1 files changed, 133 insertions, 1 deletions

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index f44e178e6..ccb664b54 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -35,6 +35,8 @@
 #include <linux/blkdev.h>
 #endif
 
+#include "../mm/internal.h"	/* For the trace_print_flags arrays */
+
 #include <asm/page.h>		/* for PAGE_SIZE */
 #include <asm/sections.h>	/* for dereference_function_descriptor() */
 #include <asm/byteorder.h>	/* cpu_to_le16 */
@@ -1407,6 +1409,72 @@ char *clock(char *buf, char *end, struct clk *clk, struct printf_spec spec,
 	}
 }
 
+static
+char *format_flags(char *buf, char *end, unsigned long flags,
+					const struct trace_print_flags *names)
+{
+	unsigned long mask;
+	const struct printf_spec strspec = {
+		.field_width = -1,
+		.precision = -1,
+	};
+	const struct printf_spec numspec = {
+		.flags = SPECIAL|SMALL,
+		.field_width = -1,
+		.precision = -1,
+		.base = 16,
+	};
+
+	for ( ; flags && names->name; names++) {
+		mask = names->mask;
+		if ((flags & mask) != mask)
+			continue;
+
+		buf = string(buf, end, names->name, strspec);
+
+		flags &= ~mask;
+		if (flags) {
+			if (buf < end)
+				*buf = '|';
+			buf++;
+		}
+	}
+
+	if (flags)
+		buf = number(buf, end, flags, numspec);
+
+	return buf;
+}
+
+static noinline_for_stack
+char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
+{
+	unsigned long flags;
+	const struct trace_print_flags *names;
+
+	switch (fmt[1]) {
+	case 'p':
+		flags = *(unsigned long *)flags_ptr;
+		/* Remove zone id */
+		flags &= (1UL << NR_PAGEFLAGS) - 1;
+		names = pageflag_names;
+		break;
+	case 'v':
+		flags = *(unsigned long *)flags_ptr;
+		names = vmaflag_names;
+		break;
+	case 'g':
+		flags = *(gfp_t *)flags_ptr;
+		names = gfpflag_names;
+		break;
+	default:
+		WARN_ONCE(1, "Unsupported flags modifier: %c\n", fmt[1]);
+		return buf;
+	}
+
+	return format_flags(buf, end, flags, names);
+}
+
 int kptr_restrict __read_mostly;
 
 /*
@@ -1495,6 +1563,11 @@ int kptr_restrict __read_mostly;
  * - 'Cn' For a clock, it prints the name (Common Clock Framework) or address
  *        (legacy clock framework) of the clock
  * - 'Cr' For a clock, it prints the current rate of the clock
+ * - 'G' For flags to be printed as a collection of symbolic strings that would
+ *       construct the specific value. Supported flags given by option:
+ *       p page flags (see struct page) given as pointer to unsigned long
+ *       g gfp flags (GFP_* and __GFP_*) given as pointer to gfp_t
+ *       v vma flags (VM_*) given as pointer to unsigned long
  *
  * ** Please update also Documentation/printk-formats.txt when making changes **
  *
@@ -1648,6 +1721,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
 		return bdev_name(buf, end, ptr, spec, fmt);
 #endif
 
+	case 'G':
+		return flags_string(buf, end, ptr, fmt);
 	}
 	spec.flags |= SMALL;
 	if (spec.field_width == -1) {
@@ -2565,8 +2640,12 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
 		if (*fmt == '*') {
 			if (!*str)
 				break;
-			while (!isspace(*fmt) && *fmt != '%' && *fmt)
+			while (!isspace(*fmt) && *fmt != '%' && *fmt) {
+				/* '%*[' not yet supported, invalid format */
+				if (*fmt == '[')
+					return num;
 				fmt++;
+			}
 			while (!isspace(*str) && *str)
 				str++;
 			continue;
@@ -2639,6 +2718,59 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
 			num++;
 		}
 		continue;
+		/*
+		 * Warning: This implementation of the '[' conversion specifier
+		 * deviates from its glibc counterpart in the following ways:
+		 * (1) It does NOT support ranges i.e. '-' is NOT a special
+		 *     character
+		 * (2) It cannot match the closing bracket ']' itself
+		 * (3) A field width is required
+		 * (4) '%*[' (discard matching input) is currently not supported
+		 *
+		 * Example usage:
+		 * ret = sscanf("00:0a:95","%2[^:]:%2[^:]:%2[^:]",
+		 *		buf1, buf2, buf3);
+		 * if (ret < 3)
+		 *    // etc..
+		 */
+		case '[':
+		{
+			char *s = (char *)va_arg(args, char *);
+			DECLARE_BITMAP(set, 256) = {0};
+			unsigned int len = 0;
+			bool negate = (*fmt == '^');
+
+			/* field width is required */
+			if (field_width == -1)
+				return num;
+
+			if (negate)
+				++fmt;
+
+			for ( ; *fmt && *fmt != ']'; ++fmt, ++len)
+				set_bit((u8)*fmt, set);
+
+			/* no ']' or no character set found */
+			if (!*fmt || !len)
+				return num;
+			++fmt;
+
+			if (negate) {
+				bitmap_complement(set, set, 256);
+				/* exclude null '\0' byte */
+				clear_bit(0, set);
+			}
+
+			/* match must be non-empty */
+			if (!test_bit((u8)*str, set))
+				return num;
+
+			while (test_bit((u8)*str, set) && field_width--)
+				*s++ = *str++;
+			*s = '\0';
+			++num;
+		}
+		continue;
 		case 'o':
 			base = 8;
 			break;