arch/powerpc/kvm/book3s_rmhandlers.S

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License, version 2, as
   4  * published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * You should have received a copy of the GNU General Public License
  12  * along with this program; if not, write to the Free Software
  13  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  14  *
  15  * Copyright SUSE Linux Products GmbH 2009
  16  *
  17  * Authors: Alexander Graf <agraf@suse.de>
  18  */
  19
  20 #include <asm/ppc_asm.h>
  21 #include <asm/kvm_asm.h>
  22 #include <asm/reg.h>
  23 #include <asm/page.h>
  24 #include <asm/asm-offsets.h>
  25
  26 #ifdef CONFIG_PPC_BOOK3S_64
  27 #include <asm/exception-64s.h>
  28 #endif
  29
  30 /*****************************************************************************
  31  *                                                                           *
  32  *        Real Mode handlers that need to be in low physical memory          *
  33  *                                                                           *
  34  ****************************************************************************/
  35
  36 #if defined(CONFIG_PPC_BOOK3S_64)
  37
  38 #define LOAD_SHADOW_VCPU(reg)                           \
  39         mfspr   reg, SPRN_SPRG_PACA
  40
  41 #define SHADOW_VCPU_OFF         PACA_KVM_SVCPU
  42 #define MSR_NOIRQ               MSR_KERNEL & ~(MSR_IR | MSR_DR)
  43 #define FUNC(name)              GLUE(.,name)
  44
  45 #elif defined(CONFIG_PPC_BOOK3S_32)
  46
  47 #define LOAD_SHADOW_VCPU(reg)                                           \
  48         mfspr   reg, SPRN_SPRG_THREAD;                                  \
  49         lwz     reg, THREAD_KVM_SVCPU(reg);                             \
  50         /* PPC32 can have a NULL pointer - let's check for that */      \
  51         mtspr   SPRN_SPRG_SCRATCH1, r12;        /* Save r12 */          \
  52         mfcr    r12;                                                    \
  53         cmpwi   reg, 0;                                                 \
  54         bne     1f;                                                     \
  55         mfspr   reg, SPRN_SPRG_SCRATCH0;                                \
  56         mtcr    r12;                                                    \
  57         mfspr   r12, SPRN_SPRG_SCRATCH1;                                \
  58         b       kvmppc_resume_\intno;                                   \
  59 1:;                                                                     \
  60         mtcr    r12;                                                    \
  61         mfspr   r12, SPRN_SPRG_SCRATCH1;                                \
  62         tophys(reg, reg)
  63
  64 #define SHADOW_VCPU_OFF         0
  65 #define MSR_NOIRQ               MSR_KERNEL
  66 #define FUNC(name)              name
  67
  68 #endif
  69
  70 .macro INTERRUPT_TRAMPOLINE intno
  71
  72 .global kvmppc_trampoline_\intno
  73 kvmppc_trampoline_\intno:
  74
  75         mtspr   SPRN_SPRG_SCRATCH0, r13         /* Save r13 */
  76
  77         /*
  78          * First thing to do is to find out if we're coming
  79          * from a KVM guest or a Linux process.
  80          *
  81          * To distinguish, we check a magic byte in the PACA/current
  82          */
  83         LOAD_SHADOW_VCPU(r13)
  84         PPC_STL r12, (SHADOW_VCPU_OFF + SVCPU_SCRATCH0)(r13)
  85         mfcr    r12
  86         stw     r12, (SHADOW_VCPU_OFF + SVCPU_SCRATCH1)(r13)
  87         lbz     r12, (SHADOW_VCPU_OFF + SVCPU_IN_GUEST)(r13)
  88         cmpwi   r12, KVM_GUEST_MODE_NONE
  89         bne     ..kvmppc_handler_hasmagic_\intno
  90         /* No KVM guest? Then jump back to the Linux handler! */
  91         lwz     r12, (SHADOW_VCPU_OFF + SVCPU_SCRATCH1)(r13)
  92         mtcr    r12
  93         PPC_LL  r12, (SHADOW_VCPU_OFF + SVCPU_SCRATCH0)(r13)
  94         mfspr   r13, SPRN_SPRG_SCRATCH0         /* r13 = original r13 */
  95         b       kvmppc_resume_\intno            /* Get back original handler */
  96
  97         /* Now we know we're handling a KVM guest */
  98 ..kvmppc_handler_hasmagic_\intno:
  99
 100         /* Should we just skip the faulting instruction? */
 101         cmpwi   r12, KVM_GUEST_MODE_SKIP
 102         beq     kvmppc_handler_skip_ins
 103
 104         /* Let's store which interrupt we're handling */
 105         li      r12, \intno
 106
 107         /* Jump into the SLB exit code that goes to the highmem handler */
 108         b       kvmppc_handler_trampoline_exit
 109
 110 .endm
 111
 112 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_SYSTEM_RESET
 113 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_MACHINE_CHECK
 114 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_DATA_STORAGE
 115 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_INST_STORAGE
 116 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_EXTERNAL
 117 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_ALIGNMENT
 118 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_PROGRAM
 119 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_FP_UNAVAIL
 120 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_DECREMENTER
 121 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_SYSCALL
 122 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_TRACE
 123 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_PERFMON
 124 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_ALTIVEC
 125
 126 /* Those are only available on 64 bit machines */
 127
 128 #ifdef CONFIG_PPC_BOOK3S_64
 129 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_DATA_SEGMENT
 130 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_INST_SEGMENT
 131 INTERRUPT_TRAMPOLINE    BOOK3S_INTERRUPT_VSX
 132 #endif
 133
 134 /*
 135  * Bring us back to the faulting code, but skip the
 136  * faulting instruction.
