diff mbox series

[2/2] target/arm: Implement ARMv8.0-PredRes

Message ID 20190220235017.1060-3-richard.henderson@linaro.org
State Superseded
Headers show
Series target/arm: SB and PredRes extensions | expand

Commit Message

Richard Henderson Feb. 20, 2019, 11:50 p.m. UTC
This is named "Execution and Data prediction restriction instructions"
within the ARMv8.5 manual, and given the name "PredRes" by binutils.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

---
 target/arm/cpu.h    | 11 ++++++++++
 target/arm/cpu.c    |  1 +
 target/arm/cpu64.c  |  2 ++
 target/arm/helper.c | 49 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 63 insertions(+)

-- 
2.17.2

Comments

Peter Maydell Feb. 26, 2019, 6:44 p.m. UTC | #1
On Wed, 20 Feb 2019 at 23:50, Richard Henderson
<richard.henderson@linaro.org> wrote:
>

> This is named "Execution and Data prediction restriction instructions"

> within the ARMv8.5 manual, and given the name "PredRes" by binutils.


The official name is v8.0-PredInv.
(You can see this used in the xml descriptions for the new insns, eg:
https://developer.arm.com/docs/ddi0595/b/aarch64-system-instructions/cfp-rctx )


>

> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

> ---

>  target/arm/cpu.h    | 11 ++++++++++

>  target/arm/cpu.c    |  1 +

>  target/arm/cpu64.c  |  2 ++

>  target/arm/helper.c | 49 +++++++++++++++++++++++++++++++++++++++++++++

>  4 files changed, 63 insertions(+)

>

> diff --git a/target/arm/cpu.h b/target/arm/cpu.h

> index 76d6a73c0e..202ff1f1ea 100644

> --- a/target/arm/cpu.h

> +++ b/target/arm/cpu.h

> @@ -1074,6 +1074,7 @@ void pmu_init(ARMCPU *cpu);

>  #define SCTLR_UMA     (1U << 9) /* v8 onward, AArch64 only */

>  #define SCTLR_F       (1U << 10) /* up to v6 */

>  #define SCTLR_SW      (1U << 10) /* v7, RES0 in v8 */

> +#define SCTLR_EnRCTX  (1U << 10) /* in v8.0-specres */


You should delete the "RES0 in v8" from the preceding comment
(and update the feature name to v8.0-PredInv).

>  #define SCTLR_Z       (1U << 11) /* in v7, RES1 in v8 */

>  #define SCTLR_EOS     (1U << 11) /* v8.5-ExS */

>  #define SCTLR_I       (1U << 12)


> +

> +    /* All v8.0-a cpus support aarch64.  */


True, but why is it relevant here ?

> +    if (cpu_isar_feature(aa64_specres, cpu)) {

> +        define_arm_cp_regs(cpu, specres_reginfo);

> +    }

>  }

>

>  void arm_cpu_register_gdb_regs_for_features(ARMCPU *cpu)

> --

> 2.17.2


Otherwise
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>


thanks
-- PMM
Richard Henderson Feb. 26, 2019, 6:52 p.m. UTC | #2
On 2/26/19 10:44 AM, Peter Maydell wrote:
> On Wed, 20 Feb 2019 at 23:50, Richard Henderson

> <richard.henderson@linaro.org> wrote:

>>

>> This is named "Execution and Data prediction restriction instructions"

>> within the ARMv8.5 manual, and given the name "PredRes" by binutils.

> 

> The official name is v8.0-PredInv.

> (You can see this used in the xml descriptions for the new insns, eg:

> https://developer.arm.com/docs/ddi0595/b/aarch64-system-instructions/cfp-rctx )


Thanks.  I may file a bug against binutils.  ;-)

>> +

>> +    /* All v8.0-a cpus support aarch64.  */

> 

> True, but why is it relevant here ?

> 

>> +    if (cpu_isar_feature(aa64_specres, cpu)) {

>> +        define_arm_cp_regs(cpu, specres_reginfo);

>> +    }


The context, I think, is that we're in a function that handles a32,
and I am not checking arm_feature(cpu, ARM_FEATURE_AARCH64) before
checking cpu_isar_feature(aa64_specres, cpu).

