Re: [PATCH] Fix broken debug output reserve_region_with_split()

From: Benjamin Herrenschmidt
Date: Fri Oct 17 2008 - 01:13:51 EST


From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

Implement %pR to print struct resource content

Add a %pR option to the kernel vsnprintf that prints the range of
addresses inside a struct resource passed by pointer.

Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
---

This one does more fancy formatting.

Index: linux-work/lib/vsprintf.c
===================================================================
--- linux-work.orig/lib/vsprintf.c 2008-10-17 13:30:18.000000000 +1100
+++ linux-work/lib/vsprintf.c 2008-10-17 16:10:49.000000000 +1100
@@ -24,6 +24,7 @@
#include <linux/kernel.h>
#include <linux/kallsyms.h>
#include <linux/uaccess.h>
+#include <linux/ioport.h>

#include <asm/page.h> /* for PAGE_SIZE */
#include <asm/div64.h>
@@ -550,18 +551,58 @@ static char *symbol_string(char *buf, ch
#endif
}

+static char *resource_string(char *buf, char *end, struct resource *res, int field_width, int precision, int flags)
+{
+#ifdef CONFIG_PHYS_ADDR_T_64BIT
+#define MEM_RSRC_SIZE 16
+#else
+#define MEM_RSRC_SIZE 8
+#endif
+
+#ifdef CONFIG_X86
+#define IO_RSRC_SIZE 4
+#elif CONFIG_PPC
+#define IO_RSRC_SIZE 8
+#else
+#define IO_RSRC_SIZE MEM_RSRC_SIZE
+#endif
+
+ /* room for the actual numbers, the two "0x", -, [, ] and the final zero */
+ char sym[4*sizeof(resource_size_t) + 8];
+ char *p = sym, *pend = sym + sizeof(sym);
+ int size = 2 * sizeof(resource_size_t);
+
+ if (res->flags & IORESOURCE_MEM)
+ size = MEM_RSRC_SIZE;
+ else if (res->flags & IORESOURCE_IO)
+ size = IO_RSRC_SIZE;
+
+ *p++ = '[';
+ p = number(p, pend, res->start, 16, size, -1, SPECIAL | SMALL | ZEROPAD);
+ *p++ = '-';
+ p = number(p, pend, res->end, 16, size, -1, SPECIAL | SMALL | ZEROPAD);
+ *p++ = ']';
+ *p = 0;
+
+ return string(buf, end, sym, field_width, precision, flags);
+}
+
/*
* Show a '%p' thing. A kernel extension is that the '%p' is followed
* by an extra set of alphanumeric characters that are extended format
* specifiers.
*
- * Right now we just handle 'F' (for symbolic Function descriptor pointers)
- * and 'S' (for Symbolic direct pointers), but this can easily be
- * extended in the future (network address types etc).
- *
- * The difference between 'S' and 'F' is that on ia64 and ppc64 function
- * pointers are really function descriptors, which contain a pointer the
- * real address.
+ * Right now we handle:
+ *
+ * - 'F' For symbolic Function descriptor pointers
+ * - 'S' For Symbolic direct pointers), but this can easily be
+ * extended in the future (network address types etc).
+ * - 'R' For a struct resouce pointer, it prints the range of
+ * addresses (not the name nor the flags)
+ *
+ * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
+ * function pointers are really function descriptors, which contain a
+ * pointer the real address.
*/
static char *pointer(const char *fmt, char *buf, char *end, void *ptr, int field_width, int precision, int flags)
{
@@ -571,6 +612,8 @@ static char *pointer(const char *fmt, ch
/* Fallthrough */
case 'S':
return symbol_string(buf, end, ptr, field_width, precision, flags);
+ case 'R':
+ return resource_string(buf, end, ptr, field_width, precision, flags);
}
flags |= SMALL;
if (field_width == -1) {
@@ -590,6 +633,7 @@ static char *pointer(const char *fmt, ch
* This function follows C99 vsnprintf, but has some extensions:
* %pS output the name of a text symbol
* %pF output the name of a function pointer
+ * %pR output the address range in a struct resource
*
* The return value is the number of characters which would
* be generated for the given input, excluding the trailing


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