Re: [PATCH] kdb: add rdmsr and wrmsr commands for i386

Bernardo Innocenti wrote:
> The syntax is:
>    rdmsr <addr>
>    wrmsr <addr> <l> <h>
>   

In the hardware documentation that I have seen, MSR values are 
conventionally shown as 64-bit numbers.  The <l> <h> ordering will make 
it necessary to do a mental flip.  The 32-bit pieces of MSR do not have 
individual addresses, so considerations of endianness are not directly 
relevant.

> Signed-off-by: Bernardo Innocenti <[email protected]>
>
>
> diff --git a/arch/i386/kdb/kdbasupport.c b/arch/i386/kdb/kdbasupport.c
> index 482b319..8ecef2e 100644
> --- a/arch/i386/kdb/kdbasupport.c
> +++ b/arch/i386/kdb/kdbasupport.c
> @@ -223,6 +223,47 @@ kdba_removedbreg(kdb_bp_t *bp)
>   	kdba_putdr7(dr7);
>   }
>
> +static int
> +kdba_rdmsr(int argc, const char **argv)
> +{
> +	unsigned long addr;
> +	uint64_t val;
> +	int diag;
> +
> +	if (argc != 1) {
> +		return KDB_ARGCOUNT;
> +	}
> +
> +	if ((diag = kdbgetularg(argv[1], &addr)))
> +		return diag;
> +
> +	kdb_printf("msr(0x%lx) = ", addr);
> +	rdmsrl(addr, val);
> +	kdb_printf("0x%llx\n", val);
> +
> +	return 0;
> +}
> +
> +static int
> +kdba_wrmsr(int argc, const char **argv)
> +{
> +	unsigned long addr;
> +	unsigned long l, h;
> +	int diag;
> +
> +	if (argc != 3)
> +		return KDB_ARGCOUNT;
> +
> +	if ((diag = kdbgetularg(argv[1], &addr))
> +			|| (diag = kdbgetularg(argv[2], &l))
> +			|| (diag = kdbgetularg(argv[3], &h)))
> +		return diag;
> +
> +	wrmsr(addr, l, h);
> +
> +	return 0;
> +}
> +
>
>   /*
>    * kdba_getregcontents
> @@ -474,12 +515,11 @@ kdba_setregcontents(const char *regname,
>    *	argument is NULL (struct pt_regs).   The alternate register
>    *	set types supported by this function:
>    *
> - *	d 		Debug registers
> + *	d		Debug registers
>    *	c		Control registers
>    *	u		User registers at most recent entry to kernel
>    *			for the process currently selected with "pid" command.
>    * Following not yet implemented:
> - *	m		Model Specific Registers (extra defines register #)
>    *	r		Memory Type Range Registers (extra defines register)
>    */
>
> @@ -546,8 +586,6 @@ kdba_dumpregs(struct pt_regs *regs,
>   			   cr[0], cr[1], cr[2], cr[3], cr[4]);
>   		return 0;
>   	}
> -	case 'm':
> -		break;
>   	case 'r':
>   		break;
>   	default:
> @@ -899,6 +937,9 @@ kdba_init(void)
>   {
>   	kdb_register("pt_regs", kdba_pt_regs, "address", "Format struct 
> pt_regs", 0);
>   	kdb_register("stackdepth", kdba_stackdepth, "[percentage]", "Print 
> processes using >= stack percentage", 0);
> +	//TODO: maybe check CPUID first
> +	kdb_register("rdmsr", kdba_rdmsr, "<maddr>", "Display Model Specific 
> Register", 0);
> +	kdb_register("wrmsr", kdba_wrmsr, "<maddr> <l> <h>", "Modify Model 
> Specific Register", 0);
>
>   	return;
>   }
> diff --git a/kdb/kdbmain.c b/kdb/kdbmain.c
> index 0b2cb91..88bf14f 100644
> --- a/kdb/kdbmain.c
> +++ b/kdb/kdbmain.c
> @@ -2596,8 +2596,7 @@ kdb_rd(int argc, const char **argv)
>    *	none.
>    * Remarks:
>    *	Currently doesn't allow modification of control or
> - *	debug registers, nor does it allow modification
> - *	of model-specific registers (MSR).
> + *	debug registers.
>    */
>
>   static int
>
>
>