AArch32: Disable Secure Cycle Counter
authorAlexei Fedorov <Alexei.Fedorov@arm.com>
Tue, 20 Aug 2019 14:22:44 +0000 (15:22 +0100)
committerPaul Beesley <paul.beesley@arm.com>
Thu, 26 Sep 2019 15:36:02 +0000 (15:36 +0000)
This patch changes implementation for disabling Secure Cycle
Counter. For ARMv8.5 the counter gets disabled by setting
SDCR.SCCD bit on CPU cold/warm boot. For the earlier
architectures PMCR register is saved/restored on secure
world entry/exit from/to Non-secure state, and cycle counting
gets disabled by setting PMCR.DP bit.
In 'include\aarch32\arch.h' header file new
ARMv8.5-PMU related definitions were added.

Change-Id: Ia8845db2ebe8de940d66dff479225a5b879316f8
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>
bl32/sp_min/aarch32/entrypoint.S
include/arch/aarch32/arch.h
include/arch/aarch32/el3_common_macros.S
include/arch/aarch32/smccc_macros.S
lib/el3_runtime/aarch32/context_mgmt.c

index 2ffef6a2ee52f3f7b201c765d6893f1a1143de78..0a684754cef8b643ee7f94b794d9c74308198689 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -183,15 +183,6 @@ func sp_min_handle_smc
        stcopr  r0, SCR
        isb
 
-       /*
-        * Set PMCR.DP to 1 to prohibit cycle counting whilst in Secure Mode.
-        * Also, the PMCR.LC field has an architecturally UNKNOWN value on reset
-        * and so set to 1 as ARM has deprecated use of PMCR.LC=0.
-        */
-       ldcopr  r0, PMCR
-       orr     r0, r0, #(PMCR_LC_BIT | PMCR_DP_BIT)
-       stcopr  r0, PMCR
-
        ldr     r0, [r2, #SMC_CTX_GPREG_R0]     /* smc_fid */
        /* Check whether an SMC64 is issued */
        tst     r0, #(FUNCID_CC_MASK << FUNCID_CC_SHIFT)
@@ -236,15 +227,6 @@ func sp_min_handle_fiq
        stcopr  r0, SCR
        isb
 
-       /*
-        * Set PMCR.DP to 1 to prohibit cycle counting whilst in Secure Mode.
-        * Also, the PMCR.LC field has an architecturally UNKNOWN value on reset
-        * and so set to 1 as ARM has deprecated use of PMCR.LC=0.
-        */
-       ldcopr  r0, PMCR
-       orr     r0, r0, #(PMCR_LC_BIT | PMCR_DP_BIT)
-       stcopr  r0, PMCR
-
        push    {r2, r3}
        bl      sp_min_fiq
        pop     {r0, r3}
index 34036d78526d328e18224e6e7f1e24698f8eb69f..20175481f002f4fb0cfc781a8edbcff4e5125aea 100644 (file)
 #define SDCR_SPD_DISABLE       U(0x2)
 #define SDCR_SPD_ENABLE                U(0x3)
 #define SDCR_SCCD_BIT          (U(1) << 23)
+#define SDCR_SPME_BIT          (U(1) << 17)
 #define SDCR_RESET_VAL         U(0x0)
 
 /* HSCTLR definitions */
 #define VTTBR_BADDR_SHIFT      U(0)
 
 /* HDCR definitions */
+#define HDCR_HLP_BIT           (U(1) << 26)
+#define HDCR_HPME_BIT          (U(1) << 7)
 #define HDCR_RESET_VAL         U(0x0)
 
 /* HSTR definitions */
 #define PMCR_N_SHIFT           U(11)
 #define PMCR_N_MASK            U(0x1f)
 #define PMCR_N_BITS            (PMCR_N_MASK << PMCR_N_SHIFT)
+#define PMCR_LP_BIT            (U(1) << 7)
 #define PMCR_LC_BIT            (U(1) << 6)
 #define PMCR_DP_BIT            (U(1) << 5)
+#define        PMCR_RESET_VAL          U(0x0)
 
 /*******************************************************************************
  * Definitions of register offsets, fields and macros for CPU system
index 0bd8978145503342ad8974337b27c4d1ea01b795..c62d7d772d58f55ab6c78e071b8b692675faf0ab 100644 (file)
         * SDCR.SPD: Disable AArch32 privileged debug. Debug exceptions from
         *  Secure EL1 are disabled.
         *
-        * SDCR: Set to one so that cycle counting by PMCCNTR is prohibited in
-        *  Secure state. This bit is RES0 in versions of the architecture
+        * SDCR.SCCD: Set to one so that cycle counting by PMCCNTR is prohibited
+        *  in Secure state. This bit is RES0 in versions of the architecture
         *  earlier than ARMv8.5, setting it to 1 doesn't have any effect on
         *  them.
         * ---------------------------------------------------------------------
         */
        ldr     r0, =(SDCR_RESET_VAL | SDCR_SPD(SDCR_SPD_DISABLE) | SDCR_SCCD_BIT)
        stcopr  r0, SDCR
+
+       /* ---------------------------------------------------------------------
+        * Initialise PMCR, setting all fields rather than relying
+        * on hw. Some fields are architecturally UNKNOWN on reset.
+        *
+        * PMCR.LP: Set to one so that event counter overflow, that
+        *  is recorded in PMOVSCLR[0-30], occurs on the increment
+        *  that changes PMEVCNTR<n>[63] from 1 to 0, when ARMv8.5-PMU
+        *  is implemented. This bit is RES0 in versions of the architecture
+        *  earlier than ARMv8.5, setting it to 1 doesn't have any effect
+        *  on them.
+        *  This bit is Reserved, UNK/SBZP in ARMv7.
+        *
+        * PMCR.LC: Set to one so that cycle counter overflow, that
+        *  is recorded in PMOVSCLR[31], occurs on the increment
+        *  that changes PMCCNTR[63] from 1 to 0.
+        *  This bit is Reserved, UNK/SBZP in ARMv7.
+        *
+        * PMCR.DP: Set to one to prohibit cycle counting whilst in Secure mode.
+        * ---------------------------------------------------------------------
+        */
+       ldr     r0, =(PMCR_RESET_VAL | PMCR_DP_BIT | PMCR_LC_BIT | \
+                     PMCR_LP_BIT)
+#else
+       ldr     r0, =(PMCR_RESET_VAL | PMCR_DP_BIT)
 #endif
+       stcopr  r0, PMCR
 
