arch/ia64/boot/bootloader.c

Can someone please tell me what the first itr mapping (the 1M page in region 0) is for? Thanks.

	/*
	 * Install a translation register that identity maps the
	 * kernel's 256MB page.
	 */
	ia64_clear_ic(flags);
	ia64_set_rr(          0, (0x1000 << 8) | (_PAGE_SIZE_1M << 2));
	ia64_set_rr(PAGE_OFFSET, (ia64_rid(0, PAGE_OFFSET) << 8) |
			(_PAGE_SIZE_256M << 2));
	ia64_srlz_d();
	ia64_itr(0x3, 0, 1024*1024,
		 pte_val(mk_pte_phys(1024*1024,
			__pgprot(__DIRTY_BITS|_PAGE_PL_0|_PAGE_AR_RWX))),
		 	_PAGE_SIZE_1M);
	ia64_itr(0x3, 1, PAGE_OFFSET,
		 pte_val(mk_pte_phys(0,
			__pgprot(__DIRTY_BITS|_PAGE_PL_0|_PAGE_AR_RWX))),
		 	_PAGE_SIZE_256M);

Alan
__________
[email protected]
School of Computer Science and Engineering
University of New South Wales

The code you're quoting is from arch/ia64/boot/bootloader.c, which is used only for the HP simulator. There, we need to emulate PAL/SAL/EFI and the bootloader is taking care of that. It lives in the low address space, so there needs to be a mapping for that code. Kludgy, but it does what we want.

	--david

Alan> Can someone please tell me what the first itr mapping (the 1M Alan> page in region 0) is for? Thanks.

Alan> /* * Install a translation register that identity maps
Alan> the * kernel's 256MB page. */ ia64_clear_ic(flags); Alan> ia64_set_rr( 0, (0x1000 << 8) | (_PAGE_SIZE_1M << 2)); Alan> ia64_set_rr(PAGE_OFFSET, (ia64_rid(0, PAGE_OFFSET) << 8) | Alan> (_PAGE_SIZE_256M << 2)); ia64_srlz_d(); ia64_itr(0x3, 0, Alan> 1024*1024, pte_val(mk_pte_phys(1024*1024,
Alan> __pgprot(__DIRTY_BITS|_PAGE_PL_0|_PAGE_AR_RWX))), Alan> _PAGE_SIZE_1M); ia64_itr(0x3, 1, PAGE_OFFSET, Alan> pte_val(mk_pte_phys(0,
Alan> __pgprot(__DIRTY_BITS|_PAGE_PL_0|_PAGE_AR_RWX))), Alan> _PAGE_SIZE_256M);

Alan> Alan __________ [email protected] School of Computer Alan> Science and Engineering University of New South Wales

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