diff options
author | Peter Zijlstra <peterz@infradead.org> | 2017-02-25 08:56:53 +0100 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2017-03-30 09:37:20 +0200 |
commit | 19d436268dde95389c616bb3819da73f0a8b28a8 (patch) | |
tree | bd08a3466744511ad2d07edd5e9be4161cfb56e2 | |
parent | 70579a86e3c8eb2ce57999e594a73b4dfe095959 (diff) | |
download | linux-stable-19d436268dde95389c616bb3819da73f0a8b28a8.tar.gz linux-stable-19d436268dde95389c616bb3819da73f0a8b28a8.tar.bz2 linux-stable-19d436268dde95389c616bb3819da73f0a8b28a8.zip |
debug: Add _ONCE() logic to report_bug()
Josh suggested moving the _ONCE logic inside the trap handler, using a
bit in the bug_entry::flags field, avoiding the need for the extra
variable.
Sadly this only works for WARN_ON_ONCE(), since the others have
printk() statements prior to triggering the trap.
Still, this saves a fair amount of text and some data:
text data filename
10682460 4530992 defconfig-build/vmlinux.orig
10665111 4530096 defconfig-build/vmlinux.patched
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r-- | arch/arm64/include/asm/bug.h | 2 | ||||
-rw-r--r-- | arch/parisc/include/asm/bug.h | 8 | ||||
-rw-r--r-- | arch/powerpc/include/asm/bug.h | 4 | ||||
-rw-r--r-- | arch/s390/include/asm/bug.h | 4 | ||||
-rw-r--r-- | arch/sh/include/asm/bug.h | 4 | ||||
-rw-r--r-- | arch/x86/include/asm/bug.h | 2 | ||||
-rw-r--r-- | include/asm-generic/bug.h | 18 | ||||
-rw-r--r-- | include/asm-generic/vmlinux.lds.h | 5 | ||||
-rw-r--r-- | include/linux/bug.h | 2 | ||||
-rw-r--r-- | lib/bug.c | 28 |
10 files changed, 52 insertions, 25 deletions
diff --git a/arch/arm64/include/asm/bug.h b/arch/arm64/include/asm/bug.h index 561190d15881..a9be1072933c 100644 --- a/arch/arm64/include/asm/bug.h +++ b/arch/arm64/include/asm/bug.h @@ -55,7 +55,7 @@ _BUGVERBOSE_LOCATION(__FILE__, __LINE__) \ unreachable(); \ } while (0) -#define __WARN_TAINT(taint) _BUG_FLAGS(BUGFLAG_TAINT(taint)) +#define __WARN_FLAGS(flags) _BUG_FLAGS(BUGFLAG_WARNING|(flags)) #endif /* ! CONFIG_GENERIC_BUG */ diff --git a/arch/parisc/include/asm/bug.h b/arch/parisc/include/asm/bug.h index 62a33338549c..d2742273a685 100644 --- a/arch/parisc/include/asm/bug.h +++ b/arch/parisc/include/asm/bug.h @@ -46,7 +46,7 @@ #endif #ifdef CONFIG_DEBUG_BUGVERBOSE -#define __WARN_TAINT(taint) \ +#define __WARN_FLAGS(flags) \ do { \ asm volatile("\n" \ "1:\t" PARISC_BUG_BREAK_ASM "\n" \ @@ -56,11 +56,11 @@ "\t.org 2b+%c3\n" \ "\t.popsection" \ : : "i" (__FILE__), "i" (__LINE__), \ - "i" (BUGFLAG_TAINT(taint)), \ + "i" (BUGFLAG_WARNING|(flags)), \ "i" (sizeof(struct bug_entry)) ); \ } while(0) #else -#define __WARN_TAINT(taint) \ +#define __WARN_FLAGS(flags) \ do { \ asm volatile("\n" \ "1:\t" PARISC_BUG_BREAK_ASM "\n" \ @@ -69,7 +69,7 @@ "\t.short %c0\n" \ "\t.org 2b+%c1\n" \ "\t.popsection" \ - : : "i" (BUGFLAG_TAINT(taint)), \ + : : "i" (BUGFLAG_WARNING|(flags)), \ "i" (sizeof(struct bug_entry)) ); \ } while(0) #endif diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h index 3a39283333c3..f2c562a0a427 100644 --- a/arch/powerpc/include/asm/bug.h +++ b/arch/powerpc/include/asm/bug.h @@ -85,12 +85,12 @@ } \ } while (0) -#define __WARN_TAINT(taint) do { \ +#define __WARN_FLAGS(flags) do { \ __asm__ __volatile__( \ "1: twi 31,0,0\n" \ _EMIT_BUG_ENTRY \ : : "i" (__FILE__), "i" (__LINE__), \ - "i" (BUGFLAG_TAINT(taint)), \ + "i" (BUGFLAG_WARNING|(flags)), \ "i" (sizeof(struct bug_entry))); \ } while (0) diff --git a/arch/s390/include/asm/bug.h b/arch/s390/include/asm/bug.h index bf90d1fd97a5..1bbd9dbfe4e0 100644 --- a/arch/s390/include/asm/bug.h +++ b/arch/s390/include/asm/bug.h @@ -46,8 +46,8 @@ unreachable(); \ } while (0) -#define __WARN_TAINT(taint) do { \ - __EMIT_BUG(BUGFLAG_TAINT(taint)); \ +#define __WARN_FLAGS(flags) do { \ + __EMIT_BUG(BUGFLAG_WARNING|(flags)); \ } while (0) #define WARN_ON(x) ({ \ diff --git a/arch/sh/include/asm/bug.h b/arch/sh/include/asm/bug.h index dcf278075429..1b77f068be2b 100644 --- a/arch/sh/include/asm/bug.h +++ b/arch/sh/include/asm/bug.h @@ -50,7 +50,7 @@ do { \ "i" (sizeof(struct bug_entry))); \ } while (0) -#define __WARN_TAINT(taint) \ +#define __WARN_FLAGS(flags) \ do { \ __asm__ __volatile__ ( \ "1:\t.short %O0\n" \ @@ -59,7 +59,7 @@ do { \ : "n" (TRAPA_BUG_OPCODE), \ "i" (__FILE__), \ "i" (__LINE__), \ - "i" (BUGFLAG_TAINT(taint)), \ + "i" (BUGFLAG_WARNING|(flags)), \ "i" (sizeof(struct bug_entry))); \ } while (0) diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h index cecf559d0012..39e702d90cdb 100644 --- a/arch/x86/include/asm/bug.h +++ b/arch/x86/include/asm/bug.h @@ -76,7 +76,7 @@ do { \ unreachable(); \ } while (0) -#define __WARN_TAINT(taint) _BUG_FLAGS(ASM_UD0, BUGFLAG_TAINT(taint)) +#define __WARN_FLAGS(flags) _BUG_FLAGS(ASM_UD0, BUGFLAG_WARNING|(flags)) #include <asm-generic/bug.h> diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h index 6f96247226a4..5fe9f39cec44 100644 --- a/include/asm-generic/bug.h +++ b/include/asm-generic/bug.h @@ -5,6 +5,8 @@ #ifdef CONFIG_GENERIC_BUG #define BUGFLAG_WARNING (1 << 0) +#define BUGFLAG_ONCE (1 << 1) +#define BUGFLAG_DONE (1 << 2) #define BUGFLAG_TAINT(taint) (BUGFLAG_WARNING | ((taint) << 8)) #define BUG_GET_TAINT(bug) ((bug)->flags >> 8) #endif @@ -55,6 +57,18 @@ struct bug_entry { #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) #endif +#ifdef __WARN_FLAGS +#define __WARN_TAINT(taint) __WARN_FLAGS(BUGFLAG_TAINT(taint)) +#define __WARN_ONCE_TAINT(taint) __WARN_FLAGS(BUGFLAG_ONCE|BUGFLAG_TAINT(taint)) + +#define WARN_ON_ONCE(condition) ({ \ + int __ret_warn_on = !!(condition); \ + if (unlikely(__ret_warn_on)) \ + __WARN_ONCE_TAINT(TAINT_WARN); \ + unlikely(__ret_warn_on); \ +}) +#endif + /* * WARN(), WARN_ON(), WARN_ON_ONCE, and so on can be used to report * significant issues that need prompt attention if they should ever @@ -97,7 +111,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint, #endif #ifndef WARN -#define WARN(condition, format...) ({ \ +#define WARN(condition, format...) ({ \ int __ret_warn_on = !!(condition); \ if (unlikely(__ret_warn_on)) \ __WARN_printf(format); \ @@ -112,6 +126,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint, unlikely(__ret_warn_on); \ }) +#ifndef WARN_ON_ONCE #define WARN_ON_ONCE(condition) ({ \ static bool __section(.data.unlikely) __warned; \ int __ret_warn_once = !!