 137  *
 138  * This is a generic exit path from the interrupt
 139  * trampolines above.
 140  *
 141  * Input Registers:
 142  *
 143  * R12            = free
 144  * R13            = Shadow VCPU (PACA)
 145  * SVCPU.SCRATCH0 = guest R12
 146  * SVCPU.SCRATCH1 = guest CR
 147  * SPRG_SCRATCH0  = guest R13
 148  *
 149  */
 150 kvmppc_handler_skip_ins:
 151
 152         /* Patch the IP to the next instruction */
 153         mfsrr0  r12
 154         addi    r12, r12, 4
 155         mtsrr0  r12
 156
 157         /* Clean up all state */
 158         lwz     r12, (SHADOW_VCPU_OFF + SVCPU_SCRATCH1)(r13)
 159         mtcr    r12
 160         PPC_LL  r12, (SHADOW_VCPU_OFF + SVCPU_SCRATCH0)(r13)
 161         mfspr   r13, SPRN_SPRG_SCRATCH0
 162
 163         /* And get back into the code */
 164         RFI
 165
 166 /*
 167  * This trampoline brings us back to a real mode handler
 168  *
 169  * Input Registers:
 170  *
 171  * R5 = SRR0
 172  * R6 = SRR1
 173  * LR = real-mode IP
 174  *
 175  */
 176 .global kvmppc_handler_lowmem_trampoline
 177 kvmppc_handler_lowmem_trampoline:
 178
 179         mtsrr0  r5
 180         mtsrr1  r6
 181         blr
 182 kvmppc_handler_lowmem_trampoline_end:
 183
 184 /*
 185  * Call a function in real mode
 186  *
 187  * Input Registers:
 188  *
 189  * R3 = function
 190  * R4 = MSR
 191  * R5 = scratch register
 192  *
 193  */
 194 _GLOBAL(kvmppc_rmcall)
 195         LOAD_REG_IMMEDIATE(r5, MSR_NOIRQ)
 196         mtmsr   r5              /* Disable relocation and interrupts, so mtsrr
 197                                    doesn't get interrupted */
 198         sync
 199         mtsrr0  r3
 200         mtsrr1  r4
 201         RFI
 202
 203 #if defined(CONFIG_PPC_BOOK3S_32)
 204 #define STACK_LR        INT_FRAME_SIZE+4
 205 #elif defined(CONFIG_PPC_BOOK3S_64)
 206 #define STACK_LR        _LINK
 207 #endif
 208
 209 /*
 210  * Activate current's external feature (FPU/Altivec/VSX)
 211  */
 212 #define define_load_up(what)                                    \
 213                                                                 \
 214 _GLOBAL(kvmppc_load_up_ ## what);                               \
 215         PPC_STLU r1, -INT_FRAME_SIZE(r1);                       \
 216         mflr    r3;                                             \
 217         PPC_STL r3, STACK_LR(r1);                               \
 218         PPC_STL r20, _NIP(r1);                                  \
 219         mfmsr   r20;                                            \
 220         LOAD_REG_IMMEDIATE(r3, MSR_DR|MSR_EE);                  \
 221         andc    r3,r20,r3;              /* Disable DR,EE */     \
 222         mtmsr   r3;                                             \
 223         sync;                                                   \
 224                                                                 \
 225         bl      FUNC(load_up_ ## what);                         \
 226                                                                 \
 227         mtmsr   r20;                    /* Enable DR,EE */      \
 228         sync;                                                   \
 229         PPC_LL  r3, STACK_LR(r1);                               \
 230         PPC_LL  r20, _NIP(r1);                                  \
 231         mtlr    r3;                                             \
 232         addi    r1, r1, INT_FRAME_SIZE;                         \
 233         blr
 234
 235 define_load_up(fpu)
 236 #ifdef CONFIG_ALTIVEC
 237 define_load_up(altivec)
 238 #endif
 239 #ifdef CONFIG_VSX
 240 define_load_up(vsx)
 241 #endif
 242
 243 .global kvmppc_trampoline_lowmem
 244 kvmppc_trampoline_lowmem:
 245         .long kvmppc_handler_lowmem_trampoline - CONFIG_KERNEL_START
 246
 247 .global kvmppc_trampoline_enter
 248 kvmppc_trampoline_enter:
 249         .long kvmppc_handler_trampoline_enter - CONFIG_KERNEL_START
 250
 251 #include "book3s_segment.S"