mirror of
https://github.com/torvalds/linux.git
synced 2026-04-18 06:44:00 -04:00
9f9d68c308
For the exception based __WARN_trap() implementation it is technically not
necessary to prevent tail-call optimization, however it may be confusing to
see warning messages like:
WARNING: arch/s390/kernel/setup.c:1017 at foobar+0x2c/0x50, CPU#0: swapper/0/0
together with a disassembly of a different function caused by tail-call
optimization for the __WARN_trap() call. Prevent that by adding an empty
asm statement. This generates slightly worse code, but should hopefully
avoid confusion.
With this the output looks like:
WARNING: arch/s390/kernel/setup.c:1017 at foobar+0x2c/0x50, CPU#0: swapper/0/0
...
Krnl PSW : 0704c00180000000 000003ffe0119788 (foobar+0x38/0x50)
...
Krnl Code: 000003ffe0119776: e3e0f0980024 stg %r14,152(%r15)
000003ffe011977c: c02000b8992a larl %r2,000003ffe182c9d0
*000003ffe0119782: c0e5007270b7 brasl %r14,000003ffe0f678f0
>000003ffe0119788: ebeff0a00004 lmg %r14,%r15,160(%r15)
000003ffe011978e: 07fe bcr 15,%r14
000003ffe0119790: 47000700 bc 0,1792
000003ffe0119794: 0707 bcr 0,%r7
000003ffe0119796: 0707 bcr 0,%r7
Call Trace:
[<000003ffe0119788>] foobar+0x38/0x50
[<000003ffe185bc2e>] arch_cpu_finalize_init+0x26/0x60
[<000003ffe185654c>] start_kernel+0x53c/0x5d8
[<000003ffe010002e>] startup_continue+0x2e/0x40
A better solution would be to replace or patch the branch instruction to
__WARN_trap() with the monitor call instruction, similar to what is done
for x86 [1]. However s390 does not support static_cond_calls(). Therefore
use the simple approach for the time being.
[1] commit 860238af7a ("x86_64/bug: Inline the UD1")
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
130 lines
3.3 KiB
C
130 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _ASM_S390_BUG_H
|
|
#define _ASM_S390_BUG_H
|
|
|
|
#include <linux/compiler.h>
|
|
#include <linux/const.h>
|
|
|
|
#define MONCODE_BUG _AC(0, U)
|
|
#define MONCODE_BUG_ARG _AC(1, U)
|
|
|
|
#ifndef __ASSEMBLER__
|
|
#if defined(CONFIG_BUG) && defined(CONFIG_CC_HAS_ASM_IMMEDIATE_STRINGS)
|
|
|
|
#ifdef CONFIG_DEBUG_BUGVERBOSE
|
|
#define __BUG_ENTRY_VERBOSE(format, file, line) \
|
|
" .long " format " - . # bug_entry::format\n" \
|
|
" .long " file " - . # bug_entry::file\n" \
|
|
" .short " line " # bug_entry::line\n"
|
|
#else
|
|
#define __BUG_ENTRY_VERBOSE(format, file, line)
|
|
#endif
|
|
|
|
#ifdef CONFIG_DEBUG_BUGVERBOSE_DETAILED
|
|
#define WARN_CONDITION_STR(cond_str) cond_str
|
|
#else
|
|
#define WARN_CONDITION_STR(cond_str) ""
|
|
#endif
|
|
|
|
#define __BUG_ENTRY(format, file, line, flags, size) \
|
|
" .section __bug_table,\"aw\"\n" \
