From f4fccac05f7f6bacb8e481a84d175e85ffcf9fe2 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 31 Oct 2013 17:24:59 +0100 Subject: x86/efi: Simplify EFI_DEBUG ... and lose one #ifdef .. #endif sandwich. Signed-off-by: Borislav Petkov Signed-off-by: Matt Fleming diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 1d3372a..f396163 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -51,7 +51,7 @@ #include #include -#define EFI_DEBUG 1 +#define EFI_DEBUG #define EFI_MIN_RESERVE 5120 @@ -398,9 +398,9 @@ int __init efi_memblock_x86_reserve_range(void) return 0; } -#if EFI_DEBUG static void __init print_efi_memmap(void) { +#ifdef EFI_DEBUG efi_memory_desc_t *md; void *p; int i; @@ -415,8 +415,8 @@ static void __init print_efi_memmap(void) md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT), (md->num_pages >> (20 - EFI_PAGE_SHIFT))); } -} #endif /* EFI_DEBUG */ +} void __init efi_reserve_boot_services(void) { @@ -696,10 +696,7 @@ void __init efi_init(void) x86_platform.set_wallclock = efi_set_rtc_mmss; } #endif - -#if EFI_DEBUG print_efi_memmap(); -#endif } void __init efi_late_init(void) -- cgit v0.10.2 From 0fd64c23fdf556e9e68580cff03b3505797bbf53 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 31 Oct 2013 17:25:00 +0100 Subject: x86/mm/pageattr: Lookup address in an arbitrary PGD This is preparatory work in order to be able to map pages into a specified PGD and not implicitly and only into init_mm. Signed-off-by: Borislav Petkov Signed-off-by: Matt Fleming diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index bb32480..c53de62 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -30,6 +30,7 @@ */ struct cpa_data { unsigned long *vaddr; + pgd_t *pgd; pgprot_t mask_set; pgprot_t mask_clr; int numpages; @@ -322,17 +323,9 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address, return prot; } -/* - * Lookup the page table entry for a virtual address. Return a pointer - * to the entry and the level of the mapping. - * - * Note: We return pud and pmd either when the entry is marked large - * or when the present bit is not set. Otherwise we would return a - * pointer to a nonexisting mapping. - */ -pte_t *lookup_address(unsigned long address, unsigned int *level) +static pte_t *__lookup_address_in_pgd(pgd_t *pgd, unsigned long address, + unsigned int *level) { - pgd_t *pgd = pgd_offset_k(address); pud_t *pud; pmd_t *pmd; @@ -361,8 +354,31 @@ pte_t *lookup_address(unsigned long address, unsigned int *level) return pte_offset_kernel(pmd, address); } + +/* + * Lookup the page table entry for a virtual address. Return a pointer + * to the entry and the level of the mapping. + * + * Note: We return pud and pmd either when the entry is marked large + * or when the present bit is not set. Otherwise we would return a + * pointer to a nonexisting mapping. + */ +pte_t *lookup_address(unsigned long address, unsigned int *level) +{ + return __lookup_address_in_pgd(pgd_offset_k(address), address, level); +} EXPORT_SYMBOL_GPL(lookup_address); +static pte_t *_lookup_address_cpa(struct cpa_data *cpa, unsigned long address, + unsigned int *level) +{ + if (cpa->pgd) + return __lookup_address_in_pgd(cpa->pgd + pgd_index(address), + address, level); + + return lookup_address(address, level); +} + /* * This is necessary because __pa() does not work on some * kinds of memory, like vmalloc() or the alloc_remap() -- cgit v0.10.2 From f3f729661e8db476ac427a97de015307aebb7404 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 31 Oct 2013 17:25:01 +0100 Subject: x86/mm/pageattr: Add a PGD pagetable populating function This allocates, if necessary, and populates the corresponding PGD entry with a PUD page. The next population level is a dummy macro which will be removed by the next patch and it is added here to keep the patch small and easily reviewable but not break bisection, at the same time. Signed-off-by: Borislav Petkov Signed-off-by: Matt Fleming diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index c53de62..4b47ae0 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -666,6 +666,45 @@ static int split_large_page(pte_t *kpte, unsigned long address) return 0; } +#define populate_pud(cpa, addr, pgd, pgprot) (-1) + +/* + * Restrictions for kernel page table do not necessarily apply when mapping in + * an alternate PGD. + */ +static int populate_pgd(struct cpa_data *cpa, unsigned long addr) +{ + pgprot_t pgprot = __pgprot(_KERNPG_TABLE); + bool allocd_pgd = false; + pgd_t *pgd_entry; + pud_t *pud = NULL; /* shut up gcc */ + int ret; + + pgd_entry = cpa->pgd + pgd_index(addr); + + /* + * Allocate a PUD page and hand it down for mapping. + */ + if (pgd_none(*pgd_entry)) { + pud = (pud_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK); + if (!pud) + return -1; + + set_pgd(pgd_entry, __pgd(__pa(pud) | _KERNPG_TABLE)); + allocd_pgd = true; + } + + pgprot_val(pgprot) &= ~pgprot_val(cpa->mask_clr); + pgprot_val(pgprot) |= pgprot_val(cpa->mask_set); + + ret = populate_pud(cpa, addr, pgd_entry, pgprot); + if (ret < 0) + return ret; + + cpa->numpages = ret; + return 0; +} + static int __cpa_process_fault(struct cpa_data *cpa, unsigned long vaddr, int primary) { -- cgit v0.10.2 From 4b23538d88c87d9c693ad87c8c808e92a505a6e6 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 31 Oct 2013 17:25:02 +0100 Subject: x86/mm/pageattr: Add a PUD pagetable populating function Add the next level of the pagetable populating function, we handle chunks around a 1G boundary by mapping them with the lower level functions - otherwise we use 1G pages for the mappings, thus using as less amount of pagetable pages as possible. Signed-off-by: Borislav Petkov Signed-off-by: Matt Fleming diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 4b47ae0..81deca7 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -666,7 +666,92 @@ static int split_large_page(pte_t *kpte, unsigned long address) return 0; } -#define populate_pud(cpa, addr, pgd, pgprot) (-1) +static int alloc_pmd_page(pud_t *pud) +{ + pmd_t *pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK); + if (!pmd) + return -1; + + set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE)); + return 0; +} + +#define populate_pmd(cpa, start, end, pages, pud, pgprot) (-1) + +static int populate_pud(struct cpa_data *cpa, unsigned long start, pgd_t *pgd, + pgprot_t pgprot) +{ + pud_t *pud; + unsigned long end; + int cur_pages = 0; + + end = start + (cpa->numpages << PAGE_SHIFT); + + /* + * Not on a Gb page boundary? => map everything up to it with + * smaller pages. + */ + if (start & (PUD_SIZE - 1)) { + unsigned long pre_end; + unsigned long next_page = (start + PUD_SIZE) & PUD_MASK; + + pre_end = min_t(unsigned long, end, next_page); + cur_pages = (pre_end - start) >> PAGE_SHIFT; + cur_pages = min_t(int, (int)cpa->numpages, cur_pages); + + pud = pud_offset(pgd, start); + + /* + * Need a PMD page? + */ + if (pud_none(*pud)) + if (alloc_pmd_page(pud)) + return -1; + + cur_pages = populate_pmd(cpa, start, pre_end, cur_pages, + pud, pgprot); + if (cur_pages < 0) + return cur_pages; + + start = pre_end; + } + + /* We mapped them all? */ + if (cpa->numpages == cur_pages) + return cur_pages; + + pud = pud_offset(pgd, start); + + /* + * Map everything starting from the Gb boundary, possibly with 1G pages + */ + while (end - start >= PUD_SIZE) { + set_pud(pud, __pud(cpa->pfn | _PAGE_PSE | massage_pgprot(pgprot))); + + start += PUD_SIZE; + cpa->pfn += PUD_SIZE; + cur_pages += PUD_SIZE >> PAGE_SHIFT; + pud++; + } + + /* Map trailing leftover */ + if (start < end) { + int tmp; + + pud = pud_offset(pgd, start); + if (pud_none(*pud)) + if (alloc_pmd_page(pud)) + return -1; + + tmp = populate_pmd(cpa, start, end, cpa->numpages - cur_pages, + pud, pgprot); + if (tmp < 0) + return cur_pages; + + cur_pages += tmp; + } + return cur_pages; +} /* * Restrictions for kernel page table do not necessarily apply when mapping in -- cgit v0.10.2 From f900a4b8ab0f462d89a9fcb6173cac1403415b16 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 31 Oct 2013 17:25:03 +0100 Subject: x86/mm/pageattr: Add a PMD pagetable populating function Handle PMD-level mappings the same as PUD ones. Signed-off-by: Borislav Petkov Signed-off-by: Matt Fleming diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 81deca7..968398b 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -666,6 +666,16 @@ static int split_large_page(pte_t *kpte, unsigned long address) return 0; } +static int alloc_pte_page(pmd_t *pmd) +{ + pte_t *pte = (pte_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK); + if (!pte) + return -1; + + set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE)); + return 0; +} + static int alloc_pmd_page(pud_t *pud) { pmd_t *pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK); @@ -676,7 +686,77 @@ static int alloc_pmd_page(pud_t *pud) return 0; } -#define populate_pmd(cpa, start, end, pages, pud, pgprot) (-1) +#define populate_pte(cpa, start, end, pages, pmd, pgprot) do {} while (0) + +static int populate_pmd(struct cpa_data *cpa, + unsigned long start, unsigned long end, + unsigned num_pages, pud_t *pud, pgprot_t pgprot) +{ + unsigned int cur_pages = 0; + pmd_t *pmd; + + /* + * Not on a 2M boundary? + */ + if (start & (PMD_SIZE - 1)) { + unsigned long pre_end = start + (num_pages << PAGE_SHIFT); + unsigned long next_page = (start + PMD_SIZE) & PMD_MASK; + + pre_end = min_t(unsigned long, pre_end, next_page); + cur_pages = (pre_end - start) >> PAGE_SHIFT; + cur_pages = min_t(unsigned int, num_pages, cur_pages); + + /* + * Need a PTE page? + */ + pmd = pmd_offset(pud, start); + if (pmd_none(*pmd)) + if (alloc_pte_page(pmd)) + return -1; + + populate_pte(cpa, start, pre_end, cur_pages, pmd, pgprot); + + start = pre_end; + } + + /* + * We mapped them all? + */ + if (num_pages == cur_pages) + return cur_pages; + + while (end - start >= PMD_SIZE) { + + /* + * We cannot use a 1G page so allocate a