        /*
         * If Data Independent Timing (DIT) functionality is implemented,
index 1fe6c64dcdc6757399e410162d0f98703f3958e9..4ec229218fdaa284a0dbabc39906b3327c3b95ad 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -58,7 +58,6 @@
        stm     r0!, {r2}
 
        stcopr  r4, SCR
-       isb
 #else
        /* Save the banked registers including the current SPSR and LR */
        mrs     r4, sp_usr
        /* lr_mon is already saved by caller */
 
        ldcopr  r4, SCR
+
+#if ARM_ARCH_MAJOR > 7
+       /*
+        * Check if earlier initialization of SDCR.SCCD to 1
+        * failed, meaning that ARMv8-PMU is not implemented,
+        * cycle counting is not disabled and PMCR should be
+        * saved in Non-secure context.
+        */
+       ldcopr  r5, SDCR
+       tst     r5, #SDCR_SCCD_BIT
+       bne     1f
+#endif
+       /* Secure Cycle Counter is not disabled */
 #endif
-       str     r4, [sp, #SMC_CTX_SCR]
-       ldcopr  r4, PMCR
-       str     r4, [sp, #SMC_CTX_PMCR]
+       ldcopr  r5, PMCR
+
+       /* Check caller's security state */
+       tst     r4, #SCR_NS_BIT
+       beq     2f
+
+       /* Save PMCR if called from Non-secure state */
+       str     r5, [sp, #SMC_CTX_PMCR]
+
+       /* Disable cycle counter when event counting is prohibited */
+2:     orr     r5, r5, #PMCR_DP_BIT
+       stcopr  r5, PMCR
+       isb
+1:     str     r4, [sp, #SMC_CTX_SCR]
        .endm
 
 /*
        stcopr  r1, SCR
        isb
 
+       /*
+        * Restore PMCR when returning to Non-secure state
+        */
+       tst     r1, #SCR_NS_BIT
+       beq     2f
+
+       /*
+        * Back to Non-secure state
+        */
+#if ARM_ARCH_MAJOR > 7
+       /*
+        * Check if earlier initialization SDCR.SCCD to 1
+        * failed, meaning that ARMv8-PMU is not implemented and
+        * PMCR should be restored from Non-secure context.
+        */
+       ldcopr  r1, SDCR
+       tst     r1, #SDCR_SCCD_BIT
+       bne     2f
+#endif
        /*
         * Restore the PMCR register.
         */
        ldr     r1, [r0, #SMC_CTX_PMCR]
        stcopr  r1, PMCR
-
+2:
        /* Restore the banked registers including the current SPSR */
        add     r1, r0, #SMC_CTX_SP_USR
 
index a4702fcc60f3d2eb7040f80c1089131c569667af..73d1e354d5f1eb798faa0cab44d78f3658ce936c 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -281,10 +281,28 @@ void cm_prepare_el3_exit(uint32_t security_state)
                         *
                         * HDCR.HPMN: Set to value of PMCR.N which is the
                         *  architecturally-defined reset value.
+                        *
+                        * HDCR.HLP: Set to one so that event counter
+                        *  overflow, that is recorded in PMOVSCLR[0-30],
+                        *  occurs on the increment that changes
+                        *  PMEVCNTR<n>[63] from 1 to 0, when ARMv8.5-PMU is
+                        *  implemented. This bit is RES0 in versions of the
+                        *  architecture earlier than ARMv8.5, setting it to 1
+                        *  doesn't have any effect on them.
+                        *  This bit is Reserved, UNK/SBZP in ARMv7.
+                        *
+                        * HDCR.HPME: Set to zero to disable EL2 Event
+                        *  counters.
                         */
-                       write_hdcr(HDCR_RESET_VAL |
-                               ((read_pmcr() & PMCR_N_BITS) >> PMCR_N_SHIFT));
-
+#if (ARM_ARCH_MAJOR > 7)
+                       write_hdcr((HDCR_RESET_VAL | HDCR_HLP_BIT |
+                                  ((read_pmcr() & PMCR_N_BITS) >>
+                                   PMCR_N_SHIFT)) & ~HDCR_HPME_BIT);
+#else
+                       write_hdcr((HDCR_RESET_VAL |
+                                  ((read_pmcr() & PMCR_N_BITS) >>
+                                   PMCR_N_SHIFT)) & ~HDCR_HPME_BIT);
+#endif
                        /*
                         * Set HSTR to its architectural reset value so that
                         * access to system registers in the cproc=1111