From: Mike Travis <mike.travis@xxxxxxx> [ Upstream commit bb3ab81bdbd53f88f26ffabc9fb15bd8466486ec ] The UV5 platform synchronizes the TSCs among all chassis, and will not proceed to OS boot without achieving synchronization. Previous UV platforms provided a register indicating successful synchronization. This is no longer available on UV5. On this platform TSC_ADJUST should not be reset by the kernel. Signed-off-by: Mike Travis <mike.travis@xxxxxxx> Signed-off-by: Steve Wahl <steve.wahl@xxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Reviewed-by: Dimitri Sivanich <dimitri.sivanich@xxxxxxx> Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220406195149.228164-3-steve.wahl@xxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- arch/x86/kernel/apic/x2apic_uv_x.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c index f5a48e66e4f5..a6e9c2794ef5 100644 --- a/arch/x86/kernel/apic/x2apic_uv_x.c +++ b/arch/x86/kernel/apic/x2apic_uv_x.c @@ -199,7 +199,13 @@ static void __init uv_tsc_check_sync(void) int mmr_shift; char *state; - /* Different returns from different UV BIOS versions */ + /* UV5 guarantees synced TSCs; do not zero TSC_ADJUST */ + if (!is_uv(UV2|UV3|UV4)) { + mark_tsc_async_resets("UV5+"); + return; + } + + /* UV2,3,4, UV BIOS TSC sync state available */ mmr = uv_early_read_mmr(UVH_TSC_SYNC_MMR); mmr_shift = is_uv2_hub() ? UVH_TSC_SYNC_SHIFT_UV2K : UVH_TSC_SYNC_SHIFT; -- 2.35.1
