![Benjamin Herrenschmidt](/assets/img/avatar_default.png)
The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7
1153 lines
26 KiB
ArmAsm
1153 lines
26 KiB
ArmAsm
/*
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* PowerPC version
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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* Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
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* Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
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* Adapted for Power Macintosh by Paul Mackerras.
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* Low-level exception handlers and MMU support
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* rewritten by Paul Mackerras.
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* Copyright (C) 1996 Paul Mackerras.
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* MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
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*
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* This file contains the system call entry code, context switch
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* code, and exception/interrupt return code for PowerPC.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/errno.h>
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#include <asm/unistd.h>
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#include <asm/processor.h>
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#include <asm/page.h>
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#include <asm/mmu.h>
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#include <asm/thread_info.h>
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#include <asm/ppc_asm.h>
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#include <asm/asm-offsets.h>
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#include <asm/cputable.h>
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#include <asm/firmware.h>
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#include <asm/bug.h>
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#include <asm/ptrace.h>
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#include <asm/irqflags.h>
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#include <asm/ftrace.h>
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#include <asm/hw_irq.h>
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/*
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* System calls.
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*/
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.section ".toc","aw"
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.SYS_CALL_TABLE:
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.tc .sys_call_table[TC],.sys_call_table
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/* This value is used to mark exception frames on the stack. */
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exception_marker:
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.tc ID_EXC_MARKER[TC],STACK_FRAME_REGS_MARKER
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.section ".text"
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.align 7
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#undef SHOW_SYSCALLS
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.globl system_call_common
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system_call_common:
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andi. r10,r12,MSR_PR
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mr r10,r1
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addi r1,r1,-INT_FRAME_SIZE
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beq- 1f
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ld r1,PACAKSAVE(r13)
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1: std r10,0(r1)
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std r11,_NIP(r1)
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std r12,_MSR(r1)
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std r0,GPR0(r1)
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std r10,GPR1(r1)
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ACCOUNT_CPU_USER_ENTRY(r10, r11)
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/*
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* This "crclr so" clears CR0.SO, which is the error indication on
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* return from this system call. There must be no cmp instruction
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* between it and the "mfcr r9" below, otherwise if XER.SO is set,
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* CR0.SO will get set, causing all system calls to appear to fail.
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*/
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crclr so
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std r2,GPR2(r1)
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std r3,GPR3(r1)
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std r4,GPR4(r1)
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std r5,GPR5(r1)
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std r6,GPR6(r1)
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std r7,GPR7(r1)
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std r8,GPR8(r1)
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li r11,0
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std r11,GPR9(r1)
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std r11,GPR10(r1)
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std r11,GPR11(r1)
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std r11,GPR12(r1)
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std r9,GPR13(r1)
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mfcr r9
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mflr r10
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li r11,0xc01
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std r9,_CCR(r1)
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std r10,_LINK(r1)
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std r11,_TRAP(r1)
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mfxer r9
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mfctr r10
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std r9,_XER(r1)
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std r10,_CTR(r1)
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std r3,ORIG_GPR3(r1)
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ld r2,PACATOC(r13)
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addi r9,r1,STACK_FRAME_OVERHEAD
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ld r11,exception_marker@toc(r2)
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std r11,-16(r9) /* "regshere" marker */
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#if defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR)
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BEGIN_FW_FTR_SECTION
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beq 33f
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/* if from user, see if there are any DTL entries to process */
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ld r10,PACALPPACAPTR(r13) /* get ptr to VPA */
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ld r11,PACA_DTL_RIDX(r13) /* get log read index */
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ld r10,LPPACA_DTLIDX(r10) /* get log write index */
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cmpd cr1,r11,r10
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beq+ cr1,33f
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bl .accumulate_stolen_time
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REST_GPR(0,r1)
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REST_4GPRS(3,r1)
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REST_2GPRS(7,r1)
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addi r9,r1,STACK_FRAME_OVERHEAD
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33:
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END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
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#endif /* CONFIG_VIRT_CPU_ACCOUNTING && CONFIG_PPC_SPLPAR */
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/*
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* A syscall should always be called with interrupts enabled
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* so we just unconditionally hard-enable here. When some kind
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* of irq tracing is used, we additionally check that condition
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* is correct
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*/
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#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_BUG)
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lbz r10,PACASOFTIRQEN(r13)
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xori r10,r10,1
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1: tdnei r10,0
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EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,BUGFLAG_WARNING
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#endif
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#ifdef CONFIG_PPC_BOOK3E
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wrteei 1
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#else
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ld r11,PACAKMSR(r13)
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ori r11,r11,MSR_EE
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mtmsrd r11,1
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#endif /* CONFIG_PPC_BOOK3E */
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/* We do need to set SOFTE in the stack frame or the return
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* from interrupt will be painful
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*/
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li r10,1
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std r10,SOFTE(r1)
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#ifdef SHOW_SYSCALLS
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bl .do_show_syscall
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REST_GPR(0,r1)
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REST_4GPRS(3,r1)
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REST_2GPRS(7,r1)
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addi r9,r1,STACK_FRAME_OVERHEAD
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#endif
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clrrdi r11,r1,THREAD_SHIFT
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ld r10,TI_FLAGS(r11)
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andi. r11,r10,_TIF_SYSCALL_T_OR_A
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bne- syscall_dotrace
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syscall_dotrace_cont:
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cmpldi 0,r0,NR_syscalls
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bge- syscall_enosys
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system_call: /* label this so stack traces look sane */
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/*
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* Need to vector to 32 Bit or default sys_call_table here,
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* based on caller's run-mode / personality.
