Re: [PATCH v5 21/31] powernv/fadump: process architected register state data provided by firmware

Hari Bathini [off-list ref] writes:

AFAICS that is only used in two places, and both of them have to call
__va() on it, so why don't we store the virtual address to start with?

Where's my christmas tree :)

+
+	memset(regs, 0, sizeof(struct pt_regs));
+
+	for (i = 0; i < regs_cnt; i++, bufp += reg_entry_size) {
+		reg_entry = (struct hdat_fadump_reg_entry *)bufp;
+		opal_fadump_set_regval_regnum(regs,
+					      be32_to_cpu(reg_entry->reg_type),
+					      be32_to_cpu(reg_entry->reg_num),
+					      be64_to_cpu(reg_entry->reg_val));
+	}
+}
+
+static inline bool __init is_thread_core_inactive(u8 core_state)
+{
+	bool is_inactive = false;
+
+	if (core_state == HDAT_FADUMP_CORE_INACTIVE)
+		is_inactive = true;
+
+	return is_inactive;

	return core_state == HDAT_FADUMP_CORE_INACTIVE;

??

In fact there's only one caller, so just drop the inline entirely.

+}
+
 /*
  * Convert CPU state data saved at the time of crash into ELF notes.
+ *
+ * Each register entry is of 16 bytes, A numerical identifier along with
+ * a GPR/SPR flag in the first 8 bytes and the register value in the next
+ * 8 bytes. For more details refer to F/W documentation.
  */
 static int __init opal_fadump_build_cpu_notes(struct fw_dump *fadump_conf)
 {
 	u32 num_cpus, *note_buf;
 	struct fadump_crash_info_header *fdh = NULL;
+	struct hdat_fadump_thread_hdr *thdr;
+	unsigned long addr;
+	u32 thread_pir;
+	char *bufp;
+	struct pt_regs regs;
+	unsigned int size_of_each_thread;
+	unsigned int regs_offset, regs_cnt, reg_esize;
+	int i;

	unsigned int size_of_each_thread, regs_offset, regs_cnt, reg_esize;
  	struct fadump_crash_info_header *fdh = NULL;
  	u32 num_cpus, thread_pir, *note_buf;
	struct hdat_fadump_thread_hdr *thdr;
	struct pt_regs regs;
	unsigned long addr;
	char *bufp;
	int i;

Ah much better :)

Though the number of variables might be an indication that this function
could be split into smaller parts.

Another r_ variable I don't understand.

How is this meant to work? If HDAT ever changes the format they will
break all existing kernels in the field.

+#define HDAT_FADUMP_CPU_DATA_VERSION		1
+
+#define HDAT_FADUMP_CORE_INACTIVE		(0x0F)
+
+/* HDAT thread header for register entries */
+struct hdat_fadump_thread_hdr {
+	__be32  pir;
+	/* 0x00 - 0x0F - The corresponding stop state of the core */
+	u8      core_state;
+	u8      reserved[3];
+
+	__be32	offset;	/* Offset to Register Entries array */
+	__be32	ecnt;	/* Number of entries */
+	__be32	esize;	/* Alloc size of each array entry in bytes */
+	__be32	eactsz;	/* Actual size of each array entry in bytes */
+} __attribute__((packed));
+
+/* Register types populated by f/w */
+#define HDAT_FADUMP_REG_TYPE_GPR		0x01
+#define HDAT_FADUMP_REG_TYPE_SPR		0x02
+
+/* ID numbers used by f/w while populating certain registers */
+#define HDAT_FADUMP_REG_ID_NIP			0x7D0
+#define HDAT_FADUMP_REG_ID_MSR			0x7D1
+#define HDAT_FADUMP_REG_ID_CCR			0x7D2
+
+/* HDAT register entry. */
+struct hdat_fadump_reg_entry {
+	__be32		reg_type;
+	__be32		reg_num;
+	__be64		reg_val;
+} __attribute__((packed));

cheers