Commit 0deae39c authored by Christophe Leroy's avatar Christophe Leroy Committed by Scott Wood
Browse files

powerpc/83xx: handle machine check caused by watchdog timer 



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: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
[scottwood: added missing #include]
Signed-off-by: default avatarScott Wood <oss@buserror.net>
parent 01f45c8f

arch/powerpc/include/asm/cputable.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

arch/powerpc/include/asm/reg.h

+2 −0
Original line number Diff line number Diff line
@@ -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 */

arch/powerpc/kernel/cputable.c

+6 −4
Original line number Diff line number Diff line
@@ -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,

arch/powerpc/platforms/83xx/misc.c

+17 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/of_platform.h>

#include <linux/pci.h>



#include <asm/debug.h>

#include <asm/io.h>

#include <asm/hw_irq.h>

#include <asm/ipic.h>
@@ -150,3 +151,19 @@ 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;

}

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