From 51a9a8284e43642fc3e85810fd54f4c245d23a14 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Mon, 18 Sep 2017 10:03:12 +0100 Subject: x86/xen: clean up clang build warning In the case where sizeof(maddr) != sizeof(long) p is initialized and never read and clang throws a warning on this. Move declaration of p to clean up the clang build warning: warning: Value stored to 'p' during its initialization is never read Signed-off-by: Colin Ian King Reviewed-by: Juergen Gross Signed-off-by: Boris Ostrovsky --- arch/x86/include/asm/xen/hypercall.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h index 9606688caa4b..e089c1675a7c 100644 --- a/arch/x86/include/asm/xen/hypercall.h +++ b/arch/x86/include/asm/xen/hypercall.h @@ -552,13 +552,13 @@ static inline void MULTI_update_descriptor(struct multicall_entry *mcl, u64 maddr, struct desc_struct desc) { - u32 *p = (u32 *) &desc; - mcl->op = __HYPERVISOR_update_descriptor; if (sizeof(maddr) == sizeof(long)) { mcl->args[0] = maddr; mcl->args[1] = *(unsigned long *)&desc; } else { + u32 *p = (u32 *)&desc; + mcl->args[0] = maddr; mcl->args[1] = maddr >> 32; mcl->args[2] = *p++; -- cgit v1.2.3 From 0d805ee70a69eabd38160dc199e183ac2f13fe4b Mon Sep 17 00:00:00 2001 From: Zhenzhong Duan Date: Wed, 27 Sep 2017 02:41:25 -0700 Subject: xen/mmu: Call xen_cleanhighmap() with 4MB aligned for page tables mapping When bootup a PVM guest with large memory(Ex.240GB), XEN provided initial mapping overlaps with kernel module virtual space. When mapping in this space is cleared by xen_cleanhighmap(), in certain case there could be an 2MB mapping left. This is due to XEN initialize 4MB aligned mapping but xen_cleanhighmap() finish at 2MB boundary. When module loading is just on top of the 2MB space, got below warning: WARNING: at mm/vmalloc.c:106 vmap_pte_range+0x14e/0x190() Call Trace: [] warn_alloc_failed+0xf3/0x160 [] __vmalloc_area_node+0x182/0x1c0 [] ? module_alloc_update_bounds+0x1e/0x80 [] __vmalloc_node_range+0xa7/0x110 [] ? module_alloc_update_bounds+0x1e/0x80 [] module_alloc+0x64/0x70 [] ? module_alloc_update_bounds+0x1e/0x80 [] module_alloc_update_bounds+0x1e/0x80 [] move_module+0x27/0x150 [] layout_and_allocate+0x120/0x1b0 [] load_module+0x78/0x640 [] ? security_file_permission+0x8b/0x90 [] sys_init_module+0x62/0x1e0 [] system_call_fastpath+0x16/0x1b Then the mapping of 2MB is cleared, finally oops when the page in that space is accessed. BUG: unable to handle kernel paging request at ffff880022600000 IP: [] clear_page_c_e+0x7/0x10 PGD 1788067 PUD 178c067 PMD 22434067 PTE 0 Oops: 0002 [#1] SMP Call Trace: [] ? prep_new_page+0x127/0x1c0 [] get_page_from_freelist+0x1e2/0x550 [] ? ii_iovec_copy_to_user+0x90/0x140 [] __alloc_pages_nodemask+0x12d/0x230 [] alloc_pages_vma+0xc6/0x1a0 [] ? pte_mfn_to_pfn+0x7d/0x100 [] do_anonymous_page+0x16b/0x350 [] handle_pte_fault+0x1e4/0x200 [] ? xen_pmd_val+0xe/0x10 [] ? __raw_callee_save_xen_pmd_val+0x11/0x1e [] handle_mm_fault+0x15b/0x270 [] do_page_fault+0x140/0x470 [] page_fault+0x25/0x30 Call xen_cleanhighmap() with 4MB aligned for page tables mapping to fix it. The unnecessory call of xen_cleanhighmap() in DEBUG mode is also removed. -v2: add comment about XEN alignment from Juergen. References: https://lists.xen.org/archives/html/xen-devel/2012-07/msg01562.html Signed-off-by: Zhenzhong Duan Reviewed-by: Juergen Gross [boris: added 'xen/mmu' tag to commit subject] Signed-off-by: Boris Ostrovsky --- arch/x86/xen/mmu_pv.c | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c index 509f560bd0c6..58b09fcadbaa 100644 --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -1238,21 +1238,16 @@ static void __init xen_pagetable_cleanhighmap(void) * from _brk_limit way up to the max_pfn_mapped (which is the end of * the ramdisk). We continue on, erasing PMD entries that point to page * tables - do note that they are accessible at this stage via __va. - * For good measure we also round up to the PMD - which means that if + * As Xen is aligning the memory end to a 4MB boundary, for good + * measure we also round up to PMD_SIZE * 2 - which means that if * anybody is using __ka address to the initial boot-stack - and try * to use it - they are going to crash. The xen_start_info has been * taken care of already in xen_setup_kernel_pagetable. */ addr = xen_start_info->pt_base; - size = roundup(xen_start_info->nr_pt_frames * PAGE_SIZE, PMD_SIZE); + size = xen_start_info->nr_pt_frames * PAGE_SIZE; - xen_cleanhighmap(addr, addr + size); + xen_cleanhighmap(addr, roundup(addr + size, PMD_SIZE * 2)); xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base)); -#ifdef DEBUG - /* This is superfluous and is not necessary, but you know what - * lets do it. The MODULES_VADDR -> MODULES_END should be clear of - * anything at this stage. */ - xen_cleanhighmap(MODULES_VADDR, roundup(MODULES_VADDR, PUD_SIZE) - 1); -#endif } #endif -- cgit v1.2.3