[PATCH v2 0/2] target/ppc: Removal of the unusable e200 CPUs

[PATCH v2 0/2] target/ppc: Removal of the unusable e200 CPUs

[Thomas Huth]

The second patch removes the unused e200 CPUs, see its patch description
for the rationale.

Since the removal of the code causes GCC to inline another function,
this suddenly triggered a false compiler warning, so we have to
rework the related code first (see the first patch).

Thomas Huth (2):
  target/ppc/cpu_init: Simplify the setup of the TLBxCFG SPR registers
  target/ppc: Remove the unusable e200 CPUs

 target/ppc/cpu-models.h |   4 -
 target/ppc/cpu-models.c |   5 --
 target/ppc/cpu_init.c   | 185 +++-------------------------------------
 3 files changed, 14 insertions(+), 180 deletions(-)

-- 
2.51.0

[PATCH v2 1/2] target/ppc/cpu_init: Simplify the setup of the TLBxCFG SPR registers

[Thomas Huth]

From: Thomas Huth <thuth@redhat.com>

The next commit is going to remove init_proc_e200(), which is one of
the two calling sites of register_BookE206_sprs(). This causes recent
versions of GCC to inline the register_BookE206_sprs() function into
the other only remaining calling site, init_proc_e500(), which in
turn causes some false-positives compiler warnings:

 In file included from ../../devel/qemu/target/ppc/cpu_init.c:46:
 In function ‘register_BookE206_sprs’,
     inlined from ‘init_proc_e500’ at ../../devel/qemu/target/ppc/cpu_init.c:2910:5:
 ../../devel/qemu/target/ppc/cpu_init.c:897:29: error:
  array subscript 3 is outside array bounds of ‘uint32_t[2]’ {aka ‘unsigned int[2]’}
  [-Werror=array-bounds=]
   897 |                      tlbncfg[3]);
       |                      ~~~~~~~^~~
 ../../devel/qemu/target/ppc/spr_common.h:61:39: note: in definition of macro ‘spr_register_kvm_hv’
    61 |                   KVM_ARG(one_reg_id) initial_value)
       |                                       ^~~~~~~~~~~~~
 ../../devel/qemu/target/ppc/spr_common.h:77:5: note: in expansion of macro ‘spr_register_kvm’
    77 |     spr_register_kvm(env, num, name, uea_read, uea_write,                    \
       |     ^~~~~~~~~~~~~~~~
 ../../devel/qemu/target/ppc/cpu_init.c:894:9: note: in expansion of macro ‘spr_register’
   894 |         spr_register(env, SPR_BOOKE_TLB3CFG, "TLB3CFG",
       |         ^~~~~~~~~~~~
 ../../devel/qemu/target/ppc/cpu_init.c: In function ‘init_proc_e500’:
 ../../devel/qemu/target/ppc/cpu_init.c:2809:14: note: at offset 12 into object ‘tlbncfg’ of size 8
  2809 |     uint32_t tlbncfg[2];
       |              ^~~~~~~
 cc1: all warnings being treated as errors

init_proc_e500() only defines "uint32_t tlbncfg[2];", but it is OK since
it also sets "env->nb_ways = 2", so the code that GCC warns about in
register_BookE206_sprs() is never reached. Unfortunately, GCC is not smart
enough to see this, so it emits these warnings.

To fix it, let's simplify the code in register_BookE206_sprs() a little
bit to set up the SPRs in a loop, so we don't reference the tlbncfg[3]
entry directly anymore.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 target/ppc/cpu_init.c | 38 ++++++++++++--------------------------
 1 file changed, 12 insertions(+), 26 deletions(-)

diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
index 3aa3aefc136..12c645699e8 100644
--- a/target/ppc/cpu_init.c
+++ b/target/ppc/cpu_init.c
@@ -850,6 +850,13 @@ static void register_BookE206_sprs(CPUPPCState *env, uint32_t mas_mask,
         SPR_BOOKE_MAS0, SPR_BOOKE_MAS1, SPR_BOOKE_MAS2, SPR_BOOKE_MAS3,
         SPR_BOOKE_MAS4, SPR_BOOKE_MAS5, SPR_BOOKE_MAS6, SPR_BOOKE_MAS7,
     };
+    const char *tlbcfg_names[4] = {
+        "TLB0CFG", "TLB1CFG", "TLB2CFG", "TLB3CFG",
+    };
+    const int tlbcfg_sprn[4] = {
+        SPR_BOOKE_TLB0CFG, SPR_BOOKE_TLB1CFG,
+        SPR_BOOKE_TLB2CFG, SPR_BOOKE_TLB3CFG,
+    };
     int i;
 
