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* [PATCH] powerpc/83xx: handle machine check caused by watchdog timer
@ 2018-12-10 11:41 ` Christophe Leroy
  0 siblings, 0 replies; 4+ messages in thread
From: Christophe Leroy @ 2018-12-10 11:41 UTC (permalink / raw)
  To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman
  Cc: linux-kernel, linuxppc-dev

When the watchdog timer is set in interrupt mode, it causes a
machine check when it times out. The purpose of this mode is to
ease debugging, not to crash the kernel and reboot the machine.

This patch implements a special handling for that, in order to not
crash the kernel if the watchdog times out while in interrupt or
within the idle task.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/include/asm/cputable.h |  1 +
 arch/powerpc/include/asm/reg.h      |  2 ++
 arch/powerpc/kernel/cputable.c      | 10 ++++++----
 arch/powerpc/platforms/83xx/misc.c  | 16 ++++++++++++++++
 4 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index a0395ccbbe9e..d05f0c28e515 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -44,6 +44,7 @@ extern int machine_check_e500(struct pt_regs *regs);
 extern int machine_check_e200(struct pt_regs *regs);
 extern int machine_check_47x(struct pt_regs *regs);
 int machine_check_8xx(struct pt_regs *regs);
+int machine_check_83xx(struct pt_regs *regs);
 
 extern void cpu_down_flush_e500v2(void);
 extern void cpu_down_flush_e500mc(void);
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 0d2139a0d5b9..1c98ef1f2d5b 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -769,6 +769,8 @@
 #define   SRR1_PROGTRAP		0x00020000 /* Trap */
 #define   SRR1_PROGADDR		0x00010000 /* SRR0 contains subsequent addr */
 
+#define   SRR1_MCE_MCP		0x00080000 /* Machine check signal caused interrupt */
+
 #define SPRN_HSRR0	0x13A	/* Save/Restore Register 0 */
 #define SPRN_HSRR1	0x13B	/* Save/Restore Register 1 */
 #define   HSRR1_DENORM		0x00100000 /* Denorm exception */
diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index 2da01340c84c..1eab54bc6ee9 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -1141,6 +1141,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
 		.machine_check		= machine_check_generic,
 		.platform		= "ppc603",
 	},
+#ifdef CONFIG_PPC_83xx
 	{	/* e300c1 (a 603e core, plus some) on 83xx */
 		.pvr_mask		= 0x7fff0000,
 		.pvr_value		= 0x00830000,
@@ -1151,7 +1152,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
 		.icache_bsize		= 32,
 		.dcache_bsize		= 32,
 		.cpu_setup		= __setup_cpu_603,
-		.machine_check		= machine_check_generic,
+		.machine_check		= machine_check_83xx,
 		.platform		= "ppc603",
 	},
 	{	/* e300c2 (an e300c1 core, plus some, minus FPU) on 83xx */
@@ -1165,7 +1166,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
 		.icache_bsize		= 32,
 		.dcache_bsize		= 32,
 		.cpu_setup		= __setup_cpu_603,
-		.machine_check		= machine_check_generic,
+		.machine_check		= machine_check_83xx,
 		.platform		= "ppc603",
 	},
 	{	/* e300c3 (e300c1, plus one IU, half cache size) on 83xx */
@@ -1179,7 +1180,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
 		.icache_bsize		= 32,
 		.dcache_bsize		= 32,
 		.cpu_setup		= __setup_cpu_603,
-		.machine_check		= machine_check_generic,
+		.machine_check		= machine_check_83xx,
 		.num_pmcs		= 4,
 		.oprofile_cpu_type	= "ppc/e300",
 		.oprofile_type		= PPC_OPROFILE_FSL_EMB,
@@ -1196,12 +1197,13 @@ static struct cpu_spec __initdata cpu_specs[] = {
 		.icache_bsize		= 32,
 		.dcache_bsize		= 32,
 		.cpu_setup		= __setup_cpu_603,
-		.machine_check		= machine_check_generic,
+		.machine_check		= machine_check_83xx,
 		.num_pmcs		= 4,
 		.oprofile_cpu_type	= "ppc/e300",
 		.oprofile_type		= PPC_OPROFILE_FSL_EMB,
 		.platform		= "ppc603",
 	},
+#endif
 	{	/* default match, we assume split I/D cache & TB (non-601)... */
 		.pvr_mask		= 0x00000000,
 		.pvr_value		= 0x00000000,
diff --git a/arch/powerpc/platforms/83xx/misc.c b/arch/powerpc/platforms/83xx/misc.c
index d75c9816a5c9..3e591d159413 100644
--- a/arch/powerpc/platforms/83xx/misc.c
+++ b/arch/powerpc/platforms/83xx/misc.c
@@ -150,3 +150,19 @@ void __init mpc83xx_setup_arch(void)
 
 	mpc83xx_setup_pci();
 }
+
+int machine_check_83xx(struct pt_regs *regs)
+{
+	u32 mask = 1 << (31 - IPIC_MCP_WDT);
+
+	if (!(regs->msr & SRR1_MCE_MCP) || !(ipic_get_mcp_status() & mask))
+		return machine_check_generic(regs);
+	ipic_clear_mcp_status(mask);
+
+	if (debugger_fault_handler(regs))
+		return 1;
+
+	die("Watchdog NMI Reset", regs, 0);
+
+	return 1;
+}
-- 
2.13.3


