diff mbox series

[v2,06/10] target/ppc: Readability improvements in exception handlers

Message ID f3cab9ad8df3a11d96be8b2c24f897d4e43c17f0.1686776990.git.balaton@eik.bme.hu
State New
Headers show
Series Misc clean ups to target/ppc exception handling | expand

Commit Message

BALATON Zoltan June 14, 2023, 9:34 p.m. UTC
Improve readability by shortening some long comments, removing
comments that state the obvious and dropping some empty lines so they
don't distract when reading the code.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Acked-by: Nicholas Piggin <npiggin@gmail.com>
---
 target/ppc/cpu.h         |   1 +
 target/ppc/excp_helper.c | 180 +++++++--------------------------------
 2 files changed, 33 insertions(+), 148 deletions(-)
diff mbox series

Patch

diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index 0ee2adc105..d7acd65176 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -2739,6 +2739,7 @@  static inline bool ppc_has_spr(PowerPCCPU *cpu, int spr)
 }
 
 #if !defined(CONFIG_USER_ONLY)
+/* Sort out endianness of interrupt. Depends on the CPU, HV mode, etc. */
 static inline bool ppc_interrupts_little_endian(PowerPCCPU *cpu, bool hv)
 {
     PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu);
diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
index 49ed3e1825..74113958b5 100644
--- a/target/ppc/excp_helper.c
+++ b/target/ppc/excp_helper.c
@@ -382,9 +382,8 @@  static void powerpc_set_excp_state(PowerPCCPU *cpu, target_ulong vector,
      * We don't use hreg_store_msr here as already have treated any
      * special case that could occur. Just store MSR and update hflags
      *
-     * Note: We *MUST* not use hreg_store_msr() as-is anyway because it
-     * will prevent setting of the HV bit which some exceptions might need
-     * to do.
+     * Note: We *MUST* not use hreg_store_msr() as-is anyway because it will
+     * prevent setting of the HV bit which some exceptions might need to do.
      */
     env->nip = vector;
     env->msr = msr;
@@ -426,25 +425,15 @@  static void powerpc_excp_40x(PowerPCCPU *cpu, int excp)
 {
     CPUPPCState *env = &cpu->env;
     target_ulong msr, new_msr, vector;
-    int srr0, srr1;
+    int srr0 = SPR_SRR0, srr1 = SPR_SRR1;
 
     /* new srr1 value excluding must-be-zero bits */
     msr = env->msr & ~0x783f0000ULL;
 
-    /*
-     * new interrupt handler msr preserves existing ME unless
-     * explicitly overriden.
-     */
+    /* new interrupt handler msr preserves ME unless explicitly overriden */
     new_msr = env->msr & (((target_ulong)1 << MSR_ME));
 
-    /* target registers */
-    srr0 = SPR_SRR0;
-    srr1 = SPR_SRR1;
-
-    /*
-     * Hypervisor emulation assistance interrupt only exists on server
-     * arch 2.05 server or later.
-     */
+    /* HV emu assistance interrupt only exists on server arch 2.05 or later */
     if (excp == POWERPC_EXCP_HV_EMU) {
         excp = POWERPC_EXCP_PROGRAM;
     }
@@ -454,7 +443,6 @@  static void powerpc_excp_40x(PowerPCCPU *cpu, int excp)
         cpu_abort(env_cpu(env),
                   "Raised an exception without defined vector %d\n", excp);
     }
-
     vector |= env->excp_prefix;
 
     switch (excp) {
@@ -466,7 +454,6 @@  static void powerpc_excp_40x(PowerPCCPU *cpu, int excp)
         powerpc_mcheck_checkstop(env);
         /* machine check exceptions don't have ME set */
         new_msr &= ~((target_ulong)1 << MSR_ME);
-
         srr0 = SPR_40x_SRR2;
         srr1 = SPR_40x_SRR3;
         break;
@@ -537,12 +524,8 @@  static void powerpc_excp_40x(PowerPCCPU *cpu, int excp)
         break;
     }
 
-    /* Save PC */
     env->spr[srr0] = env->nip;
-
-    /* Save MSR */
     env->spr[srr1] = msr;
-
     powerpc_set_excp_state(cpu, vector, new_msr);
 }
 
