root/arch/powerpc/kvm/book3s_rmhandlers.S

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  *
   4  * Copyright SUSE Linux Products GmbH 2009
   5  *
   6  * Authors: Alexander Graf <agraf@suse.de>
   7  */
   8 
   9 #include <asm/ppc_asm.h>
  10 #include <asm/kvm_asm.h>
  11 #include <asm/reg.h>
  12 #include <asm/mmu.h>
  13 #include <asm/page.h>
  14 #include <asm/asm-offsets.h>
  15 #include <asm/asm-compat.h>
  16 
  17 #ifdef CONFIG_PPC_BOOK3S_64
  18 #include <asm/exception-64s.h>
  19 #endif
  20 
  21 /*****************************************************************************
  22  *                                                                           *
  23  *        Real Mode handlers that need to be in low physical memory          *
  24  *                                                                           *
  25  ****************************************************************************/
  26 
  27 #if defined(CONFIG_PPC_BOOK3S_64)
  28 
  29 #ifdef PPC64_ELF_ABI_v2
  30 #define FUNC(name)              name
  31 #else
  32 #define FUNC(name)              GLUE(.,name)
  33 #endif
  34 
  35 #elif defined(CONFIG_PPC_BOOK3S_32)
  36 
  37 #define FUNC(name)              name
  38 
  39 #define RFI_TO_KERNEL   RFI
  40 #define RFI_TO_GUEST    RFI
  41 
  42 .macro INTERRUPT_TRAMPOLINE intno
  43 
  44 .global kvmppc_trampoline_\intno
  45 kvmppc_trampoline_\intno:
  46 
  47         mtspr   SPRN_SPRG_SCRATCH0, r13         /* Save r13 */
  48 
  49         /*
  50          * First thing to do is to find out if we're coming
  51          * from a KVM guest or a Linux process.
  52          *
  53          * To distinguish, we check a magic byte in the PACA/current
  54          */
  55         mfspr   r13, SPRN_SPRG_THREAD
  56         lwz     r13, THREAD_KVM_SVCPU(r13)
  57         /* PPC32 can have a NULL pointer - let's check for that */
  58         mtspr   SPRN_SPRG_SCRATCH1, r12         /* Save r12 */
  59         mfcr    r12
  60         cmpwi   r13, 0
  61         bne     1f
  62 2:      mtcr    r12
  63         mfspr   r12, SPRN_SPRG_SCRATCH1
  64         mfspr   r13, SPRN_SPRG_SCRATCH0         /* r13 = original r13 */
  65         b       kvmppc_resume_\intno            /* Get back original handler */
  66 
  67 1:      tophys(r13, r13)
  68         stw     r12, HSTATE_SCRATCH1(r13)
  69         mfspr   r12, SPRN_SPRG_SCRATCH1
  70         stw     r12, HSTATE_SCRATCH0(r13)
  71         lbz     r12, HSTATE_IN_GUEST(r13)
  72         cmpwi   r12, KVM_GUEST_MODE_NONE
  73         bne     ..kvmppc_handler_hasmagic_\intno
  74         /* No KVM guest? Then jump back to the Linux handler! */
  75         lwz     r12, HSTATE_SCRATCH1(r13)
  76         b       2b
  77 
  78         /* Now we know we're handling a KVM guest */
  79 ..kvmppc_handler_hasmagic_\intno:
  80 
  81         /* Should we just skip the faulting instruction? */
  82         cmpwi   r12, KVM_GUEST_MODE_SKIP
  83         beq     kvmppc_handler_skip_ins
  84 
  85         /* Let's store which interrupt we're handling */
  86         li      r12, \intno
  87 
  88         /* Jump into the SLB exit code that goes to the highmem handler */
  89         b       kvmppc_handler_trampoline_exit
  90 
  91 .endm
  92 
  93 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_SYSTEM_RESET
  94 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_MACHINE_CHECK
  95 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_DATA_STORAGE
  96 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_INST_STORAGE
  97 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_EXTERNAL
  98 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_ALIGNMENT
  99 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_PROGRAM
 100 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_FP_UNAVAIL
 101 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_DECREMENTER
 102 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_SYSCALL
 103 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_TRACE
 104 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_PERFMON
 105 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_ALTIVEC
 106 
 107 /*
 108  * Bring us back to the faulting code, but skip the
 109  * faulting instruction.
 110  *
 111  * This is a generic exit path from the interrupt
 112  * trampolines above.
 113  *
 114  * Input Registers:
 115  *
 116  * R12            = free
 117  * R13            = Shadow VCPU (PACA)
 118  * HSTATE.SCRATCH0 = guest R12
 119  * HSTATE.SCRATCH1 = guest CR
 120  * SPRG_SCRATCH0  = guest R13
 121  *
 122  */
 123 kvmppc_handler_skip_ins:
 124 
 125         /* Patch the IP to the next instruction */
 126         mfsrr0  r12
 127         addi    r12, r12, 4
 128         mtsrr0  r12
 129 
 130         /* Clean up all state */
 131         lwz     r12, HSTATE_SCRATCH1(r13)
 132         mtcr    r12
 133         PPC_LL  r12, HSTATE_SCRATCH0(r13)
 134         GET_SCRATCH0(r13)
 135 
 136         /* And get back into the code */
 137         RFI_TO_KERNEL
 138 #endif
 139 
 140 /*
 141  * Call kvmppc_handler_trampoline_enter in real mode
 142  *
 143  * On entry, r4 contains the guest shadow MSR
 144  * MSR.EE has to be 0 when calling this function
 145  */
 146 _GLOBAL_TOC(kvmppc_entry_trampoline)
 147         mfmsr   r5
 148         LOAD_REG_ADDR(r7, kvmppc_handler_trampoline_enter)
 149         toreal(r7)
 150 
 151         li      r6, MSR_IR | MSR_DR
 152         andc    r6, r5, r6      /* Clear DR and IR in MSR value */
 153         /*
 154          * Set EE in HOST_MSR so that it's enabled when we get into our
 155          * C exit handler function.
 156          */
 157         ori     r5, r5, MSR_EE
 158         mtsrr0  r7
 159         mtsrr1  r6
 160         RFI_TO_KERNEL
 161 
 162 #include "book3s_segment.S"