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* [PATCH] powerpc/83xx: handle machine check caused by watchdog timer
@ 2018-12-10 11:41 ` Christophe Leroy
  0 siblings, 0 replies; 4+ messages in thread
From: Christophe Leroy @ 2018-12-10 11:41 UTC (permalink / raw)
  To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman
  Cc: linuxppc-dev, linux-kernel

When the watchdog timer is set in interrupt mode, it causes a
machine check when it times out. The purpose of this mode is to
ease debugging, not to crash the kernel and reboot the machine.

This patch implements a special handling for that, in order to not
crash the kernel if the watchdog times out while in interrupt or
within the idle task.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/include/asm/cputable.h |  1 +
 arch/powerpc/include/asm/reg.h      |  2 ++
 arch/powerpc/kernel/cputable.c      | 10 ++++++----
 arch/powerpc/platforms/83xx/misc.c  | 16 ++++++++++++++++
 4 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index a0395ccbbe9e..d05f0c28e515 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -44,6 +44,7 @@ extern int machine_check_e500(struct pt_regs *regs);
 extern int machine_check_e200(struct pt_regs *regs);
 extern int machine_check_47x(struct pt_regs *regs);
 int machine_check_8xx(struct pt_regs *regs);
+int machine_check_83xx(struct pt_regs *regs);
 
 extern void cpu_down_flush_e500v2(void);
 extern void cpu_down_flush_e500mc(void);
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 0d2139a0d5b9..1c98ef1f2d5b 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -769,6 +769,8 @@
 #define   SRR1_PROGTRAP		0x00020000 /* Trap */
 #define   SRR1_PROGADDR		0x00010000 /* SRR0 contains subsequent addr */
 
+#define   SRR1_MCE_MCP		0x00080000 /* Machine check signal caused interrupt */
+
 #define SPRN_HSRR0	0x13A	/* Save/Restore Register 0 */
 #define SPRN_HSRR1	0x13B	/* Save/Restore Register 1 */
 #define   HSRR1_DENORM		0x00100000 /* Denorm exception */
diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index 2da01340c84c..1eab54bc6ee9 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -1141,6 +1141,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
 		.machine_check		= machine_check_generic,
 		.platform		= "ppc603",
 	},
+#ifdef CONFIG_PPC_83xx
 	{	/* e300c1 (a 603e core, plus some) on 83xx */
 		.pvr_mask		= 0x7fff0000,
 		.pvr_value		= 0x00830000,
@@ -1151,7 +1152,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
 		.icache_bsize		= 32,
 		.dcache_bsize		= 32,
 		.cpu_setup		= __setup_cpu_603,
-		.machine_check		= machine_check_generic,
+		.machine_check		= machine_check_83xx,
 		.platform		= "ppc603",
 	},
 	{	/* e300c2 (an e300c1 core, plus some, minus FPU) on 83xx */
@@ -1165,7 +1166,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
 		.icache_bsize		= 32,
 		.dcache_bsize		= 32,
 		.cpu_setup		= __setup_cpu_603,
-		.machine_check		= machine_check_generic,
+		.machine_check		= machine_check_83xx,
 		.platform		= "ppc603",
 	},
 	{	/* e300c3 (e300c1, plus one IU, half cache size) on 83xx */
@@ -1179,7 +1180,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
 		.icache_bsize		= 32,
 		.dcache_bsize		= 32,
 		.cpu_setup		= __setup_cpu_603,
-		.machine_check		= machine_check_generic,
+		.machine_check		= machine_check_83xx,
 		.num_pmcs		= 4,
 		.oprofile_cpu_type	= "ppc/e300",
 		.oprofile_type		= PPC_OPROFILE_FSL_EMB,
@@ -1196,12 +1197,13 @@ static struct cpu_spec __initdata cpu_specs[] = {
 		.icache_bsize		= 32,
 		.dcache_bsize		= 32,
 		.cpu_setup		= __setup_cpu_603,
-		.machine_check		= machine_check_generic,
+		.machine_check		= machine_check_83xx,
 		.num_pmcs		= 4,
 		.oprofile_cpu_type	= "ppc/e300",
 		.oprofile_type		= PPC_OPROFILE_FSL_EMB,
 		.platform		= "ppc603",
 	},
+#endif
 	{	/* default match, we assume split I/D cache & TB (non-601)... */
 		.pvr_mask		= 0x00000000,
 		.pvr_value		= 0x00000000,
diff --git a/arch/powerpc/platforms/83xx/misc.c b/arch/powerpc/platforms/83xx/misc.c
index d75c9816a5c9..3e591d159413 100644
--- a/arch/powerpc/platforms/83xx/misc.c
+++ b/arch/powerpc/platforms/83xx/misc.c
@@ -150,3 +150,19 @@ void __init mpc83xx_setup_arch(void)
 
