/* Generic support for BUG() This respects the following config options: CONFIG_BUG - emit BUG traps. Nothing happens without this. CONFIG_GENERIC_BUG - enable this code. CONFIG_GENERIC_BUG_RELATIVE_POINTERS - use 32-bit pointers relative to the containing struct bug_entry for bug_addr and file. CONFIG_DEBUG_BUGVERBOSE - emit full file+line information for each BUG CONFIG_BUG and CONFIG_DEBUG_BUGVERBOSE are potentially user-settable (though they're generally always on). CONFIG_GENERIC_BUG is set by each architecture using this code. To use this, your architecture must: 1. Set up the config options: - Enable CONFIG_GENERIC_BUG if CONFIG_BUG 2. Implement BUG (and optionally BUG_ON, WARN, WARN_ON) - Define HAVE_ARCH_BUG - Implement BUG() to generate a faulting instruction - NOTE: struct bug_entry does not have "file" or "line" entries when CONFIG_DEBUG_BUGVERBOSE is not enabled, so you must generate the values accordingly. 3. Implement the trap - In the illegal instruction trap handler (typically), verify that the fault was in kernel mode, and call report_bug() - report_bug() will return whether it was a false alarm, a warning, or an actual bug. - You must implement the is_valid_bugaddr(bugaddr) callback which returns true if the eip is a real kernel address, and it points to the expected BUG trap instruction. Jeremy Fitzhardinge 2006 */ #define pr_fmt(fmt) fmt #include #include #include #include #include extern const struct bug_entry __start___bug_table[], __stop___bug_table[]; static inline unsigned long bug_addr(const struct bug_entry *bug) { #ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS return bug->bug_addr; #else return (unsigned long)bug + bug->bug_addr_disp; #endif } #ifdef CONFIG_MODULES /* Updates are protected by module mutex */ static LIST_HEAD(module_bug_list); static const struct bug_entry *module_find_bug(unsigned long bugaddr) { struct module *mod; const struct bug_entry *bug = NULL; rcu_read_lock_sched(); list_for_each_entry_rcu(mod, &module_bug_list, bug_list) { unsigned i; bug = mod->bug_table; for (i = 0; i < mod->num_bugs; ++i, ++bug) if (bugaddr == bug_addr(bug)) goto out; } bug = NULL; out: rcu_read_unlock_sched(); return bug; } void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *mod) { char *secstrings; unsigned int i; lockdep_assert_held(&module_mutex); mod->bug_table = NULL; mod->num_bugs = 0; /* Find the __bug_table section, if present */ secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; for (i = 1; i < hdr->e_shnum; i++) { if (strcmp(secstrings+sechdrs[i].sh_name, "__bug_table")) continue; mod->bug_table = (void *) sechdrs[i].sh_addr; mod->num_bugs = sechdrs[i].sh_size / sizeof(struct bug_entry); break; } /* * Strictly speaking this should have a spinlock to protect against * traversals, but since we only traverse on BUG()s, a spinlock * could potentially lead to deadlock and thus be counter-productive. * Thus, this uses RCU to safely manipulate the bug list, since BUG * must run in non-interruptive state. */ list_add_rcu(&mod->bug_list, &module_bug_list); } void module_bug_cleanup(struct module *mod) { lockdep_assert_held(&module_mutex); list_del_rcu(&mod->bug_list); } #else static inline const struct bug_entry *module_find_bug(unsigned long bugaddr) { return NULL; } #endif const struct bug_entry *find_bug(unsigned long bugaddr) { const struct bug_entry *bug; for (bug = __start___bug_table; bug < __stop___bug_table; ++bug) if (bugaddr == bug_addr(bug)) return bug; return module_find_bug(bugaddr); } enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs) { const struct bug_entry *bug; const char *file; unsigned line, warning; if (!is_valid_bugaddr(bugaddr)) return BUG_TRAP_TYPE_NONE; bug = find_bug(bugaddr); file = NULL; line = 0; warning = 0; if (bug) { #ifdef CONFIG_DEBUG_BUGVERBOSE #ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS file = bug->file; #else file = (const char *)bug + bug->file_disp; #endif line = bug->line; #endif warning = (bug->flags & BUGFLAG_WARNING) != 0; } if (warning) { /* this is a WARN_ON rather than BUG/BUG_ON */ __warn(file, line, (void *)bugaddr, BUG_GET_TAINT(bug), regs, NULL); return BUG_TRAP_TYPE_WARN; } printk(KERN_DEFAULT "------------[ cut here ]------------\n"); if (file) pr_crit("kernel BUG at %s:%u!\n", file, line); else pr_crit("Kernel BUG at %p [verbose debug info unavailable]\n", (void *)bugaddr); return BUG_TRAP_TYPE_BUG; } ss='label'>mode:
authorJiri Kosina <jkosina@suse.cz>2017-01-27 22:25:52 +0000
committerIngo Molnar <mingo@kernel.org>2017-01-28 09:18:56 +0100
commitbf29bddf0417a4783da3b24e8c9e017ac649326f (patch)
tree54a05a4883b73f80e4e1d8c4b15750aa01c39932 /tools/build/feature/test-glibc.c
parent883af14e67e8b8702b5560aa64c888c0cd0bd66c (diff)
x86/efi: Always map the first physical page into the EFI pagetables
Commit: 129766708 ("x86/efi: Only map RAM into EFI page tables if in mixed-mode") stopped creating 1:1 mappings for all RAM, when running in native 64-bit mode. It turns out though that there are 64-bit EFI implementations in the wild (this particular problem has been reported on a Lenovo Yoga 710-11IKB), which still make use of the first physical page for their own private use, even though they explicitly mark it EFI_CONVENTIONAL_MEMORY in the memory map. In case there is no mapping for this particular frame in the EFI pagetables, as soon as firmware tries to make use of it, a triple fault occurs and the system reboots (in case of the Yoga 710-11IKB this is very early during bootup). Fix that by always mapping the first page of physical memory into the EFI pagetables. We're free to hand this page to the BIOS, as trim_bios_range() will reserve the first page and isolate it away from memory allocators anyway. Note that just reverting 129766708 alone is not enough on v4.9-rc1+ to fix the regression on affected hardware, as this commit: ab72a27da ("x86/efi: Consolidate region mapping logic") later made the first physical frame not to be mapped anyway. Reported-by: Hanka Pavlikova <hanka@ucw.cz> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Laura Abbott <labbott@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vojtech Pavlik <vojtech@ucw.cz> Cc: Waiman Long <waiman.long@hpe.com> Cc: linux-efi@vger.kernel.org Cc: stable@kernel.org # v4.8+ Fixes: 129766708 ("x86/efi: Only map RAM into EFI page tables if in mixed-mode") Link: http://lkml.kernel.org/r/20170127222552.22336-1-matt@codeblueprint.co.uk [ Tidied up the changelog and the comment. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'tools/build/feature/test-glibc.c')