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*/
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ld r11,.SYS_CALL_TABLE@toc(2)
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andi. r10,r10,_TIF_32BIT
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beq 15f
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addi r11,r11,8 /* use 32-bit syscall entries */
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clrldi r3,r3,32
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clrldi r4,r4,32
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clrldi r5,r5,32
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clrldi r6,r6,32
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clrldi r7,r7,32
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clrldi r8,r8,32
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15:
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slwi r0,r0,4
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ldx r10,r11,r0 /* Fetch system call handler [ptr] */
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mtctr r10
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bctrl /* Call handler */
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syscall_exit:
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std r3,RESULT(r1)
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#ifdef SHOW_SYSCALLS
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bl .do_show_syscall_exit
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ld r3,RESULT(r1)
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#endif
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clrrdi r12,r1,THREAD_SHIFT
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ld r8,_MSR(r1)
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#ifdef CONFIG_PPC_BOOK3S
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/* No MSR:RI on BookE */
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andi. r10,r8,MSR_RI
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beq- unrecov_restore
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#endif
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/*
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* Disable interrupts so current_thread_info()->flags can't change,
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* and so that we don't get interrupted after loading SRR0/1.
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*/
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#ifdef CONFIG_PPC_BOOK3E
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wrteei 0
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#else
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ld r10,PACAKMSR(r13)
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mtmsrd r10,1
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#endif /* CONFIG_PPC_BOOK3E */
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ld r9,TI_FLAGS(r12)
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li r11,-_LAST_ERRNO
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andi. r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)
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bne- syscall_exit_work
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cmpld r3,r11
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ld r5,_CCR(r1)
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bge- syscall_error
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syscall_error_cont:
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ld r7,_NIP(r1)
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BEGIN_FTR_SECTION
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stdcx. r0,0,r1 /* to clear the reservation */
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END_FTR_SECTION_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
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andi. r6,r8,MSR_PR
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ld r4,_LINK(r1)
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/*
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* Clear RI before restoring r13. If we are returning to
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* userspace and we take an exception after restoring r13,
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* we end up corrupting the userspace r13 value.
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*/
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#ifdef CONFIG_PPC_BOOK3S
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/* No MSR:RI on BookE */
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li r12,MSR_RI
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andc r11,r10,r12
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mtmsrd r11,1 /* clear MSR.RI */
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#endif /* CONFIG_PPC_BOOK3S */
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beq- 1f
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ACCOUNT_CPU_USER_EXIT(r11, r12)
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ld r13,GPR13(r1) /* only restore r13 if returning to usermode */
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1: ld r2,GPR2(r1)
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ld r1,GPR1(r1)
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mtlr r4
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mtcr r5
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mtspr SPRN_SRR0,r7
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mtspr SPRN_SRR1,r8
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RFI
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b . /* prevent speculative execution */
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syscall_error:
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oris r5,r5,0x1000 /* Set SO bit in CR */
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neg r3,r3
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std r5,_CCR(r1)
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b syscall_error_cont
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/* Traced system call support */
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syscall_dotrace:
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bl .save_nvgprs
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addi r3,r1,STACK_FRAME_OVERHEAD
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bl .do_syscall_trace_enter
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/*
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* Restore argument registers possibly just changed.
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* We use the return value of do_syscall_trace_enter
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* for the call number to look up in the table (r0).
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*/
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mr r0,r3
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ld r3,GPR3(r1)
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ld r4,GPR4(r1)
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ld r5,GPR5(r1)
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ld r6,GPR6(r1)
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ld r7,GPR7(r1)
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ld r8,GPR8(r1)
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addi r9,r1,STACK_FRAME_OVERHEAD
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clrrdi r10,r1,THREAD_SHIFT
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ld r10,TI_FLAGS(r10)
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b syscall_dotrace_cont
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syscall_enosys:
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li r3,-ENOSYS
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b syscall_exit
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syscall_exit_work:
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/* If TIF_RESTOREALL is set, don't scribble on either r3 or ccr.
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If TIF_NOERROR is set, just save r3 as it is. */
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andi. r0,r9,_TIF_RESTOREALL
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beq+ 0f
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REST_NVGPRS(r1)
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b 2f
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0: cmpld r3,r11 /* r10 is -LAST_ERRNO */
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blt+ 1f
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andi. r0,r9,_TIF_NOERROR
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bne- 1f
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ld r5,_CCR(r1)
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neg r3,r3
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oris r5,r5,0x1000 /* Set SO bit in CR */
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std r5,_CCR(r1)
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1: std r3,GPR3(r1)
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2: andi. r0,r9,(_TIF_PERSYSCALL_MASK)
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beq 4f
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/* Clear per-syscall TIF flags if any are set. */
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li r11,_TIF_PERSYSCALL_MASK
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addi r12,r12,TI_FLAGS
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3: ldarx r10,0,r12
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andc r10,r10,r11
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stdcx. r10,0,r12
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bne- 3b
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subi r12,r12,TI_FLAGS
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4: /* Anything else left to do? */
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andi. r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SINGLESTEP)
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beq .ret_from_except_lite
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/* Re-enable interrupts */
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#ifdef CONFIG_PPC_BOOK3E
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wrteei 1
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#else
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ld r10,PACAKMSR(r13)
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ori r10,r10,MSR_EE
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mtmsrd r10,1
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#endif /* CONFIG_PPC_BOOK3E */
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bl .save_nvgprs
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addi r3,r1,STACK_FRAME_OVERHEAD
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bl .do_syscall_trace_leave
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b .ret_from_except
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/* Save non-volatile GPRs, if not already saved. */
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_GLOBAL(save_nvgprs)
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ld r11,_TRAP(r1)
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andi. r0,r11,1
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beqlr-
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SAVE_NVGPRS(r1)
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clrrdi r0,r11,1
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std r0,_TRAP(r1)
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blr
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/*
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* The sigsuspend and rt_sigsuspend system calls can call do_signal
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* and thus put the process into the stopped state where we might
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* want to examine its user state with ptrace. Therefore we need
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* to save all the nonvolatile registers (r14 - r31) before calling
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* the C code. Similarly, fork, vfork and clone need the full
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* register state on the stack so that it can be copied to the child.