@@ -554,16 +537,10 @@  static void powerpc_excp_6xx(PowerPCCPU *cpu, int excp)
     /* new srr1 value excluding must-be-zero bits */
     msr = env->msr & ~0x783f0000ULL;
 
-    /*
-     * new interrupt handler msr preserves existing ME unless
-     * explicitly overriden
-     */
+    /* new interrupt handler msr preserves ME unless explicitly overriden */
     new_msr = env->msr & ((target_ulong)1 << MSR_ME);
 
-    /*
-     * Hypervisor emulation assistance interrupt only exists on server
-     * arch 2.05 server or later.
-     */
+    /* HV emu assistance interrupt only exists on server arch 2.05 or later */
     if (excp == POWERPC_EXCP_HV_EMU) {
         excp = POWERPC_EXCP_PROGRAM;
     }
@@ -573,7 +550,6 @@  static void powerpc_excp_6xx(PowerPCCPU *cpu, int excp)
         cpu_abort(env_cpu(env),
                   "Raised an exception without defined vector %d\n", excp);
     }
-
     vector |= env->excp_prefix;
 
     switch (excp) {
@@ -583,7 +559,6 @@  static void powerpc_excp_6xx(PowerPCCPU *cpu, int excp)
         powerpc_mcheck_checkstop(env);
         /* machine check exceptions don't have ME set */
         new_msr &= ~((target_ulong)1 << MSR_ME);
-
         break;
     case POWERPC_EXCP_DSI:       /* Data storage exception                   */
         trace_ppc_excp_dsi(env->spr[SPR_DSISR], env->spr[SPR_DAR]);
@@ -611,11 +586,9 @@  static void powerpc_excp_6xx(PowerPCCPU *cpu, int excp)
                 powerpc_reset_excp_state(cpu);
                 return;
             }
-
             /*
-             * FP exceptions always have NIP pointing to the faulting
-             * instruction, so always use store_next and claim we are
-             * precise in the MSR.
+             * NIP always points to the faulting instruction for FP exceptions,
+             * so always use store_next and claim we are precise in the MSR.
              */
             msr |= 0x00100000;
             break;
@@ -691,20 +664,11 @@  static void powerpc_excp_6xx(PowerPCCPU *cpu, int excp)
         break;
     }
 
-    /*
-     * Sort out endianness of interrupt, this differs depending on the
-     * CPU, the HV mode, etc...
-     */
     if (ppc_interrupts_little_endian(cpu, !!(new_msr & MSR_HVB))) {
         new_msr |= (target_ulong)1 << MSR_LE;
     }
-
-    /* Save PC */
     env->spr[SPR_SRR0] = env->nip;
-
-    /* Save MSR */
     env->spr[SPR_SRR1] = msr;
-
     powerpc_set_excp_state(cpu, vector, new_msr);
 }
 
@@ -716,16 +680,10 @@  static void powerpc_excp_7xx(PowerPCCPU *cpu, int excp)
     /* new srr1 value excluding must-be-zero bits */
     msr = env->msr & ~0x783f0000ULL;
 
-    /*
-     * new interrupt handler msr preserves existing ME unless
-     * explicitly overriden
-     */
+    /* new interrupt handler msr preserves ME unless explicitly overriden */
     new_msr = env->msr & ((target_ulong)1 << MSR_ME);
 
-    /*
-     * Hypervisor emulation assistance interrupt only exists on server
-     * arch 2.05 server or later.
-     */
+    /* HV emu assistance interrupt only exists on server arch 2.05 or later */
     if (excp == POWERPC_EXCP_HV_EMU) {
         excp = POWERPC_EXCP_PROGRAM;
     }
@@ -735,7 +693,6 @@  static void powerpc_excp_7xx(PowerPCCPU *cpu, int excp)
         cpu_abort(env_cpu(env),
                   "Raised an exception without defined vector %d\n", excp);
     }
-
     vector |= env->excp_prefix;
 
