[tip: x86/platform] x86/platform/uv: Update UV5 TSC checking

From: tip-bot2 for Mike Travis
Date: Wed Oct 07 2020 - 03:12:12 EST


The following commit has been merged into the x86/platform branch of tip:

Commit-ID: 6a7cf55e9f2b743695adac84375548aa18112327
Gitweb: https://git.kernel.org/tip/6a7cf55e9f2b743695adac84375548aa18112327
Author: Mike Travis <mike.travis@xxxxxxx>
AuthorDate: Mon, 05 Oct 2020 15:39:27 -05:00
Committer: Borislav Petkov <bp@xxxxxxx>
CommitterDate: Wed, 07 Oct 2020 09:09:04 +02:00

x86/platform/uv: Update UV5 TSC checking

Update check of BIOS TSC sync status to include both possible "invalid"
states provided by newer UV5 BIOS.

Signed-off-by: Mike Travis <mike.travis@xxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Steve Wahl <steve.wahl@xxxxxxx>
Link: https://lkml.kernel.org/r/20201005203929.148656-12-mike.travis@xxxxxxx
---
arch/x86/include/asm/uv/uv_hub.h | 2 +-
arch/x86/kernel/apic/x2apic_uv_x.c | 24 ++++++++++--------------
2 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/uv/uv_hub.h b/arch/x86/include/asm/uv/uv_hub.h
index ecf5c93..07079b5 100644
--- a/arch/x86/include/asm/uv/uv_hub.h
+++ b/arch/x86/include/asm/uv/uv_hub.h
@@ -726,7 +726,7 @@ extern void uv_nmi_setup_hubless(void);
#define UVH_TSC_SYNC_SHIFT_UV2K 16 /* UV2/3k have different bits */
#define UVH_TSC_SYNC_MASK 3 /* 0011 */
#define UVH_TSC_SYNC_VALID 3 /* 0011 */
-#define UVH_TSC_SYNC_INVALID 2 /* 0010 */
+#define UVH_TSC_SYNC_UNKNOWN 0 /* 0000 */

/* BMC sets a bit this MMR non-zero before sending an NMI */
#define UVH_NMI_MMR UVH_BIOS_KERNEL_MMR
diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index 9b44f45..9a83aa1 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -197,36 +197,32 @@ static void __init uv_tsc_check_sync(void)
int sync_state;
int mmr_shift;
char *state;
- bool valid;

- /* Accommodate different UV arch BIOSes */
+ /* Different returns from different UV BIOS versions */
mmr = uv_early_read_mmr(UVH_TSC_SYNC_MMR);
mmr_shift =
is_uv2_hub() ? UVH_TSC_SYNC_SHIFT_UV2K : UVH_TSC_SYNC_SHIFT;
sync_state = (mmr >> mmr_shift) & UVH_TSC_SYNC_MASK;

+ /* Check if TSC is valid for all sockets */
switch (sync_state) {
case UVH_TSC_SYNC_VALID:
state = "in sync";
- valid = true;
+ mark_tsc_async_resets("UV BIOS");
break;

- case UVH_TSC_SYNC_INVALID:
- state = "unstable";
- valid = false;
+ /* If BIOS state unknown, don't do anything */
+ case UVH_TSC_SYNC_UNKNOWN:
+ state = "unknown";
break;
+
+ /* Otherwise, BIOS indicates problem with TSC */
default:
- state = "unknown: assuming valid";
- valid = true;
+ state = "unstable";
+ mark_tsc_unstable("UV BIOS");
break;
}
pr_info("UV: TSC sync state from BIOS:0%d(%s)\n", sync_state, state);
-
- /* Mark flag that says TSC != 0 is valid for socket 0 */
- if (valid)
- mark_tsc_async_resets("UV BIOS");
- else
- mark_tsc_unstable("UV BIOS");
}

/* Selector for (4|4A|5) structs */