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*/
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_GLOBAL(ppc_fork)
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bl .save_nvgprs
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bl .sys_fork
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b syscall_exit
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_GLOBAL(ppc_vfork)
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bl .save_nvgprs
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bl .sys_vfork
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b syscall_exit
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_GLOBAL(ppc_clone)
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bl .save_nvgprs
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bl .sys_clone
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b syscall_exit
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_GLOBAL(ppc32_swapcontext)
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bl .save_nvgprs
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bl .compat_sys_swapcontext
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b syscall_exit
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_GLOBAL(ppc64_swapcontext)
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bl .save_nvgprs
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bl .sys_swapcontext
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b syscall_exit
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_GLOBAL(ret_from_fork)
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bl .schedule_tail
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REST_NVGPRS(r1)
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li r3,0
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b syscall_exit
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/*
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* This routine switches between two different tasks. The process
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* state of one is saved on its kernel stack. Then the state
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* of the other is restored from its kernel stack. The memory
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* management hardware is updated to the second process's state.
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* Finally, we can return to the second process, via ret_from_except.
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* On entry, r3 points to the THREAD for the current task, r4
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* points to the THREAD for the new task.
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*
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* Note: there are two ways to get to the "going out" portion
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* of this code; either by coming in via the entry (_switch)
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* or via "fork" which must set up an environment equivalent
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* to the "_switch" path. If you change this you'll have to change
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* the fork code also.
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*
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* The code which creates the new task context is in 'copy_thread'
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* in arch/powerpc/kernel/process.c
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*/
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.align 7
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_GLOBAL(_switch)
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mflr r0
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std r0,16(r1)
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stdu r1,-SWITCH_FRAME_SIZE(r1)
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/* r3-r13 are caller saved -- Cort */
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SAVE_8GPRS(14, r1)
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SAVE_10GPRS(22, r1)
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mflr r20 /* Return to switch caller */
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mfmsr r22
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li r0, MSR_FP
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#ifdef CONFIG_VSX
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BEGIN_FTR_SECTION
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oris r0,r0,MSR_VSX@h /* Disable VSX */
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END_FTR_SECTION_IFSET(CPU_FTR_VSX)
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#endif /* CONFIG_VSX */
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#ifdef CONFIG_ALTIVEC
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BEGIN_FTR_SECTION
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oris r0,r0,MSR_VEC@h /* Disable altivec */
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mfspr r24,SPRN_VRSAVE /* save vrsave register value */
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std r24,THREAD_VRSAVE(r3)
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END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
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#endif /* CONFIG_ALTIVEC */
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#ifdef CONFIG_PPC64
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BEGIN_FTR_SECTION
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mfspr r25,SPRN_DSCR
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std r25,THREAD_DSCR(r3)
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END_FTR_SECTION_IFSET(CPU_FTR_DSCR)
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#endif
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and. r0,r0,r22
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beq+ 1f
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andc r22,r22,r0
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MTMSRD(r22)
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isync
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1: std r20,_NIP(r1)
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mfcr r23
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|
std r23,_CCR(r1)
|
|
std r1,KSP(r3) /* Set old stack pointer */
|
|
|
|
#ifdef CONFIG_SMP
|
|
/* We need a sync somewhere here to make sure that if the
|
|
* previous task gets rescheduled on another CPU, it sees all
|
|
* stores it has performed on this one.
|
|
*/
|
|
sync
|
|
#endif /* CONFIG_SMP */
|
|
|
|
/*
|
|
* If we optimise away the clear of the reservation in system
|
|
* calls because we know the CPU tracks the address of the
|
|
* reservation, then we need to clear it here to cover the
|
|
* case that the kernel context switch path has no larx
|
|
* instructions.
|
|
*/
|
|
BEGIN_FTR_SECTION
|
|
ldarx r6,0,r1
|
|
END_FTR_SECTION_IFSET(CPU_FTR_STCX_CHECKS_ADDRESS)
|
|
|
|
addi r6,r4,-THREAD /* Convert THREAD to 'current' */
|
|
std r6,PACACURRENT(r13) /* Set new 'current' */
|
|
|
|
ld r8,KSP(r4) /* new stack pointer */
|
|
#ifdef CONFIG_PPC_BOOK3S
|
|
BEGIN_FTR_SECTION
|
|
BEGIN_FTR_SECTION_NESTED(95)
|
|
clrrdi r6,r8,28 /* get its ESID */
|
|
clrrdi r9,r1,28 /* get current sp ESID */
|
|
FTR_SECTION_ELSE_NESTED(95)
|
|
clrrdi r6,r8,40 /* get its 1T ESID */
|
|
clrrdi r9,r1,40 /* get current sp 1T ESID */
|
|
ALT_MMU_FTR_SECTION_END_NESTED_IFCLR(MMU_FTR_1T_SEGMENT, 95)
|
|
FTR_SECTION_ELSE
|
|
b 2f
|
|
ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_SLB)
|
|
clrldi. r0,r6,2 /* is new ESID c00000000? */
|
|
cmpd cr1,r6,r9 /* or is new ESID the same as current ESID? */
|
|
cror eq,4*cr1+eq,eq
|
|
beq 2f /* if yes, don't slbie it */
|
|
|
|
/* Bolt in the new stack SLB entry */
|
|
ld r7,KSP_VSID(r4) /* Get new stack's VSID */
|
|
oris r0,r6,(SLB_ESID_V)@h
|
|
ori r0,r0,(SLB_NUM_BOLTED-1)@l
|
|
BEGIN_FTR_SECTION
|
|
li r9,MMU_SEGSIZE_1T /* insert B field */
|
|
oris r6,r6,(MMU_SEGSIZE_1T << SLBIE_SSIZE_SHIFT)@h
|
|
rldimi r7,r9,SLB_VSID_SSIZE_SHIFT,0
|
|
END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
|
|
|
|
/* Update the last bolted SLB. No write barriers are needed
|
|
* here, provided we only update the current CPU's SLB shadow
|
|
* buffer.
