From ef6bea6ddf0e76077d0798e57b374015b23a837e Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Sat, 18 Jan 2014 12:48:14 +0100 Subject: x86, ptdump: Add the functionality to dump an arbitrary pagetable With reusing the ->trampoline_pgd page table for mapping EFI regions in order to use them after having switched to EFI virtual mode, it is very useful to be able to dump aforementioned page table in dmesg. This adds that functionality through the walk_pgd_level() interface which can be called from somewhere else. The original functionality of dumping to debugfs remains untouched. Cc: Arjan van de Ven Signed-off-by: Borislav Petkov Tested-by: Toshi Kani Signed-off-by: Matt Fleming --- arch/x86/mm/dump_pagetables.c | 84 +++++++++++++++++++++++++++---------------- 1 file changed, 54 insertions(+), 30 deletions(-) (limited to 'arch/x86/mm') diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c index 0002a3a33081..20621d753d5f 100644 --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -30,6 +30,7 @@ struct pg_state { unsigned long start_address; unsigned long current_address; const struct addr_marker *marker; + bool to_dmesg; }; struct addr_marker { @@ -88,10 +89,28 @@ static struct addr_marker address_markers[] = { #define PUD_LEVEL_MULT (PTRS_PER_PMD * PMD_LEVEL_MULT) #define PGD_LEVEL_MULT (PTRS_PER_PUD * PUD_LEVEL_MULT) +#define pt_dump_seq_printf(m, to_dmesg, fmt, args...) \ +({ \ + if (to_dmesg) \ + printk(KERN_INFO fmt, ##args); \ + else \ + if (m) \ + seq_printf(m, fmt, ##args); \ +}) + +#define pt_dump_cont_printf(m, to_dmesg, fmt, args...) \ +({ \ + if (to_dmesg) \ + printk(KERN_CONT fmt, ##args); \ + else \ + if (m) \ + seq_printf(m, fmt, ##args); \ +}) + /* * Print a readable form of a pgprot_t to the seq_file */ -static void printk_prot(struct seq_file *m, pgprot_t prot, int level) +static void printk_prot(struct seq_file *m, pgprot_t prot, int level, bool dmsg) { pgprotval_t pr = pgprot_val(prot); static const char * const level_name[] = @@ -99,47 +118,47 @@ static void printk_prot(struct seq_file *m, pgprot_t prot, int level) if (!pgprot_val(prot)) { /* Not present */ - seq_printf(m, " "); + pt_dump_cont_printf(m, dmsg, " "); } else { if (pr & _PAGE_USER) - seq_printf(m, "USR "); + pt_dump_cont_printf(m, dmsg, "USR "); else - seq_printf(m, " "); + pt_dump_cont_printf(m, dmsg, " "); if (pr & _PAGE_RW) - seq_printf(m, "RW "); + pt_dump_cont_printf(m, dmsg, "RW "); else - seq_printf(m, "ro "); + pt_dump_cont_printf(m, dmsg, "ro "); if (pr & _PAGE_PWT) - seq_printf(m, "PWT "); + pt_dump_cont_printf(m, dmsg, "PWT "); else - seq_printf(m, " "); + pt_dump_cont_printf(m, dmsg, " "); if (pr & _PAGE_PCD) - seq_printf(m, "PCD "); + pt_dump_cont_printf(m, dmsg, "PCD "); else - seq_printf(m, " "); + pt_dump_cont_printf(m, dmsg, " "); /* Bit 9 has a different meaning on level 3 vs 4 */ if (level <= 3) { if (pr & _PAGE_PSE) - seq_printf(m, "PSE "); + pt_dump_cont_printf(m, dmsg, "PSE "); else - seq_printf(m, " "); + pt_dump_cont_printf(m, dmsg, " "); } else { if (pr & _PAGE_PAT) - seq_printf(m, "pat "); + pt_dump_cont_printf(m, dmsg, "pat "); else - seq_printf(m, " "); + pt_dump_cont_printf(m, dmsg, " "); } if (pr & _PAGE_GLOBAL) - seq_printf(m, "GLB "); + pt_dump_cont_printf(m, dmsg, "GLB "); else - seq_printf(m, " "); + pt_dump_cont_printf(m, dmsg, " "); if (pr & _PAGE_NX) - seq_printf(m, "NX "); + pt_dump_cont_printf(m, dmsg, "NX "); else - seq_printf(m, "x "); + pt_dump_cont_printf(m, dmsg, "x "); } - seq_printf(m, "%s\n", level_name[level]); + pt_dump_cont_printf(m, dmsg, "%s\n", level_name[level]); } /* @@ -178,7 +197,8 @@ static void note_page(struct seq_file *m, struct pg_state *st, st->current_prot = new_prot; st->level = level; st->marker = address_markers; - seq_printf(m, "---[ %s ]---\n", st->marker->name); + pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n", + st->marker->name); } else if (prot != cur || level != st->level || st->current_address >= st->marker[1].start_address) { const char *unit = units; @@ -188,17 +208,17 @@ static void note_page(struct seq_file *m, struct pg_state *st, /* * Now print the actual finished series */ - seq_printf(m, "0x%0*lx-0x%0*lx ", - width, st->start_address, - width, st->current_address); + pt_dump_seq_printf(m, st->to_dmesg, "0x%0*lx-0x%0*lx ", + width, st->start_address, + width, st->current_address); delta = (st->current_address - st->start_address) >> 10; while (!