[PATCH 5.10 14/36] perf/x86/intel/uncore: Remove uncore extra PCI dev HSWEP_PCI_PCU_3

Greg Kroah-Hartman
2021-04-26T07:49:55Z

From: Kan Liang <kan.liang@linux.intel.com>

[ Upstream commit 9d480158ee86ad606d3a8baaf81e6b71acbfd7d5 ]

There may be a kernel panic on the Haswell server and the Broadwell
server, if the snbep_pci2phy_map_init() return error.

The uncore_extra_pci_dev[HSWEP_PCI_PCU_3] is used in the cpu_init() to
detect the existence of the SBOX, which is a MSR type of PMON unit.
The uncore_extra_pci_dev is allocated in the uncore_pci_init(). If the
snbep_pci2phy_map_init() returns error, perf doesn't initialize the
PCI type of the PMON units, so the uncore_extra_pci_dev will not be
allocated. But perf may continue initializing the MSR type of PMON
units. A null dereference kernel panic will be triggered.

The sockets in a Haswell server or a Broadwell server are identical.
Only need to detect the existence of the SBOX once.
Current perf probes all available PCU devices and stores them into the
uncore_extra_pci_dev. It's unnecessary.
Use the pci_get_device() to replace the uncore_extra_pci_dev. Only
detect the existence of the SBOX on the first available PCU device once.

Factor out hswep_has_limit_sbox(), since the Haswell server and the
Broadwell server uses the same way to detect the existence of the SBOX.

Add some macros to replace the magic number.

Fixes: 5306c31c5733 ("perf/x86/uncore/hsw-ep: Handle systems with only two SBOXes")
Reported-by: Steve Wahl <steve.wahl@hpe.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Steve Wahl <steve.wahl@hpe.com>
Link: https://lkml.kernel.org/r/1618521764-100923-1-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/events/intel/uncore_snbep.c | 61 ++++++++++++----------------
1 file changed, 26 insertions(+), 35 deletions(-)

diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
index 7bdb1821215d..3112186a4f4b 100644
--- a/arch/x86/events/intel/uncore_snbep.c
+++ b/arch/x86/events/intel/uncore_snbep.c
@@ -1159,7 +1159,6 @@ enum {
SNBEP_PCI_QPI_PORT0_FILTER,
SNBEP_PCI_QPI_PORT1_FILTER,
BDX_PCI_QPI_PORT2_FILTER,
- HSWEP_PCI_PCU_3,
};

static int snbep_qpi_hw_config(struct intel_uncore_box *box, struct perf_event *event)
@@ -2816,22 +2815,33 @@ static struct intel_uncore_type *hswep_msr_uncores[] = {
NULL,
};

-void hswep_uncore_cpu_init(void)
+#define HSWEP_PCU_DID 0x2fc0
+#define HSWEP_PCU_CAPID4_OFFET 0x94
+#define hswep_get_chop(_cap) (((_cap) >> 6) & 0x3)
+
+static bool hswep_has_limit_sbox(unsigned int device)
{
- int pkg = boot_cpu_data.logical_proc_id;
+ struct pci_dev *dev = pci_get_device(PCI_VENDOR_ID_INTEL, device, NULL);
+ u32 capid4;
+
+ if (!dev)
+ return false;
+
+ pci_read_config_dword(dev, HSWEP_PCU_CAPID4_OFFET, &capid4);
+ if (!hswep_get_chop(capid4))
+ return true;

+ return false;
+}
+
+void hswep_uncore_cpu_init(void)
+{
if (hswep_uncore_cbox.num_boxes > boot_cpu_data.x86_max_cores)
hswep_uncore_cbox.num_boxes = boot_cpu_data.x86_max_cores;

/* Detect 6-8 core systems with only two SBOXes */
- if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
- u32 capid4;
-
- pci_read_config_dword(uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3],
- 0x94, &capid4);
- if (((capid4 >> 6) & 0x3) == 0)
- hswep_uncore_sbox.num_boxes = 2;
- }
+ if (hswep_has_limit_sbox(HSWEP_PCU_DID))
+ hswep_uncore_sbox.num_boxes = 2;

uncore_msr_uncores = hswep_msr_uncores;
}
@@ -3094,11 +3104,6 @@ static const struct pci_device_id hswep_uncore_pci_ids[] = {
.driver_data = UNCORE_PCI_DEV_DATA(UNCORE_EXTRA_PCI_DEV,
SNBEP_PCI_QPI_PORT1_FILTER),
},
- { /* PCU.3 (for Capability registers) */
- PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x2fc0),
- .driver_data = UNCORE_PCI_DEV_DATA(UNCORE_EXTRA_PCI_DEV,
- HSWEP_PCI_PCU_3),
- },
{ /* end: all zeroes */ }
};

@@ -3190,27 +3195,18 @@ static struct event_constraint bdx_uncore_pcu_constraints[] = {
EVENT_CONSTRAINT_END
};

+#define BDX_PCU_DID 0x6fc0
+
void bdx_uncore_cpu_init(void)
{
- int pkg = topology_phys_to_logical_pkg(boot_cpu_data.phys_proc_id);
-
if (bdx_uncore_cbox.num_boxes > boot_cpu_data.x86_max_cores)
bdx_uncore_cbox.num_boxes = boot_cpu_data.x86_max_cores;
uncore_msr_uncores = bdx_msr_uncores;

- /* BDX-DE doesn't have SBOX */
- if (boot_cpu_data.x86_model == 86) {
- uncore_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
/* Detect systems with no SBOXes */
- } else if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
- struct pci_dev *pdev;
- u32 capid4;
-
- pdev = uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3];
- pci_read_config_dword(pdev, 0x94, &capid4);
- if (((capid4 >> 6) & 0x3) == 0)
- bdx_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
- }
+ if ((boot_cpu_data.x86_model == 86) || hswep_has_limit_sbox(BDX_PCU_DID))
+ uncore_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
+
hswep_uncore_pcu.constraints = bdx_uncore_pcu_constraints;
}

@@ -3431,11 +3427,6 @@ static const struct pci_device_id bdx_uncore_pci_ids[] = {
.driver_data = UNCORE_PCI_DEV_DATA(UNCORE_EXTRA_PCI_DEV,
BDX_PCI_QPI_PORT2_FILTER),
},
- { /* PCU.3 (for Capability registers) */
- PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x6fc0),
- .driver_data = UNCORE_PCI_DEV_DATA(UNCORE_EXTRA_PCI_DEV,
- HSWEP_PCI_PCU_3),
- },
{ /* end: all zeroes */ }
};

--
2.30.2