From 393eff5a7b357a23db3e786e24b5ba8762cc6820 Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@gmail.com>
Date: Mon, 3 May 2021 23:02:42 +1000
Subject: [PATCH] powerpc/pesries: Get STF barrier requirement from
H_GET_CPU_CHARACTERISTICS
References: bsc#1188885 ltc#193722
Patch-mainline: v5.14-rc1
Git-commit: 393eff5a7b357a23db3e786e24b5ba8762cc6820
This allows the hypervisor / firmware to describe this workarounds to
the guest.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210503130243.891868-4-npiggin@gmail.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/include/asm/hvcall.h | 1 +
arch/powerpc/platforms/pseries/setup.c | 3 +++
2 files changed, 4 insertions(+)
diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index d769ffbb04f2..2a6346b6472f 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -402,6 +402,7 @@
#define H_CPU_BEHAV_FLUSH_LINK_STACK (1ull << 57) // IBM bit 6
#define H_CPU_BEHAV_NO_L1D_FLUSH_ENTRY (1ull << 56) // IBM bit 7
#define H_CPU_BEHAV_NO_L1D_FLUSH_UACCESS (1ull << 55) // IBM bit 8
+#define H_CPU_BEHAV_NO_STF_BARRIER (1ull << 54) // IBM bit 9
/* Flag values used in H_REGISTER_PROC_TBL hcall */
#define PROC_TABLE_OP_MASK 0x18
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 287f33645419..631a0d57b6cd 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -555,6 +555,9 @@ static void init_cpu_char_feature_flags(struct h_cpu_char_result *result)
if (result->behaviour & H_CPU_BEHAV_NO_L1D_FLUSH_UACCESS)
security_ftr_clear(SEC_FTR_L1D_FLUSH_UACCESS);
+ if (result->behaviour & H_CPU_BEHAV_NO_STF_BARRIER)
+ security_ftr_clear(SEC_FTR_STF_BARRIER);
+
if (!(result->behaviour & H_CPU_BEHAV_BNDS_CHK_SPEC_BAR))
security_ftr_clear(SEC_FTR_BNDS_CHK_SPEC_BAR);
}
--
2.26.2