|
|
*/
|
|
ld r9,PACA_SLBSHADOWPTR(r13)
|
|
li r12,0
|
|
std r12,SLBSHADOW_STACKESID(r9) /* Clear ESID */
|
|
std r7,SLBSHADOW_STACKVSID(r9) /* Save VSID */
|
|
std r0,SLBSHADOW_STACKESID(r9) /* Save ESID */
|
|
|
|
/* No need to check for MMU_FTR_NO_SLBIE_B here, since when
|
|
* we have 1TB segments, the only CPUs known to have the errata
|
|
* only support less than 1TB of system memory and we'll never
|
|
* actually hit this code path.
|
|
*/
|
|
|
|
slbie r6
|
|
slbie r6 /* Workaround POWER5 < DD2.1 issue */
|
|
slbmte r7,r0
|
|
isync
|
|
2:
|
|
#endif /* !CONFIG_PPC_BOOK3S */
|
|
|
|
clrrdi r7,r8,THREAD_SHIFT /* base of new stack */
|
|
/* Note: this uses SWITCH_FRAME_SIZE rather than INT_FRAME_SIZE
|
|
because we don't need to leave the 288-byte ABI gap at the
|
|
top of the kernel stack. */
|
|
addi r7,r7,THREAD_SIZE-SWITCH_FRAME_SIZE
|
|
|
|
mr r1,r8 /* start using new stack pointer */
|
|
std r7,PACAKSAVE(r13)
|
|
|
|
ld r6,_CCR(r1)
|
|
mtcrf 0xFF,r6
|
|
|
|
#ifdef CONFIG_ALTIVEC
|
|
BEGIN_FTR_SECTION
|
|
ld r0,THREAD_VRSAVE(r4)
|
|
mtspr SPRN_VRSAVE,r0 /* if G4, restore VRSAVE reg */
|
|
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
|
|
#endif /* CONFIG_ALTIVEC */
|
|
#ifdef CONFIG_PPC64
|
|
BEGIN_FTR_SECTION
|
|
ld r0,THREAD_DSCR(r4)
|
|
cmpd r0,r25
|
|
beq 1f
|
|
mtspr SPRN_DSCR,r0
|
|
1:
|
|
END_FTR_SECTION_IFSET(CPU_FTR_DSCR)
|
|
#endif
|
|
|
|
/* r3-r13 are destroyed -- Cort */
|
|
REST_8GPRS(14, r1)
|
|
REST_10GPRS(22, r1)
|
|
|
|
/* convert old thread to its task_struct for return value */
|
|
addi r3,r3,-THREAD
|
|
ld r7,_NIP(r1) /* Return to _switch caller in new task */
|
|
mtlr r7
|
|
addi r1,r1,SWITCH_FRAME_SIZE
|
|
blr
|
|
|
|
.align 7
|
|
_GLOBAL(ret_from_except)
|
|
ld r11,_TRAP(r1)
|
|
andi. r0,r11,1
|
|
bne .ret_from_except_lite
|
|
REST_NVGPRS(r1)
|
|
|
|
_GLOBAL(ret_from_except_lite)
|
|
/*
|
|
* Disable interrupts so that current_thread_info()->flags
|
|
* can't change between when we test it and when we return
|
|
* from the interrupt.
|
|
*/
|
|
#ifdef CONFIG_PPC_BOOK3E
|
|
wrteei 0
|
|
#else
|
|
ld r10,PACAKMSR(r13) /* Get kernel MSR without EE */
|
|
mtmsrd r10,1 /* Update machine state */
|
|
#endif /* CONFIG_PPC_BOOK3E */
|
|
|
|
#ifdef CONFIG_PREEMPT
|
|
clrrdi r9,r1,THREAD_SHIFT /* current_thread_info() */
|
|
li r0,_TIF_NEED_RESCHED /* bits to check */
|
|
ld r3,_MSR(r1)
|
|
ld r4,TI_FLAGS(r9)
|
|
/* Move MSR_PR bit in r3 to _TIF_SIGPENDING position in r0 */
|
|
rlwimi r0,r3,32+TIF_SIGPENDING-MSR_PR_LG,_TIF_SIGPENDING
|
|
and. r0,r4,r0 /* check NEED_RESCHED and maybe SIGPENDING */
|
|
bne do_work
|
|
|
|
#else /* !CONFIG_PREEMPT */
|
|
ld r3,_MSR(r1) /* Returning to user mode? */
|
|
andi. r3,r3,MSR_PR
|
|
beq restore /* if not, just restore regs and return */
|
|
|
|
/* Check current_thread_info()->flags */
|
|
clrrdi r9,r1,THREAD_SHIFT
|
|
ld r4,TI_FLAGS(r9)
|
|
andi. r0,r4,_TIF_USER_WORK_MASK
|
|
bne do_work
|
|
#endif /* !CONFIG_PREEMPT */
|
|
|
|
.globl fast_exc_return_irq
|
|
fast_exc_return_irq:
|
|
restore:
|
|
/*
|
|
* This is the main kernel exit path, we first check if we
|
|
* have to change our interrupt state.
