[PATCH AUTOSEL 4.14 053/130] x86/mce: Lower throttling MCE messages' priority to warning

[PATCH AUTOSEL 4.14 053/130] x86/mce: Lower throttling MCE messages' priority to warning

[Sasha Levin]

From: Benjamin Berg <bberg@redhat.com>

[ Upstream commit 9c3bafaa1fd88e4dd2dba3735a1f1abb0f2c7bb7 ]

On modern CPUs it is quite normal that the temperature limits are
reached and the CPU is throttled. In fact, often the thermal design is
not sufficient to cool the CPU at full load and limits can quickly be
reached when a burst in load happens. This will even happen with
technologies like RAPL limitting the long term power consumption of
the package.

Also, these limits are "softer", as Srinivas explains:

"CPU temperature doesn't have to hit max(TjMax) to get these warnings.
OEMs ha[ve] an ability to program a threshold where a thermal interrupt
can be generated. In some systems the offset is 20C+ (Read only value).

In recent systems, there is another offset on top of it which can be
programmed by OS, once some agent can adjust power limits dynamically.
By default this is set to low by the firmware, which I guess the
prime motivation of Benjamin to submit the patch."

So these messages do not usually indicate a hardware issue (e.g.
insufficient cooling). Log them as warnings to avoid confusion about
their severity.

 [ bp: Massage commit mesage. ]

Signed-off-by: Benjamin Berg <bberg@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Christian Kellner <ckellner@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20191009155424.249277-1-bberg@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kernel/cpu/mcheck/therm_throt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index ee229ceee745c..ec6a07b04fdbb 100644
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -185,7 +185,7 @@ static void therm_throt_process(bool new_event, int event, int level)
 	/* if we just entered the thermal event */
 	if (new_event) {
 		if (event == THERMAL_THROTTLING_EVENT)
-			pr_crit("CPU%d: %s temperature above threshold, cpu clock throttled (total events = %lu)\n",
+			pr_warn("CPU%d: %s temperature above threshold, cpu clock throttled (total events = %lu)\n",
 				this_cpu,
 				level == CORE_LEVEL ? "Core" : "Package",
 				state->count);
-- 
2.20.1

[PATCH AUTOSEL 4.14 101/130] EDAC/ghes: Fix grain calculation

[Sasha Levin]

From: Robert Richter <rrichter@marvell.com>

[ Upstream commit 7088e29e0423d3195e09079b4f849ec4837e5a75 ]

The current code to convert a physical address mask to a grain
(defined as granularity in bytes) is:

	e->grain = ~(mem_err->physical_addr_mask & ~PAGE_MASK);

This is broken in several ways:

1) It calculates to wrong grain values. E.g., a physical address mask
of ~0xfff should give a grain of 0x1000. Without considering
PAGE_MASK, there is an off-by-one. Things are worse when also
filtering it with ~PAGE_MASK. This will calculate to a grain with the
upper bits set. In the example it even calculates to ~0.

2) The grain does not depend on and is unrelated to the kernel's
page-size. The page-size only matters when unmapping memory in
memory_failure(). Smaller grains are wrongly rounded up to the
page-size, on architectures with a configurable page-size (e.g. arm64)
this could round up to the even bigger page-size of the hypervisor.

Fix this with:

	e->grain = ~mem_err->physical_addr_mask + 1;

The grain_bits are defined as:

	grain = 1 << grain_bits;

Change also the grain_bits calculation accordingly, it is the same
formula as in edac_mc.c now and the code can be unified.

The value in ->physical_addr_mask coming from firmware is assumed to
be contiguous, but this is not sanity-checked. However, in case the
mask is non-contiguous, a conversion to grain_bits effectively
converts the grain bit mask to a power of 2 by rounding it up.

Suggested-by: James Morse <james.morse@arm.com>
Signed-off-by: Robert Richter <rrichter@marvell.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: "linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20191106093239.25517-11-rrichter@marvell.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/edac/ghes_edac.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/edac/ghes_edac.c b/drivers/edac/ghes_edac.c
index 6f80eb65c26ca..acae392786695 100644
--- a/drivers/edac/ghes_edac.c
+++ b/drivers/edac/ghes_edac.c
@@ -187,6 +187,7 @@ void ghes_edac_report_mem_error(struct ghes *ghes, int sev,
 	/* Cleans the error report buffer */
 	memset(e, 0, sizeof (*e));
 	e->error_count = 1;
+	e->grain = 1;
 	strcpy(e->label, "unknown label");
 	e->msg = pvt->msg;
 	e->other_detail = pvt->other_detail;
@@ -282,7 +283,7 @@ void ghes_edac_report_mem_error(struct ghes *ghes, int sev,
 
 	/* Error grain */
 	if (mem_err->validation_bits & CPER_MEM_VALID_PA_MASK)
-		e->grain = ~(mem_err->physical_addr_mask & ~PAGE_MASK);
+		e->grain = ~mem_err->physical_addr_mask + 1;
 
 	/* Memory error location, mapped on e->location */
 	p = e->location;
@@ -389,8 +390,13 @@ void ghes_edac_report_mem_error(struct ghes *ghes, int sev,
 	if (p > pvt->other_detail)
 		*(p - 1) = '\0';
 
+	/* Sanity-check driver-supplied grain value. */
+	if (WARN_ON_ONCE(!e->grain))
+		e->grain = 1;
+
+	grain_bits = fls_long(e->grain - 1);
+
 	/* Generate the trace event */
-	grain_bits = fls_long(e->grain);
 	snprintf(pvt->detail_location, sizeof(pvt->detail_location),
 		 "APEI location: %s %s", e->location, e->other_detail);
 	trace_mc_event(type, e->msg, e->label, e->error_count,
-- 
2.20.1