ia64/xen-unstable

changeset 19474:69108560c7eb

x86: unify BUG() & Co, reduce overhead on x86-64

Since it's only the string pointer representations that differ between
i386 and x86-64, abstract out those and make everything else shared.

While touching this code, also use
- proper instructions rather than a mixture of such and raw .byte/
.long/.quad data emissions,
- PC-relative pointers on x86-64 to cut the amount of storage (and
in particular cache space) needed for string references by half.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Tue Mar 31 13:23:11 2009 +0100 (2009-03-31)
parents 2fa1d38097da
children d7bf5a03cf07
files xen/arch/x86/traps.c xen/include/asm-x86/bug.h xen/include/asm-x86/x86_32/bug.h xen/include/asm-x86/x86_64/bug.h
line diff
     1.1 --- a/xen/arch/x86/traps.c	Tue Mar 31 13:22:12 2009 +0100
     1.2 +++ b/xen/arch/x86/traps.c	Tue Mar 31 13:23:11 2009 +0100
     1.3 @@ -841,7 +841,7 @@ asmlinkage void do_invalid_op(struct cpu
     1.4  {
     1.5      struct bug_frame bug;
     1.6      struct bug_frame_str bug_str;
     1.7 -    char *filename, *predicate, *eip = (char *)regs->eip;
     1.8 +    const char *filename, *predicate, *eip = (char *)regs->eip;
     1.9      unsigned long fixup;
    1.10      int id, lineno;
    1.11  
    1.12 @@ -873,11 +873,13 @@ asmlinkage void do_invalid_op(struct cpu
    1.13      /* WARN, BUG or ASSERT: decode the filename pointer and line number. */
    1.14      if ( !is_kernel(eip) ||
    1.15           __copy_from_user(&bug_str, eip, sizeof(bug_str)) ||
    1.16 -         memcmp(bug_str.mov, BUG_MOV_STR, sizeof(bug_str.mov)) )
    1.17 +         (bug_str.mov != 0xbc) )
    1.18          goto die;
    1.19 +    filename = bug_str(bug_str, eip);
    1.20      eip += sizeof(bug_str);
    1.21  
    1.22 -    filename = is_kernel(bug_str.str) ? (char *)bug_str.str : "<unknown>";
    1.23 +    if ( !is_kernel(filename) )
    1.24 +        filename = "<unknown>";
    1.25      lineno   = bug.id >> 2;
    1.26  
    1.27      if ( id == BUGFRAME_warn )
    1.28 @@ -900,11 +902,13 @@ asmlinkage void do_invalid_op(struct cpu
    1.29      ASSERT(id == BUGFRAME_assert);
    1.30      if ( !is_kernel(eip) ||
    1.31           __copy_from_user(&bug_str, eip, sizeof(bug_str)) ||
    1.32 -         memcmp(bug_str.mov, BUG_MOV_STR, sizeof(bug_str.mov)) )
    1.33 +         (bug_str.mov != 0xbc) )
    1.34          goto die;
    1.35 +    predicate = bug_str(bug_str, eip);
    1.36      eip += sizeof(bug_str);
    1.37  
    1.38 -    predicate = is_kernel(bug_str.str) ? (char *)bug_str.str : "<unknown>";
    1.39 +    if ( !is_kernel(predicate) )
    1.40 +        predicate = "<unknown>";
    1.41      printk("Assertion '%s' failed at %.50s:%d\n",
    1.42             predicate, filename, lineno);
    1.43      DEBUGGER_trap_fatal(TRAP_invalid_op, regs);
     2.1 --- a/xen/include/asm-x86/bug.h	Tue Mar 31 13:22:12 2009 +0100
     2.2 +++ b/xen/include/asm-x86/bug.h	Tue Mar 31 13:23:11 2009 +0100
     2.3 @@ -18,4 +18,28 @@ struct bug_frame {
     2.4  #define BUGFRAME_bug    2
     2.5  #define BUGFRAME_assert 3
     2.6  
     2.7 +#define dump_execution_state()                     \
     2.8 +    asm volatile (                                 \
     2.9 +        "ud2 ; ret $0"                             \
    2.10 +        : : "i" (BUGFRAME_dump) )
    2.11 +
    2.12 +#define WARN()                                     \
    2.13 +    asm volatile (                                 \
    2.14 +        "ud2 ; ret %0" BUG_STR(1)                  \
    2.15 +        : : "i" (BUGFRAME_warn | (__LINE__<<2)),   \
    2.16 +            "i" (__FILE__) )
    2.17 +
    2.18 +#define BUG()                                      \
    2.19 +    asm volatile (                                 \
    2.20 +        "ud2 ; ret %0" BUG_STR(1)                  \
    2.21 +        : : "i" (BUGFRAME_bug | (__LINE__<<2)),    \
    2.22 +            "i" (__FILE__) )
    2.23 +
    2.24 +#define assert_failed(p)                           \
    2.25 +    asm volatile (                                 \