|
|
*/
|
|
ld r5,SOFTE(r1)
|
|
lbz r6,PACASOFTIRQEN(r13)
|
|
cmpwi cr1,r5,0
|
|
cmpw cr0,r5,r6
|
|
beq cr0,4f
|
|
|
|
/* We do, handle disable first, which is easy */
|
|
bne cr1,3f;
|
|
li r0,0
|
|
stb r0,PACASOFTIRQEN(r13);
|
|
TRACE_DISABLE_INTS
|
|
b 4f
|
|
|
|
3: /*
|
|
* We are about to soft-enable interrupts (we are hard disabled
|
|
* at this point). We check if there's anything that needs to
|
|
* be replayed first.
|
|
*/
|
|
lbz r0,PACAIRQHAPPENED(r13)
|
|
cmpwi cr0,r0,0
|
|
bne- restore_check_irq_replay
|
|
|
|
/*
|
|
* Get here when nothing happened while soft-disabled, just
|
|
* soft-enable and move-on. We will hard-enable as a side
|
|
* effect of rfi
|
|
*/
|
|
restore_no_replay:
|
|
TRACE_ENABLE_INTS
|
|
li r0,1
|
|
stb r0,PACASOFTIRQEN(r13);
|
|
|
|
/*
|
|
* Final return path. BookE is handled in a different file
|
|
*/
|
|
4:
|
|
#ifdef CONFIG_PPC_BOOK3E
|
|
b .exception_return_book3e
|
|
#else
|
|
/*
|
|
* Clear the reservation. If we know the CPU tracks the address of
|
|
* the reservation then we can potentially save some cycles and use
|
|
* a larx. On POWER6 and POWER7 this is significantly faster.
|
|
*/
|
|
BEGIN_FTR_SECTION
|
|
stdcx. r0,0,r1 /* to clear the reservation */
|
|
FTR_SECTION_ELSE
|
|
ldarx r4,0,r1
|
|
ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
|
|
|
|
/*
|
|
* Some code path such as load_up_fpu or altivec return directly
|
|
* here. They run entirely hard disabled and do not alter the
|
|
* interrupt state. They also don't use lwarx/stwcx. and thus
|
|
* are known not to leave dangling reservations.
|
|
*/
|
|
.globl fast_exception_return
|
|
fast_exception_return:
|
|
ld r3,_MSR(r1)
|
|
ld r4,_CTR(r1)
|
|
ld r0,_LINK(r1)
|
|
mtctr r4
|
|
mtlr r0
|
|
ld r4,_XER(r1)
|
|
mtspr SPRN_XER,r4
|
|
|
|
REST_8GPRS(5, r1)
|
|
|
|
andi. r0,r3,MSR_RI
|
|
beq- unrecov_restore
|
|
|
|
/*
|
|
* Clear RI before restoring r13. If we are returning to
|
|
* userspace and we take an exception after restoring r13,
|
|
* we end up corrupting the userspace r13 value.
|
|
*/
|
|
ld r4,PACAKMSR(r13) /* Get kernel MSR without EE */
|
|
andc r4,r4,r0 /* r0 contains MSR_RI here */
|
|
mtmsrd r4,1
|
|
|
|
/*
|
|
* r13 is our per cpu area, only restore it if we are returning to
|
|
* userspace the value stored in the stack frame may belong to
|
|
* another CPU.
|
|
*/
|
|
andi. r0,r3,MSR_PR
|
|
beq 1f
|
|
ACCOUNT_CPU_USER_EXIT(r2, r4)
|
|
REST_GPR(13, r1)
|
|
1:
|
|
mtspr SPRN_SRR1,r3
|
|
|
|
ld r2,_CCR(r1)
|
|
mtcrf 0xFF,r2
|
|
ld r2,_NIP(r1)
|
|
mtspr SPRN_SRR0,r2
|
|
|
|
ld r0,GPR0(r1)
|
|
ld r2,GPR2(r1)
|
|
ld r3,GPR3(r1)
|
|
ld r4,GPR4(r1)
|
|
ld r1,GPR1(r1)
|
|
|
|
rfid
|
|
b . /* prevent speculative execution */
|
|
|
|
#endif /* CONFIG_PPC_BOOK3E */
|
|
|
|
/*
|
|
* Something did happen, check if a re-emit is needed
|
|
* (this also clears paca->irq_happened)
|
|
*/
|
|
restore_check_irq_replay:
|
|
/* XXX: We could implement a fast path here where we check
|
|
* for irq_happened being just 0x01, in which case we can
|
|
* clear it and return. That means that we would potentially
|
|
* miss a decrementer having wrapped all the way around.
|
|
*
|
|
* Still, this might be useful for things like hash_page
|
|
*/
|
|
bl .__check_irq_replay
|
|
cmpwi cr0,r3,0
|
|
beq restore_no_replay
|
|
|
|
/*
|
|
* We need to re-emit an interrupt. We do so by re-using our
|
|
* existing exception frame. We first change the trap value,
|
|
* but we need to ensure we preserve the low nibble of it
|
|
*/
|
|
ld r4,_TRAP(r1)
|
|
clrldi r4,r4,60
|
|
or r4,r4,r3
|
|
std r4,_TRAP(r1)
|
|
|
|
/*
|
|
* Then find the right handler and call it. Interrupts are
|
|
* still soft-disabled and we keep them that way.