|
|
"1: .long 0b - . # bug_entry::bug_addr\n" \
|
|
__BUG_ENTRY_VERBOSE(format, file, line) \
|
|
" .short "flags" # bug_entry::flags\n" \
|
|
" .org 1b+"size"\n" \
|
|
" .previous"
|
|
|
|
#define __BUG_ASM(cond_str, flags) \
|
|
do { \
|
|
asm_inline volatile("\n" \
|
|
"0: mc %[monc](%%r0),0\n" \
|
|
__BUG_ENTRY("%[frmt]", "%[file]", "%[line]", \
|
|
"%[flgs]", "%[size]") \
|
|
: \
|
|
: [monc] "i" (MONCODE_BUG), \
|
|
[frmt] "i" (WARN_CONDITION_STR(cond_str)), \
|
|
[file] "i" (__FILE__), \
|
|
[line] "i" (__LINE__), \
|
|
[flgs] "i" (flags), \
|
|
[size] "i" (sizeof(struct bug_entry))); \
|
|
} while (0)
|
|
|
|
#define BUG() \
|
|
do { \
|
|
__BUG_ASM("", 0); \
|
|
unreachable(); \
|
|
} while (0)
|
|
|
|
#define __WARN_FLAGS(cond_str, flags) \
|
|
do { \
|
|
__BUG_ASM(cond_str, BUGFLAG_WARNING | (flags)); \
|
|
} while (0)
|
|
|
|
#define __WARN_bug_entry(flags, format) \
|
|
({ \
|
|
struct bug_entry *bug; \
|
|
\
|
|
asm_inline volatile("\n" \
|
|
"0: larl %[bug],1f\n" \
|
|
__BUG_ENTRY("%[frmt]", "%[file]", "%[line]", \
|
|
"%[flgs]", "%[size]") \
|
|
: [bug] "=d" (bug) \
|
|
: [frmt] "i" (format), \
|
|
[file] "i" (__FILE__), \
|
|
[line] "i" (__LINE__), \
|
|
[flgs] "i" (flags), \
|
|
[size] "i" (sizeof(struct bug_entry))); \
|
|
bug; \
|
|
})
|
|
|
|
/*
|
|
* Variable Argument List (va_list) as defined in ELF Application
|
|
* Binary Interface s390x Supplement documentation.
|
|
*/
|
|
struct arch_va_list {
|
|
long __gpr;
|
|
long __fpr;
|
|
void *__overflow_arg_area;
|
|
void *__reg_save_area;
|
|
};
|
|
|
|
struct bug_entry;
|
|
struct pt_regs;
|
|
|
|
void *__warn_args(struct arch_va_list *args, struct pt_regs *regs);
|
|
void __WARN_trap(struct bug_entry *bug, ...);
|
|
|
|
#define __WARN_print_arg(flags, format, arg...) \
|
|
do { \
|
|
int __flags = (flags) | BUGFLAG_WARNING | BUGFLAG_ARGS; \
|
|
\
|
|
__WARN_trap(__WARN_bug_entry(__flags, format), ## arg); \
|
|
/* prevent tail-call optimization */ \
|
|
asm(""); \
|
|
} while (0)
|
|
|
|
#define __WARN_printf(taint, fmt, arg...) \
|
|
__WARN_print_arg(BUGFLAG_TAINT(taint), fmt, ## arg)
|
|
|
|
#define WARN_ONCE(cond, format, arg...) \
|
|
({ \
|
|
int __ret_warn_on = !!(cond); \
|
|
\
|
|
if (unlikely(__ret_warn_on)) { \
|
|
__WARN_print_arg(BUGFLAG_ONCE|BUGFLAG_TAINT(TAINT_WARN),\
|
|
format, ## arg); \
|
|
} \
|
|
__ret_warn_on; \
|
|
})
|
|
|
|
#define HAVE_ARCH_BUG
|
|
#define HAVE_ARCH_BUG_FORMAT
|
|
#define HAVE_ARCH_BUG_FORMAT_ARGS
|
|
|
|
#endif /* CONFIG_BUG && CONFIG_CC_HAS_ASM_IMMEDIATE_STRINGS */
|
|
#endif /* __ASSEMBLER__ */
|
|
|
|
#include <asm-generic/bug.h>
|
|
|
|
#endif /* _ASM_S390_BUG_H */
|