Re: [Xen-ia64-devel] [patch 01/12] ia64: kexec: Define macros for EFI RID

[Simon Horman <horms@xxxxxxxxxxxx>]

Please ignore the version of the patch below.
It renames XEN_EFI_RID to XEN_EFI_RR which causes several problems
(including inconsistency within this patch).

I'll post a working version shortly.

On Mon, Apr 28, 2008 at 10:10:34AM +1000, Simon Horman wrote:
> Macros to be called by PAL, SAL and EFI to switch into
> and out of EFI RID.
> 
> Cc: Tristan Gingold <tgingold@xxxxxxx>
> Cc: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
> Cc: Alex Williamson <alex.williamson@xxxxxx>
> Cc: Aron Griffis <aron@xxxxxx>
> Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>
> 
> --- 
> 
> Thu, 22 Nov 2007 00:20:54 -0700
> * Add XEN_EFI_RR_DECLARE to help consistent declarations
> * Fix up vairous compile errors in the !XEN case
> * Pass unsigned long as the second argement to to ia64_rid
>   to ensure that it is wide enough
> 
> Mon, 03 Dec 2007 17:29:04 +0900
> * Shift VRN 61 bits to the left when calling ia64_get_rr() and
>   ia64_set_rr()
> 
> 
> Thu, 24 Jan 2008 12:15:55 +0900
> * Use set_one_rr_efi() instead of set_rr() so
>   that TR (TLB) entries are repined as neccessary.
> * Do not enable VHPT in EFI RID.
>   - There seems to be no good reason to enable it,
>     and the current code dies if it is enabled.
>     Perhaps the VHPT TR would need to be repined?
> 
> Mon, 21 Apr 2008 11:40:32 +1000
> * Remove ia64_srlz_d from XEN_EFI_RR_RESTORE and XEN_EFI_RR_SAVE
>   as serialisation is done by set_one_rr_efi()
> 
> Fri, 25 Apr 2008 13:39:24 +1000
> * Use __IA64_UL_CONST() to simplify the declaration of XEN_EFI_RID_NO 
>   Thanks to Yamahata-san
> 
> Fri, 25 Apr 2008 16:50:08 +1000
> * Tidy up comment describing RID selection
>   Thanks to Tristan Gingold
> 
> Index: xen-unstable.hg/xen/include/asm-ia64/linux-xen/linux/efi.h
> ===================================================================
> --- xen-unstable.hg.orig/xen/include/asm-ia64/linux-xen/linux/efi.h   
> 2008-04-25 13:55:13.000000000 +1000
> +++ xen-unstable.hg/xen/include/asm-ia64/linux-xen/linux/efi.h        
> 2008-04-25 15:31:48.000000000 +1000
> @@ -1,6 +1,8 @@
>  #ifndef _LINUX_EFI_H
>  #define _LINUX_EFI_H
>  
> +#ifndef __ASSEMBLY__
> +
>  /*
>   * Extensible Firmware Interface
>   * Based on 'Extensible Firmware Interface Specification' version 0.9, April 
> 30, 1999
> @@ -419,4 +421,93 @@ struct efi_generic_dev_path {
>       u16 length;
>  } __attribute ((packed));
>  
> +#ifdef XEN
> +/*
> + * According to xen/arch/ia64/xen/regionreg.c the RID space is broken up
> + * into large-blocks. Each block belongs to a domain, except 0th block,
> + * which is broken up into small-blocks. The small-blocks are used for
> + * metaphysical mappings, again one per domain, except for the 0th
> + * small-block which is unused other than very early on in the
> + * hypervisor boot.
> + *
> + * By default each large-block is 18 bits wide, which is also the minimum
> + * allowed width for a block. Each small-block is by default 1/64 the width
> + * of a large-block, which is the maximum division allowed. In other words
> + * each small-block is at least 12 bits wide.
> + *
> + * The portion of the 0th small-block that is used early on during
> + * the hypervisor boot relates to IA64_REGION_ID_KERNEL, which is
> + * used to form an RID using the following scheme which seems to be
> + * have been inherited from Linux:
> + *
> + * a: bits 0-2: Region Number (0-7)
