[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 10/35] xen/arm64: head: Improve coding style and document create_pages_tables()
On Mon, 22 Jul 2019, Julien Grall wrote: > Adjust the coding style used in the comments within create_pages_tables() > > Lastly, document the behavior and the main registers usage within the > function. Note that x25 is now only used within the function, so it does > not need to be part of the common register. > > Signed-off-by: Julien Grall <julien.grall@xxxxxxx> Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx> > --- > xen/arch/arm/arm64/head.S | 34 +++++++++++++++++++++++----------- > 1 file changed, 23 insertions(+), 11 deletions(-) > > diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S > index ddc5167020..eddf663021 100644 > --- a/xen/arch/arm/arm64/head.S > +++ b/xen/arch/arm/arm64/head.S > @@ -70,7 +70,7 @@ > * x22 - is_secondary_cpu > * x23 - UART address > * x24 - > - * x25 - identity map in place > + * x25 - > * x26 - skip_zero_bss (boot cpu only) > * x27 - > * x28 - > @@ -436,16 +436,27 @@ cpu_init: > ret > ENDPROC(cpu_init) > > +/* > + * Rebuild the boot pagetable's first-level entries. The structure > + * is described in mm.c. > + * > + * After the CPU enables paging it will add the fixmap mapping > + * to these page tables, however this may clash with the 1:1 > + * mapping. So each CPU must rebuild the page tables here with > + * the 1:1 in place. > + * > + * Inputs: > + * x19: paddr(start) > + * x20: phys offset > + * > + * Clobbers x0 - x4, x25 > + * > + * Register usage within this function: > + * x25: Identity map in place > + */ > create_page_tables: > - /* Rebuild the boot pagetable's first-level entries. The structure > - * is described in mm.c. > - * > - * After the CPU enables paging it will add the fixmap mapping > - * to these page tables, however this may clash with the 1:1 > - * mapping. So each CPU must rebuild the page tables here with > - * the 1:1 in place. */ > - > - /* If Xen is loaded at exactly XEN_VIRT_START then we don't > + /* > + * If Xen is loaded at exactly XEN_VIRT_START then we don't > * need an additional 1:1 mapping, the virtual mapping will > * suffice. > */ > @@ -469,7 +480,8 @@ create_page_tables: > cbz x1, 1f /* It's in slot 0, map in boot_first > * or boot_second later on */ > > - /* Level zero does not support superpage mappings, so we have > + /* > + * Level zero does not support superpage mappings, so we have > * to use an extra first level page in which we create a 1GB mapping. > */ > load_paddr x2, boot_first_id > -- > 2.11.0 > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
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