PMD page if needed. + */ + if (pud_none(*pud)) + if (alloc_pmd_page(pud)) + return -1; + + pmd = pmd_offset(pud, start); + + set_pmd(pmd, __pmd(cpa->pfn | _PAGE_PSE | massage_pgprot(pgprot))); + + start += PMD_SIZE; + cpa->pfn += PMD_SIZE; + cur_pages += PMD_SIZE >> PAGE_SHIFT; + } + + /* + * Map trailing 4K pages. + */ + if (start < end) { + pmd = pmd_offset(pud, start); + if (pmd_none(*pmd)) + if (alloc_pte_page(pmd)) + return -1; + + populate_pte(cpa, start, end, num_pages - cur_pages, + pmd, pgprot); + } + return num_pages; +} static int populate_pud(struct cpa_data *cpa, unsigned long start, pgd_t *pgd, pgprot_t pgprot) -- cgit v0.10.2 From c6b6f363f7b24aa448994e3a65c4d5b3116acfcc Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 31 Oct 2013 17:25:04 +0100 Subject: x86/mm/pageattr: Add a PTE pagetable populating function Handle last level by unconditionally writing the PTEs into the PTE page while paying attention to the NX bit. Signed-off-by: Borislav Petkov Signed-off-by: Matt Fleming diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 968398b..2a1308a 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -686,7 +686,27 @@ static int alloc_pmd_page(pud_t *pud) return 0; } -#define populate_pte(cpa, start, end, pages, pmd, pgprot) do {} while (0) +static void populate_pte(struct cpa_data *cpa, + unsigned long start, unsigned long end, + unsigned num_pages, pmd_t *pmd, pgprot_t pgprot) +{ + pte_t *pte; + + pte = pte_offset_kernel(pmd, start); + + while (num_pages-- && start < end) { + + /* deal with the NX bit */ + if (!(pgprot_val(pgprot) & _PAGE_NX)) + cpa->pfn &= ~_PAGE_NX; + + set_pte(pte, pfn_pte(cpa->pfn >> PAGE_SHIFT, pgprot)); + + start += PAGE_SIZE; + cpa->pfn += PAGE_SIZE; + pte++; + } +} static int populate_pmd(struct cpa_data *cpa, unsigned long start, unsigned long end, -- cgit v0.10.2 From 0bb8aeee7b73b21e09d3ea12f2120d974f70b669 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 31 Oct 2013 17:25:05 +0100 Subject: x86/mm/pageattr: Add a PUD error unwinding path In case we encounter an error during the mapping of a region, we want to unwind what we've established so far exactly the way we did the mapping. This is the PUD part kept deliberately small for easier review. Signed-off-by: Borislav Petkov Signed-off-by: Matt Fleming diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 2a1308a..1cbdbbc 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -666,6 +666,51 @@ static int split_large_page(pte_t *kpte, unsigned long address) return 0; } +#define unmap_pmd_range(pud, start, pre_end) do {} while (0) + +static void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end) +{ + pud_t *pud = pud_offset(pgd, start); + + /* + * Not on a GB page boundary? + */ + if (start & (PUD_SIZE - 1)) { + unsigned long next_page = (start + PUD_SIZE) & PUD_MASK; + unsigned long pre_end = min_t(unsigned long, end, next_page); + + unmap_pmd_range(pud, start, pre_end); + + start = pre_end; + pud++; + } + + /* + * Try to unmap in 1G chunks? + */ + while (end - start >= PUD_SIZE) { + + if (pud_large(*pud)) + pud_clear(pud); + else + unmap_pmd_range(pud, start, start + PUD_SIZE); + + start += PUD_SIZE; + pud++; + } + + /* + * 2M leftovers? + */ + if (start < end) + unmap_pmd_range(pud, start, end); + + /* + * No need to try to free the PUD page because we'll free it in + * populate_pgd's error path + */ +} + static int alloc_pte_page(pmd_t *pmd) { pte_t *pte = (pte_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK); @@ -883,9 +928,20 @@ static int populate_pgd(struct cpa_data *cpa, unsigned long addr) pgprot_val(pgprot) |= pgprot_val(cpa->mask_set); ret = populate_pud(cpa, addr, pgd_entry, pgprot); - if (ret < 0) - return ret; + if (ret < 0) { + unmap_pud_range(pgd_entry, addr, + addr + (cpa->numpages << PAGE_SHIFT)); + if (allocd_pgd) { + /* + * If I allocated this PUD page, I can just as well + * free it in this error path. + */ + pgd_clear(pgd_entry); + free_page((unsigned long)pud); + } + return ret; + } cpa->numpages = ret; return 0; } -- cgit v0.10.2 From 52a628fb454d13d944bb3c8a89a314cc3affa417 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 31 Oct 2013 17:25:06 +0100 Subject: x86/mm/pageattr: Add last levels of error path We try to free the pagetable pages once we've unmapped our portion. Signed-off-by: Borislav Petkov Signed-off-by: Matt Fleming diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 1cbdbbc..db8ace2 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -666,7 +666,99 @@ static int split_large_page(pte_t *kpte, unsigned long address) return 0; } -#define unmap_pmd_range(pud, start, pre_end) do {} while (0) +static bool try_to_free_pte_page(pte_t *pte) +{ + int i; + + for (i = 0; i < PTRS_PER_PTE; i++) + if (!pte_none(pte[i])) + return false; + + free_page((unsigned long)pte); + return true; +} + +static bool try_to_free_pmd_page(pmd_t *pmd) +{ + int i; + + for (i = 0; i < PTRS_PER_PMD; i++) + if (!pmd_none(pmd[i])) + return