This is a note to let you know that I've just added the patch titled
powerpc/pseries: Get entry and uaccess flush required bits from H_GET_CPU_CHARACTERISTICS
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-pseries-get-entry-and-uaccess-flush-required-bits-from-h_get_cpu_characteristics.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 65c7d070850e109a8a75a431f5a7f6eb4c007b77 Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@xxxxxxxxx>
Date: Mon, 3 May 2021 23:02:40 +1000
Subject: powerpc/pseries: Get entry and uaccess flush required bits from H_GET_CPU_CHARACTERISTICS
From: Nicholas Piggin <npiggin@xxxxxxxxx>
commit 65c7d070850e109a8a75a431f5a7f6eb4c007b77 upstream.
This allows the hypervisor / firmware to describe these workarounds to
the guest.
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210503130243.891868-2-npiggin@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/hvcall.h | 2 ++
arch/powerpc/platforms/pseries/setup.c | 6 ++++++
2 files changed, 8 insertions(+)
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -382,6 +382,8 @@
#define H_CPU_BEHAV_BNDS_CHK_SPEC_BAR (1ull << 61) // IBM bit 2
#define H_CPU_BEHAV_FLUSH_COUNT_CACHE (1ull << 58) // IBM bit 5
#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
/* Flag values used in H_REGISTER_PROC_TBL hcall */
#define PROC_TABLE_OP_MASK 0x18
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -538,6 +538,12 @@ static void init_cpu_char_feature_flags(
if (!(result->behaviour & H_CPU_BEHAV_L1D_FLUSH_PR))
security_ftr_clear(SEC_FTR_L1D_FLUSH_PR);
+ if (result->behaviour & H_CPU_BEHAV_NO_L1D_FLUSH_ENTRY)
+ security_ftr_clear(SEC_FTR_L1D_FLUSH_ENTRY);
+
+ if (result->behaviour & H_CPU_BEHAV_NO_L1D_FLUSH_UACCESS)
+ security_ftr_clear(SEC_FTR_L1D_FLUSH_UACCESS);
+
if (!(result->behaviour & H_CPU_BEHAV_BNDS_CHK_SPEC_BAR))
security_ftr_clear(SEC_FTR_BNDS_CHK_SPEC_BAR);
}
Patches currently in stable-queue which might be from npiggin@xxxxxxxxx are
queue-5.10/powerpc-pseries-get-entry-and-uaccess-flush-required-bits-from-h_get_cpu_characteristics.patch