(delta & 1023) && unit[1]) { delta >>= 10; unit++; } - seq_printf(m, "%9lu%c ", delta, *unit); - printk_prot(m, st->current_prot, st->level); + pt_dump_cont_printf(m, st->to_dmesg, "%9lu%c ", delta, *unit); + printk_prot(m, st->current_prot, st->level, st->to_dmesg); /* * We print markers for special areas of address space, @@ -207,7 +227,8 @@ static void note_page(struct seq_file *m, struct pg_state *st, */ if (st->current_address >= st->marker[1].start_address) { st->marker++; - seq_printf(m, "---[ %s ]---\n", st->marker->name); + pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n", + st->marker->name); } st->start_address = st->current_address; @@ -296,7 +317,7 @@ static void walk_pud_level(struct seq_file *m, struct pg_state *st, pgd_t addr, #define pgd_none(a) pud_none(__pud(pgd_val(a))) #endif -static void walk_pgd_level(struct seq_file *m) +void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd) { #ifdef CONFIG_X86_64 pgd_t *start = (pgd_t *) &init_level4_pgt; @@ -304,9 +325,12 @@ static void walk_pgd_level(struct seq_file *m) pgd_t *start = swapper_pg_dir; #endif int i; - struct pg_state st; + struct pg_state st = {}; - memset(&st, 0, sizeof(st)); + if (pgd) { + start = pgd; + st.to_dmesg = true; + } for (i = 0; i < PTRS_PER_PGD; i++) { st.current_address = normalize_addr(i * PGD_LEVEL_MULT); @@ -331,7 +355,7 @@ static void walk_pgd_level(struct seq_file *m) static int ptdump_show(struct seq_file *m, void *v) { - walk_pgd_level(m); + ptdump_walk_pgd_level(m, NULL); return 0; } -- cgit v1.2.3 From 42a5477251f0e0f33ad5f6a95c48d685ec03191e Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Sat, 18 Jan 2014 12:48:16 +0100 Subject: x86, pageattr: Export page unmapping interface We will use it in efi so expose it. Signed-off-by: Borislav Petkov Tested-by: Toshi Kani Signed-off-by: Matt Fleming --- arch/x86/include/asm/pgtable_types.h | 2 ++ arch/x86/mm/pageattr.c | 44 +++++++++++++++++++++++++----------- 2 files changed, 33 insertions(+), 13 deletions(-) (limited to 'arch/x86/mm') diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 1aa9ccd43223..94e40f1efdfd 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -385,6 +385,8 @@ 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); +void kernel_unmap_pages_in_pgd(pgd_t *root, unsigned long address, + unsigned numpages); #endif /* !__ASSEMBLY__ */ #endif /* _ASM_X86_PGTABLE_DEFS_H */ diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index b3b19f46c016..a3488689e301 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -692,6 +692,18 @@ static bool try_to_free_pmd_page(pmd_t *pmd) return true; } +static bool try_to_free_pud_page(pud_t *pud) +{ + int i; + + for (i = 0; i < PTRS_PER_PUD; i++) + if (!pud_none(pud[i])) + return false; + + free_page((unsigned long)pud); + return true; +} + static bool unmap_pte_range(pmd_t *pmd, unsigned long start, unsigned long end) { pte_t *pte = pte_offset_kernel(pmd, start); @@ -805,6 +817,16 @@ static void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end) */ } +static void unmap_pgd_range(pgd_t *root, unsigned long addr, unsigned long end) +{ + pgd_t *pgd_entry = root + pgd_index(addr); + + unmap_pud_range(pgd_entry, addr, end); + + if (try_to_free_pud_page((pud_t *)pgd_page_vaddr(*pgd_entry))) + pgd_clear(pgd_entry); +} + static int alloc_pte_page(pmd_t *pmd) { pte_t *pte = (pte_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK); @@ -999,9 +1021,8 @@ static