     switch (excp) {
@@ -743,7 +700,6 @@  static void powerpc_excp_7xx(PowerPCCPU *cpu, int excp)
         powerpc_mcheck_checkstop(env);
         /* machine check exceptions don't have ME set */
         new_msr &= ~((target_ulong)1 << MSR_ME);
-
         break;
     case POWERPC_EXCP_DSI:       /* Data storage exception                   */
         trace_ppc_excp_dsi(env->spr[SPR_DSISR], env->spr[SPR_DAR]);
@@ -771,11 +727,9 @@  static void powerpc_excp_7xx(PowerPCCPU *cpu, int excp)
                 powerpc_reset_excp_state(cpu);
                 return;
             }
-
             /*
-             * FP exceptions always have NIP pointing to the faulting
-             * instruction, so always use store_next and claim we are
-             * precise in the MSR.
+             * NIP always points to the faulting instruction for FP exceptions,
+             * so always use store_next and claim we are precise in the MSR.
              */
             msr |= 0x00100000;
             break;
@@ -843,12 +797,10 @@  static void powerpc_excp_7xx(PowerPCCPU *cpu, int excp)
     case POWERPC_EXCP_DLTLB:     /* Data load TLB miss                       */
     case POWERPC_EXCP_DSTLB:     /* Data store TLB miss                      */
         ppc_excp_debug_sw_tlb(env, excp);
-
         msr |= env->crf[0] << 28;
         msr |= env->error_code; /* key, D/I, S/L bits */
         /* Set way using a LRU mechanism */
         msr |= ((env->last_way + 1) & (env->nb_ways - 1)) << 17;
-
         break;
     case POWERPC_EXCP_IABR:      /* Instruction address breakpoint           */
     case POWERPC_EXCP_SMI:       /* System management interrupt              */
@@ -863,20 +815,11 @@  static void powerpc_excp_7xx(PowerPCCPU *cpu, int excp)
         break;
     }
 
-    /*
-     * Sort out endianness of interrupt, this differs depending on the
-     * CPU, the HV mode, etc...
-     */
     if (ppc_interrupts_little_endian(cpu, !!(new_msr & MSR_HVB))) {
         new_msr |= (target_ulong)1 << MSR_LE;
     }
-
-    /* Save PC */
     env->spr[SPR_SRR0] = env->nip;
-
-    /* Save MSR */
     env->spr[SPR_SRR1] = msr;
-
     powerpc_set_excp_state(cpu, vector, new_msr);
 }
 
@@ -888,16 +831,10 @@  static void powerpc_excp_74xx(PowerPCCPU *cpu, int excp)
     /* new srr1 value excluding must-be-zero bits */
     msr = env->msr & ~0x783f0000ULL;
 
-    /*
-     * new interrupt handler msr preserves existing ME unless
-     * explicitly overriden
-     */
+    /* new interrupt handler msr preserves ME unless explicitly overriden */
     new_msr = env->msr & ((target_ulong)1 << MSR_ME);
 
-    /*
-     * Hypervisor emulation assistance interrupt only exists on server
-     * arch 2.05 server or later.
-     */
+    /* HV emu assistance interrupt only exists on server arch 2.05 or later */
     if (excp == POWERPC_EXCP_HV_EMU) {
         excp = POWERPC_EXCP_PROGRAM;
     }
@@ -907,7 +844,6 @@  static void powerpc_excp_74xx(PowerPCCPU *cpu, int excp)
         cpu_abort(env_cpu(env),
                   "Raised an exception without defined vector %d\n", excp);
     }
-
     vector |= env->excp_prefix;
 
     switch (excp) {
@@ -915,7 +851,6 @@  static void powerpc_excp_74xx(PowerPCCPU *cpu, int excp)
         powerpc_mcheck_checkstop(env);
         /* machine check exceptions don't have ME set */
         new_msr &= ~((target_ulong)1 << MSR_ME);
-
         break;
     case POWERPC_EXCP_DSI:       /* Data storage exception                   */
         trace_ppc_excp_dsi(env->spr[SPR_DSISR], env->spr[SPR_DAR]);
@@ -943,11 +878,9 @@  static void powerpc_excp_74xx(PowerPCCPU *cpu, int excp)
                 powerpc_reset_excp_state(cpu);
                 return;
             }
-
             /*
-             * FP exceptions always have NIP pointing to the faulting
-             * instruction, so always use store_next and claim we are
-             * precise in the MSR.
+             * NIP always points to the faulting instruction for FP exceptions,
+             * so always use store_next and claim we are precise in the MSR.
              */
             msr |= 0x00100000;
             break;
@@ -1027,20 +960,11 @@  static void powerpc_excp_74xx(PowerPCCPU *cpu, int excp)
         break;
     }
 