> + * b: 3-N:      IA64_REGION_ID_KERNEL (0)
> + * c: N-23:     reserved (0)
> + *
> + * N is defined by the platform.
> + *
> + * For EFI we use the following RID:
> + *
> + * a: bits 0-2:  Region Number (0-7)
> + * e: bits 3-N:  IA64_REGION_ID_KERNEL (1)
> + * f: bits N-53: reserved (0)
> + *
> + * + Only 0 is used as we only need one RID. Its not really important
> + *   what this number is, so long as its between 0 and 7.
> + *
> + * The nice thing about this is that we are only using 4 bits of RID
> + * space, so it shouldn't have any chance of running into an adjacent
> + * small-block since small-blocks are at least 12 bits wide.
> + *
> + * It would actually be possible to just use a IA64_REGION_ID_KERNEL
> + * based RID for EFI use. The important thing is that it is in the 0th
> + * small block, and thus not available to domains. But as we have
> + * lots of space, its seems to be nice and clean to just use a separate
> + * RID for EFI.
> + *
> + * This can be trivially changed by updating the definition of XEN_EFI_RID.
> + *
> + * For reference, the RID is used to produce the value inserted
> + * in to a region register in the following way:
> + *
> + * A: bit 0:     VHPT (0 = off, 1 = on)
> + * B: bit 1:     reserved (0)
> + * C: bits 2-7:  log 2 page_size
> + * D: bits 8-N:  RID
> + * E: bits N-53: reserved (0)
> + */
> +
> +#define XEN_EFI_RR_SAVE(rr6, rr7) do {                       \
> +     rr6 = ia64_get_rr(6UL << 61);                   \
> +     rr7 = ia64_get_rr(7UL << 61);                   \
> +     set_one_rr_efi(6UL << 61, XEN_EFI_RID);         \
> +     set_one_rr_efi(7UL << 61, XEN_EFI_RID);         \
> +} while (0)
> +
> +#define XEN_EFI_RR_RESTORE(rr6, rr7) do {            \
> +     set_one_rr_efi(6UL << 61, rr6);                 \
> +     set_one_rr_efi(7UL << 61, rr7);                 \
> +} while (0)
> +
> +#else
> +/* Just use rr6 and rr7 in a dummy fashion here to get
> + * rid of compiler warnings - a better solution should
> + * be found if this code is ever actually used */
> +#define XEN_EFI_RR_SAVE(rr6, rr7)       do { rr6 = 0; rr7 = 0; } while (0)
> +#define XEN_EFI_RR_RESTORE(rr6, rr7)    do {} while (0)
> +#endif /* XEN */
> +
> +#define XEN_EFI_RR_DECLARE(rr6, rr7) unsigned long rr6, rr7;
> +
> +#endif /* !__ASSEMBLY__ */
> +
> +#ifdef XEN
> +#include <asm/mmu_context.h> /* For IA64_REGION_ID_EFI and ia64_rid() */
> +#include <asm/pgtable.h>     /* IA64_GRANULE_SHIFT */
> +#define XEN_EFI_REGION_NO __IA64_UL_CONST(0)
> +#define XEN_EFI_RR ((ia64_rid(XEN_IA64_REGION_ID_EFI,                        
> \
> +                           XEN_EFI_REGION_NO) << 8) |                \
> +                 (IA64_GRANULE_SHIFT << 2))
> +#endif /* XEN */
> +
>  #endif /* _LINUX_EFI_H */
> Index: xen-unstable.hg/xen/include/asm-ia64/mmu_context.h
> ===================================================================
> --- xen-unstable.hg.orig/xen/include/asm-ia64/mmu_context.h   2008-04-25 
> 13:55:13.000000000 +1000
> +++ xen-unstable.hg/xen/include/asm-ia64/mmu_context.h        2008-04-25 
> 14:43:00.000000000 +1000
> @@ -3,6 +3,7 @@
>  //dummy file to resolve non-arch-indep include
>  #ifdef XEN
>  #define IA64_REGION_ID_KERNEL 0
> +#define XEN_IA64_REGION_ID_EFI 1
>  #define ia64_rid(ctx,addr)   (((ctx) << 3) | (addr >> 61))
>  
>  #ifndef __ASSEMBLY__
> 
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-- 
Horms


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