    2.26 +        "ud2 ; ret %0" BUG_STR(1) BUG_STR(2)       \
    2.27 +        : : "i" (BUGFRAME_assert | (__LINE__<<2)), \
    2.28 +            "i" (__FILE__), "i" (#p) )
    2.29 +
    2.30 +
    2.31  #endif /* __X86_BUG_H__ */
     3.1 --- a/xen/include/asm-x86/x86_32/bug.h	Tue Mar 31 13:22:12 2009 +0100
     3.2 +++ b/xen/include/asm-x86/x86_32/bug.h	Tue Mar 31 13:23:11 2009 +0100
     3.3 @@ -2,33 +2,10 @@
     3.4  #define __X86_32_BUG_H__
     3.5  
     3.6  struct bug_frame_str {
     3.7 -    unsigned char mov[1];
     3.8 +    unsigned char mov;
     3.9      unsigned long str;
    3.10  } __attribute__((packed));
    3.11 -#define BUG_MOV_STR "\xbc"
    3.12 -
    3.13 -#define dump_execution_state()                          \
    3.14 -    asm volatile (                                      \
    3.15 -        "ud2 ; ret $%c0"                                \
    3.16 -        : : "i" (BUGFRAME_dump) )
    3.17 -
    3.18 -#define WARN()                                          \
    3.19 -    asm volatile (                                      \
    3.20 -        "ud2 ; ret $%c0 ; .byte 0xbc ; .long %c1"       \
    3.21 -        : : "i" (BUGFRAME_warn | (__LINE__<<2)),        \
    3.22 -            "i" (__FILE__) )
    3.23 -
    3.24 -#define BUG()                                           \
    3.25 -    asm volatile (                                      \
    3.26 -        "ud2 ; ret $%c0 ; .byte 0xbc ; .long %c1"       \
    3.27 -        : : "i" (BUGFRAME_bug | (__LINE__<<2)),         \
    3.28 -            "i" (__FILE__) )
    3.29 -
    3.30 -#define assert_failed(p)                                \
    3.31 -    asm volatile (                                      \
    3.32 -        "ud2 ; ret $%c0 ; .byte 0xbc ; .long %c1"       \
    3.33 -        " ; .byte 0xbc ; .long %c2"                     \
    3.34 -        : : "i" (BUGFRAME_assert | (__LINE__<<2)),      \
    3.35 -            "i" (__FILE__), "i" (#p) )
    3.36 +#define bug_str(b, eip) ((const char *)(b).str)
    3.37 +#define BUG_STR(n) "; movl %" #n ", %%esp"
    3.38  
    3.39  #endif /* __X86_32_BUG_H__ */
     4.1 --- a/xen/include/asm-x86/x86_64/bug.h	Tue Mar 31 13:22:12 2009 +0100
     4.2 +++ b/xen/include/asm-x86/x86_64/bug.h	Tue Mar 31 13:23:11 2009 +0100
     4.3 @@ -2,33 +2,10 @@
     4.4  #define __X86_64_BUG_H__
     4.5  
     4.6  struct bug_frame_str {
     4.7 -    unsigned char mov[2];
     4.8 -    unsigned long str;
     4.9 +    unsigned char mov;
    4.10 +    signed int str_disp;
    4.11  } __attribute__((packed));
    4.12 -#define BUG_MOV_STR "\x48\xbc"
    4.13 -
    4.14 -#define dump_execution_state()                          \
    4.15 -    asm volatile (                                      \
    4.16 -        "ud2 ; ret $%c0"                                \
    4.17 -        : : "i" (BUGFRAME_dump) )
    4.18 -
    4.19 -#define WARN()                                          \
    4.20 -    asm volatile (                                      \
    4.21 -        "ud2 ; ret $%c0 ; .byte 0x48,0xbc ; .quad %c1"  \
    4.22 -        : : "i" (BUGFRAME_warn | (__LINE__<<2)),        \
    4.23 -            "i" (__FILE__) )
    4.24 -
    4.25 -#define BUG()                                           \
    4.26 -    asm volatile (                                      \
    4.27 -        "ud2 ; ret $%c0 ; .byte 0x48,0xbc ; .quad %c1"  \
    4.28 -        : : "i" (BUGFRAME_bug | (__LINE__<<2)),         \
    4.29 -            "i" (__FILE__) )
    4.30 -
    4.31 -#define assert_failed(p)                                \
    4.32 -    asm volatile (                                      \
    4.33 -        "ud2 ; ret $%c0 ; .byte 0x48,0xbc ; .quad %c1"  \
    4.34 -        " ; .byte 0x48,0xbc ; .quad %c2"                \
    4.35 -        : : "i" (BUGFRAME_assert | (__LINE__<<2)),      \
    4.36 -            "i" (__FILE__), "i" (#p) )
    4.37 +#define bug_str(b, rip) ((const char *)(rip) + (b).str_disp)
    4.38 +#define BUG_STR(n) "; movl %" #n " - ., %%esp"
    4.39  
    4.40  #endif /* __X86_64_BUG_H__ */