false; + + free_page((unsigned long)pmd); + return true; +} + +static bool unmap_pte_range(pmd_t *pmd, unsigned long start, unsigned long end) +{ + pte_t *pte = pte_offset_kernel(pmd, start); + + while (start < end) { + set_pte(pte, __pte(0)); + + start += PAGE_SIZE; + pte++; + } + + if (try_to_free_pte_page((pte_t *)pmd_page_vaddr(*pmd))) { + pmd_clear(pmd); + return true; + } + return false; +} + +static void __unmap_pmd_range(pud_t *pud, pmd_t *pmd, + unsigned long start, unsigned long end) +{ + if (unmap_pte_range(pmd, start, end)) + if (try_to_free_pmd_page((pmd_t *)pud_page_vaddr(*pud))) + pud_clear(pud); +} + +static void unmap_pmd_range(pud_t *pud, unsigned long start, unsigned long end) +{ + pmd_t *pmd = pmd_offset(pud, start); + + /* + * Not on a 2MB page boundary? + */ + if (start & (PMD_SIZE - 1)) { + unsigned long next_page = (start + PMD_SIZE) & PMD_MASK; + unsigned long pre_end = min_t(unsigned long, end, next_page); + + __unmap_pmd_range(pud, pmd, start, pre_end); + + start = pre_end; + pmd++; + } + + /* + * Try to unmap in 2M chunks. + */ + while (end - start >= PMD_SIZE) { + if (pmd_large(*pmd)) + pmd_clear(pmd); + else + __unmap_pmd_range(pud, pmd, start, start + PMD_SIZE); + + start += PMD_SIZE; + pmd++; + } + + /* + * 4K leftovers? + */ + if (start < end) + return __unmap_pmd_range(pud, pmd, start, end); + + /* + * Try again to free the PMD page if haven't succeeded above. + */ + if (!pud_none(*pud)) + if (try_to_free_pmd_page((pmd_t *)pud_page_vaddr(*pud))) + pud_clear(pud); +} static void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end) { -- cgit v0.10.2 From 82f0712ca0f947170e785300b5c39d9c25e2f6ff Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 31 Oct 2013 17:25:07 +0100 Subject: x86/mm/cpa: Map in an arbitrary pgd Add the ability to map pages in an arbitrary pgd. This wires in the remaining stuff so that there's a new interface with which you can map a region into an arbitrary PGD. Signed-off-by: Borislav Petkov Signed-off-by: Matt Fleming diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index db8ace2..b3b19f4 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -453,7 +453,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, * Check for races, another CPU might have split this page * up already: */ - tmp = lookup_address(address, &level); + tmp = _lookup_address_cpa(cpa, address, &level); if (tmp != kpte) goto out_unlock; @@ -559,7 +559,8 @@ out_unlock: } static int -__split_large_page(pte_t *kpte, unsigned long address, struct page *base) +__split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, + struct page *base) { pte_t *pbase = (pte_t *)page_address(base); unsigned long pfn, pfninc = 1; @@ -572,7 +573,7 @@ __split_large_page(pte_t *kpte, unsigned long address, struct page *base) * Check for races, another CPU might have split this page * up for us already: */ - tmp = lookup_address(address, &level); + tmp = _lookup_address_cpa(cpa, address, &level); if (tmp != kpte) { spin_unlock(&pgd_lock); return 1; @@ -648,7 +649,8 @@ __split_large_page(pte_t *kpte, unsigned long address, struct page *base) return 0; } -static int split_large_page(pte_t *kpte, unsigned long address) +static int split_large_page(struct cpa_data *cpa, pte_t *kpte, + unsigned long address) { struct page *base; @@ -660,7 +662,7 @@ static int split_large_page(pte_t *kpte, unsigned long address) if (!base) return -ENOMEM; - if (__split_large_page(kpte, address, base)) + if (__split_large_page(cpa, kpte, address, base)) __free_page(base); return 0; @@ -1041,6 +1043,9 @@ static int populate_pgd(struct cpa_data *cpa, unsigned long addr) static int __cpa_process_fault(struct cpa_data *cpa, unsigned long vaddr, int primary) { + if (cpa->pgd) + return populate_pgd(cpa, vaddr); + /* * Ignore all non primary paths. */ @@ -1085,7 +1090,7 @@ static int __change_page_attr(struct cpa_data *cpa, int primary) else address = *cpa->vaddr; repeat: - kpte = lookup_address(address, &level); + kpte = _lookup_address_cpa(cpa, address, &level); if (!kpte) return __cpa_process_fault(cpa, address, primary); @@ -1149,7 +1154,7 @@ repeat: /* * We have to split the large page: */ - err = split_large_page(kpte, address); + err = split_large_page(cpa, kpte, address); if (!err) { /* * Do a global flush tlb after splitting the large page @@ -1298,6 +1303,8 @@ static int change_page_attr_set_clr(unsigned long *addr, int numpages, int ret, cache, checkalias; unsigned long baddr = 0; + memset(&cpa, 0, sizeof(cpa)); + /* * Check, if we are requested to change a not supported * feature: @@ -1744,6 +1751,7 @@ static int __set_pages_p(struct page *page, int numpages) { unsigned long tempaddr = (unsigned long) page_address(page); struct cpa_data cpa = { .vaddr = &tempaddr, + .pgd = NULL, .numpages = numpages, .mask_set = __pgprot(_PAGE_PRESENT | _PAGE_RW), .mask_clr = __pgprot(0), @@ -1762,6 +1770,7 @@ static int __set_pages_np(struct page *page, int numpages) { unsigned long tempaddr = (unsigned long) page_address(page); struct cpa_data cpa = { .vaddr = &tempaddr, + .pgd = NULL, .numpages = numpages, .mask_set = __pgprot(0), .mask_clr = __pgprot(_PAGE_PRESENT | _PAGE_RW), @@ -1822,6 +1831,36 @@ bool kernel_page_present(struct page *page) #endif /* CONFIG_DEBUG_PAGEALLOC */ +int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, + unsigned numpages, unsigned long page_flags) +{ + int retval = -EINVAL; + + struct cpa_data cpa = { + .vaddr = &address, + .pfn = pfn, + .pgd = pgd, + .numpages = numpages, + .mask_set = __pgprot(0), + .mask_clr = __pgprot(0), + .flags = 0, + }; + + if (!