int populate_pud(struct cpa_data *cpa, unsigned long start, pgd_t *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 */ + pgd_t *pgd_entry; int ret; pgd_entry = cpa->pgd + pgd_index(addr); @@ -1015,7 +1036,6 @@ static int populate_pgd(struct cpa_data *cpa, unsigned long addr) return -1; set_pgd(pgd_entry, __pgd(__pa(pud) | _KERNPG_TABLE)); - allocd_pgd = true; } pgprot_val(pgprot) &= ~pgprot_val(cpa->mask_clr); @@ -1023,19 +1043,11 @@ static int populate_pgd(struct cpa_data *cpa, unsigned long addr) ret = populate_pud(cpa, addr, pgd_entry, pgprot); if (ret < 0) { - unmap_pud_range(pgd_entry, addr, + unmap_pgd_range(cpa->pgd, 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; } @@ -1861,6 +1873,12 @@ out: return retval; } +void kernel_unmap_pages_in_pgd(pgd_t *root, unsigned long address, + unsigned numpages) +{ + unmap_pgd_range(root, address, address + (numpages << PAGE_SHIFT)); +} + /* * The testcases use internal knowledge of the implementation that shouldn't * be exposed to the rest of the kernel. Include these directly here. -- cgit v1.2.3 From 426e34cc4f6094cefe4f3175764cdf583128e7cd Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Fri, 6 Dec 2013 21:13:04 +0000 Subject: x86/mm/pageattr: Always dump the right page table in an oops Now that we have EFI-specific page tables we need to lookup the pgd when dumping those page tables, rather than assuming that swapper_pgdir is the current pgdir. Remove the double underscore prefix, which is usually reserved for static functions. Acked-by: Borislav Petkov Signed-off-by: Matt Fleming --- arch/x86/include/asm/pgtable_types.h | 2 ++ arch/x86/mm/fault.c | 7 ++++++- arch/x86/mm/pageattr.c | 12 ++++++++---- 3 files changed, 16 insertions(+), 5 deletions(-) (limited to 'arch/x86/mm') diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 1aa9ccd43223..24ae4211ba34 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -382,6 +382,8 @@ static inline void update_page_count(int level, unsigned long pages) { } * as a pte too. */ extern pte_t *lookup_address(unsigned long address, unsigned int *level); +extern pte_t *lookup_address_in_pgd(pgd_t *pgd, 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); diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 6dea040cc3a1..6055a2001b27 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -584,8 +584,13 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, if (error_code & PF_INSTR) { unsigned int level; + pgd_t *pgd; + pte_t *pte; - pte_t *pte = lookup_address(address, &level); + pgd = __va(read_cr3() & PHYSICAL_PAGE_MASK); + pgd += pgd_index(address); + + pte = lookup_address_in_pgd(pgd, address, &level); if (pte && pte_present(*pte) && !pte_exec(*pte)) printk(nx_warning, from_kuid(&init_user_ns, current_uid())); diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index b3b19f46c016..14c656f0483b 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -323,8 +323,12 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address, return prot; } -static pte_t *__lookup_address_in_pgd(pgd_t *pgd, unsigned long address, - unsigned int *level) +/* + * Lookup the page table entry for a virtual address in a specific pgd. + * Return a pointer to the entry and the level of the mapping. + */ +pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigned long address, + unsigned int *level) { pud_t *pud; pmd_t *pmd; @@ -365,7 +369,7 @@ static pte_t *__lookup_address_in_pgd(pgd_t *pgd, unsigned long address, */ pte_t *lookup_address(unsigned long address, unsigned int *level) { - return __lookup_address_in_pgd(pgd_offset_k(address), address, level); + return lookup_address_in_pgd(pgd_offset_k(address), address, level); } EXPORT_SYMBOL_GPL(lookup_address); @@ -373,7 +377,7 @@ 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), + return lookup_address_in_pgd(cpa->pgd + pgd_index(address), address, level); return lookup_address(address, level); -- cgit v1.2.3