-    /*
-     * Sort out endianness of interrupt, this differs depending on the
-     * CPU, the HV mode, etc...
-     */
     if (ppc_interrupts_little_endian(cpu, !!(new_msr & MSR_HVB))) {
         new_msr |= (target_ulong)1 << MSR_LE;
     }
-
-    /* Save PC */
     env->spr[SPR_SRR0] = env->nip;
-
-    /* Save MSR */
     env->spr[SPR_SRR1] = msr;
-
     powerpc_set_excp_state(cpu, vector, new_msr);
 }
 
@@ -1048,24 +972,18 @@  static void powerpc_excp_booke(PowerPCCPU *cpu, int excp)
 {
     CPUPPCState *env = &cpu->env;
     target_ulong msr, new_msr, vector;
-    int srr0, srr1;
-
-    msr = env->msr;
+    int srr0 = SPR_SRR0, srr1 = SPR_SRR1;
 
     /*
-     * new interrupt handler msr preserves existing ME unless
-     * explicitly overriden
+     * Book E does not play games with certain bits of xSRR1 being MSR save
+     * bits and others being error status. xSRR1 is the old MSR, period.
      */
-    new_msr = env->msr & ((target_ulong)1 << MSR_ME);
+    msr = env->msr;
 
-    /* target registers */
-    srr0 = SPR_SRR0;
-    srr1 = SPR_SRR1;
+    /* new interrupt handler msr preserves ME unless explicitly overriden */
+    new_msr = env->msr & ((target_ulong)1 << MSR_ME);
 
-    /*
-     * Hypervisor emulation assistance interrupt only exists on server
-     * arch 2.05 server or later.
-     */
+    /* HV emu assistance interrupt only exists on server arch 2.05 or later */
     if (excp == POWERPC_EXCP_HV_EMU) {
         excp = POWERPC_EXCP_PROGRAM;
     }
@@ -1085,7 +1003,6 @@  static void powerpc_excp_booke(PowerPCCPU *cpu, int excp)
         cpu_abort(env_cpu(env),
                   "Raised an exception without defined vector %d\n", excp);
     }
-
     vector |= env->excp_prefix;
 
     switch (excp) {
@@ -1129,11 +1046,9 @@  static void powerpc_excp_booke(PowerPCCPU *cpu, int excp)
                 powerpc_reset_excp_state(cpu);
                 return;
             }
-
             /*
-             * FP exceptions always have NIP pointing to the faulting
-             * instruction, so always use store_next and claim we are
-             * precise in the MSR.
+             * NIP always points to the faulting instruction for FP exceptions,
+             * so always use store_next and claim we are precise in the MSR.
              */
             msr |= 0x00100000;
             env->spr[SPR_BOOKE_ESR] = ESR_FP;
@@ -1234,12 +1149,8 @@  static void powerpc_excp_booke(PowerPCCPU *cpu, int excp)
     }
 #endif
 
-    /* Save PC */
     env->spr[srr0] = env->nip;
-
-    /* Save MSR */
     env->spr[srr1] = msr;
-
     powerpc_set_excp_state(cpu, vector, new_msr);
 }
 
@@ -1286,21 +1197,17 @@  static void powerpc_excp_books(PowerPCCPU *cpu, int excp)
 {
     CPUPPCState *env = &cpu->env;
     target_ulong msr, new_msr, vector;
-    int srr0, srr1, lev = -1;
+    int srr0 = SPR_SRR0, srr1 = SPR_SRR1, lev = -1;
 
     /* new srr1 value excluding must-be-zero bits */
     msr = env->msr & ~0x783f0000ULL;
 
     /*
-     * new interrupt handler msr preserves existing HV and ME unless
-     * explicitly overriden
+     * new interrupt handler msr preserves HV and ME unless explicitly
+     * overriden
      */
     new_msr = env->msr & (((target_ulong)1 << MSR_ME) | MSR_HVB);
 