|
|
*/
|
|
cmpwi cr0,r3,0x500
|
|
bne 1f
|
|
addi r3,r1,STACK_FRAME_OVERHEAD;
|
|
bl .do_IRQ
|
|
b .ret_from_except
|
|
1: cmpwi cr0,r3,0x900
|
|
bne 1f
|
|
addi r3,r1,STACK_FRAME_OVERHEAD;
|
|
bl .timer_interrupt
|
|
b .ret_from_except
|
|
#ifdef CONFIG_PPC_BOOK3E
|
|
1: cmpwi cr0,r3,0x280
|
|
bne 1f
|
|
addi r3,r1,STACK_FRAME_OVERHEAD;
|
|
bl .doorbell_exception
|
|
b .ret_from_except
|
|
#endif /* CONFIG_PPC_BOOK3E */
|
|
1: b .ret_from_except /* What else to do here ? */
|
|
|
|
do_work:
|
|
#ifdef CONFIG_PREEMPT
|
|
andi. r0,r3,MSR_PR /* Returning to user mode? */
|
|
bne user_work
|
|
/* Check that preempt_count() == 0 and interrupts are enabled */
|
|
lwz r8,TI_PREEMPT(r9)
|
|
cmpwi cr1,r8,0
|
|
ld r0,SOFTE(r1)
|
|
cmpdi r0,0
|
|
crandc eq,cr1*4+eq,eq
|
|
bne restore
|
|
|
|
/*
|
|
* Here we are preempting the current task. We want to make
|
|
* sure we are soft-disabled first
|
|
*/
|
|
SOFT_DISABLE_INTS(r3,r4)
|
|
1: bl .preempt_schedule_irq
|
|
|
|
/* Hard-disable interrupts again (and update PACA) */
|
|
#ifdef CONFIG_PPC_BOOK3E
|
|
wrteei 0
|
|
#else
|
|
ld r10,PACAKMSR(r13) /* Get kernel MSR without EE */
|
|
mtmsrd r10,1
|
|
#endif /* CONFIG_PPC_BOOK3E */
|
|
li r0,PACA_IRQ_HARD_DIS
|
|
stb r0,PACAIRQHAPPENED(r13)
|
|
|
|
/* Re-test flags and eventually loop */
|
|
clrrdi r9,r1,THREAD_SHIFT
|
|
ld r4,TI_FLAGS(r9)
|
|
andi. r0,r4,_TIF_NEED_RESCHED
|
|
bne 1b
|
|
b restore
|
|
|
|
user_work:
|
|
#endif /* CONFIG_PREEMPT */
|
|
|
|
/* Enable interrupts */
|
|
#ifdef CONFIG_PPC_BOOK3E
|
|
wrteei 1
|
|
#else
|
|
ori r10,r10,MSR_EE
|
|
mtmsrd r10,1
|
|
#endif /* CONFIG_PPC_BOOK3E */
|
|
|
|
andi. r0,r4,_TIF_NEED_RESCHED
|
|
beq 1f
|
|
bl .restore_interrupts
|
|
bl .schedule
|
|
b .ret_from_except_lite
|
|
|
|
1: bl .save_nvgprs
|
|
bl .restore_interrupts
|
|
addi r3,r1,STACK_FRAME_OVERHEAD
|
|
bl .do_notify_resume
|
|
b .ret_from_except
|
|
|
|
unrecov_restore:
|
|
addi r3,r1,STACK_FRAME_OVERHEAD
|
|
bl .unrecoverable_exception
|
|
b unrecov_restore
|
|
|
|
#ifdef CONFIG_PPC_RTAS
|
|
/*
|
|
* On CHRP, the Run-Time Abstraction Services (RTAS) have to be
|
|
* called with the MMU off.
|
|
*
|
|
* In addition, we need to be in 32b mode, at least for now.
|
|
*
|
|
* Note: r3 is an input parameter to rtas, so don't trash it...
|
|
*/
|
|
_GLOBAL(enter_rtas)
|
|
mflr r0
|
|
std r0,16(r1)
|
|
stdu r1,-RTAS_FRAME_SIZE(r1) /* Save SP and create stack space. */
|
|
|
|
/* Because RTAS is running in 32b mode, it clobbers the high order half
|
|
* of all registers that it saves. We therefore save those registers
|
|
* RTAS might touch to the stack. (r0, r3-r13 are caller saved)
|
|
*/
|
|
SAVE_GPR(2, r1) /* Save the TOC */
|
|
SAVE_GPR(13, r1) /* Save paca */
|
|
SAVE_8GPRS(14, r1) /* Save the non-volatiles */
|
|
SAVE_10GPRS(22, r1) /* ditto */
|
|
|
|
mfcr r4
|
|
std r4,_CCR(r1)
|
|
mfctr r5
|
|
std r5,_CTR(r1)
|
|
mfspr r6,SPRN_XER
|
|
std r6,_XER(r1)
|
|
mfdar r7
|
|
std r7,_DAR(r1)
|
|
mfdsisr r8
|
|
std r8,_DSISR(r1)
|
|
|
|
/* Temporary workaround to clear CR until RTAS can be modified to
|
|
* ignore all bits.
