mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-27 20:16:05 +07:00
325cdacd03
Mike Galbraith reported a situation where a WARN_ON_ONCE() call in DRM code turned into an oops. As it turns out, WARN_ON_ONCE() seems to be completely broken when called from a module. The bug was introduced with the following commit:19d436268d("debug: Add _ONCE() logic to report_bug()") That commit changed WARN_ON_ONCE() to move its 'once' logic into the bug trap handler. It requires a writable bug table so that the BUGFLAG_DONE bit can be written to the flags to indicate the first warning has occurred. The bug table was made writable for vmlinux, which relies on vmlinux.lds.S and vmlinux.lds.h for laying out the sections. However, it wasn't made writable for modules, which rely on the ELF section header flags. Reported-by: Mike Galbraith <efault@gmx.de> Tested-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes:19d436268d("debug: Add _ONCE() logic to report_bug()") Link: http://lkml.kernel.org/r/a53b04235a65478dd9afc51f5b329fdc65c84364.1500095401.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
141 lines
3.5 KiB
C
141 lines
3.5 KiB
C
#ifndef _ASM_POWERPC_BUG_H
|
|
#define _ASM_POWERPC_BUG_H
|
|
#ifdef __KERNEL__
|
|
|
|
#include <asm/asm-compat.h>
|
|
|
|
/*
|
|
* Define an illegal instr to trap on the bug.
|
|
* We don't use 0 because that marks the end of a function
|
|
* in the ELF ABI. That's "Boo Boo" in case you wonder...
|
|
*/
|
|
#define BUG_OPCODE .long 0x00b00b00 /* For asm */
|
|
#define BUG_ILLEGAL_INSTR "0x00b00b00" /* For BUG macro */
|
|
|
|
#ifdef CONFIG_BUG
|
|
|
|
#ifdef __ASSEMBLY__
|
|
#include <asm/asm-offsets.h>
|
|
#ifdef CONFIG_DEBUG_BUGVERBOSE
|
|
.macro EMIT_BUG_ENTRY addr,file,line,flags
|
|
.section __bug_table,"aw"
|
|
5001: PPC_LONG \addr, 5002f
|
|
.short \line, \flags
|
|
.org 5001b+BUG_ENTRY_SIZE
|
|
.previous
|
|
.section .rodata,"a"
|
|
5002: .asciz "\file"
|
|
.previous
|
|
.endm
|
|
#else
|
|
.macro EMIT_BUG_ENTRY addr,file,line,flags
|
|
.section __bug_table,"aw"
|
|
5001: PPC_LONG \addr
|
|
.short \flags
|
|
.org 5001b+BUG_ENTRY_SIZE
|
|
.previous
|
|
.endm
|
|
#endif /* verbose */
|
|
|
|
#else /* !__ASSEMBLY__ */
|
|
/* _EMIT_BUG_ENTRY expects args %0,%1,%2,%3 to be FILE, LINE, flags and
|
|
sizeof(struct bug_entry), respectively */
|
|
#ifdef CONFIG_DEBUG_BUGVERBOSE
|
|
#define _EMIT_BUG_ENTRY \
|
|
".section __bug_table,\"aw\"\n" \
|
|
"2:\t" PPC_LONG "1b, %0\n" \
|
|
"\t.short %1, %2\n" \
|
|
".org 2b+%3\n" \
|
|
".previous\n"
|
|
#else
|
|
#define _EMIT_BUG_ENTRY \
|
|
".section __bug_table,\"aw\"\n" \
|
|
"2:\t" PPC_LONG "1b\n" \
|
|
"\t.short %2\n" \
|
|
".org 2b+%3\n" \
|
|
".previous\n"
|
|
#endif
|
|
|
|
/*
|
|
* BUG_ON() and WARN_ON() do their best to cooperate with compile-time
|
|
* optimisations. However depending on the complexity of the condition
|
|
* some compiler versions may not produce optimal results.
|
|
*/
|
|
|
|
#define BUG() do { \
|
|
__asm__ __volatile__( \
|
|
"1: twi 31,0,0\n" \
|
|
_EMIT_BUG_ENTRY \
|
|
: : "i" (__FILE__), "i" (__LINE__), \
|
|
"i" (0), "i" (sizeof(struct bug_entry))); \
|
|
unreachable(); \
|
|
} while (0)
|
|
|
|
#define BUG_ON(x) do { \
|
|
if (__builtin_constant_p(x)) { \
|
|
if (x) \
|
|
BUG(); \
|
|
} else { \
|
|
__asm__ __volatile__( \
|
|
"1: "PPC_TLNEI" %4,0\n" \
|
|
_EMIT_BUG_ENTRY \
|
|
: : "i" (__FILE__), "i" (__LINE__), "i" (0), \
|
|
"i" (sizeof(struct bug_entry)), \
|
|
"r" ((__force long)(x))); \
|
|
} \
|
|
} while (0)
|
|
|
|
#define __WARN_FLAGS(flags) do { \
|
|
__asm__ __volatile__( \
|
|
"1: twi 31,0,0\n" \
|
|
_EMIT_BUG_ENTRY \
|
|
: : "i" (__FILE__), "i" (__LINE__), \
|
|
"i" (BUGFLAG_WARNING|(flags)), \
|
|
"i" (sizeof(struct bug_entry))); \
|
|
} while (0)
|
|
|
|
#define WARN_ON(x) ({ \
|
|
int __ret_warn_on = !!(x); \
|
|
if (__builtin_constant_p(__ret_warn_on)) { \
|
|
if (__ret_warn_on) \
|
|
__WARN(); \
|
|
} else { \
|
|
__asm__ __volatile__( \
|
|
"1: "PPC_TLNEI" %4,0\n" \
|
|
_EMIT_BUG_ENTRY \
|
|
: : "i" (__FILE__), "i" (__LINE__), \
|
|
"i" (BUGFLAG_WARNING|BUGFLAG_TAINT(TAINT_WARN)),\
|
|
"i" (sizeof(struct bug_entry)), \
|
|
"r" (__ret_warn_on)); \
|
|
} \
|
|
unlikely(__ret_warn_on); \
|
|
})
|
|
|
|
#define HAVE_ARCH_BUG
|
|
#define HAVE_ARCH_BUG_ON
|
|
#define HAVE_ARCH_WARN_ON
|
|
#endif /* __ASSEMBLY __ */
|
|
#else
|
|
#ifdef __ASSEMBLY__
|
|
.macro EMIT_BUG_ENTRY addr,file,line,flags
|
|
.endm
|
|
#else /* !__ASSEMBLY__ */
|
|
#define _EMIT_BUG_ENTRY
|
|
#endif
|
|
#endif /* CONFIG_BUG */
|
|
|
|
#include <asm-generic/bug.h>
|
|
|
|
#ifndef __ASSEMBLY__
|
|
|
|
struct pt_regs;
|
|
extern int do_page_fault(struct pt_regs *, unsigned long, unsigned long);
|
|
extern void bad_page_fault(struct pt_regs *, unsigned long, int);
|
|
extern void _exception(int, struct pt_regs *, int, unsigned long);
|
|
extern void die(const char *, struct pt_regs *, long);
|
|
|
|
#endif /* !__ASSEMBLY__ */
|
|
|
|
#endif /* __KERNEL__ */
|
|
#endif /* _ASM_POWERPC_BUG_H */
|