Re: [Xen-devel] [PATCH v9 04/19] amd64: introduce hook for custom preload metadata parsers

On 03/01/14 21:59, Konrad Rzeszutek Wilk wrote:
> On Thu, Jan 02, 2014 at 04:43:38PM +0100, Roger Pau Monne wrote:
>> ---
>>  sys/amd64/amd64/machdep.c   |   41 ++++++++++++++++------
>>  sys/amd64/include/sysarch.h |   12 ++++++
>>  sys/x86/xen/pv.c            |   82 +++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 124 insertions(+), 11 deletions(-)
>>
>> diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
>> index eae657b..e073eea 100644
>> --- a/sys/amd64/amd64/machdep.c
>> +++ b/sys/amd64/amd64/machdep.c
>> _at__at_ -126,6 +126,7 _at__at_ __FBSDID("$FreeBSD$");
>>  #include <machine/reg.h>
>>  #include <machine/sigframe.h>
>>  #include <machine/specialreg.h>
>> +#include <machine/sysarch.h>
>>  #ifdef PERFMON
>>  #include <machine/perfmon.h>
>>  #endif
>> _at__at_ -165,6 +166,14 _at__at_ static int  set_fpcontext(struct thread *td, const mcontext_t *mcp,
>>      char *xfpustate, size_t xfpustate_len);
>>  SYSINIT(cpu, SI_SUB_CPU, SI_ORDER_FIRST, cpu_startup, NULL);
>>  
>> +/* Preload data parse function */
>> +static caddr_t native_parse_preload_data(u_int64_t);
>> +
>> +/* Default init_ops implementation. */
>> +struct init_ops init_ops = {
>> +	.parse_preload_data =	native_parse_preload_data,
> 
> Extra space there.

It's for alignment, looks strange now because there's only one hook.

>> +};
>> +
>>  /*
>>   * The file "conf/ldscript.amd64" defines the symbol "kernphys".  Its value is
>>   * the physical address at which the kernel is loaded.
>> _at__at_ -1683,6 +1692,26 _at__at_ do_next:
>>  	msgbufp = (struct msgbuf *)PHYS_TO_DMAP(phys_avail[pa_indx]);
>>  }
>>  
>> +static caddr_t
>> +native_parse_preload_data(u_int64_t modulep)
>> +{
>> +	caddr_t kmdp;
>> +
>> +	preload_metadata = (caddr_t)(uintptr_t)(modulep + KERNBASE);
> 
> Two casts? Could it be done via one?
> 
>> +	preload_bootstrap_relocate(KERNBASE);
>> +	kmdp = preload_search_by_type("elf kernel");
>> +	if (kmdp == NULL)
>> +		kmdp = preload_search_by_type("elf64 kernel");
>> +	boothowto = MD_FETCH(kmdp, MODINFOMD_HOWTO, int);
>> +	kern_envp = MD_FETCH(kmdp, MODINFOMD_ENVP, char *) + KERNBASE;
>> +#ifdef DDB
>> +	ksym_start = MD_FETCH(kmdp, MODINFOMD_SSYM, uintptr_t);
>> +	ksym_end = MD_FETCH(kmdp, MODINFOMD_ESYM, uintptr_t);
>> +#endif
>> +
>> +	return (kmdp);
>> +}
>> +
>>  u_int64_t
>>  hammer_time(u_int64_t modulep, u_int64_t physfree)
>>  {
>> _at__at_ -1707,17 +1736,7 _at__at_ hammer_time(u_int64_t modulep, u_int64_t physfree)
>>  	 */
>>  	proc_linkup0(&proc0, &thread0);
>>  
>> -	preload_metadata = (caddr_t)(uintptr_t)(modulep + KERNBASE);
> 
> Oh, you just moved the code - right, lets not modify it in this patch.

Yes, it's just code movement.