At least that's my recollection.


r~
Peter Maydell Feb. 26, 2019, 6:53 p.m. UTC | #3
On Tue, 26 Feb 2019 at 18:52, Richard Henderson
<richard.henderson@linaro.org> wrote:
>

> On 2/26/19 10:44 AM, Peter Maydell wrote:

> > On Wed, 20 Feb 2019 at 23:50, Richard Henderson

> > <richard.henderson@linaro.org> wrote:

> >>

> >> This is named "Execution and Data prediction restriction instructions"

> >> within the ARMv8.5 manual, and given the name "PredRes" by binutils.

> >

> > The official name is v8.0-PredInv.

> > (You can see this used in the xml descriptions for the new insns, eg:

> > https://developer.arm.com/docs/ddi0595/b/aarch64-system-instructions/cfp-rctx )

>

> Thanks.  I may file a bug against binutils.  ;-)

>

> >> +

> >> +    /* All v8.0-a cpus support aarch64.  */

> >

> > True, but why is it relevant here ?

> >

> >> +    if (cpu_isar_feature(aa64_specres, cpu)) {

> >> +        define_arm_cp_regs(cpu, specres_reginfo);

> >> +    }

>

> The context, I think, is that we're in a function that handles a32,

> and I am not checking arm_feature(cpu, ARM_FEATURE_AARCH64) before

> checking cpu_isar_feature(aa64_specres, cpu).

>

> At least that's my recollection.


Ah, so in theory if we had a v8.0 CPU which was AArch32 only
it would not have those ID bits set and fail to register
these registers. I'm pretty sure it would also not work in
a bunch of other ways too...

thanks
-- PMM
diff mbox series

Patch

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 76d6a73c0e..202ff1f1ea 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -1074,6 +1074,7 @@  void pmu_init(ARMCPU *cpu);
 #define SCTLR_UMA     (1U << 9) /* v8 onward, AArch64 only */
 #define SCTLR_F       (1U << 10) /* up to v6 */
 #define SCTLR_SW      (1U << 10) /* v7, RES0 in v8 */
+#define SCTLR_EnRCTX  (1U << 10) /* in v8.0-specres */
 #define SCTLR_Z       (1U << 11) /* in v7, RES1 in v8 */
 #define SCTLR_EOS     (1U << 11) /* v8.5-ExS */
 #define SCTLR_I       (1U << 12)
@@ -3307,6 +3308,11 @@  static inline bool isar_feature_aa32_sb(const ARMISARegisters *id)
     return FIELD_EX32(id->id_isar6, ID_ISAR6, SB) != 0;
 }
 
+static inline bool isar_feature_aa32_specres(const ARMISARegisters *id)
+{
+    return FIELD_EX32(id->id_isar6, ID_ISAR6, SPECRES) != 0;
+}
+
 static inline bool isar_feature_aa32_fp16_arith(const ARMISARegisters *id)
 {
     /*
@@ -3415,6 +3421,11 @@  static inline bool isar_feature_aa64_sb(const ARMISARegisters *id)
     return FIELD_EX64(id->id_aa64isar1, ID_AA64ISAR1, SB) != 0;
 }
 
+static inline bool isar_feature_aa64_specres(const ARMISARegisters *id)
+{
+    return FIELD_EX64(id->id_aa64isar1, ID_AA64ISAR1, SPECRES) != 0;
+}
+
 static inline bool isar_feature_aa64_fp16(const ARMISARegisters *id)
 {
     /* We always set the AdvSIMD and FP fields identically wrt FP16.  */
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 5cd27f2f64..c1d2848baa 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -2028,6 +2028,7 @@  static void arm_max_initfn(Object *obj)
             t = cpu->isar.id_isar6;
             t = FIELD_DP32(t, ID_ISAR6, DP, 1);
             t = FIELD_DP32(t, ID_ISAR6, SB, 1);
+            t = FIELD_DP32(t, ID_ISAR6, SPECRES, 1);
             cpu->isar.id_isar6 = t;
 