(__supported_pte_mask & _PAGE_NX)) + goto out; + + if (!(page_flags & _PAGE_NX)) + cpa.mask_clr = __pgprot(_PAGE_NX); + + cpa.mask_set = __pgprot(_PAGE_PRESENT | page_flags); + + retval = __change_page_attr_set_clr(&cpa, 0); + __flush_tlb_all(); + +out: + return retval; +} + /* * The testcases use internal knowledge of the implementation that shouldn't * be exposed to the rest of the kernel. Include these directly here. -- cgit v0.10.2 From d2f7cbe7b26a74dbbbf8f325b2a6fd01bc34032c Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 31 Oct 2013 17:25:08 +0100 Subject: x86/efi: Runtime services virtual mapping We map the EFI regions needed for runtime services non-contiguously, with preserved alignment on virtual addresses starting from -4G down for a total max space of 64G. This way, we provide for stable runtime services addresses across kernels so that a kexec'd kernel can still use them. Thus, they're mapped in a separate pagetable so that we don't pollute the kernel namespace. Add an efi= kernel command line parameter for passing miscellaneous options and chicken bits from the command line. While at it, add a chicken bit called "efi=old_map" which can be used as a fallback to the old runtime services mapping method in case there's some b0rkage with a particular EFI implementation (haha, it is hard to hold up the sarcasm here...). Also, add the UEFI RT VA space to Documentation/x86/x86_64/mm.txt. Signed-off-by: Borislav Petkov Signed-off-by: Matt Fleming diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 7a0f202..ed43e92 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -835,6 +835,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. edd= [EDD] Format: {"off" | "on" | "skip[mbr]"} + efi= [EFI] + Format: { "old_map" } + old_map [X86-64]: switch to the old ioremap-based EFI + runtime services mapping. 32-bit still uses this one by + default. + efi_no_storage_paranoia [EFI; X86] Using this parameter you can use more than 50% of your efi variable storage. Use this parameter only if diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt index 881582f..c584a51 100644 --- a/Documentation/x86/x86_64/mm.txt +++ b/Documentation/x86/x86_64/mm.txt @@ -28,4 +28,11 @@ reference. Current X86-64 implementations only support 40 bits of address space, but we support up to 46 bits. This expands into MBZ space in the page tables. +->trampoline_pgd: + +We map EFI runtime services in the aforementioned PGD in the virtual +range of 64Gb (arbitrarily set, can be raised if needed) + +0xffffffef00000000 - 0xffffffff00000000 + -Andi Kleen, Jul 2004 diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index 65c6e6e..89a05b0 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -1,6 +1,24 @@ #ifndef _ASM_X86_EFI_H #define _ASM_X86_EFI_H +/* + * We map the EFI regions needed for runtime services non-contiguously, + * with preserved alignment on virtual addresses starting from -4G down + * for a total max space of 64G. This way, we provide for stable runtime + * services addresses across kernels so that a kexec'd kernel can still + * use them. + * + * This is the main reason why we're doing stable VA mappings for RT + * services. + * + * This flag is used in conjuction with a chicken bit called + * "efi=old_map" which can be used as a fallback to the old runtime + * services mapping method in case there's some b0rkage with a + * particular EFI implementation (haha, it is hard to hold up the + * sarcasm here...). + */ +#define EFI_OLD_MEMMAP EFI_ARCH_1 + #ifdef CONFIG_X86_32 #define EFI_LOADER_SIGNATURE "EL32" @@ -69,24 +87,31 @@ extern u64 efi_call6(void *fp, u64 arg1, u64 arg2, u64 arg3, efi_call6((f), (u64)(a1), (u64)(a2), (u64)(a3), \ (u64)(a4), (u64)(a5), (u64)(a6)) +#define _efi_call_virtX(x, f, ...) \ +({ \ + efi_status_t __s; \ + \ + efi_sync_low_kernel_mappings(); \ + preempt_disable(); \ + __s = efi_call##x((void *)efi.systab->runtime->f, __VA_ARGS__); \ + preempt_enable(); \ + __s; \ +}) + #define efi_call_virt0(f) \ - efi_call0((efi.systab->runtime->f)) -#define efi_call_virt1(f, a1) \ - efi_call1((efi.systab->runtime->f), (u64)(a1)) -#define efi_call_virt2(f, a1, a2) \ - efi_call2((efi.systab->runtime->f), (u64)(a1), (u64)(a2)) -#define efi_call_virt3(f, a1, a2, a3) \ - efi_call3((efi.systab->runtime->f), (u64)(a1), (u64)(a2), \ - (u64)(a3)) -#define efi_call_virt4(f, a1, a2, a3, a4) \ - efi_call4((efi.systab->runtime->f), (u64)(a1), (u64)(a2), \ - (u64)(a3), (u64)(a4)) -#define efi_call_virt5(f, a1, a2, a3, a4, a5) \ - efi_call5((efi.systab->runtime->f), (u64)(a1), (u64)(a2), \ - (u64)(a3), (u64)(a4), (u64)(a5)) -#define efi_call_virt6(f, a1, a2, a3, a4, a5, a6) \ - efi_call6((efi.systab->runtime->f), (u64)(a1), (u64)(a2), \ - (u64)(a3), (u64)(a4), (u64)(a5), (u64)(a6)) + _efi_call_virtX(0, f) +#define efi_call_virt1(f, a1) \ + _efi_call_virtX(1, f, (u64)(a1)) +#define efi_call_virt2(f, a1, a2) \ + _efi_call_virtX(2, f, (u64)(a1), (u64)(a2)) +#define efi_call_virt3(f, a1, a2, a3) \ + _efi_call_virtX(3, f, (u64)(a1), (u64)(a2), (u64)(a3)) +#define efi_call_virt4(f, a1, a2, a3, a4) \ + _efi_call_virtX(4, f, (u64)(a1), (u64)(a2), (u64)(a3), (u64)(a4)) +#define efi_call_virt5(f, a1, a2, a3, a4, a5) \ + _efi_call_virtX(5, f, (u64)(a1), (u64)(a2), (u64)(a3), (u64)(a4), (u64)(a5)) +#define efi_call_virt6(f, a1, a2, a3, a4, a5, a6) \ + _efi_call_virtX(6, f, (u64)(a1), (u64)(a2), (u64)(a3), (u64)(a4), (u64)(a5), (u64)(a6)) extern void __iomem *efi_ioremap(unsigned long addr, unsigned long size, u32 type, u64 attribute); @@ -95,12 +120,17 @@ extern void __iomem *efi_ioremap(unsigned long addr, unsigned long size, extern int add_efi_memmap; extern unsigned long x86_efi_facility; +extern struct efi_scratch efi_scratch; extern void efi_set_executable(efi_memory_desc_t *md, bool executable); extern int efi_memblock_x86_reserve_range(void); extern void efi_call_phys_prelog(void); extern void efi_call_phys_epilog(void); extern void efi_unmap_memmap(void); extern void efi_memory_uc(u64 addr, unsigned long size); +extern void __init efi_map_region(efi_memory_desc_t *md); +extern void efi_sync_low_kernel_mappings(void); +extern void efi_setup_page_tables(void); +extern void __init old_map_region(efi_memory_desc_t *md); #ifdef CONFIG_EFI diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index f4843e0..028e28b 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -379,7 +379,8 @@ static inline void update_page_count(int level, unsigned long pages) { } */ extern pte_t *lookup_address(unsigned long address, unsigned int *level); extern phys_addr_t slow_virt_to_phys(void *__address); - +extern int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, + unsigned numpages, unsigned long page_flags); #endif /* !__ASSEMBLY__ */ #endif /* _ASM_X86_PGTABLE_DEFS_H */ diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index f396163..b453069 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -12,6 +12,8 @@ * Bibo Mao * Chandramouli Narayanan * Huang Ying + * Copyright (C) 2013 SuSE Labs + * Borislav Petkov - runtime services VA mapping * * Copied from efi_32.c to eliminate the duplicated code between EFI * 32/64 support code. --ying 2007-10-26 @@ -745,21 +747,56 @@ void efi_memory_uc(u64 addr, unsigned long size) set_memory_uc(addr, npages); } +void __init old_map_region(efi_memory_desc_t *md) +{ + u64 start_pfn, end_pfn, end; + unsigned long size; + void *va; + + start_pfn = PFN_DOWN(md->phys_addr); + size = md->num_pages << PAGE_SHIFT; + end = md->phys_addr + size; + end_pfn = PFN_UP(end); + + if (pfn_range_is_mapped(start_pfn, end_pfn)) { + va = __va(md->phys_addr); + + if (!(md->attribute & EFI_MEMORY_WB)) + efi_memory_uc((u64)(unsigned long)va, size); + } else + va = efi_ioremap(md->phys_addr, size, + md->type, md->attribute); + + md->virt_addr = (u64) (unsigned long) va; + if (!va) + pr_err("ioremap of 0x%llX failed!\n", + (unsigned long long)md->phys_addr); +} + /* * This function will switch the EFI runtime services to virtual mode. - * Essentially, look through the EFI memmap and map every region that - * has the runtime attribute bit set in its memory descriptor and update - * that memory descriptor with the virtual address obtained from ioremap(). - * This enables the runtime services to be called without having to + * Essentially, we look through the EFI memmap and map every region that + * has the runtime attribute bit set in its memory descriptor into the + * ->trampoline_pgd page table using a top-down VA allocation scheme. + * + * The old method which used to update that memory descriptor with the + * virtual address obtained from ioremap() is still supported when the + * kernel is booted with efi=old_map on its command line. Same old + * method enabled the runtime services to be called without having to * thunk back into physical mode for every invocation. + * + * The new method does a pagetable switch in a preemption-safe manner + * so that we're in a different address space when calling a runtime + * function. For function arguments passing we do copy the PGDs of the + * kernel page table into ->trampoline_pgd prior to each call. */ void __init efi_enter_virtual_mode(void) { efi_memory_desc_t *md, *prev_md = NULL; - efi_status_t status; + void *p, *new_memmap = NULL; unsigned long size; - u64 