     /* TLB assist registers */
@@ -889,34 +896,13 @@ static void register_BookE206_sprs(CPUPPCState *env, uint32_t mas_mask,
                  SPR_NOACCESS, SPR_NOACCESS,
                  &spr_read_generic, SPR_NOACCESS,
                  mmucfg);
-    switch (env->nb_ways) {
-    case 4:
-        spr_register(env, SPR_BOOKE_TLB3CFG, "TLB3CFG",
-                     SPR_NOACCESS, SPR_NOACCESS,
-                     &spr_read_generic, SPR_NOACCESS,
-                     tlbncfg[3]);
-        /* Fallthru */
-    case 3:
-        spr_register(env, SPR_BOOKE_TLB2CFG, "TLB2CFG",
-                     SPR_NOACCESS, SPR_NOACCESS,
-                     &spr_read_generic, SPR_NOACCESS,
-                     tlbncfg[2]);
-        /* Fallthru */
-    case 2:
-        spr_register(env, SPR_BOOKE_TLB1CFG, "TLB1CFG",
-                     SPR_NOACCESS, SPR_NOACCESS,
-                     &spr_read_generic, SPR_NOACCESS,
-                     tlbncfg[1]);
-        /* Fallthru */
-    case 1:
-        spr_register(env, SPR_BOOKE_TLB0CFG, "TLB0CFG",
+
+    assert(env->nb_ways <= ARRAY_SIZE(tlbcfg_names));
+    for (i = 0; i < env->nb_ways; i++) {
+        spr_register(env, tlbcfg_sprn[i], tlbcfg_names[i],
                      SPR_NOACCESS, SPR_NOACCESS,
                      &spr_read_generic, SPR_NOACCESS,
-                     tlbncfg[0]);
-        /* Fallthru */
-    case 0:
-    default:
-        break;
+                     tlbncfg[i]);
     }
 #endif
 }
-- 
2.51.0

[PATCH v2 2/2] target/ppc: Remove the unusable e200 CPUs

[Thomas Huth]

From: Thomas Huth <thuth@redhat.com>

There is currently no machine in QEMU (except the "none" machine)
that can be run with with one of the e200 ppc CPUs - all machines
either complain about an invalid CPU type or crash QEMU immediately.

Looking at the history of this CPU type, it seems like it has never
been used in QEMU and only implemented as a placeholder (see e.g. the
comment about unimplemented instructions in the POWERPC_FAMILY(e200)
section of cpu_init.c). Being completely unused and unusable since
such a long time, let's just remove it now (without deprecation phase,
since there were no users of this dead code anyway).

Note: The init_excp_e200() is used by the e500 CPUs, too, so we
rename this function to init_excp_e500() instead of removing it.

Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 target/ppc/cpu-models.h |   4 --
 target/ppc/cpu-models.c |   5 --
 target/ppc/cpu_init.c   | 147 +---------------------------------------
 3 files changed, 2 insertions(+), 154 deletions(-)

diff --git a/target/ppc/cpu-models.h b/target/ppc/cpu-models.h
index c6cd27f390e..a439eb37ee4 100644
--- a/target/ppc/cpu-models.h
+++ b/target/ppc/cpu-models.h
@@ -120,10 +120,6 @@ enum {
 #define CPU_POWERPC_MPC5200_v12      CPU_POWERPC_G2LEgp1
 #define CPU_POWERPC_MPC5200B_v20     CPU_POWERPC_G2LEgp1
 #define CPU_POWERPC_MPC5200B_v21     CPU_POWERPC_G2LEgp1
-    /* e200 family */
-    /* e200 cores */
-    CPU_POWERPC_e200z5             = 0x81000000,
-    CPU_POWERPC_e200z6             = 0x81120000,
     /* e300 family */
     /* e300 cores */
     CPU_POWERPC_e300c1             = 0x00830010,
diff --git a/target/ppc/cpu-models.c b/target/ppc/cpu-models.c
index 89ae763c7f6..26b6debcfc9 100644
--- a/target/ppc/cpu-models.c
+++ b/target/ppc/cpu-models.c
@@ -244,11 +244,6 @@
                     CPU_POWERPC_MPC5200B_v20, POWERPC_SVR_5200B_v20, G2LE)
     POWERPC_DEF_SVR("mpc5200b_v21", "MPC5200B v2.1",
                     CPU_POWERPC_MPC5200B_v21, POWERPC_SVR_5200B_v21, G2LE)
-    /* e200 family                                                           */
-    POWERPC_DEF("e200z5",        CPU_POWERPC_e200z5,                 e200,
-                "PowerPC e200z5 core")
-    POWERPC_DEF("e200z6",        CPU_POWERPC_e200z6,                 e200,
-                "PowerPC e200z6 core")
     /* e300 family                                                           */
     POWERPC_DEF("e300c1",        CPU_POWERPC_e300c1,                 e300,
                 "PowerPC e300c1 core")
diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
index 12c645699e8..86ead740eec 100644
--- a/target/ppc/cpu_init.c
+++ b/target/ppc/cpu_init.c
@@ -1811,7 +1811,7 @@ static void init_excp_G2(CPUPPCState *env)
 #endif
 }
 
