linux-kernel - [PATCH v2] perf/x86/intel/uncore: Remove hardcoded socket 0 in Haswell init code

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Date:   Thu,  5 Jan 2017 10:09:25 -0500
From:   Prarit Bhargava <prarit@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     Prarit Bhargava <prarit@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Kan Liang <kan.liang@...el.com>, Borislav Petkov <bp@...e.de>,
        Harish Chegondi <harish.chegondi@...el.com>
Subject: [PATCH v2] perf/x86/intel/uncore: Remove hardcoded socket 0 in Haswell init code

In case anyone finds the actual panic interesting ...

BUG: unable to handle kernel paging request at 00000000006563a1
IP: [<ffffffff8101b582>] hswep_uncore_cpu_init+0x52/0xa0
PGD 0 [    2.313897]
Oops: 0000 [#1] SMP
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.9.0 #1
Hardware name: NEC Express5800/T120f [N8100-2285Y]/GA-7WESV-NJ, BIOS 5.0.4009 08/01/2016
task: ffff88002bdb8000 task.stack: ffffc90000014000
RIP: 0010:[<ffffffff8101b582>]  [<ffffffff8101b582>] hswep_uncore_cpu_init+0x52/0xa0
RSP: 0000:ffffc90000017db8  EFLAGS: 00010206
RAX: 0000000000656369 RBX: 0000000000000000 RCX: 0000000000001e03
RDX: ffff88002b224780 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000017dc8 R08: 000000000001c880 R09: ffffffff813667e1
R10: ffff880030c1c880 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff81c1c090 R14: afafafafafafafaf R15: afafafafafafafaf
FS:  0000000000000000(0000) GS:ffff880030c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000006563a1 CR3: 000000002fc07000 CR4: 00000000001406b0
Stack:
 ffffc90000017dc8 00000000352bd002 ffffc90000017e00 ffffffff81da17f8
 0000000000000000 ffffffff81da16f9 00000000000000f0 afafafafafafafaf
 afafafafafafafaf ffffc90000017e78 ffffffff81002190 ffffc90000017e00
Call Trace:
 [<ffffffff81da17f8>] intel_uncore_init+0xff/0x2e6
 [<ffffffff81da16f9>] ? uncore_type_init+0x158/0x158
 [<ffffffff81002190>] do_one_initcall+0x50/0x190
 [<ffffffff810af27b>] ? parse_args+0x27b/0x460
 [<ffffffff81d9c357>] kernel_init_freeable+0x1a5/0x249
 [<ffffffff81d9ba27>] ? set_debug_rodata+0x12/0x12
 [<ffffffff81702010>] ? rest_init+0x80/0x80
 [<ffffffff8170201e>] kernel_init+0xe/0x110
 [<ffffffff8170f715>] ret_from_fork+0x25/0x30
Code: 1a d5 00 39 15 cc 1c c0 00 7e 06 89 15 c4 1c c0 00 48 98 48 8b 15 d7 c3 f7 00 48 8d 04 40 48 8d 04 c2 48 8b 40 10 48 85 c0 74 1b <8b> 70 38 48 8b 78 10 48 8d 4d f4 ba 94 00 00 00 e8 b9 db 38 00
RIP  [<ffffffff8101b582>] hswep_uncore_cpu_init+0x52/0xa0

----8<----

On multi-socket Intel v3 processor systems (aka Haswell) kdump can panic
in hswep_uncore_cpu_init() since 9d85eb9119f4 ("x86/smpboot: Make logical
package management more robust") corrected the physical ID to logical ID
mapping of the threads if the panic occurs on any socket other than socket 0.

hswep_uncore_cpu_init() is hard coded for physical socket 0 and if the
system is kdump'ing on any other socket the logical package value will be
incorrect.  The code should not use 0 as the physical ID, and should use
the boot cpu's logical package ID in this calculation.

v2: switched to using boot_cpu_data.logical_proc_id

Signed-off-by: Prarit Bhargava <prarit@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: x86@...nel.org
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Kan Liang <kan.liang@...el.com>
Cc: Borislav Petkov <bp@...e.de>
Cc: Harish Chegondi <harish.chegondi@...el.com>
---
 arch/x86/events/intel/uncore_snbep.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
index e6832be714bc..dae2fedc1601 100644
--- a/arch/x86/events/intel/uncore_snbep.c
+++ b/arch/x86/events/intel/uncore_snbep.c
@@ -2686,7 +2686,7 @@ static int hswep_pcu_hw_config(struct intel_uncore_box *box, struct perf_event *
 
 void hswep_uncore_cpu_init(void)
 {
-	int pkg = topology_phys_to_logical_pkg(0);
+	int pkg = boot_cpu_data.logical_proc_id;
 
 	if (hswep_uncore_cbox.num_boxes > boot_cpu_data.x86_max_cores)
 		hswep_uncore_cbox.num_boxes = boot_cpu_data.x86_max_cores;
-- 
1.7.9.3