83 lines
3.2 KiB
Diff
83 lines
3.2 KiB
Diff
From 4cab22343b32fec515813584a2620d6dafe0b1c2 Mon Sep 17 00:00:00 2001
|
|
From: Ard Biesheuvel <ardb@kernel.org>
|
|
Date: Wed, 4 Jan 2023 16:51:35 +0100
|
|
Subject: [PATCH 33/34] ArmVirtPkg/ArmVirtQemu: Avoid early ID map on ThunderX
|
|
|
|
The early ID map used by ArmVirtQemu uses ASID scoped non-global
|
|
mappings, as this allows us to switch to the permanent ID map seamlessly
|
|
without the need for explicit TLB maintenance.
|
|
|
|
However, this triggers a known erratum on ThunderX, which does not
|
|
tolerate non-global mappings that are executable at EL1, as this appears
|
|
to result in I-cache corruption. (Linux disables the KPTI based Meltdown
|
|
mitigation on ThunderX for the same reason)
|
|
|
|
So work around this, by detecting the CPU implementor and part number,
|
|
and proceeding without the early ID map if a ThunderX CPU is detected.
|
|
|
|
Note that this requires the C code to be built with strict alignment
|
|
again, as we may end up executing it with the MMU and caches off.
|
|
|
|
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
|
|
Acked-by: Laszlo Ersek <lersek@redhat.com>
|
|
Tested-by: dann frazier <dann.frazier@canonical.com>
|
|
(cherry picked from commit ec54ce1f1ab41b92782b37ae59e752fff0ef9c41)
|
|
---
|
|
ArmVirtPkg/ArmVirtQemu.dsc | 5 +++++
|
|
.../AArch64/ArmPlatformHelper.S | 15 +++++++++++++++
|
|
2 files changed, 20 insertions(+)
|
|
|
|
diff --git a/ArmVirtPkg/ArmVirtQemu.dsc b/ArmVirtPkg/ArmVirtQemu.dsc
|
|
index a3d744931a15..6b4dc213a7f7 100644
|
|
--- a/ArmVirtPkg/ArmVirtQemu.dsc
|
|
+++ b/ArmVirtPkg/ArmVirtQemu.dsc
|
|
@@ -31,6 +31,7 @@ [Defines]
|
|
DEFINE SECURE_BOOT_ENABLE = FALSE
|
|
DEFINE TPM2_ENABLE = FALSE
|
|
DEFINE TPM2_CONFIG_ENABLE = FALSE
|
|
+ DEFINE CAVIUM_ERRATUM_27456 = FALSE
|
|
|
|
#
|
|
# Network definition
|
|
@@ -117,7 +118,11 @@ [LibraryClasses.common.UEFI_DRIVER]
|
|
UefiScsiLib|MdePkg/Library/UefiScsiLib/UefiScsiLib.inf
|
|
|
|
[BuildOptions]
|
|
+!if $(CAVIUM_ERRATUM_27456) == TRUE
|
|
+ GCC:*_*_AARCH64_PP_FLAGS = -DCAVIUM_ERRATUM_27456
|
|
+!else
|
|
GCC:*_*_AARCH64_CC_XIPFLAGS ==
|
|
+!endif
|
|
|
|
!include NetworkPkg/NetworkBuildOptions.dsc.inc
|
|
|
|
diff --git a/ArmVirtPkg/Library/ArmPlatformLibQemu/AArch64/ArmPlatformHelper.S b/ArmVirtPkg/Library/ArmPlatformLibQemu/AArch64/ArmPlatformHelper.S
|
|
index 05ccc7f9f043..1c0022c1efd9 100644
|
|
--- a/ArmVirtPkg/Library/ArmPlatformLibQemu/AArch64/ArmPlatformHelper.S
|
|
+++ b/ArmVirtPkg/Library/ArmPlatformLibQemu/AArch64/ArmPlatformHelper.S
|
|
@@ -44,6 +44,21 @@
|
|
|
|
|
|
ASM_FUNC(ArmPlatformPeiBootAction)
|
|
+#ifdef CAVIUM_ERRATUM_27456
|
|
+ /*
|
|
+ * On Cavium ThunderX, using non-global mappings that are executable at EL1
|
|
+ * results in I-cache corruption. So just avoid the early ID mapping there.
|
|
+ *
|
|
+ * MIDR implementor 0x43
|
|
+ * MIDR part numbers 0xA1 0xA2 (but not 0xAF)
|
|
+ */
|
|
+ mrs x0, midr_el1 // read the MIDR into X0
|
|
+ ubfx x1, x0, #24, #8 // grab implementor id
|
|
+ ubfx x0, x0, #7, #9 // grab part number bits [11:3]
|
|
+ cmp x1, #0x43 // compare implementor id
|
|
+ ccmp x0, #0xA0 >> 3, #0, eq // compare part# bits [11:3]
|
|
+ b.eq 0f
|
|
+#endif
|
|
mrs x0, CurrentEL // check current exception level
|
|
tbz x0, #3, 0f // bail if above EL1
|
|
ret
|
|
--
|
|
2.39.0
|
|
|