linux-kernel - Re: [patch 1/7 v2] Add function efi_remap_region for remapping to saved virt address

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Message-ID: <20131114013818.GB4081@dhcp-16-126.nay.redhat.com>
Date:	Thu, 14 Nov 2013 09:38:19 +0800
From:	Dave Young <dyoung@...hat.com>
To:	Matt Fleming <matt@...sole-pimps.org>
Cc:	linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
	x86@...nel.org, mjg59@...f.ucam.org, hpa@...or.com,
	James.Bottomley@...senPartnership.com, vgoyal@...hat.com,
	ebiederm@...ssion.com, horms@...ge.net.au,
	kexec@...ts.infradead.org, bp@...en8.de
Subject: Re: [patch 1/7 v2] Add function efi_remap_region for remapping to
 saved virt address

On 11/13/13 at 03:50pm, Matt Fleming wrote:
> On Tue, 05 Nov, at 04:20:08PM, dyoung@...hat.com wrote:
> > Kexec kernel will use saved runtime virtual mapping, so add a
> > new function efi_remap_region to remapping it directly without
> > calculate the virt addr from efi_va.
> > 
> > The md is passed in from 1st kernel, the virtual addr is
> > saved in md->virt_addr.
> > 
> > Signed-off-by: Dave Young <dyoung@...hat.com>
> > ---
> >  arch/x86/include/asm/efi.h     |    1 +
> >  arch/x86/platform/efi/efi_32.c |    3 +++
> >  arch/x86/platform/efi/efi_64.c |   19 +++++++++++++++++++
> >  3 files changed, 23 insertions(+)
> 
> [...]
> 
> > @@ -203,6 +203,25 @@ void __init efi_map_region(efi_memory_de
> >  	md->virt_addr = efi_va;
> >  }
> >  
> > +/*
> > + * kexec kernel will use efi_map_region_fixed to map efi
> > + * runtime memory ranges. md->virt_addr is the original virtual
> > + * address which had been mapped in kexec 1st kernel.
> > + */
> > +void __init efi_map_region_fixed(efi_memory_desc_t *md)
> > +{
> > +	pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
> > +	unsigned long pf = 0;
> > +
> > +	if (!(md->attribute & EFI_MEMORY_WB))
> > +		pf |= _PAGE_PCD;
> > +
> > +	if (kernel_map_pages_in_pgd(pgd, md->phys_addr, md->virt_addr,
> > +			md->num_pages, pf))
> > +		pr_warn("Error mapping PA 0x%llx -> VA 0x%llx!\n",
> > +			   md->phys_addr, md->virt_addr);
> > +}
> > +
> 
> This function is almost identical to __map_region(). Please implement
> efi_map_region_fixed() in terms of __map_region(), e.g.
> 
> void __init efi_map_region_fixed(efi_memory_desc_t *md)
> {
> 	__map_region(md, md->virt_addr);
> }

Good suggestion, will do

> 
> > @@ -47,6 +47,9 @@ void __init efi_map_region(efi_memory_de
> >  	old_map_region(md);
> >  }
> >  
> > +void __init efi_map_region_fixed(efi_memory_desc_t *md)
> > +{}
> > +
> 
> The braces should be on the same line as the rest of the function
> prototype. Look at how it's done elsewhere in this file.

Ok, will do

> 
> -- 
> Matt Fleming, Intel Open Source Technology Center
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