             t = cpu->id_mmfr4;
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index 95c6ee4cda..5f273399db 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -344,6 +344,7 @@  static void aarch64_max_initfn(Object *obj)
         t = FIELD_DP64(t, ID_AA64ISAR1, GPA, 1);
         t = FIELD_DP64(t, ID_AA64ISAR1, GPI, 0);
         t = FIELD_DP64(t, ID_AA64ISAR1, SB, 1);
+        t = FIELD_DP64(t, ID_AA64ISAR1, SPECRES, 1);
         cpu->isar.id_aa64isar1 = t;
 
         t = cpu->isar.id_aa64pfr0;
@@ -375,6 +376,7 @@  static void aarch64_max_initfn(Object *obj)
         u = cpu->isar.id_isar6;
         u = FIELD_DP32(u, ID_ISAR6, DP, 1);
         u = FIELD_DP32(u, ID_ISAR6, SB, 1);
+        u = FIELD_DP32(u, ID_ISAR6, SPECRES, 1);
         cpu->isar.id_isar6 = u;
 
         /*
diff --git a/target/arm/helper.c b/target/arm/helper.c
index a2ab300051..c34b1401bd 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -5884,6 +5884,50 @@  static const ARMCPRegInfo mte_reginfo[] = {
 };
 #endif
 
+static CPAccessResult access_specres(CPUARMState *env, const ARMCPRegInfo *ri,
+                                     bool isread)
+{
+    int el = arm_current_el(env);
+
+    if (el == 0) {
+        uint64_t sctlr = arm_sctlr(env, el);
+        if (!(sctlr & SCTLR_EnRCTX)) {
+            return CP_ACCESS_TRAP;
+        }
+    } else if (el == 1) {
+        uint64_t hcr = arm_hcr_el2_eff(env);
+        if (hcr & HCR_NV) {
+            return CP_ACCESS_TRAP_EL2;
+        }
+    }
+    return CP_ACCESS_OK;
+}
+
+static const ARMCPRegInfo specres_reginfo[] = {
+    { .name = "CFP_RCTX", .state = ARM_CP_STATE_AA64,
+      .opc0 = 1, .opc1 = 3, .crn = 7, .crm = 3, .opc2 = 4,
+      .type = ARM_CP_NOP, .access = PL0_W, .accessfn = access_specres },
+    { .name = "DVP_RCTX", .state = ARM_CP_STATE_AA64,
+      .opc0 = 1, .opc1 = 3, .crn = 7, .crm = 3, .opc2 = 5,
+      .type = ARM_CP_NOP, .access = PL0_W, .accessfn = access_specres },
+    { .name = "CPP_RCTX", .state = ARM_CP_STATE_AA64,
+      .opc0 = 1, .opc1 = 3, .crn = 7, .crm = 3, .opc2 = 7,
+      .type = ARM_CP_NOP, .access = PL0_W, .accessfn = access_specres },
+    /*
+     * Note the AArch32 opcodes have a different OPC1.
+     */
+    { .name = "CFPRCTX", .state = ARM_CP_STATE_AA32,
+      .cp = 15, .opc1 = 0, .crn = 7, .crm = 3, .opc2 = 4,
+      .type = ARM_CP_NOP, .access = PL0_W, .accessfn = access_specres },
+    { .name = "DVPRCTX", .state = ARM_CP_STATE_AA32,
+      .cp = 15, .opc1 = 0, .crn = 7, .crm = 3, .opc2 = 5,
+      .type = ARM_CP_NOP, .access = PL0_W, .accessfn = access_specres },
+    { .name = "CPPRCTX", .state = ARM_CP_STATE_AA32,
+      .cp = 15, .opc1 = 0, .crn = 7, .crm = 3, .opc2 = 7,
+      .type = ARM_CP_NOP, .access = PL0_W, .accessfn = access_specres },
+    REGINFO_SENTINEL
+};
+
 void register_cp_regs_for_features(ARMCPU *cpu)
 {
     /* Register all the coprocessor registers based on feature bits */
@@ -6786,6 +6830,11 @@  void register_cp_regs_for_features(ARMCPU *cpu)
         define_arm_cp_regs(cpu, mte_reginfo);
     }
 #endif
+
+    /* All v8.0-a cpus support aarch64.  */
+    if (cpu_isar_feature(aa64_specres, cpu)) {
+        define_arm_cp_regs(cpu, specres_reginfo);
+    }
 }
 
 void arm_cpu_register_gdb_regs_for_features(ARMCPU *cpu)