linux-kernel - [PATCH 4.14 38/49] x86/mce/AMD, EDAC/mce_amd: Enumerate Reserved SMCA bank type

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Date:   Tue, 17 Apr 2018 17:59:17 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Yazen Ghannam <yazen.ghannam@....com>,
        Borislav Petkov <bp@...e.de>, Borislav Petkov <bp@...en8.de>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Tony Luck <tony.luck@...el.com>,
        linux-edac <linux-edac@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>
Subject: [PATCH 4.14 38/49] x86/mce/AMD, EDAC/mce_amd: Enumerate Reserved SMCA bank type

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Yazen Ghannam <yazen.ghannam@....com>

commit 68627a697c195937672ce07683094c72b1174786 upstream.

Currently, bank 4 is reserved on Fam17h, so we chose not to initialize
bank 4 in the smca_banks array. This means that when we check if a bank
is initialized, like during boot or resume, we will see that bank 4 is
not initialized and try to initialize it.

This will cause a call trace, when resuming from suspend, due to
rdmsr_*on_cpu() calls in the init path. The rdmsr_*on_cpu() calls issue
an IPI but we're running with interrupts disabled. This triggers:

  WARNING: CPU: 0 PID: 11523 at kernel/smp.c:291 smp_call_function_single+0xdc/0xe0
  ...

Reserved banks will be read-as-zero, so their MCA_IPID register will be
zero. So, like the smca_banks array, the threshold_banks array will not
have an entry for a reserved bank since all its MCA_MISC* registers will
be zero.

Enumerate a "Reserved" bank type that matches on a HWID_MCATYPE of 0,0.

Use the "Reserved" type when checking if a bank is reserved. It's
possible that other bank numbers may be reserved on future systems.

Don't try to find the block address on reserved banks.

Signed-off-by: Yazen Ghannam <yazen.ghannam@....com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: <stable@...r.kernel.org> # 4.14.x
Cc: Borislav Petkov <bp@...en8.de>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Tony Luck <tony.luck@...el.com>
Cc: linux-edac <linux-edac@...r.kernel.org>
Link: http://lkml.kernel.org/r/20180221101900.10326-7-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/x86/include/asm/mce.h           |    1 +
 arch/x86/kernel/cpu/mcheck/mce_amd.c |    7 +++++++
 drivers/edac/mce_amd.c               |   11 +++++++----
 3 files changed, 15 insertions(+), 4 deletions(-)

--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -346,6 +346,7 @@ enum smca_bank_types {
 	SMCA_IF,	/* Instruction Fetch */
 	SMCA_L2_CACHE,	/* L2 Cache */
 	SMCA_DE,	/* Decoder Unit */
+	SMCA_RESERVED,	/* Reserved */
 	SMCA_EX,	/* Execution Unit */
 	SMCA_FP,	/* Floating Point */
 	SMCA_L3_CACHE,	/* L3 Cache */
--- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
@@ -82,6 +82,7 @@ static struct smca_bank_name smca_names[
 	[SMCA_IF]	= { "insn_fetch",	"Instruction Fetch Unit" },
 	[SMCA_L2_CACHE]	= { "l2_cache",		"L2 Cache" },
 	[SMCA_DE]	= { "decode_unit",	"Decode Unit" },
+	[SMCA_RESERVED]	= { "reserved",		"Reserved" },
 	[SMCA_EX]	= { "execution_unit",	"Execution Unit" },
 	[SMCA_FP]	= { "floating_point",	"Floating Point Unit" },
 	[SMCA_L3_CACHE]	= { "l3_cache",		"L3 Cache" },
@@ -127,6 +128,9 @@ static enum smca_bank_types smca_get_ban
 static struct smca_hwid smca_hwid_mcatypes[] = {
 	/* { bank_type, hwid_mcatype, xec_bitmap } */
 
+	/* Reserved type */
+	{ SMCA_RESERVED, HWID_MCATYPE(0x00, 0x0), 0x0 },
+
 	/* ZN Core (HWID=0xB0) MCA types */
 	{ SMCA_LS,	 HWID_MCATYPE(0xB0, 0x0), 0x1FFFEF },
 	{ SMCA_IF,	 HWID_MCATYPE(0xB0, 0x1), 0x3FFF },
@@ -431,6 +435,9 @@ static u32 get_block_address(unsigned in
 	u32 addr = 0, offset = 0;
 
 	if (mce_flags.smca) {
+		if (smca_get_bank_type(bank) == SMCA_RESERVED)
+			return addr;
+
 		if (!block) {
 			addr = MSR_AMD64_SMCA_MCx_MISC(bank);
 		} else {
--- a/drivers/edac/mce_amd.c
+++ b/drivers/edac/mce_amd.c
@@ -854,21 +854,24 @@ static void decode_mc6_mce(struct mce *m
 static void decode_smca_error(struct mce *m)
 {
 	struct smca_hwid *hwid;
-	unsigned int bank_type;
+	enum smca_bank_types bank_type;
 	const char *ip_name;
 	u8 xec = XEC(m->status, xec_mask);
 
 	if (m->bank >= ARRAY_SIZE(smca_banks))
 		return;
 
-	if (x86_family(m->cpuid) >= 0x17 && m->bank == 4)
-		pr_emerg(HW_ERR "Bank 4 is reserved on Fam17h.\n");
-
 	hwid = smca_banks[m->bank].hwid;
 	if (!hwid)
 		return;
 
 	bank_type = hwid->bank_type;
+
+	if (bank_type == SMCA_RESERVED) {
+		pr_emerg(HW_ERR "Bank %d is reserved.\n", m->bank);
+		return;
+	}
+
 	ip_name = smca_get_long_name(bank_type);
 
 	pr_emerg(HW_ERR "%s Extended Error Code: %d\n", ip_name, xec);