[PATCH] arm64: only enable BHI mitigation on affected CPUs

[DENG Qingfang]

When kernel 5.15 support was added, a new config symbol for ARM64 BHI
mitigation was enabled, which was also later backported to 5.10. However,
only a few CPUs are affected by BHI [0].
Disable it by default, and enable it only on Cortex-A72 targets.

[0] https://developer.arm.com/Arm%20Security%20Center/Spectre-BHB
Fixes: 9a038e7fd12e ("generic: 5.15: copy config and patch from 5.10")
Fixes: 048f0b170296 ("kernel: bump 5.10 to 5.10.105")
Signed-off-by: DENG Qingfang <dqfext at gmail.com>
---
 target/linux/bcm27xx/bcm2711/config-5.15 | 1 +
 target/linux/generic/config-5.10         | 2 +-
 target/linux/generic/config-5.15         | 2 +-
 target/linux/mvebu/cortexa72/config-5.10 | 1 +
 target/linux/mvebu/cortexa72/config-5.15 | 1 +
 5 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/target/linux/bcm27xx/bcm2711/config-5.15 b/target/linux/bcm27xx/bcm2711/config-5.15
index d98d76c333..37bc00b942 100644
--- a/target/linux/bcm27xx/bcm2711/config-5.15
+++ b/target/linux/bcm27xx/bcm2711/config-5.15
@@ -296,6 +296,7 @@ CONFIG_MFD_CORE=y
 # CONFIG_MFD_RPISENSE_CORE is not set
 CONFIG_MFD_SYSCON=y
 CONFIG_MIGRATION=y
+CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY=y
 CONFIG_MMC=y
 CONFIG_MMC_BCM2835=y
 CONFIG_MMC_BCM2835_DMA=y
diff --git a/target/linux/generic/config-5.10 b/target/linux/generic/config-5.10
index 5220f65b56..3d229c0f4c 100644
--- a/target/linux/generic/config-5.10
+++ b/target/linux/generic/config-5.10
@@ -3419,7 +3419,7 @@ CONFIG_MISC_FILESYSTEMS=y
 # CONFIG_MISDN_NETJET is not set
 # CONFIG_MISDN_SPEEDFAX is not set
 # CONFIG_MISDN_W6692 is not set
-CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY=y
+# CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY is not set
 # CONFIG_MKISS is not set
 # CONFIG_MLX4_CORE is not set
 # CONFIG_MLX4_EN is not set
diff --git a/target/linux/generic/config-5.15 b/target/linux/generic/config-5.15
index 699be4d6fb..fcfa51254c 100644
--- a/target/linux/generic/config-5.15
+++ b/target/linux/generic/config-5.15
@@ -3572,7 +3572,7 @@ CONFIG_MISC_FILESYSTEMS=y
 # CONFIG_MISDN_NETJET is not set
 # CONFIG_MISDN_SPEEDFAX is not set
 # CONFIG_MISDN_W6692 is not set
-CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY=y
+# CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY is not set
 # CONFIG_MKISS is not set
 # CONFIG_MLX4_CORE is not set
 # CONFIG_MLX4_EN is not set
diff --git a/target/linux/mvebu/cortexa72/config-5.10 b/target/linux/mvebu/cortexa72/config-5.10
index 584c3fc9b8..94d04602b0 100644
--- a/target/linux/mvebu/cortexa72/config-5.10
+++ b/target/linux/mvebu/cortexa72/config-5.10
@@ -65,6 +65,7 @@ CONFIG_MDIO_DEVRES=y
 CONFIG_MFD_CORE=y
 CONFIG_MFD_IEI_WT61P803_PUZZLE=y
 CONFIG_MFD_SYSCON=y
+CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY=y
 CONFIG_MMC_SDHCI_XENON=y
 CONFIG_MODULES_USE_ELF_RELA=y
 CONFIG_MVEBU_GICP=y
diff --git a/target/linux/mvebu/cortexa72/config-5.15 b/target/linux/mvebu/cortexa72/config-5.15
index cb27e0285f..7981609b12 100644
--- a/target/linux/mvebu/cortexa72/config-5.15
+++ b/target/linux/mvebu/cortexa72/config-5.15
@@ -52,6 +52,7 @@ CONFIG_MARVELL_10G_PHY=y
 CONFIG_MFD_CORE=y
 CONFIG_MFD_IEI_WT61P803_PUZZLE=y
 CONFIG_MFD_SYSCON=y
+CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY=y
 CONFIG_MMC_SDHCI_XENON=y
 CONFIG_MODULES_USE_ELF_RELA=y
 CONFIG_MVEBU_GICP=y
-- 
2.34.1