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From: Peter Maydell <peter.maydell@linaro.org>
To: qemu-arm@nongnu.org, qemu-devel@nongnu.org
Cc: "Eric Auger" <eric.auger@redhat.com>,
	"Aaron Lindsay" <aaron@os.amperecomputing.com>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Philippe Mathieu-Daudé" <philmd@redhat.com>
Subject: [PATCH v2 17/21] target/arm: Correct handling of PMCR_EL0.LC bit
Date: Fri, 14 Feb 2020 17:51:12 +0000	[thread overview]
Message-ID: <20200214175116.9164-18-peter.maydell@linaro.org> (raw)
In-Reply-To: <20200214175116.9164-1-peter.maydell@linaro.org>

The LC bit in the PMCR_EL0 register is supposed to be:
 * read/write
 * RES1 on an AArch64-only implementation
 * an architecturally UNKNOWN value on reset
(and use of LC==0 by software is deprecated).

We were implementing it incorrectly as read-only always zero,
though we do have all the code needed to test it and behave
accordingly.

Instead make it a read-write bit which resets to 1 always, which
satisfies all the architectural requirements above.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/helper.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 2ebfa6c6545..468e4e89848 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -1023,6 +1023,11 @@ static const ARMCPRegInfo v6_cp_reginfo[] = {
 #define PMCRC   0x4
 #define PMCRP   0x2
 #define PMCRE   0x1
+/*
+ * Mask of PMCR bits writeable by guest (not including WO bits like C, P,
+ * which can be written as 1 to trigger behaviour but which stay RAZ).
+ */
+#define PMCR_WRITEABLE_MASK (PMCRLC | PMCRDP | PMCRX | PMCRD | PMCRE)
 
 #define PMXEVTYPER_P          0x80000000
 #define PMXEVTYPER_U          0x40000000
@@ -1577,9 +1582,8 @@ static void pmcr_write(CPUARMState *env, const ARMCPRegInfo *ri,
         }
     }
 
-    /* only the DP, X, D and E bits are writable */
-    env->cp15.c9_pmcr &= ~0x39;
-    env->cp15.c9_pmcr |= (value & 0x39);
+    env->cp15.c9_pmcr &= ~PMCR_WRITEABLE_MASK;
+    env->cp15.c9_pmcr |= (value & PMCR_WRITEABLE_MASK);
 
     pmu_op_finish(env);
 }
@@ -6370,7 +6374,8 @@ static void define_pmu_regs(ARMCPU *cpu)
         .access = PL0_RW, .accessfn = pmreg_access,
         .type = ARM_CP_IO,
         .fieldoffset = offsetof(CPUARMState, cp15.c9_pmcr),
-        .resetvalue = (cpu->midr & 0xff000000) | (pmcrn << PMCRN_SHIFT),
+        .resetvalue = (cpu->midr & 0xff000000) | (pmcrn << PMCRN_SHIFT) |
+                      PMCRLC,
         .writefn = pmcr_write, .raw_writefn = raw_write,
     };
     define_one_arm_cp_reg(cpu, &pmcr);
-- 
2.20.1



  parent reply	other threads:[~2020-02-14 18:03 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-14 17:50 [PATCH v2 00/21] arm: ARMv8.1- and v8.4-PMU, ID reg cleanup, [H]ACTLR2 Peter Maydell
2020-02-14 17:50 ` [PATCH v2 01/21] target/arm: Add _aa32_ to isar_feature functions testing 32-bit ID registers Peter Maydell
2020-02-14 17:50 ` [PATCH v2 02/21] target/arm: Check aa32_pan in take_aarch32_exception(), not aa64_pan Peter Maydell
2020-02-14 20:10   ` Richard Henderson
2020-02-14 17:50 ` [PATCH v2 03/21] target/arm: Add isar_feature_any_fp16 and document naming/usage conventions Peter Maydell
2020-02-14 17:50 ` [PATCH v2 04/21] target/arm: Define and use any_predinv isar_feature test Peter Maydell
2020-02-14 17:51 ` [PATCH v2 05/21] target/arm: Factor out PMU register definitions Peter Maydell
2020-02-14 17:51 ` [PATCH v2 06/21] target/arm: Add and use FIELD definitions for ID_AA64DFR0_EL1 Peter Maydell
2020-02-14 17:51 ` [PATCH v2 07/21] target/arm: Use FIELD macros for clearing ID_DFR0 PERFMON field Peter Maydell
2020-02-14 17:51 ` [PATCH v2 08/21] target/arm: Define an aa32_pmu_8_1 isar feature test function Peter Maydell
2020-02-14 17:51 ` [PATCH v2 09/21] target/arm: Add _aa64_ and _any_ versions of pmu_8_1 isar checks Peter Maydell
2020-02-14 17:51 ` [PATCH v2 10/21] target/arm: Stop assuming DBGDIDR always exists Peter Maydell
2020-02-14 20:15   ` Richard Henderson
2020-02-14 17:51 ` [PATCH v2 11/21] target/arm: Move DBGDIDR into ARMISARegisters Peter Maydell
2020-02-14 20:16   ` Richard Henderson
2020-02-14 17:51 ` [PATCH v2 12/21] target/arm: Read debug-related ID registers from KVM Peter Maydell
2020-02-14 20:27   ` Richard Henderson
2020-02-14 17:51 ` [PATCH v2 13/21] target/arm: Implement ARMv8.1-PMU extension Peter Maydell
2020-02-14 17:51 ` [PATCH v2 14/21] target/arm: Implement ARMv8.4-PMU extension Peter Maydell
2020-02-14 17:51 ` [PATCH v2 15/21] target/arm: Provide ARMv8.4-PMU in '-cpu max' Peter Maydell
2020-02-14 17:51 ` [PATCH v2 16/21] target/arm: Correct definition of PMCRDP Peter Maydell
2020-02-14 17:51 ` Peter Maydell [this message]
2020-02-14 17:51 ` [PATCH v2 18/21] target/arm: Test correct register in aa32_pan and aa32_ats1e1 checks Peter Maydell
2020-02-14 20:30   ` Richard Henderson
2020-02-14 17:51 ` [PATCH v2 19/21] target/arm: Use isar_feature function for testing AA32HPD feature Peter Maydell
2020-02-14 20:32   ` Richard Henderson
2020-02-14 17:51 ` [PATCH v2 20/21] target/arm: Use FIELD_EX32 for testing 32-bit fields Peter Maydell
2020-02-14 20:32   ` Richard Henderson
2020-02-14 17:51 ` [PATCH v2 21/21] target/arm: Correctly implement ACTLR2, HACTLR2 Peter Maydell
2020-02-14 20:42   ` Richard Henderson

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