> 
>> -	preload_bootstrap_relocate(KERNBASE);
>> -	kmdp = preload_search_by_type("elf kernel");
>> -	if (kmdp == NULL)
>> -		kmdp = preload_search_by_type("elf64 kernel");
>> -	boothowto = MD_FETCH(kmdp, MODINFOMD_HOWTO, int);
>> -	kern_envp = MD_FETCH(kmdp, MODINFOMD_ENVP, char *) + KERNBASE;
>> -#ifdef DDB
>> -	ksym_start = MD_FETCH(kmdp, MODINFOMD_SSYM, uintptr_t);
>> -	ksym_end = MD_FETCH(kmdp, MODINFOMD_ESYM, uintptr_t);
>> -#endif
>> +	kmdp = init_ops.parse_preload_data(modulep);
>>  
>>  	/* Init basic tunables, hz etc */
>>  	init_param1();
>> diff --git a/sys/amd64/include/sysarch.h b/sys/amd64/include/sysarch.h
>> index cd380d4..58ac8cd 100644
>> --- a/sys/amd64/include/sysarch.h
>> +++ b/sys/amd64/include/sysarch.h
>> _at__at_ -4,3 +4,15 _at__at_
>>  /* $FreeBSD$ */
>>  
>>  #include <x86/sysarch.h>
>> +
>> +/*
>> + * Struct containing pointers to init functions whose
>> + * implementation is run time selectable.  Selection can be made,
>> + * for example, based on detection of a BIOS variant or
>> + * hypervisor environment.
>> + */
>> +struct init_ops {
>> +	caddr_t	(*parse_preload_data)(u_int64_t);
>> +};
>> +
>> +extern struct init_ops init_ops;
>> diff --git a/sys/x86/xen/pv.c b/sys/x86/xen/pv.c
>> index db3b7a3..908b50b 100644
>> --- a/sys/x86/xen/pv.c
>> +++ b/sys/x86/xen/pv.c
>> _at__at_ -46,6 +46,8 _at__at_ __FBSDID("$FreeBSD$");
>>  #include <vm/vm_pager.h>
>>  #include <vm/vm_param.h>
>>  
>> +#include <machine/sysarch.h>
>> +
>>  #include <xen/xen-os.h>
>>  #include <xen/hypervisor.h>
>>  
>> _at__at_ -54,6 +56,36 _at__at_ extern u_int64_t hammer_time(u_int64_t, u_int64_t);
>>  /* Xen initial function */
>>  extern u_int64_t hammer_time_xen(start_info_t *, u_int64_t);
>>  
>> +/*--------------------------- Forward Declarations ---------------------------*/
>> +static caddr_t xen_pv_parse_preload_data(u_int64_t);
>> +
>> +static void xen_pv_set_init_ops(void);
>> +
>> +/*-------------------------------- Global Data -------------------------------*/
>> +/* Xen init_ops implementation. */
>> +struct init_ops xen_init_ops = {
>> +	.parse_preload_data =	xen_pv_parse_preload_data,
>> +};
>> +
>> +static struct
>> +{
>> +	const char	*ev;
>> +	int		mask;
>> +} howto_names[] = {
>> +	{"boot_askname",	RB_ASKNAME},
>> +	{"boot_single",		RB_SINGLE},
>> +	{"boot_nosync",		RB_NOSYNC},
>> +	{"boot_halt",		RB_ASKNAME},
>> +	{"boot_serial",		RB_SERIAL},
>> +	{"boot_cdrom",		RB_CDROM},
>> +	{"boot_gdb",		RB_GDB},
>> +	{"boot_gdb_pause",	RB_RESERVED1},
>> +	{"boot_verbose",	RB_VERBOSE},
>> +	{"boot_multicons",	RB_MULTIPLE},
>> +	{NULL,	0}
>> +};
>> +
>> +/*-------------------------------- Xen PV init -------------------------------*/
>>  /*
>>   * First function called by the Xen PVH boot sequence.
>>   *
>> _at__at_ -118,6 +150,56 _at__at_ hammer_time_xen(start_info_t *si, u_int64_t xenstack)
>>  	}
>>  	load_cr3(((u_int64_t)&PT4[0]) - KERNBASE);
>>  
>> +	/* Set the hooks for early functions that diverge from bare metal */
>> +	xen_pv_set_init_ops();
>> +
>>  	/* Now we can jump into the native init function */
>>  	return (hammer_time(0, physfree));
>>  }
>> +
>> +/*-------------------------------- PV specific -------------------------------*/
>> +/*
>> + * Functions to convert the "extra" parameters passed by Xen
>> + * into FreeBSD boot options (from the i386 Xen port).
>> + */
>> +static char *
>> +xen_setbootenv(char *cmd_line)
>> +{
>> +	char *cmd_line_next;
>> +
>> +        /* Skip leading spaces */
>> +        for (; *cmd_line == ' '; cmd_line++);
> 
> Spaces?
> 
>> +
>> +	for (cmd_line_next = cmd_line; strsep(&cmd_line_next, ",") != NULL;);
>> +	return (cmd_line);
>> +}
>> +
>> +static int
>> +xen_boothowto(char *envp)
>> +{
>> +	int i, howto = 0;
>> +
>> +	/* get equivalents from the environment */
>> +	for (i = 0; howto_names[i].ev != NULL; i++)
>> +		if (getenv(howto_names[i].ev) != NULL)
>> +			howto |= howto_names[i].mask;
> 
> You don't believe in '{}' do you ? :-)

All this code has also been taken from the FreeBSD Xen i386 PV port, but
maybe some refactoring wouldn't be bad :).

>> +	return (howto);
>> +}
>> +
>> +static caddr_t
>> +xen_pv_parse_preload_data(u_int64_t modulep)
>> +{
>> +	/* Parse the extra boot information given by Xen */
>> +	if (HYPERVISOR_start_info->cmd_line)
>> +		kern_envp = xen_setbootenv(HYPERVISOR_start_info->cmd_line);
>> +	boothowto |= xen_boothowto(kern_envp);
>> +
>> +	return (NULL);
>> +}
>> +
>> +static void
>> +xen_pv_set_init_ops(void)
>> +{
>> +	/* Init ops for Xen PV */
>> +	init_ops = xen_init_ops;
>> +}
>> -- 
>> 1.7.7.5 (Apple Git-26)
>>
>>
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