[PATCH AUTOSEL 4.14 076/127] powerpc/83xx: handle machine check caused by watchdog timer
From: Sasha Levin <sashal@kernel.org>
Date: 2019-11-22 06:09:25
Also in:
lkml, stable
Subsystem:
linux for powerpc (32-bit and 64-bit), linux for powerpc embedded ppc8xx and ppc83xx, the rest · Maintainers:
Madhavan Srinivasan, Christophe Leroy, Linus Torvalds
From: Christophe Leroy <redacted> [ Upstream commit 0deae39cec6dab3a66794f3e9e83ca4dc30080f1 ] 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 <redacted> [scottwood: added missing #include] Signed-off-by: Scott Wood <oss@buserror.net> Signed-off-by: Sasha Levin <sashal@kernel.org> --- 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 | 17 +++++++++++++++++ 4 files changed, 26 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index 7e3ccf21830e6..e4451b30d7e32 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h@@ -45,6 +45,7 @@ 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 b779f3ccd4126..05f3c2b3aa0ec 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h@@ -733,6 +733,8 @@ #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 760872916013d..da4b0e3792380 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c@@ -1185,6 +1185,7 @@ 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,
@@ -1195,7 +1196,7 @@ 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 */
@@ -1209,7 +1210,7 @@ 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 */
@@ -1223,7 +1224,7 @@ 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,
@@ -1240,12 +1241,13 @@ 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 d75c9816a5c92..2b6589fe812dd 100644
--- a/arch/powerpc/platforms/83xx/misc.c
+++ b/arch/powerpc/platforms/83xx/misc.c@@ -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; +}
--
2.20.1