(condition); \ @@ -122,6 +137,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint, } \ unlikely(__ret_warn_once); \ }) +#endif #define WARN_ONCE(condition, format...) ({ \ static bool __section(.data.unlikely) __warned; \ diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 0968d13b3885..51c8dbe8e8d9 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -286,8 +286,6 @@ *(.rodata1) \ } \ \ - BUG_TABLE \ - \ /* PCI quirks */ \ .pci_fixup : AT(ADDR(.pci_fixup) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start_pci_fixups_early) = .; \ @@ -855,7 +853,8 @@ READ_MOSTLY_DATA(cacheline) \ DATA_DATA \ CONSTRUCTORS \ - } + } \ + BUG_TABLE #define INIT_TEXT_SECTION(inittext_align) \ . = ALIGN(inittext_align); \ diff --git a/include/linux/bug.h b/include/linux/bug.h index 5828489309bb..687b557fc5eb 100644 --- a/include/linux/bug.h +++ b/include/linux/bug.h @@ -105,7 +105,7 @@ static inline int is_warning_bug(const struct bug_entry *bug) return bug->flags & BUGFLAG_WARNING; } -const struct bug_entry *find_bug(unsigned long bugaddr); +struct bug_entry *find_bug(unsigned long bugaddr); enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs); diff --git a/lib/bug.c b/lib/bug.c index 06edbbef0623..a6a1137d06db 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -47,7 +47,7 @@ #include <linux/sched.h> #include <linux/rculist.h> -extern const struct bug_entry __start___bug_table[], __stop___bug_table[]; +extern struct bug_entry __start___bug_table[], __stop___bug_table[]; static inline unsigned long bug_addr(const struct bug_entry *bug) { @@ -62,10 +62,10 @@ static inline unsigned long bug_addr(const struct bug_entry *bug) /* Updates are protected by module mutex */ static LIST_HEAD(module_bug_list); -static const struct bug_entry *module_find_bug(unsigned long bugaddr) +static struct bug_entry *module_find_bug(unsigned long bugaddr) { struct module *mod; - const struct bug_entry *bug = NULL; + struct bug_entry *bug = NULL; rcu_read_lock_sched(); list_for_each_entry_rcu(mod, &module_bug_list, bug_list) { @@ -122,15 +122,15 @@ void module_bug_cleanup(struct module *mod) #else -static inline const struct bug_entry *module_find_bug(unsigned long bugaddr) +static inline struct bug_entry *module_find_bug(unsigned long bugaddr) { return NULL; } #endif -const struct bug_entry *find_bug(unsigned long bugaddr) +struct bug_entry *find_bug(unsigned long bugaddr) { - const struct bug_entry *bug; + struct bug_entry *bug; for (bug = __start___bug_table; bug < __stop___bug_table; ++bug) if (bugaddr == bug_addr(bug)) @@ -141,9 +141,9 @@ const struct bug_entry *find_bug(unsigned long bugaddr) enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs) { - const struct bug_entry *bug; + struct bug_entry *bug; const char *file; - unsigned line, warning; + unsigned line, warning, once, done; if (!is_valid_bugaddr(bugaddr)) return BUG_TRAP_TYPE_NONE; @@ -164,6 +164,18 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs) line = bug->line; #endif warning = (bug->flags & BUGFLAG_WARNING) != 0; + once = (bug->flags & BUGFLAG_ONCE) != 0; + done = (bug->flags & BUGFLAG_DONE) != 0; + + if (warning && once) { + if (done) + return BUG_TRAP_TYPE_WARN; + + /* + * Since this is the only store, concurrency is not an issue. + */ + bug->flags |= BUGFLAG_DONE; + } } if (warning) { |