[PATCH v5 21/31] powernv/fadump: process architected register state data provided by firmware
Michael Ellerman
mpe at ellerman.id.au
Wed Sep 4 22:20:56 AEST 2019
Hari Bathini <hbathini at linux.ibm.com> writes:
> diff --git a/arch/powerpc/kernel/fadump-common.h b/arch/powerpc/kernel/fadump-common.h
> index 7107cf2..fc408b0 100644
> --- a/arch/powerpc/kernel/fadump-common.h
> +++ b/arch/powerpc/kernel/fadump-common.h
> @@ -98,7 +98,11 @@ struct fw_dump {
> /* cmd line option during boot */
> unsigned long reserve_bootvar;
>
> + unsigned long cpu_state_destination_addr;
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?
> diff --git a/arch/powerpc/platforms/powernv/opal-fadump.c b/arch/powerpc/platforms/powernv/opal-fadump.c
> index f75b861..9a32a7f 100644
> --- a/arch/powerpc/platforms/powernv/opal-fadump.c
> +++ b/arch/powerpc/platforms/powernv/opal-fadump.c
> @@ -282,15 +283,122 @@ static void opal_fadump_cleanup(struct fw_dump *fadump_conf)
> pr_warn("Could not reset (%llu) kernel metadata tag!\n", ret);
> }
>
> +static inline void opal_fadump_set_regval_regnum(struct pt_regs *regs,
> + u32 reg_type, u32 reg_num,
> + u64 reg_val)
> +{
> + if (reg_type == HDAT_FADUMP_REG_TYPE_GPR) {
> + if (reg_num < 32)
> + regs->gpr[reg_num] = reg_val;
> + return;
> + }
> +
> + switch (reg_num) {
> + case SPRN_CTR:
> + regs->ctr = reg_val;
> + break;
> + case SPRN_LR:
> + regs->link = reg_val;
> + break;
> + case SPRN_XER:
> + regs->xer = reg_val;
> + break;
> + case SPRN_DAR:
> + regs->dar = reg_val;
> + break;
> + case SPRN_DSISR:
> + regs->dsisr = reg_val;
> + break;
> + case HDAT_FADUMP_REG_ID_NIP:
> + regs->nip = reg_val;
> + break;
> + case HDAT_FADUMP_REG_ID_MSR:
> + regs->msr = reg_val;
> + break;
> + case HDAT_FADUMP_REG_ID_CCR:
> + regs->ccr = reg_val;
> + break;
> + }
> +}
> +
> +static inline void opal_fadump_read_regs(char *bufp, unsigned int regs_cnt,
> + unsigned int reg_entry_size,
> + struct pt_regs *regs)
> +{
> + int i;
> + struct hdat_fadump_reg_entry *reg_entry;
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.
> @@ -473,6 +627,26 @@ int __init opal_fadump_dt_scan(struct fw_dump *fadump_conf, ulong node)
> return 1;
> }
>
> + ret = opal_mpipl_query_tag(OPAL_MPIPL_TAG_CPU, &addr);
> + if ((ret != OPAL_SUCCESS) || !addr) {
> + pr_err("Failed to get CPU metadata (%lld)\n", ret);
> + return 1;
> + }
> +
> + addr = be64_to_cpu(addr);
> + pr_debug("CPU metadata addr: %llx\n", addr);
> +
> + opal_cpu_metadata = __va(addr);
> + r_opal_cpu_metadata = (void *)addr;
Another r_ variable I don't understand.
> diff --git a/arch/powerpc/platforms/powernv/opal-fadump.h b/arch/powerpc/platforms/powernv/opal-fadump.h
> index 19cac1f..ce4c522 100644
> --- a/arch/powerpc/platforms/powernv/opal-fadump.h
> +++ b/arch/powerpc/platforms/powernv/opal-fadump.h
> @@ -30,4 +30,43 @@ struct opal_fadump_mem_struct {
> struct opal_mpipl_region rgn[OPAL_FADUMP_MAX_MEM_REGS];
> } __attribute__((packed));
>
> +/*
> + * CPU state data is provided by f/w. Below are the definitions
> + * provided in HDAT spec. Refer to latest HDAT specification for
> + * any update to this format.
> + */
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
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