Subject: [PATCH v4 7/7] powerpc/64: Sanitise user registers on interrupt in pseries, POWERNV

From: Rohan McLure <[email-masked]>
Date: Tue, 29 Nov 2022 15:43:54 +1100

Cause pseries and POWERNV platforms to default to zeroising all potentially
user-defined registers when entering the kernel by means of any interrupt
source, reducing user-influence of the kernel and the likelihood or
producing speculation gadgets.

Signed-off-by: Rohan McLure <[email-masked]>
---
Resubmitting patches as their own series after v6 partially merged:
Link: https://lore.kernel.org/all/[email-masked]/t/
v4: Default on POWERNV as well.
---
 arch/powerpc/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 280c797e0f30..2ab114a02f62 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -534,7 +534,7 @@ config HOTPLUG_CPU
 config INTERRUPT_SANITIZE_REGISTERS
 	bool "Clear gprs on interrupt arrival"
 	depends on PPC64 && ARCH_HAS_SYSCALL_WRAPPER
-	default PPC_BOOK3E_64
+	default PPC_BOOK3E_64 || PPC_PSERIES || PPC_POWERNV
 	help
 	  Reduce the influence of user register state on interrupt handlers and
 	  syscalls through clearing user state from registers before handling
-- 
2.37.2