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gerrit.openbmc.org / openbmc / openbmc / ea144b037776e892b9e05c4d22be842901e2138c / . / meta-arm / meta-arm-bsp / recipes-bsp / u-boot / u-boot / fvp-baser-aemv8r64 / 0005-armv8-Make-disabling-HVC-configurable-when-switching.patch
blob: f64db3bf464900e10e20686b6a8116b0ec7bec36 [file] [log] [blame]
Andrew Geisslerea144b032023-01-27 16:03:57 -0600[diff] [blame^]1From a6daca56b77d7f1b26483f10eb33ebdd6e157d3e Mon Sep 17 00:00:00 2001
Brad Bishopbec4ebc2022-08-03 09:55:16 -0400[diff] [blame]2From: Peter Hoyes <Peter.Hoyes@arm.com>
3Date: Fri, 10 Dec 2021 16:37:26 +0000
4Subject: [PATCH 5/9] armv8: Make disabling HVC configurable when switching to
5 EL1
6
7On the BASER_FVP there is no EL3, so HVC is used to provide PSCI
8services. Therefore we cannot disable hypercalls.
9
10Create CONFIG_ARMV8_DISABLE_HVC (dependent on CONFIG_ARMV8_TO_EL1) to
11control whether to disable HVC exceptions in HCR_EL2->HCD
12
13Issue-Id: SCM-3728
14Upstream-Status: Inappropriate [other]
15 Implementation pending further discussion
16Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
17Change-Id: I463d82f1db8a3cafcab40a9c0c208753569cc300
18---
19 arch/arm/cpu/armv8/Kconfig | 9 +++++++++
20 arch/arm/include/asm/macro.h | 10 ++++++++--
21 configs/vexpress_aemv8r_defconfig | 1 +
22 3 files changed, 18 insertions(+), 2 deletions(-)
23
24diff --git a/arch/arm/cpu/armv8/Kconfig b/arch/arm/cpu/armv8/Kconfig
Andrew Geisslerea144b032023-01-27 16:03:57 -0600[diff] [blame^]25index dec4be0e30..95c03487a2 100644
Brad Bishopbec4ebc2022-08-03 09:55:16 -0400[diff] [blame]26--- a/arch/arm/cpu/armv8/Kconfig
27+++ b/arch/arm/cpu/armv8/Kconfig
Andrew Geisslerea144b032023-01-27 16:03:57 -0600[diff] [blame^]28@@ -208,4 +208,13 @@ config ARMV8_CE_SHA256
29
30 endif
Brad Bishopbec4ebc2022-08-03 09:55:16 -0400[diff] [blame]31
32+config ARMV8_DISABLE_HVC
33+ bool "Disable HVC calls before switching to EL1"
34+ depends on ARMV8_SWITCH_TO_EL1
35+ default y
36+ help
37+ If switching to EL1 before loading the operating system, disable taking
38+ hypercalls back to EL2. May be disabled if, for example, PSCI services are
39+ running at EL2.
40+
41 endif
42diff --git a/arch/arm/include/asm/macro.h b/arch/arm/include/asm/macro.h
43index 1a1edc9870..7167739210 100644
44--- a/arch/arm/include/asm/macro.h
45+++ b/arch/arm/include/asm/macro.h
46@@ -296,9 +296,12 @@ lr .req x30
47 ldr \tmp2, =(ID_AA64ISAR1_EL1_GPI | ID_AA64ISAR1_EL1_GPA | \
48 ID_AA64ISAR1_EL1_API | ID_AA64ISAR1_EL1_APA)
49 tst \tmp, \tmp2
50- mov \tmp2, #(HCR_EL2_RW_AARCH64 | HCR_EL2_HCD_DIS)
51+ mov \tmp2, #(HCR_EL2_RW_AARCH64)
52 orr \tmp, \tmp2, #(HCR_EL2_APK | HCR_EL2_API)
53 csel \tmp, \tmp2, \tmp, eq
54+#ifdef CONFIG_ARMV8_DISABLE_HVC
55+ orr \tmp, \tmp, #(HCR_EL2_HCD_DIS)
56+#endif
57 msr hcr_el2, \tmp
58
59 /* Return to the EL1_SP1 mode from EL2 */
60@@ -311,7 +314,10 @@ lr .req x30
61
62 1:
63 /* Initialize HCR_EL2 */
64- ldr \tmp, =(HCR_EL2_RW_AARCH32 | HCR_EL2_HCD_DIS)
65+ ldr \tmp, =(HCR_EL2_RW_AARCH32)
66+#ifdef CONFIG_ARMV8_DISABLE_HVC
67+ orr \tmp, \tmp, #(HCR_EL2_HCD_DIS)
68+#endif
69 msr hcr_el2, \tmp
70
71 /* Return to AArch32 Supervisor mode from EL2 */
72diff --git a/configs/vexpress_aemv8r_defconfig b/configs/vexpress_aemv8r_defconfig
Andrew Geisslerea144b032023-01-27 16:03:57 -0600[diff] [blame^]73index 6044f82b00..6226f6b2c1 100644
Brad Bishopbec4ebc2022-08-03 09:55:16 -0400[diff] [blame]74--- a/configs/vexpress_aemv8r_defconfig
75+++ b/configs/vexpress_aemv8r_defconfig
Andrew Geisslerea144b032023-01-27 16:03:57 -0600[diff] [blame^]76@@ -18,3 +18,4 @@ CONFIG_SYS_PBSIZE=541
Brad Bishopbec4ebc2022-08-03 09:55:16 -0400[diff] [blame]77 CONFIG_VIRTIO_MMIO=y
78 CONFIG_ARMV8_EXCEPTION_VECTORS=n
79 CONFIG_ARMV8_SWITCH_TO_EL1=y
80+CONFIG_ARMV8_DISABLE_HVC=n
81--
822.25.1
83