Re: [PATCH v2 09/16] powernv/fadump: process architected register state data provided by firmware

[Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com>]

On 2019-04-16 16:05:06 Tue, Hari Bathini wrote:
> From: Hari Bathini <hbathini@linux.vnet.ibm.com>
> 
> Firmware provides architected register state data at the time of crash.
> Process this data and build CPU notes to append to ELF core.
> 
> Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
> Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
> ---
> 
> Changes in v2:
> * Updated reg type values according to recent OPAL changes
> 
> 
>  arch/powerpc/include/asm/opal-api.h          |   23 +++
>  arch/powerpc/kernel/fadump-common.h          |    3 
>  arch/powerpc/platforms/powernv/opal-fadump.c |  187 ++++++++++++++++++++++++--
>  arch/powerpc/platforms/powernv/opal-fadump.h |    4 +
>  4 files changed, 206 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
> index 75471c2..91f2735 100644
> --- a/arch/powerpc/include/asm/opal-api.h
> +++ b/arch/powerpc/include/asm/opal-api.h
> @@ -976,6 +976,29 @@ struct opal_sg_list {
>   * Firmware-Assisted Dump (FADump)
>   */
>  
> +/* FADump thread header for register entries */
> +struct opal_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 */
> +} __packed;
> +
> +#define OPAL_REG_TYPE_GPR		0x01
> +#define OPAL_REG_TYPE_SPR		0x02
> +
> +/* FADump register entry. */
> +struct opal_fadump_reg_entry {
> +	__be32		reg_type;
> +	__be32		reg_num;
> +	__be64		reg_val;
> +};
> +
>  /* The maximum number of dump sections supported by OPAL */
>  #define OPAL_FADUMP_NR_SECTIONS			64
>  
> diff --git a/arch/powerpc/kernel/fadump-common.h b/arch/powerpc/kernel/fadump-common.h
> index ff764d4..8d47382 100644
> --- a/arch/powerpc/kernel/fadump-common.h
> +++ b/arch/powerpc/kernel/fadump-common.h
> @@ -117,6 +117,9 @@ struct fadump_memory_range {
>  
>  /* Firmware-assisted dump configuration details. */
>  struct fw_dump {
> +	unsigned long	cpu_state_destination_addr;
> +	unsigned long	cpu_state_data_version;
> +	unsigned long	cpu_state_entry_size;
>  	unsigned long	cpu_state_data_size;
>  	unsigned long	hpte_region_size;
>  	unsigned long	boot_memory_size;
> diff --git a/arch/powerpc/platforms/powernv/opal-fadump.c b/arch/powerpc/platforms/powernv/opal-fadump.c
> index da8480d..853f663 100644
> --- a/arch/powerpc/platforms/powernv/opal-fadump.c
> +++ b/arch/powerpc/platforms/powernv/opal-fadump.c
> @@ -94,6 +94,12 @@ static void update_fadump_config(struct fw_dump *fadump_conf,
>  
>  				last_end = base + size;
>  				j++;
> +			} else if (fdm->section[i].src_type ==
> +				   OPAL_FADUMP_CPU_STATE_DATA) {
> +				fadump_conf->cpu_state_destination_addr =
> +					be64_to_cpu(fdm->section[i].dest_addr);
> +				fadump_conf->cpu_state_data_size =
> +					be64_to_cpu(fdm->section[i].dest_size);
>  			}
>  		}
>  		fadump_conf->rmr_regions_cnt = j;
> @@ -199,6 +205,75 @@ static int opal_invalidate_fadump(struct fw_dump *fadump_conf)
>  	return 0;
>  }
>  
> +static inline void fadump_set_regval_regnum(struct pt_regs *regs, u32 reg_type,
> +					    u32 reg_num, u64 reg_val)
> +{
> +	if (reg_type == OPAL_REG_TYPE_GPR) {
> +		if (reg_num < 32)
> +			regs->gpr[reg_num] = reg_val;
> +		return;
> +	}
> +
> +	switch (reg_num) {
> +	case 2000:
> +		regs->nip = reg_val;
> +		break;
> +	case 2001:
> +		regs->msr = reg_val;
> +		break;
> +	case 9:
> +		regs->ctr = reg_val;
> +		break;
> +	case 8:
> +		regs->link = reg_val;
> +		break;
> +	case 1:
> +		regs->xer = reg_val;
> +		break;
> +	case 2002:
> +		regs->ccr = reg_val;
> +		break;
> +	case 19:
> +		regs->dar = reg_val;
> +		break;
> +	case 18:
> +		regs->dsisr = reg_val;
> +		break;

Can we use SPRN_* #defines which are already present in asm/reg.h instead of
hard coding numbers for switch cases ? You may want to add new #defines
for NIP, MSR and CCR.

Thanks,
-Mahesh.