end, systab, start_pfn, end_pfn; - void *p, *va, *new_memmap = NULL; + efi_status_t status; + u64 end, systab; int count = 0; efi.systab = NULL; @@ -768,7 +805,6 @@ void __init efi_enter_virtual_mode(void) * We don't do virtual mode, since we don't do runtime services, on * non-native EFI */ - if (!efi_is_native()) { efi_unmap_memmap(); return; @@ -799,6 +835,7 @@ void __init efi_enter_virtual_mode(void) continue; } prev_md = md; + } for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { @@ -808,33 +845,18 @@ void __init efi_enter_virtual_mode(void) md->type != EFI_BOOT_SERVICES_DATA) continue; + efi_map_region(md); + size = md->num_pages << EFI_PAGE_SHIFT; end = md->phys_addr + size; - start_pfn = PFN_DOWN(md->phys_addr); - end_pfn = PFN_UP(end); - if (pfn_range_is_mapped(start_pfn, end_pfn)) { - va = __va(md->phys_addr); - - if (!(md->attribute & EFI_MEMORY_WB)) - efi_memory_uc((u64)(unsigned long)va, size); - } else - va = efi_ioremap(md->phys_addr, size, - md->type, md->attribute); - - md->virt_addr = (u64) (unsigned long) va; - - if (!va) { - pr_err("ioremap of 0x%llX failed!\n", - (unsigned long long)md->phys_addr); - continue; - } - systab = (u64) (unsigned long) efi_phys.systab; if (md->phys_addr <= systab && systab < end) { systab += md->virt_addr - md->phys_addr; + efi.systab = (efi_system_table_t *) (unsigned long) systab; } + new_memmap = krealloc(new_memmap, (count + 1) * memmap.desc_size, GFP_KERNEL); @@ -845,6 +867,9 @@ void __init efi_enter_virtual_mode(void) BUG_ON(!efi.systab); + efi_setup_page_tables(); + efi_sync_low_kernel_mappings(); + status = phys_efi_set_virtual_address_map( memmap.desc_size * count, memmap.desc_size, @@ -877,7 +902,8 @@ void __init efi_enter_virtual_mode(void) efi.query_variable_info = virt_efi_query_variable_info; efi.update_capsule = virt_efi_update_capsule; efi.query_capsule_caps = virt_efi_query_capsule_caps; - if (__supported_pte_mask & _PAGE_NX) + + if (efi_enabled(EFI_OLD_MEMMAP) && (__supported_pte_mask & _PAGE_NX)) runtime_code_page_mkexec(); kfree(new_memmap); @@ -1007,3 +1033,15 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size) return EFI_SUCCESS; } EXPORT_SYMBOL_GPL(efi_query_variable_store); + +static int __init parse_efi_cmdline(char *str) +{ + if (*str == '=') + str++; + + if (!strncmp(str, "old_map", 7)) + set_bit(EFI_OLD_MEMMAP, &x86_efi_facility); + + return 0; +} +early_param("efi", parse_efi_cmdline); diff --git a/arch/x86/platform/efi/efi_32.c b/arch/x86/platform/efi/efi_32.c index 40e4469..e94557c 100644 --- a/arch/x86/platform/efi/efi_32.c +++ b/arch/x86/platform/efi/efi_32.c @@ -37,9 +37,16 @@ * claim EFI runtime service handler exclusively and to duplicate a memory in * low memory space say 0 - 3G. */ - static unsigned long efi_rt_eflags; +void efi_sync_low_kernel_mappings(void) {} +void efi_setup_page_tables(void) {} + +void __init efi_map_region(efi_memory_desc_t *md) +{ + old_map_region(md); +} + void efi_call_phys_prelog(void) { struct desc_ptr gdt_descr; diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index 39a0e7f..bf286c3 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -38,10 +38,28 @@ #include #include #include +#include static pgd_t *save_pgd __initdata; static unsigned long efi_flags __initdata; +/* + * We allocate runtime services regions bottom-up, starting from -4G, i.e. + * 0xffff_ffff_0000_0000 and limit EFI VA mapping space to 64G. + */ +static u64 efi_va = -4 * (1UL << 30); +#define EFI_VA_END (-68 * (1UL << 30)) + +/* + * Scratch space used for switching the pagetable in the EFI stub + */ +struct efi_scratch { + u64 r15; + u64 prev_cr3; + pgd_t *efi_pgt; + bool use_pgd; +}; + static void __init early_code_mapping_set_exec(int executable) { efi_memory_desc_t *md; @@ -65,6 +83,9 @@ void __init efi_call_phys_prelog(void) int pgd; int n_pgds; + if (!efi_enabled(EFI_OLD_MEMMAP)) + return; + early_code_mapping_set_exec(1); local_irq_save(efi_flags); @@ -86,6 +107,10 @@ void __init efi_call_phys_epilog(void) */ int pgd; int n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE); + + if (!efi_enabled(EFI_OLD_MEMMAP)) + return; + for (pgd = 0; pgd < n_pgds; pgd++) set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), save_pgd[pgd]); kfree(save_pgd); @@ -94,6 +119,90 @@ void __init efi_call_phys_epilog(void) early_code_mapping_set_exec(0); } +/* + * Add low kernel mappings for passing arguments to EFI functions. + */ +void efi_sync_low_kernel_mappings(void) +{ + unsigned num_pgds; + pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd); + + if (efi_enabled(EFI_OLD_MEMMAP)) + return; + + num_pgds = pgd_index(MODULES_END - 1) - pgd_index(PAGE_OFFSET); + + memcpy(pgd + pgd_index(PAGE_OFFSET), + init_mm.pgd + pgd_index(PAGE_OFFSET), + sizeof(pgd_t) * num_pgds); +} + +void efi_setup_page_tables(void) +{ + efi_scratch.efi_pgt = (pgd_t *)(unsigned long)real_mode_header->trampoline_pgd; + + if (!efi_enabled(EFI_OLD_MEMMAP)) + efi_scratch.use_pgd = true; +} + +static void __init __map_region(efi_memory_desc_t *md, u64 va) +{ + pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd); + unsigned long pf = 0, size; + u64 end; + + if (!