[PATCH 1/2] target/ppc: Implement the DEXCR and HDEXCR

[Nicholas Miehlbradt]

Define the DEXCR and HDEXCR as special purpose registers.

Each register occupies two SPR indicies, one which can be read in an
unprivileged state and one which can be modified in the appropriate
priviliged state, however both indicies refer to the same underlying
value.

Note that the ISA uses the abbreviation UDEXCR in two different
contexts: the userspace DEXCR, the SPR index which can be read from
userspace (implemented in this patch), and the ultravisor DEXCR, the
equivalent register for the ultravisor state (not implemented).

Signed-off-by: Nicholas Miehlbradt <nicholas@linux.ibm.com>
---
 target/ppc/cpu.h        | 19 +++++++++++++++++++
 target/ppc/cpu_init.c   | 25 +++++++++++++++++++++++++
 target/ppc/spr_common.h |  1 +
 target/ppc/translate.c  |  9 +++++++++
 4 files changed, 54 insertions(+)

diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index 81d4263a07..0ed9f2ae35 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -1068,6 +1068,21 @@ struct ppc_radix_page_info {
     uint32_t entries[PPC_PAGE_SIZES_MAX_SZ];
 };
 
+/*****************************************************************************/
+/* Dynamic Execution Control Register */
+
+#define DEXCR_ASPECT(name, num)                    \
+FIELD(DEXCR, PNH_##name, PPC_BIT_NR(num), 1)       \
+FIELD(DEXCR, PRO_##name, PPC_BIT_NR(num + 32), 1)  \
+FIELD(HDEXCR, HNU_##name, PPC_BIT_NR(num), 1)      \
+FIELD(HDEXCR, ENF_##name, PPC_BIT_NR(num + 32), 1) \
+
+DEXCR_ASPECT(SBHE, 0)
+DEXCR_ASPECT(IDRTPB, 1)
+DEXCR_ASPECT(SRAPD, 4)
+DEXCR_ASPECT(NPHIE, 5)
+DEXCR_ASPECT(PHIE, 6)
+
 /*****************************************************************************/
 /* The whole PowerPC CPU context */
 
@@ -1674,9 +1689,11 @@ void ppc_compat_add_property(Object *obj, const char 
*name,
 #define SPR_BOOKE_GIVOR13     (0x1BC)
 #define SPR_BOOKE_GIVOR14     (0x1BD)
 #define SPR_TIR               (0x1BE)
+#define SPR_UHDEXCR           (0x1C7)
 #define SPR_PTCR              (0x1D0)
 #define SPR_HASHKEYR          (0x1D4)
 #define SPR_HASHPKEYR         (0x1D5)
+#define SPR_HDEXCR            (0x1D7)
 #define SPR_BOOKE_SPEFSCR     (0x200)
 #define SPR_Exxx_BBEAR        (0x201)
 #define SPR_Exxx_BBTAR        (0x202)
@@ -1865,8 +1882,10 @@ void ppc_compat_add_property(Object *obj, const char 
*name,
 #define SPR_RCPU_L2U_RA2      (0x32A)
 #define SPR_MPC_MD_DBRAM1     (0x32A)
 #define SPR_RCPU_L2U_RA3      (0x32B)
+#define SPR_UDEXCR            (0x32C)
 #define SPR_TAR               (0x32F)
 #define SPR_ASDR              (0x330)
+#define SPR_DEXCR             (0x33C)
 #define SPR_IC                (0x350)
 #define SPR_VTB               (0x351)
 #define SPR_MMCRC             (0x353)
diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
index cbf0081374..d6b950feb6 100644
--- a/target/ppc/cpu_init.c
+++ b/target/ppc/cpu_init.c
@@ -5727,6 +5727,30 @@ static void register_power10_hash_sprs(CPUPPCState *env)
             hashpkeyr_initial_value);
 }
 
+static void register_power10_dexcr_sprs(CPUPPCState *env)
+{
+    spr_register(env, SPR_DEXCR, "DEXCR",
+            SPR_NOACCESS, SPR_NOACCESS,
+            &spr_read_generic, &spr_write_dexcr,
+            0);
+
+    spr_register(env, SPR_UDEXCR, "DEXCR",
+            &spr_read_generic, SPR_NOACCESS,
+            &spr_read_generic, SPR_NOACCESS,
+            0);
+
+    spr_register_hv(env, SPR_HDEXCR, "HDEXCR",
+            SPR_NOACCESS, SPR_NOACCESS,
+            SPR_NOACCESS, SPR_NOACCESS,
+            &spr_read_generic, &spr_write_dexcr,
+            0);
+
+    spr_register(env, SPR_UHDEXCR, "HDEXCR",
+            &spr_read_generic, SPR_NOACCESS,
+            &spr_read_generic, SPR_NOACCESS,
+            0);
+}
+
 /*
  * Initialize PMU counter overflow timers for Power8 and
  * newer Power chips when using TCG.
@@ -6402,6 +6426,7 @@ static void init_proc_POWER10(CPUPPCState *env)
     register_power8_rpr_sprs(env);
     register_power9_mmu_sprs(env);
     register_power10_hash_sprs(env);
+    register_power10_dexcr_sprs(env);
 
     /* FIXME: Filter fields properly based on privilege level */
     spr_register_kvm_hv(env, SPR_PSSCR, "PSSCR", NULL, NULL, NULL, NULL,
diff --git a/target/ppc/spr_common.h b/target/ppc/spr_common.h
index b5a5bc6895..3cfa500250 100644
--- a/target/ppc/spr_common.h
+++ b/target/ppc/spr_common.h
@@ -195,6 +195,7 @@ void spr_read_ebb_upper32(DisasContext *ctx, int gprn, int 
sprn);
 void spr_write_ebb_upper32(DisasContext *ctx, int sprn, int gprn);
 void spr_write_hmer(DisasContext *ctx, int sprn, int gprn);
 void spr_write_lpcr(DisasContext *ctx, int sprn, int gprn);
+void spr_write_dexcr(DisasContext *ctx, int sprn, int gprn);
 #endif
 
 void register_low_BATs(CPUPPCState *env);
diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index 19c1d17cb0..24e9e2fece 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -1249,6 +1249,15 @@ void spr_write_ebb_upper32(DisasContext *ctx, int sprn, 
int gprn)
     gen_fscr_facility_check(ctx, SPR_FSCR, FSCR_EBB, sprn, FSCR_IC_EBB);
     spr_write_prev_upper32(ctx, sprn, gprn);
 }
+
+void spr_write_dexcr(DisasContext *ctx, int sprn, int gprn)
+{
+    TCGv t0 = tcg_temp_new();
+    spr_write_generic(ctx, sprn, gprn);
+    tcg_gen_ext32u_tl(t0, cpu_gpr[gprn]);
+    gen_store_spr(sprn - 16, t0);
+    tcg_temp_free(t0);
+}
 #endif
 
 #define GEN_HANDLER(name, opc1, opc2, opc3, inval, type)                      \
-- 
2.34.1