLAGS
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/*
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* If MSR is changing we need to keep interrupts disabled at this point
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* otherwise we might risk taking an interrupt before we tell lockdep
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* they are enabled.
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*/
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LOAD_MSR_KERNEL(r10, MSR_KERNEL)
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rlwimi r10, r9, 0, MSR_EE
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#else
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LOAD_MSR_KERNEL(r10, MSR_KERNEL | MSR_EE)
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#endif
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#if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS)
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mtspr SPRN_NRI, r0
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#endif
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mtspr SPRN_SRR1,r10
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mtspr SPRN_SRR0,r11
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SYNC
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RFI /* jump to handler, enable MMU */
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.endm
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/*
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* Note: code which follows this uses cr0.eq (set if from kernel),
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* r11, r12 (SRR0), and r9 (SRR1).
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*
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* Note2: once we have set r1 we are in a position to take exceptions
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* again, and we could thus set MSR:RI at that point.
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*/
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/*
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* Exception vectors.
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*/
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#ifdef CONFIG_PPC_BOOK3S
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#define START_EXCEPTION(n, label) \
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. = n; \
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DO_KVM n; \
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label:
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#else
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#define START_EXCEPTION(n, label) \
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. = n; \
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label:
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#endif
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#define EXCEPTION(n, label, hdlr, xfer) \
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START_EXCEPTION(n, label) \
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EXCEPTION_PROLOG; \
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addi r3,r1,STACK_FRAME_OVERHEAD; \
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xfer(n, hdlr)
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#define EXC_XFER_TEMPLATE(hdlr, trap, msr, tfer, ret) \
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li r10,trap; \
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stw r10,_TRAP(r11); \
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LOAD_MSR_KERNEL(r10, msr); \
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bl tfer; \
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.long hdlr; \
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.long ret
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#define EXC_XFER_STD(n, hdlr) \
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EXC_XFER_TEMPLATE(hdlr, n, MSR_KERNEL, transfer_to_handler_full, \
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ret_from_except_full)
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#define EXC_XFER_LITE(n, hdlr) \
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EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL, transfer_to_handler, \
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ret_from_except)
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#endif /* __HEAD_32_H__ */
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