Re: [PATCH V8 04/10] arm64: exception: handle Synchronous External Abort

"Baicar, Tyler" <tbaicar@xxxxxxxxxxxxxx> · Fri, 3 Feb 2017 13:24:38 -0700

Hello James,


On 2/3/2017 8:59 AM, James Morse wrote:
On 01/02/17 17:16, Tyler Baicar wrote:
SEA exceptions are often caused by an uncorrected hardware
error, and are handled when data abort and instruction abort
exception classes have specific values for their Fault Status
Code.
When SEA occurs, before killing the process, report the error
in the kernel logs.
Update fault_info[] with specific SEA faults so that the
new SEA handler is used.

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 156169c..9ae7e65 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -487,6 +487,31 @@ static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs)
  	return 1;
  }
  
+#define SEA_FnV_MASK	0x00000400
There are a glut of ESR_ELx_ macros in arch/arm64/include/asm/esr.h, could this
be fitted in there in a similar format?


--- a/arch/arm64/include/asm/esr.h
+++ b/arch/arm64/include/asm/esr.h
@@ -83,6 +83,7 @@
  #define ESR_ELx_WNR            (UL(1) << 6)

  /* Shared ISS field definitions for Data/Instruction aborts */
+#define ESR_ELx_FnV            (UL(1) << 10)
  #define ESR_ELx_EA             (UL(1) << 9)
  #define ESR_ELx_S1PTW          (UL(1) << 7)
I'll make this change in the next version.
+
+/*
+ * This abort handler deals with Synchronous External Abort.
+ * It calls notifiers, and then returns "fault".
+ */
+static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
+{
+	struct siginfo info;
+
+	pr_err("Synchronous External Abort: %s (0x%08x) at 0x%016lx\n",
+		 fault_name(esr), esr, addr);
+
+	info.si_signo = SIGBUS;
+	info.si_errno = 0;
+	info.si_code  = 0;
+	if (esr & SEA_FnV_MASK)
+		info.si_addr = 0;
+	else
+		info.si_addr  = (void __user *)addr;
+	arm64_notify_die("", regs, &info, esr);
+
+	return 0;
+}
+
  static const struct fault_info {
  	int	(*fn)(unsigned long addr, unsigned int esr, struct pt_regs *regs);
  	int	sig;
@@ -509,22 +534,22 @@ static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs)
  	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 1 permission fault"	},
  	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 2 permission fault"	},
  	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 3 permission fault"	},
-	{ do_bad,		SIGBUS,  0,		"synchronous external abort"	},
+	{ do_sea,		SIGBUS,  0,		"synchronous external abort"	},
This will print:
Synchronous External Abort: synchronous external abort
It looks odd, but I can't think of anything better to put there.


  	{ do_bad,		SIGBUS,  0,		"unknown 17"			},
  	{ do_bad,		SIGBUS,  0,		"unknown 18"			},
  	{ do_bad,		SIGBUS,  0,		"unknown 19"			},
-	{ do_bad,		SIGBUS,  0,		"synchronous external abort (translation table walk)" },
-	{ do_bad,		SIGBUS,  0,		"synchronous external abort (translation table walk)" },
-	{ do_bad,		SIGBUS,  0,		"synchronous external abort (translation table walk)" },
-	{ do_bad,		SIGBUS,  0,		"synchronous external abort (translation table walk)" },
-	{ do_bad,		SIGBUS,  0,		"synchronous parity error"	},
+	{ do_sea,		SIGBUS,  0,		"level 0 (translation table walk)"	},
+	{ do_sea,		SIGBUS,  0,		"level 1 (translation table walk)"	},
+	{ do_sea,		SIGBUS,  0,		"level 2 (translation table walk)"	},
+	{ do_sea,		SIGBUS,  0,		"level 3 (translation table walk)"	},
+	{ do_sea,		SIGBUS,  0,		"synchronous parity or ECC error" },
  	{ do_bad,		SIGBUS,  0,		"unknown 25"			},
  	{ do_bad,		SIGBUS,  0,		"unknown 26"			},
  	{ do_bad,		SIGBUS,  0,		"unknown 27"			},
-	{ do_bad,		SIGBUS,  0,		"synchronous parity error (translation table walk)" },
-	{ do_bad,		SIGBUS,  0,		"synchronous parity error (translation table walk)" },
-	{ do_bad,		SIGBUS,  0,		"synchronous parity error (translation table walk)" },
-	{ do_bad,		SIGBUS,  0,		"synchronous parity error (translation table walk)" },
+	{ do_sea,		SIGBUS,  0,		"level 0 synchronous parity error (translation table walk)"	},
+	{ do_sea,		SIGBUS,  0,		"level 1 synchronous parity error (translation table walk)"	},
+	{ do_sea,		SIGBUS,  0,		"level 2 synchronous parity error (translation table walk)"	},
+	{ do_sea,		SIGBUS,  0,		"level 3 synchronous parity error (translation table walk)"	},
  	{ do_bad,		SIGBUS,  0,		"unknown 32"			},
  	{ do_alignment_fault,	SIGBUS,  BUS_ADRALN,	"alignment fault"		},
  	{ do_bad,		SIGBUS,  0,		"unknown 34"			},


With the ESR_ELx_FnV change above,
Reviewed-by: James Morse <james.morse@xxxxxxx>

Great, thanks!

Tyler

--
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.

--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html