(md->attribute & EFI_MEMORY_WB)) + pf |= _PAGE_PCD; + + size = md->num_pages << PAGE_SHIFT; + end = va + size; + + if (kernel_map_pages_in_pgd(pgd, md->phys_addr, va, md->num_pages, pf)) + pr_warn("Error mapping PA 0x%llx -> VA 0x%llx!\n", + md->phys_addr, va); +} + +void __init efi_map_region(efi_memory_desc_t *md) +{ + unsigned long size = md->num_pages << PAGE_SHIFT; + u64 pa = md->phys_addr; + + if (efi_enabled(EFI_OLD_MEMMAP)) + return old_map_region(md); + + /* + * Make sure the 1:1 mappings are present as a catch-all for b0rked + * firmware which doesn't update all internal pointers after switching + * to virtual mode and would otherwise crap on us. + */ + __map_region(md, md->phys_addr); + + efi_va -= size; + + /* Is PA 2M-aligned? */ + if (!(pa & (PMD_SIZE - 1))) { + efi_va &= PMD_MASK; + } else { + u64 pa_offset = pa & (PMD_SIZE - 1); + u64 prev_va = efi_va; + + /* get us the same offset within this 2M page */ + efi_va = (efi_va & PMD_MASK) + pa_offset; + + if (efi_va > prev_va) + efi_va -= PMD_SIZE; + } + + if (efi_va < EFI_VA_END) { + pr_warn(FW_WARN "VA address range overflow!\n"); + return; + } + + /* Do the VA map */ + __map_region(md, efi_va); + md->virt_addr = efi_va; +} + void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size, u32 type, u64 attribute) { diff --git a/arch/x86/platform/efi/efi_stub_64.S b/arch/x86/platform/efi/efi_stub_64.S index 4c07cca..88073b1 100644 --- a/arch/x86/platform/efi/efi_stub_64.S +++ b/arch/x86/platform/efi/efi_stub_64.S @@ -34,10 +34,47 @@ mov %rsi, %cr0; \ mov (%rsp), %rsp + /* stolen from gcc */ + .macro FLUSH_TLB_ALL + movq %r15, efi_scratch(%rip) + movq %r14, efi_scratch+8(%rip) + movq %cr4, %r15 + movq %r15, %r14 + andb $0x7f, %r14b + movq %r14, %cr4 + movq %r15, %cr4 + movq efi_scratch+8(%rip), %r14 + movq efi_scratch(%rip), %r15 + .endm + + .macro SWITCH_PGT + cmpb $0, efi_scratch+24(%rip) + je 1f + movq %r15, efi_scratch(%rip) # r15 + # save previous CR3 + movq %cr3, %r15 + movq %r15, efi_scratch+8(%rip) # prev_cr3 + movq efi_scratch+16(%rip), %r15 # EFI pgt + movq %r15, %cr3 + 1: + .endm + + .macro RESTORE_PGT + cmpb $0, efi_scratch+24(%rip) + je 2f + movq efi_scratch+8(%rip), %r15 + movq %r15, %cr3 + movq efi_scratch(%rip), %r15 + FLUSH_TLB_ALL + 2: + .endm + ENTRY(efi_call0) SAVE_XMM subq $32, %rsp + SWITCH_PGT call *%rdi + RESTORE_PGT addq $32, %rsp RESTORE_XMM ret @@ -47,7 +84,9 @@ ENTRY(efi_call1) SAVE_XMM subq $32, %rsp mov %rsi, %rcx + SWITCH_PGT call *%rdi + RESTORE_PGT addq $32, %rsp RESTORE_XMM ret @@ -57,7 +96,9 @@ ENTRY(efi_call2) SAVE_XMM subq $32, %rsp mov %rsi, %rcx + SWITCH_PGT call *%rdi + RESTORE_PGT addq $32, %rsp RESTORE_XMM ret @@ -68,7 +109,9 @@ ENTRY(efi_call3) subq $32, %rsp mov %rcx, %r8 mov %rsi, %rcx + SWITCH_PGT call *%rdi + RESTORE_PGT addq $32, %rsp RESTORE_XMM ret @@ -80,7 +123,9 @@ ENTRY(efi_call4) mov %r8, %r9 mov %rcx, %r8 mov %rsi, %rcx + SWITCH_PGT call *%rdi + RESTORE_PGT addq $32, %rsp RESTORE_XMM ret @@ -93,7 +138,9 @@ ENTRY(efi_call5) mov %r8, %r9 mov %rcx, %r8 mov %rsi, %rcx + SWITCH_PGT call *%rdi + RESTORE_PGT addq $48, %rsp RESTORE_XMM ret @@ -109,8 +156,15 @@ ENTRY(efi_call6) mov %r8, %r9 mov %rcx, %r8 mov %rsi, %rcx + SWITCH_PGT call *%rdi + RESTORE_PGT addq $48, %rsp RESTORE_XMM ret ENDPROC(efi_call6) + + .data +ENTRY(efi_scratch) + .fill 3,8,0 + .byte 0 diff --git a/include/linux/efi.h b/include/linux/efi.h index bc5687d..6c0ca52 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -653,6 +653,7 @@ extern int __init efi_setup_pcdp_console(char *); #define EFI_RUNTIME_SERVICES 3 /* Can we use runtime services? */ #define EFI_MEMMAP 4 /* Can we use EFI memory map? */ #define EFI_64BIT 5 /* Is the firmware 64-bit? */ +#define EFI_ARCH_1 6 /* First arch-specific bit */ #ifdef CONFIG_EFI # ifdef CONFIG_X86 -- cgit v0.10.2 From ee41143027706d9f342dfe05487a00b20887fde7 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 31 Oct 2013 17:25:09 +0100 Subject: x86/efi: Check krealloc return value Check it just in case. We might just as well panic there because runtime won't be functioning anyway. Signed-off-by: Borislav Petkov Signed-off-by: Matt Fleming diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index b453069..3fac4de 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -860,6 +860,9 @@ void __init efi_enter_virtual_mode(void) new_memmap = krealloc(new_memmap, (count + 1) * memmap.desc_size, GFP_KERNEL); + if (!new_memmap) + goto err_out; + memcpy(new_memmap + (count * memmap.desc_size), md, memmap.desc_size); count++; @@ -914,6 +917,11 @@ void __init efi_enter_virtual_mode(void) EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS, 0, NULL); + + return; + + err_out: + pr_err("Error reallocating memory, EFI runtime non-functional!\n"); } /* -- cgit v0.10.2