-    /* target registers */
-    srr0 = SPR_SRR0;
-    srr1 = SPR_SRR1;
-
     /*
      * check for special resume at 0x100 from doze/nap/sleep/winkle on
      * P7/P8/P9
@@ -1325,7 +1232,6 @@  static void powerpc_excp_books(PowerPCCPU *cpu, int excp)
         cpu_abort(env_cpu(env),
                   "Raised an exception without defined vector %d\n", excp);
     }
-
     vector |= env->excp_prefix;
 
     switch (excp) {
@@ -1338,10 +1244,8 @@  static void powerpc_excp_books(PowerPCCPU *cpu, int excp)
              */
             new_msr |= (target_ulong)MSR_HVB;
         }
-
         /* machine check exceptions don't have ME set */
         new_msr &= ~((target_ulong)1 << MSR_ME);
-
         break;
     case POWERPC_EXCP_DSI:       /* Data storage exception                   */
         trace_ppc_excp_dsi(env->spr[SPR_DSISR], env->spr[SPR_DAR]);
@@ -1354,23 +1258,17 @@  static void powerpc_excp_books(PowerPCCPU *cpu, int excp)
     {
         bool lpes0;
 
-        /*
-         * LPES0 is only taken into consideration if we support HV
-         * mode for this CPU.
-         */
+        /* LPES0 is only taken into consideration if we support HV mode */
         if (!env->has_hv_mode) {
             break;
         }
-
         lpes0 = !!(env->spr[SPR_LPCR] & LPCR_LPES0);
-
         if (!lpes0) {
             new_msr |= (target_ulong)MSR_HVB;
             new_msr |= env->msr & ((target_ulong)1 << MSR_RI);
             srr0 = SPR_HSRR0;
             srr1 = SPR_HSRR1;
         }
-
         break;
     }
     case POWERPC_EXCP_ALIGN:     /* Alignment exception                      */
@@ -1393,11 +1291,9 @@  static void powerpc_excp_books(PowerPCCPU *cpu, int excp)
                 powerpc_reset_excp_state(cpu);
                 return;
             }
-
             /*
-             * FP exceptions always have NIP pointing to the faulting
-             * instruction, so always use store_next and claim we are
-             * precise in the MSR.
+             * NIP always points to the faulting instruction for FP exceptions,
+             * so always use store_next and claim we are precise in the MSR.
              */
             msr |= 0x00100000;
             break;
@@ -1539,21 +1435,13 @@  static void powerpc_excp_books(PowerPCCPU *cpu, int excp)
         break;
     }
 
-    /*
-     * Sort out endianness of interrupt, this differs depending on the
-     * CPU, the HV mode, etc...
-     */
     if (ppc_interrupts_little_endian(cpu, !!(new_msr & MSR_HVB))) {
         new_msr |= (target_ulong)1 << MSR_LE;
     }
-
     new_msr |= (target_ulong)1 << MSR_SF;
 
     if (excp != POWERPC_EXCP_SYSCALL_VECTORED) {
-        /* Save PC */
         env->spr[srr0] = env->nip;
-
-        /* Save MSR */
         env->spr[srr1] = msr;
     }
 
@@ -1562,19 +1450,15 @@  static void powerpc_excp_books(PowerPCCPU *cpu, int excp)
             PPC_VIRTUAL_HYPERVISOR_GET_CLASS(cpu->vhyp);
         /* Deliver interrupt to L1 by returning from the H_ENTER_NESTED call */
         vhc->deliver_hv_excp(cpu, excp);
-
         powerpc_reset_excp_state(cpu);
-
     } else {
         /* Sanity check */
         if (!(env->msr_mask & MSR_HVB) && srr0 == SPR_HSRR0) {
             cpu_abort(env_cpu(env), "Trying to deliver HV exception (HSRR) %d "
                       "with no HV support\n", excp);
         }
-
         /* This can update new_msr and vector if AIL applies */
         ppc_excp_apply_ail(cpu, excp, msr, &new_msr, &vector);
-
         powerpc_set_excp_state(cpu, vector, new_msr);
     }
 }