|
|
*/
|
|
li r0,0
|
|
mtcr r0
|
|
|
|
#ifdef CONFIG_BUG
|
|
/* There is no way it is acceptable to get here with interrupts enabled,
|
|
* check it with the asm equivalent of WARN_ON
|
|
*/
|
|
lbz r0,PACASOFTIRQEN(r13)
|
|
1: tdnei r0,0
|
|
EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,BUGFLAG_WARNING
|
|
#endif
|
|
|
|
/* Hard-disable interrupts */
|
|
mfmsr r6
|
|
rldicl r7,r6,48,1
|
|
rotldi r7,r7,16
|
|
mtmsrd r7,1
|
|
|
|
/* Unfortunately, the stack pointer and the MSR are also clobbered,
|
|
* so they are saved in the PACA which allows us to restore
|
|
* our original state after RTAS returns.
|
|
*/
|
|
std r1,PACAR1(r13)
|
|
std r6,PACASAVEDMSR(r13)
|
|
|
|
/* Setup our real return addr */
|
|
LOAD_REG_ADDR(r4,.rtas_return_loc)
|
|
clrldi r4,r4,2 /* convert to realmode address */
|
|
mtlr r4
|
|
|
|
li r0,0
|
|
ori r0,r0,MSR_EE|MSR_SE|MSR_BE|MSR_RI
|
|
andc r0,r6,r0
|
|
|
|
li r9,1
|
|
rldicr r9,r9,MSR_SF_LG,(63-MSR_SF_LG)
|
|
ori r9,r9,MSR_IR|MSR_DR|MSR_FE0|MSR_FE1|MSR_FP|MSR_RI
|
|
andc r6,r0,r9
|
|
sync /* disable interrupts so SRR0/1 */
|
|
mtmsrd r0 /* don't get trashed */
|
|
|
|
LOAD_REG_ADDR(r4, rtas)
|
|
ld r5,RTASENTRY(r4) /* get the rtas->entry value */
|
|
ld r4,RTASBASE(r4) /* get the rtas->base value */
|
|
|
|
mtspr SPRN_SRR0,r5
|
|
mtspr SPRN_SRR1,r6
|
|
rfid
|
|
b . /* prevent speculative execution */
|
|
|
|
_STATIC(rtas_return_loc)
|
|
/* relocation is off at this point */
|
|
GET_PACA(r4)
|
|
clrldi r4,r4,2 /* convert to realmode address */
|
|
|
|
bcl 20,31,$+4
|
|
0: mflr r3
|
|
ld r3,(1f-0b)(r3) /* get &.rtas_restore_regs */
|
|
|
|
mfmsr r6
|
|
li r0,MSR_RI
|
|
andc r6,r6,r0
|
|
sync
|
|
mtmsrd r6
|
|
|
|
ld r1,PACAR1(r4) /* Restore our SP */
|
|
ld r4,PACASAVEDMSR(r4) /* Restore our MSR */
|
|
|
|
mtspr SPRN_SRR0,r3
|
|
mtspr SPRN_SRR1,r4
|
|
rfid
|
|
b . /* prevent speculative execution */
|
|
|
|
.align 3
|
|
1: .llong .rtas_restore_regs
|
|
|
|
_STATIC(rtas_restore_regs)
|
|
/* relocation is on at this point */
|
|
REST_GPR(2, r1) /* Restore the TOC */
|
|
REST_GPR(13, r1) /* Restore paca */
|
|
REST_8GPRS(14, r1) /* Restore the non-volatiles */
|
|
REST_10GPRS(22, r1) /* ditto */
|
|
|
|
GET_PACA(r13)
|
|
|
|
ld r4,_CCR(r1)
|
|
mtcr r4
|
|
ld r5,_CTR(r1)
|
|
mtctr r5
|
|
ld r6,_XER(r1)
|
|
mtspr SPRN_XER,r6
|
|
ld r7,_DAR(r1)
|
|
mtdar r7
|
|
ld r8,_DSISR(r1)
|
|
mtdsisr r8
|
|
|
|
addi r1,r1,RTAS_FRAME_SIZE /* Unstack our frame */
|
|
ld r0,16(r1) /* get return address */
|
|
|
|
mtlr r0
|
|
blr /* return to caller */
|
|
|
|
#endif /* CONFIG_PPC_RTAS */
|
|
|
|
_GLOBAL(enter_prom)
|
|
mflr r0
|
|
std r0,16(r1)
|
|
stdu r1,-PROM_FRAME_SIZE(r1) /* Save SP and create stack space */
|
|
|
|
/* Because PROM is running in 32b mode, it clobbers the high order half
|
|
* of all registers that it saves. We therefore save those registers
|
|
* PROM might touch to the stack. (r0, r3-r13 are caller saved)
|
|
*/
|
|
SAVE_GPR(2, r1)
|
|
SAVE_GPR(13, r1)
|
|
SAVE_8GPRS(14, r1)
|
|
SAVE_10GPRS(22, r1)
|
|
mfcr r10
|
|
mfmsr r11
|
|
std r10,_CCR(r1)
|
|
std r11,_MSR(r1)
|
|
|
|
/* Get the PROM entrypoint */
|
|
mtlr r4
|
|
|
|
/* Switch MSR to 32 bits mode
|
|
*/
|
|
#ifdef CONFIG_PPC_BOOK3E
|
|
rlwinm r11,r11,0,1,31
|
|
mtmsr r11
|
|
#else /* CONFIG_PPC_BOOK3E */
|
|
mfmsr r11
|
|
li r12,1
|
|
rldicr r12,r12,MSR_SF_LG,(63-MSR_SF_LG)
|
|