-static void init_excp_e200(CPUPPCState *env, target_ulong ivpr_mask)
+static void init_excp_e500(CPUPPCState *env, target_ulong ivpr_mask)
 {
 #if !defined(CONFIG_USER_ONLY)
     env->excp_vectors[POWERPC_EXCP_RESET]    = 0x00000FFC;
@@ -2782,149 +2782,6 @@ POWERPC_FAMILY(G2LE)(ObjectClass *oc, const void *data)
                  POWERPC_FLAG_BE | POWERPC_FLAG_BUS_CLK;
 }
 
-static void init_proc_e200(CPUPPCState *env)
-{
-    register_BookE_sprs(env, 0x000000070000FFFFULL);
-
-    spr_register(env, SPR_BOOKE_SPEFSCR, "SPEFSCR",
-                 &spr_read_spefscr, &spr_write_spefscr,
-                 &spr_read_spefscr, &spr_write_spefscr,
-                 0x00000000);
-    /* Memory management */
-    register_BookE206_sprs(env, 0x0000005D, NULL, 0);
-    register_usprgh_sprs(env);
-
-    spr_register(env, SPR_HID0, "HID0",
-                 SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
-                 0x00000000);
-
-    spr_register(env, SPR_HID1, "HID1",
-                 SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
-                 0x00000000);
-
-    spr_register(env, SPR_Exxx_ALTCTXCR, "ALTCTXCR",
-                 SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
-                 0x00000000);
-
-    spr_register(env, SPR_Exxx_BUCSR, "BUCSR",
-                 SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
-                 0x00000000);
-
-    spr_register(env, SPR_Exxx_CTXCR, "CTXCR",
-                 SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
-                 0x00000000);
-
-    spr_register(env, SPR_Exxx_DBCNT, "DBCNT",
-                 SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
-                 0x00000000);
-
-    spr_register(env, SPR_Exxx_DBCR3, "DBCR3",
-                 SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
-                 0x00000000);
-
-    spr_register(env, SPR_Exxx_L1CFG0, "L1CFG0",
-                 &spr_read_generic, SPR_NOACCESS,
-                 &spr_read_generic, SPR_NOACCESS,
-                 0x00000000);
-
-    spr_register(env, SPR_Exxx_L1CSR0, "L1CSR0",
-                 SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
-                 0x00000000);
-
-    spr_register(env, SPR_Exxx_L1FINV0, "L1FINV0",
-                 SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
-                 0x00000000);
-
-    spr_register(env, SPR_BOOKE_TLB0CFG, "TLB0CFG",
-                 SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
-                 0x00000000);
-
-    spr_register(env, SPR_BOOKE_TLB1CFG, "TLB1CFG",
-                 SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
-                 0x00000000);
-
-    spr_register(env, SPR_BOOKE_IAC3, "IAC3",
-                 SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
-                 0x00000000);
-
-    spr_register(env, SPR_BOOKE_IAC4, "IAC4",
-                 SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
-                 0x00000000);
-
-    spr_register(env, SPR_MMUCSR0, "MMUCSR0",
-                 SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
-                 0x00000000); /* TOFIX */
-
-    init_tlbs_emb(env);
-    init_excp_e200(env, 0xFFFF0000UL);
-    env->dcache_line_size = 32;
-    env->icache_line_size = 32;
-    /* XXX: TODO: allocate internal IRQ controller */
-}
-
-POWERPC_FAMILY(e200)(ObjectClass *oc, const void *data)
-{
-    DeviceClass *dc = DEVICE_CLASS(oc);
-    PowerPCCPUClass *pcc = POWERPC_CPU_CLASS(oc);
-
-    dc->desc = "e200 core";
-    pcc->init_proc = init_proc_e200;
-    pcc->check_pow = check_pow_hid0;
-    pcc->check_attn = check_attn_none;
-    /*
-     * XXX: unimplemented instructions:
-     * dcblc
-     * dcbtlst
-     * dcbtstls
-     * icblc
-     * icbtls
-     * tlbivax
-     * all SPE multiply-accumulate instructions
-     */
-    pcc->insns_flags = PPC_INSNS_BASE | PPC_ISEL |
-                       PPC_SPE | PPC_SPE_SINGLE |
-                       PPC_WRTEE | PPC_RFDI |
-                       PPC_CACHE | PPC_CACHE_LOCK | PPC_CACHE_ICBI |
-                       PPC_CACHE_DCBZ | PPC_CACHE_DCBA |
-                       PPC_MEM_TLBSYNC | PPC_TLBIVAX |
-                       PPC_BOOKE;
-    pcc->msr_mask = (1ull << MSR_UCLE) |
-                    (1ull << MSR_SPE) |
-                    (1ull << MSR_POW) |
-                    (1ull << MSR_CE) |
-                    (1ull << MSR_EE) |
-                    (1ull << MSR_PR) |
-                    (1ull << MSR_FP) |
-                    (1ull << MSR_ME) |
-                    (1ull << MSR_FE0) |
-                    (1ull << MSR_DWE) |
-                    (1ull << MSR_DE) |
-                    (1ull << MSR_FE1) |
-                    (1ull << MSR_IR) |
-                    (1ull << MSR_DR);
-    pcc->mmu_model = POWERPC_MMU_BOOKE206;
-    pcc->excp_model = POWERPC_EXCP_BOOKE;
-    pcc->bus_model = PPC_FLAGS_INPUT_BookE;
-    pcc->bfd_mach = bfd_mach_ppc_860;
-    pcc->flags = POWERPC_FLAG_SPE | POWERPC_FLAG_CE |
-                 POWERPC_FLAG_UBLE | POWERPC_FLAG_DE |
-                 POWERPC_FLAG_BUS_CLK;
-}
-
 enum fsl_e500_version {
     fsl_e500v1,
     fsl_e500v2,
@@ -3159,7 +3016,7 @@ static void init_proc_e500(CPUPPCState *env, int version)
     }
 #endif
 