 	mpc83xx_setup_pci();
 }
+
+int machine_check_83xx(struct pt_regs *regs)
+{
+	u32 mask = 1 << (31 - IPIC_MCP_WDT);
+
+	if (!(regs->msr & SRR1_MCE_MCP) || !(ipic_get_mcp_status() & mask))
+		return machine_check_generic(regs);
+	ipic_clear_mcp_status(mask);
+
+	if (debugger_fault_handler(regs))
+		return 1;
+
+	die("Watchdog NMI Reset", regs, 0);
+
+	return 1;
+}
-- 
2.13.3


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* Re: [PATCH] powerpc/83xx: handle machine check caused by watchdog timer
  2018-12-10 11:41 ` Christophe Leroy
@ 2018-12-18 16:07   ` kbuild test robot
  -1 siblings, 0 replies; 4+ messages in thread
From: kbuild test robot @ 2018-12-18 16:07 UTC (permalink / raw)
  To: Christophe Leroy
  Cc: kbuild-all, Benjamin Herrenschmidt, Paul Mackerras,
	Michael Ellerman, linux-kernel, linuxppc-dev

[-- Attachment #1: Type: text/plain, Size: 1793 bytes --]

Hi Christophe,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on powerpc/next]
[also build test ERROR on v4.20-rc7 next-20181218]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Christophe-Leroy/powerpc-83xx-handle-machine-check-caused-by-watchdog-timer/20181210-222612
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-mpc83xx_defconfig (attached as .config)
compiler: powerpc-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.2.0 make.cross ARCH=powerpc 

All errors (new ones prefixed by >>):

   arch/powerpc//platforms/83xx/misc.c: In function 'machine_check_83xx':
>> arch/powerpc//platforms/83xx/misc.c:162:6: error: implicit declaration of function 'debugger_fault_handler' [-Werror=implicit-function-declaration]
     if (debugger_fault_handler(regs))
         ^~~~~~~~~~~~~~~~~~~~~~
   cc1: all warnings being treated as errors

vim +/debugger_fault_handler +162 arch/powerpc//platforms/83xx/misc.c

   153	
   154	int machine_check_83xx(struct pt_regs *regs)
   155	{
   156		u32 mask = 1 << (31 - IPIC_MCP_WDT);
   157	
   158		if (!(regs->msr & SRR1_MCE_MCP) || !(ipic_get_mcp_status() & mask))
   159			return machine_check_generic(regs);
   160		ipic_clear_mcp_status(mask);
   161	
 > 162		if (debugger_fault_handler(regs))

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 17189 bytes --]

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH] powerpc/83xx: handle machine check caused by watchdog timer
@ 2018-12-18 16:07   ` kbuild test robot
  0 siblings, 0 replies; 4+ messages in thread
From: kbuild test robot @ 2018-12-18 16:07 UTC (permalink / raw)
  To: Christophe Leroy; +Cc: linux-kernel, Paul Mackerras, kbuild-all, linuxppc-dev

[-- Attachment #1: Type: text/plain, Size: 1793 bytes --]

Hi Christophe,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on powerpc/next]
[also build test ERROR on v4.20-rc7 next-20181218]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Christophe-Leroy/powerpc-83xx-handle-machine-check-caused-by-watchdog-timer/20181210-222612
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-mpc83xx_defconfig (attached as .config)
compiler: powerpc-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.2.0 make.cross ARCH=powerpc 

All errors (new ones prefixed by >>):

   arch/powerpc//platforms/83xx/misc.c: In function 'machine_check_83xx':
>> arch/powerpc//platforms/83xx/misc.c:162:6: error: implicit declaration of function 'debugger_fault_handler' [-Werror=implicit-function-declaration]
     if (debugger_fault_handler(regs))
         ^~~~~~~~~~~~~~~~~~~~~~
   cc1: all warnings being treated as errors

vim +/debugger_fault_handler +162 arch/powerpc//platforms/83xx/misc.c

   153	
   154	int machine_check_83xx(struct pt_regs *regs)
   155	{
   156		u32 mask = 1 << (31 - IPIC_MCP_WDT);
   157	
   158		if (!(regs->msr & SRR1_MCE_MCP) || !(ipic_get_mcp_status() & mask))
   159			return machine_check_generic(regs);
   160		ipic_clear_mcp_status(mask);
   161	
 > 162		if (debugger_fault_handler(regs))

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 17189 bytes --]

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-12-18 16:10 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-12-10 11:41 [PATCH] powerpc/83xx: handle machine check caused by watchdog timer Christophe Leroy
2018-12-10 11:41 ` Christophe Leroy
2018-12-18 16:07 ` kbuild test robot
2018-12-18 16:07   ` kbuild test robot

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