andc r11,r11,r12
|
|
li r12,1
|
|
rldicr r12,r12,MSR_ISF_LG,(63-MSR_ISF_LG)
|
|
andc r11,r11,r12
|
|
mtmsrd r11
|
|
#endif /* CONFIG_PPC_BOOK3E */
|
|
isync
|
|
|
|
/* Enter PROM here... */
|
|
blrl
|
|
|
|
/* Just make sure that r1 top 32 bits didn't get
|
|
* corrupt by OF
|
|
*/
|
|
rldicl r1,r1,0,32
|
|
|
|
/* Restore the MSR (back to 64 bits) */
|
|
ld r0,_MSR(r1)
|
|
MTMSRD(r0)
|
|
isync
|
|
|
|
/* Restore other registers */
|
|
REST_GPR(2, r1)
|
|
REST_GPR(13, r1)
|
|
REST_8GPRS(14, r1)
|
|
REST_10GPRS(22, r1)
|
|
ld r4,_CCR(r1)
|
|
mtcr r4
|
|
|
|
addi r1,r1,PROM_FRAME_SIZE
|
|
ld r0,16(r1)
|
|
mtlr r0
|
|
blr
|
|
|
|
#ifdef CONFIG_FUNCTION_TRACER
|
|
#ifdef CONFIG_DYNAMIC_FTRACE
|
|
_GLOBAL(mcount)
|
|
_GLOBAL(_mcount)
|
|
blr
|
|
|
|
_GLOBAL(ftrace_caller)
|
|
/* Taken from output of objdump from lib64/glibc */
|
|
mflr r3
|
|
ld r11, 0(r1)
|
|
stdu r1, -112(r1)
|
|
std r3, 128(r1)
|
|
ld r4, 16(r11)
|
|
subi r3, r3, MCOUNT_INSN_SIZE
|
|
.globl ftrace_call
|
|
ftrace_call:
|
|
bl ftrace_stub
|
|
nop
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
.globl ftrace_graph_call
|
|
ftrace_graph_call:
|
|
b ftrace_graph_stub
|
|
_GLOBAL(ftrace_graph_stub)
|
|
#endif
|
|
ld r0, 128(r1)
|
|
mtlr r0
|
|
addi r1, r1, 112
|
|
_GLOBAL(ftrace_stub)
|
|
blr
|
|
#else
|
|
_GLOBAL(mcount)
|
|
blr
|
|
|
|
_GLOBAL(_mcount)
|
|
/* Taken from output of objdump from lib64/glibc */
|
|
mflr r3
|
|
ld r11, 0(r1)
|
|
stdu r1, -112(r1)
|
|
std r3, 128(r1)
|
|
ld r4, 16(r11)
|
|
|
|
subi r3, r3, MCOUNT_INSN_SIZE
|
|
LOAD_REG_ADDR(r5,ftrace_trace_function)
|
|
ld r5,0(r5)
|
|
ld r5,0(r5)
|
|
mtctr r5
|
|
bctrl
|
|
nop
|
|
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
b ftrace_graph_caller
|
|
#endif
|
|
ld r0, 128(r1)
|
|
mtlr r0
|
|
addi r1, r1, 112
|
|
_GLOBAL(ftrace_stub)
|
|
blr
|
|
|
|
#endif /* CONFIG_DYNAMIC_FTRACE */
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
_GLOBAL(ftrace_graph_caller)
|
|
/* load r4 with local address */
|
|
ld r4, 128(r1)
|
|
subi r4, r4, MCOUNT_INSN_SIZE
|
|
|
|
/* get the parent address */
|
|
ld r11, 112(r1)
|
|
addi r3, r11, 16
|
|
|
|
bl .prepare_ftrace_return
|
|
nop
|
|
|
|
ld r0, 128(r1)
|
|
mtlr r0
|
|
addi r1, r1, 112
|
|
blr
|
|
|
|
_GLOBAL(return_to_handler)
|
|
/* need to save return values */
|
|
std r4, -24(r1)
|
|
std r3, -16(r1)
|
|
std r31, -8(r1)
|
|
mr r31, r1
|
|
stdu r1, -112(r1)
|
|
|
|
bl .ftrace_return_to_handler
|
|
nop
|
|
|
|
/* return value has real return address */
|
|
mtlr r3
|
|
|
|
ld r1, 0(r1)
|
|
ld r4, -24(r1)
|
|
ld r3, -16(r1)
|
|
ld r31, -8(r1)
|
|
|
|
/* Jump back to real return address */
|
|
blr
|
|
|
|
_GLOBAL(mod_return_to_handler)
|
|
/* need to save return values */
|
|
std r4, -32(r1)
|
|
std r3, -24(r1)
|
|
/* save TOC */
|
|
std r2, -16(r1)
|
|
std r31, -8(r1)
|
|
mr r31, r1
|
|
stdu r1, -112(r1)
|
|
|
|
/*
|
|
* We are in a module using the module's TOC.
|
|
* Switch to our TOC to run inside the core kernel.
|
|
*/
|
|
ld r2, PACATOC(r13)
|
|
|
|
bl .ftrace_return_to_handler
|
|
nop
|
|
|
|
/* return value has real return address */
|
|
mtlr r3
|
|
|
|
ld r1, 0(r1)
|
|
ld r4, -32(r1)
|
|
ld r3, -24(r1)
|
|
ld r2, -16(r1)
|
|
ld r31, -8(r1)
|
|
|
|
/* Jump back to real return address */
|
|
blr
|
|
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
|
|
#endif /* CONFIG_FUNCTION_TRACER */
|