-    init_excp_e200(env, ivpr_mask);
+    init_excp_e500(env, ivpr_mask);
     /* Allocate hardware IRQ controller */
     ppce500_irq_init(env_archcpu(env));
 }
-- 
2.51.0

Re: [PATCH v2 2/2] target/ppc: Remove the unusable e200 CPUs

[Philippe Mathieu-Daudé]

On 24/10/25 08:57, Thomas Huth wrote:
> From: Thomas Huth <thuth@redhat.com>
> 
> There is currently no machine in QEMU (except the "none" machine)
> that can be run with with one of the e200 ppc CPUs - all machines
> either complain about an invalid CPU type or crash QEMU immediately.
> 
> Looking at the history of this CPU type, it seems like it has never
> been used in QEMU and only implemented as a placeholder (see e.g. the
> comment about unimplemented instructions in the POWERPC_FAMILY(e200)
> section of cpu_init.c). Being completely unused and unusable since
> such a long time, let's just remove it now (without deprecation phase,
> since there were no users of this dead code anyway).
> 
> Note: The init_excp_e200() is used by the e500 CPUs, too, so we
> rename this function to init_excp_e500() instead of removing it.
> 
> Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>   target/ppc/cpu-models.h |   4 --
>   target/ppc/cpu-models.c |   5 --
>   target/ppc/cpu_init.c   | 147 +---------------------------------------
>   3 files changed, 2 insertions(+), 154 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

Re: [PATCH v2 0/2] target/ppc: Removal of the unusable e200 CPUs

[Harsh Prateek Bora]

On 10/24/25 12:27, Thomas Huth wrote:
> The second patch removes the unused e200 CPUs, see its patch description
> for the rationale.
> 
> Since the removal of the code causes GCC to inline another function,
> this suddenly triggered a false compiler warning, so we have to
> rework the related code first (see the first patch).
> 
> Thomas Huth (2):
>    target/ppc/cpu_init: Simplify the setup of the TLBxCFG SPR registers
>    target/ppc: Remove the unusable e200 CPUs
> 
>   target/ppc/cpu-models.h |   4 -
>   target/ppc/cpu-models.c |   5 --
>   target/ppc/cpu_init.c   | 185 +++-------------------------------------
>   3 files changed, 14 insertions(+), 180 deletions(-)
> 

Queued.