From eee5715efd8c268724b14c956de6af5d4931f470 Mon Sep 17 00:00:00 2001 From: Mike Travis Date: Fri, 13 Jan 2017 09:21:11 -0600 Subject: [PATCH] x86/platform/UV: Fix panic with missing UVsystab support Fix the panic where KEXEC'd kernel does not have access to EFI runtime mappings. This may cause the extended UVsystab to not be available. The solution is to revert to non-UV mode and continue with limited capabilities. Signed-off-by: Mike Travis Reviewed-by: Russ Anderson Reviewed-by: Alex Thorlton Acked-by: Dimitri Sivanich Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170113152111.118886202@asylum.americas.sgi.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/apic/x2apic_uv_x.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c index 35690a168cf7..43930787cab9 100644 --- a/arch/x86/kernel/apic/x2apic_uv_x.c +++ b/arch/x86/kernel/apic/x2apic_uv_x.c @@ -1172,19 +1172,25 @@ static void __init decode_gam_rng_tbl(unsigned long ptr) index, _min_socket, _max_socket, _min_pnode, _max_pnode); } -static void __init decode_uv_systab(void) +static int __init decode_uv_systab(void) { struct uv_systab *st; int i; + if (uv_hub_info->hub_revision < UV4_HUB_REVISION_BASE) + return 0; /* No extended UVsystab required */ + st = uv_systab; - if ((!st || st->revision < UV_SYSTAB_VERSION_UV4) && !is_uv4_hub()) - return; - if (st->revision != UV_SYSTAB_VERSION_UV4_LATEST) { - pr_crit( + if ((!st) || (st->revision < UV_SYSTAB_VERSION_UV4_LATEST)) { + int rev = st ? st->revision : 0; + + pr_err( "UV: BIOS UVsystab version(%x) mismatch, expecting(%x)\n", - st->revision, UV_SYSTAB_VERSION_UV4_LATEST); - BUG(); + rev, UV_SYSTAB_VERSION_UV4_LATEST); + pr_err( + "UV: Cannot support UV operations, switching to generic PC\n"); + uv_system_type = UV_NONE; + return -EINVAL; } for (i = 0; st->entry[i].type != UV_SYSTAB_TYPE_UNUSED; i++) { @@ -1205,6 +1211,7 @@ static void __init decode_uv_systab(void) break; } } + return 0; } /* @@ -1373,7 +1380,8 @@ void __init uv_system_init(void) map_low_mmrs(); uv_bios_init(); /* get uv_systab for decoding */ - decode_uv_systab(); + if (decode_uv_systab() < 0) + return; /* UVsystab problem, abort UV init */ build_socket_tables(); build_uv_gr_table(); uv_init_hub_info(&hub_info); -- 2.20.1