target/ppc: Implement the DEXCR and HDEXCR

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>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20221220042330.2387944-2-nicholas@linux.ibm.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>

diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index 81d4263a073fadd9b80cfa4c94b277459178cbfd..3923f174f8c63dd427274e8184a0ac63d12cf908 100644 (file)
--- 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(IBRTPD, 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 95d25856a0e092864613e44a215ed677a9300a94..abee71d4072c8b4a8fe1aef9ebf6da84b6f3d816 100644 (file)
--- 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_generic,
+            0);
+
+    spr_register(env, SPR_UDEXCR, "DEXCR",
+            &spr_read_dexcr_ureg, SPR_NOACCESS,
+            &spr_read_dexcr_ureg, SPR_NOACCESS,
+            0);
+
+    spr_register_hv(env, SPR_HDEXCR, "HDEXCR",
+            SPR_NOACCESS, SPR_NOACCESS,
+            SPR_NOACCESS, SPR_NOACCESS,
+            &spr_read_generic, &spr_write_generic,
+            0);
+
+    spr_register(env, SPR_UHDEXCR, "HDEXCR",
+            &spr_read_dexcr_ureg, SPR_NOACCESS,
+            &spr_read_dexcr_ureg, 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 b5a5bc68952e28436cb542c7619c37f0704e6125..8437eb03401cc708397ac2af57b22f5d3ba45dd7 100644 (file)
--- 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_read_dexcr_ureg(DisasContext *ctx, int gprn, int sprn);
 #endif
 
 void register_low_BATs(CPUPPCState *env);

diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index 19c1d17cb026e5981ad311f896fd69246a619f72..edb3daa9b503921b95a9fc82fa5c2f323a6e0fa5 100644 (file)
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -1249,6 +1249,25 @@ 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_read_dexcr_ureg(DisasContext *ctx, int gprn, int sprn)
+{
+    TCGv t0 = tcg_temp_new();
+
+    /*
+     * Access to the (H)DEXCR in problem state is done using separated
+     * SPR indexes which are 16 below the SPR indexes which have full
+     * access to the (H)DEXCR in privileged state. Problem state can
+     * only read bits 32:63, bits 0:31 return 0.
+     *
+     * See section 9.3.1-9.3.2 of PowerISA v3.1B
+     */
+
+    gen_load_spr(t0, sprn + 16);
+    tcg_gen_ext32u_tl(cpu_gpr[gprn], t0);
+
+    tcg_temp_free(t0);
+}
 #endif
 
 #define GEN_HANDLER(name, opc1, opc2, opc3, inval, type)                      \