diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-06 19:43:12 -0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-06 19:55:51 -0400 |
commit | 0fe1ef24f7bd0020f29ffe287dfdb9ead33ca0b2 (patch) | |
tree | 0069dd9dba6554f74436ea1d836ecc054a6b95d7 /lib | |
parent | 4d8a743cdd2690c0bc8d1b8cbd02cffb1ead849f (diff) |
vsprintf: add support for '%pS' and '%pF' pointer formats
They print out a pointer in symbolic format, if possible (ie using
symbolic KALLSYMS information). The '%pS' format is for regular direct
pointers (which can point to data or code and that you find on the stack
during backtraces etc), while '%pF' is for C function pointer types.
On most architectures, the two mean exactly the same thing, but some
architectures use an indirect pointer for C function pointers, where the
function pointer points to a function descriptor (which in turn contains
the actual pointer to the code). The '%pF' code automatically does the
appropriate function descriptor dereference on such architectures.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r-- | lib/vsprintf.c | 41 |
1 files changed, 40 insertions, 1 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 5d6f0718b6d9..1dc2d1d18fa8 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c | |||
@@ -22,6 +22,8 @@ | |||
22 | #include <linux/string.h> | 22 | #include <linux/string.h> |
23 | #include <linux/ctype.h> | 23 | #include <linux/ctype.h> |
24 | #include <linux/kernel.h> | 24 | #include <linux/kernel.h> |
25 | #include <linux/kallsyms.h> | ||
26 | #include <linux/uaccess.h> | ||
25 | 27 | ||
26 | #include <asm/page.h> /* for PAGE_SIZE */ | 28 | #include <asm/page.h> /* for PAGE_SIZE */ |
27 | #include <asm/div64.h> | 29 | #include <asm/div64.h> |
@@ -511,15 +513,52 @@ static char *string(char *buf, char *end, char *s, int field_width, int precisio | |||
511 | return buf; | 513 | return buf; |
512 | } | 514 | } |
513 | 515 | ||
516 | static inline void *dereference_function_descriptor(void *ptr) | ||
517 | { | ||
518 | #if defined(CONFIG_IA64) || defined(CONFIG_PPC64) | ||
519 | void *p; | ||
520 | if (!probe_kernel_address(ptr, p)) | ||
521 | ptr = p; | ||
522 | #endif | ||
523 | return ptr; | ||
524 | } | ||
525 | |||
526 | static char *symbol_string(char *buf, char *end, void *ptr, int field_width, int precision, int flags) | ||
527 | { | ||
528 | unsigned long value = (unsigned long) ptr; | ||
529 | #ifdef CONFIG_KALLSYMS | ||
530 | char sym[KSYM_SYMBOL_LEN]; | ||
531 | sprint_symbol(sym, value); | ||
532 | return string(buf, end, sym, field_width, precision, flags); | ||
533 | #else | ||
534 | field_width = 2*sizeof(void *); | ||
535 | flags |= SPECIAL | SMALL | ZEROPAD; | ||
536 | return number(buf, end, value, 16, field_width, precision, flags); | ||
537 | #endif | ||
538 | } | ||
539 | |||
514 | /* | 540 | /* |
515 | * Show a '%p' thing. A kernel extension is that the '%p' is followed | 541 | * Show a '%p' thing. A kernel extension is that the '%p' is followed |
516 | * by an extra set of alphanumeric characters that are extended format | 542 | * by an extra set of alphanumeric characters that are extended format |
517 | * specifiers. | 543 | * specifiers. |
518 | * | 544 | * |
519 | * Right now don't actually handle any such, but we will.. | 545 | * Right now we just handle 'F' (for symbolic Function descriptor pointers) |
546 | * and 'S' (for Symbolic direct pointers), but this can easily be | ||
547 | * extended in the future (network address types etc). | ||
548 | * | ||
549 | * The difference between 'S' and 'F' is that on ia64 and ppc64 function | ||
550 | * pointers are really function descriptors, which contain a pointer the | ||
551 | * real address. | ||
520 | */ | 552 | */ |
521 | static char *pointer(const char *fmt, char *buf, char *end, void *ptr, int field_width, int precision, int flags) | 553 | static char *pointer(const char *fmt, char *buf, char *end, void *ptr, int field_width, int precision, int flags) |
522 | { | 554 | { |
555 | switch (*fmt) { | ||
556 | case 'F': | ||
557 | ptr = dereference_function_descriptor(ptr); | ||
558 | /* Fallthrough */ | ||
559 | case 'S': | ||
560 | return symbol_string(buf, end, ptr, field_width, precision, flags); | ||
561 | } | ||
523 | flags |= SMALL; | 562 | flags |= SMALL; |
524 | if (field_width == -1) { | 563 | if (field_width == -1) { |
525 | field_width = 2*sizeof(void *); | 564 | field_width = 2*sizeof(void *); |