From 084a2a4e7656209ea93aac9778defa03213ca31d Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Tue, 8 Jul 2008 15:06:50 -0700 Subject: [PATCH] xen64: early mapping setup Set up the initial pagetables to map the kernel mapping into the physical mapping space. This makes __va() usable, since it requires physical mappings. Signed-off-by: Jeremy Fitzhardinge Cc: Stephen Tweedie Cc: Eduardo Habkost Cc: Mark McLoughlin Signed-off-by: Ingo Molnar --- arch/x86/xen/enlighten.c | 192 ++++++++++++++++++++++++++++++++--- include/asm-x86/pgtable_64.h | 2 + 2 files changed, 178 insertions(+), 16 deletions(-) diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 2b7bea3bb6f3..a991ee7ade9e 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -33,6 +33,7 @@ #include #include #include +#include #include #include @@ -1294,6 +1295,157 @@ static void __init xen_reserve_top(void) #endif /* CONFIG_X86_32 */ } +#ifdef CONFIG_X86_64 +/* + * Like __va(), but returns address in the kernel mapping (which is + * all we have until the physical memory mapping has been set up. + */ +static void *__ka(phys_addr_t paddr) +{ + return (void *)(paddr + __START_KERNEL_map); +} + +/* Convert a machine address to physical address */ +static unsigned long m2p(phys_addr_t maddr) +{ + phys_addr_t paddr; + + maddr &= PTE_MASK; + paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT; + + return paddr; +} + +/* Convert a machine address to kernel virtual */ +static void *m2v(phys_addr_t maddr) +{ + return __ka(m2p(maddr)); +} + +static void walk(pgd_t *pgd, unsigned long addr) +{ + unsigned l4idx = pgd_index(addr); + unsigned l3idx = pud_index(addr); + unsigned l2idx = pmd_index(addr); + unsigned l1idx = pte_index(addr); + pgd_t l4; + pud_t l3; + pmd_t l2; + pte_t l1; + + xen_raw_printk("walk %p, %lx -> %d %d %d %d\n", + pgd, addr, l4idx, l3idx, l2idx, l1idx); + + l4 = pgd[l4idx]; + xen_raw_printk(" l4: %016lx\n", l4.pgd); + xen_raw_printk(" %016lx\n", pgd_val(l4)); + + l3 = ((pud_t *)(m2v(l4.pgd)))[l3idx]; + xen_raw_printk(" l3: %016lx\n", l3.pud); + xen_raw_printk(" %016lx\n", pud_val(l3)); + + l2 = ((pmd_t *)(m2v(l3.pud)))[l2idx]; + xen_raw_printk(" l2: %016lx\n", l2.pmd); + xen_raw_printk(" %016lx\n", pmd_val(l2)); + + l1 = ((pte_t *)(m2v(l2.pmd)))[l1idx]; + xen_raw_printk(" l1: %016lx\n", l1.pte); + xen_raw_printk(" %016lx\n", pte_val(l1)); +} + +static void set_page_prot(void *addr, pgprot_t prot) +{ + unsigned long pfn = __pa(addr) >> PAGE_SHIFT; + pte_t pte = pfn_pte(pfn, prot); + + xen_raw_printk("addr=%p pfn=%lx mfn=%lx prot=%016x pte=%016x\n", + addr, pfn, get_phys_to_machine(pfn), + pgprot_val(prot), pte.pte); + + if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0)) + BUG(); +} + +static void convert_pfn_mfn(void *v) +{ + pte_t *pte = v; + int i; + + /* All levels are converted the same way, so just treat them + as ptes. */ + for(i = 0; i < PTRS_PER_PTE; i++) + pte[i] = xen_make_pte(pte[i].pte); +} + +/* + * Set up the inital kernel pagetable. + * + * We can construct this by grafting the Xen provided pagetable into + * head_64.S's preconstructed pagetables. We copy the Xen L2's into + * level2_ident_pgt, level2_kernel_pgt and level2_fixmap_pgt. This + * means that only the kernel has a physical mapping to start with - + * but that's enough to get __va working. We need to fill in the rest + * of the physical mapping once some sort of allocator has been set + * up. + */ +static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd) +{ + pud_t *l3; + pmd_t *l2; + + /* Zap identity mapping */ + init_level4_pgt[0] = __pgd(0); + + /* Pre-constructed entries are in pfn, so convert to mfn */ + convert_pfn_mfn(init_level4_pgt); + convert_pfn_mfn(level3_ident_pgt); + convert_pfn_mfn(level3_kernel_pgt); + + l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd); + l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud); + + memcpy(level2_ident_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD); + memcpy(level2_kernel_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD); + + l3 = m2v(pgd[pgd_index(__START_KERNEL_map + PMD_SIZE)].pgd); + l2 = m2v(l3[pud_index(__START_KERNEL_map + PMD_SIZE)].pud); + memcpy(level2_fixmap_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD); + + /* Make pagetable pieces RO */ + set_page_prot(init_level4_pgt, PAGE_KERNEL_RO); + set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO); + set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO); + set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO); + set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO); + set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO); + + /* Pin down new L4 */ + pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(init_level4_pgt))); + + /* Unpin Xen-provided one */ + pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd))); + + /* Switch over */ + pgd = init_level4_pgt; + xen_write_cr3(__pa(pgd)); + + max_pfn_mapped = PFN_DOWN(__pa(pgd) + + xen_start_info->nr_pt_frames*PAGE_SIZE + + 512*1024); + + return pgd; +} +#else +static __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd) +{ + init_pg_tables_start = __pa(pgd); + init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE; + max_pfn_mapped = PFN_DOWN(init_pg_tables_end + 512*1024); + + return pgd; +} +#endif /* CONFIG_X86_64 */ + /* First C function to be called on Xen boot */ asmlinkage void __init xen_start_kernel(void) { @@ -1336,32 +1488,29 @@ asmlinkage void __init xen_start_kernel(void) pgd = (pgd_t *)xen_start_info->pt_base; -#ifdef CONFIG_X86_32 - init_pg_tables_start = __pa(pgd); - init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE; - max_pfn_mapped = (init_pg_tables_end + 512*1024) >> PAGE_SHIFT; -#endif + /* Prevent unwanted bits from being set in PTEs. */ + __supported_pte_mask &= ~_PAGE_GLOBAL; + if (!is_initial_xendomain()) + __supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD); + + /* Don't do the full vcpu_info placement stuff until we have a + possible map and a non-dummy shared_info. */ + per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; + + xen_raw_console_write("mapping kernel into physical memory\n"); + pgd = xen_setup_kernel_pagetable(pgd); - init_mm.pgd = pgd; /* use the Xen pagetables to start */ + init_mm.pgd = pgd; /* keep using Xen gdt for now; no urgent need to change it */ x86_write_percpu(xen_cr3, __pa(pgd)); x86_write_percpu(xen_current_cr3, __pa(pgd)); - /* Don't do the full vcpu_info placement stuff until we have a - possible map and a non-dummy shared_info. */ - per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; - pv_info.kernel_rpl = 1; if (xen_feature(XENFEAT_supervisor_mode_kernel)) pv_info.kernel_rpl = 0; - /* Prevent unwanted bits from being set in PTEs. */ - __supported_pte_mask &= ~_PAGE_GLOBAL; - if (!is_initial_xendomain()) - __supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD); - /* set the limit of our address space */ xen_reserve_top(); @@ -1384,10 +1533,21 @@ asmlinkage void __init xen_start_kernel(void) add_preferred_console("hvc", 0, NULL); } + xen_raw_console_write("about to get started...\n"); + +#if 0 + xen_raw_printk("&boot_params=%p __pa(&boot_params)=%lx __va(__pa(&boot_params))=%lx\n", + &boot_params, __pa_symbol(&boot_params), + __va(__pa_symbol(&boot_params))); + + walk(pgd, &boot_params); + walk(pgd, __va(__pa(&boot_params))); +#endif + /* Start the world */ #ifdef CONFIG_X86_32 i386_start_kernel(); #else - x86_64_start_kernel((char *)&boot_params); + x86_64_start_reservations((char *)__pa_symbol(&boot_params)); #endif } diff --git a/include/asm-x86/pgtable_64.h b/include/asm-x86/pgtable_64.h index fa7208b483ca..805d3128bfc4 100644 --- a/include/asm-x86/pgtable_64.h +++ b/include/asm-x86/pgtable_64.h @@ -16,6 +16,8 @@ extern pud_t level3_kernel_pgt[512]; extern pud_t level3_ident_pgt[512]; extern pmd_t level2_kernel_pgt[512]; +extern pmd_t level2_fixmap_pgt[512]; +extern pmd_t level2_ident_pgt[512]; extern pgd_t init_level4_pgt[]; #define swapper_pg_dir init_level4_pgt -- GitLab