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arm-trusted-firmware/AArch32-Disable-Secure-Cycle-Counter.patch
wang_yue111 5b4284482d fix CVE-2017-15031
2020-09-17 10:58:53 +08:00

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From 659a2c0e2ce3d8cb72020234095ecec10a1d0ebd Mon Sep 17 00:00:00 2001
From: Alexei Fedorov <Alexei.Fedorov@arm.com>
Date: Tue, 20 Aug 2019 15:22:44 +0100
Subject: AArch32: Disable Secure Cycle Counter
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 | 20 +-------
include/common/aarch32/el3_common_macros.S | 5 ++
include/lib/aarch32/arch.h | 5 ++
include/lib/aarch32/smccc_macros.S | 54 +++++++++++++++++++---
lib/el3_runtime/aarch32/context_mgmt.c | 26 +++++++++--
5 files changed, 81 insertions(+), 29 deletions(-)
diff --git a/bl32/sp_min/aarch32/entrypoint.S b/bl32/sp_min/aarch32/entrypoint.S
index d6853cc..d9cb176 100644
--- a/bl32/sp_min/aarch32/entrypoint.S
+++ b/bl32/sp_min/aarch32/entrypoint.S
@@ -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}
diff --git a/include/common/aarch32/el3_common_macros.S b/include/common/aarch32/el3_common_macros.S
index 5db8854..a0abf88 100644
--- a/include/common/aarch32/el3_common_macros.S
+++ b/include/common/aarch32/el3_common_macros.S
@@ -108,7 +108,12 @@
*/
ldr r0, =(SDCR_RESET_VAL | SDCR_SPD(SDCR_SPD_DISABLE))
stcopr r0, SDCR
+ 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
.endm
diff --git a/include/lib/aarch32/arch.h b/include/lib/aarch32/arch.h
index f9ed56e..a0135b3 100644
--- a/include/lib/aarch32/arch.h
+++ b/include/lib/aarch32/arch.h
@@ -124,6 +124,7 @@
#define SDCR_SPD_LEGACY U(0x0)
#define SDCR_SPD_DISABLE U(0x2)
#define SDCR_SPD_ENABLE U(0x3)
+#define SDCR_SPME_BIT (U(1) << 17)
#define SDCR_RESET_VAL U(0x0)
#if !ERROR_DEPRECATED
@@ -208,6 +209,8 @@
#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 */
@@ -386,8 +389,10 @@
#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
diff --git a/include/lib/aarch32/smccc_macros.S b/include/lib/aarch32/smccc_macros.S
index fdb65e8..09bc3fd 100644
--- a/include/lib/aarch32/smccc_macros.S
+++ b/include/lib/aarch32/smccc_macros.S
@@ -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
@@ -85,10 +84,34 @@
/* 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
/*
@@ -113,12 +136,31 @@
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
diff --git a/lib/el3_runtime/aarch32/context_mgmt.c b/lib/el3_runtime/aarch32/context_mgmt.c
index 11ef6e5..98796d2 100644
--- a/lib/el3_runtime/aarch32/context_mgmt.c
+++ b/lib/el3_runtime/aarch32/context_mgmt.c
@@ -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
*/
@@ -278,10 +278,28 @@ 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
--
2.23.0
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