From: Arvind Sankar <nivedita@alum.mit.edu>
Date: Mon, 18 May 2020 15:06:59 -0400
Subject: efi/printf: Add 64-bit and 8-bit integer support
Patch-mainline: v5.8-rc1
Git-commit: ce5e3f909fc0ed67e58367b9c56a54c20a51080b
References: jsc#SLE-16407
Support 'll' qualifier for long long by copying the decimal printing
code from lib/vsprintf.c. For simplicity, the 32-bit code is used on
64-bit architectures as well.
Support 'hh' qualifier for signed/unsigned char type integers.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200518190716.751506-8-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Lee, Chun-Yi <jlee@suse.com>
---
drivers/firmware/efi/libstub/vsprintf.c | 170 ++++++++++++++++++++++++++------
1 file changed, 143 insertions(+), 27 deletions(-)
--- a/drivers/firmware/efi/libstub/vsprintf.c
+++ b/drivers/firmware/efi/libstub/vsprintf.c
@@ -7,10 +7,7 @@
* ----------------------------------------------------------------------- */
/*
- * Oh, it's a waste of space, but oh-so-yummy for debugging. This
- * version of printf() does not include 64-bit support. "Live with
- * it."
- *
+ * Oh, it's a waste of space, but oh-so-yummy for debugging.
*/
#include <stdarg.h>
@@ -28,6 +25,86 @@ static int skip_atoi(const char **s)
return i;
}
+/*
+ * put_dec_full4 handles numbers in the range 0 <= r < 10000.
+ * The multiplier 0xccd is round(2^15/10), and the approximation
+ * r/10 == (r * 0xccd) >> 15 is exact for all r < 16389.
+ */
+static
+void put_dec_full4(char *buf, unsigned int r)
+{
+ int i;
+
+ for (i = 0; i < 3; i++) {
+ unsigned int q = (r * 0xccd) >> 15;
+ *buf++ = '0' + (r - q * 10);
+ r = q;
+ }
+ *buf++ = '0' + r;
+}
+
+/* put_dec is copied from lib/vsprintf.c with small modifications */
+
+/*
+ * Call put_dec_full4 on x % 10000, return x / 10000.
+ * The approximation x/10000 == (x * 0x346DC5D7) >> 43
+ * holds for all x < 1,128,869,999. The largest value this
+ * helper will ever be asked to convert is 1,125,520,955.
+ * (second call in the put_dec code, assuming n is all-ones).
+ */
+static
+unsigned int put_dec_helper4(char *buf, unsigned int x)
+{
+ unsigned int q = (x * 0x346DC5D7ULL) >> 43;
+
+ put_dec_full4(buf, x - q * 10000);
+ return q;
+}
+
+/* Based on code by Douglas W. Jones found at
+ * <http://www.cs.uiowa.edu/~jones/bcd/decimal.html#sixtyfour>
+ * (with permission from the author).
+ * Performs no 64-bit division and hence should be fast on 32-bit machines.
+ */
+static
+int put_dec(char *buf, unsigned long long n)
+{
+ unsigned int d3, d2, d1, q, h;
+ char *p = buf;
+
+ d1 = ((unsigned int)n >> 16); /* implicit "& 0xffff" */
+ h = (n >> 32);
+ d2 = (h ) & 0xffff;
+ d3 = (h >> 16); /* implicit "& 0xffff" */
+
+ /* n = 2^48 d3 + 2^32 d2 + 2^16 d1 + d0
+ = 281_4749_7671_0656 d3 + 42_9496_7296 d2 + 6_5536 d1 + d0 */
+ q = 656 * d3 + 7296 * d2 + 5536 * d1 + ((unsigned int)n & 0xffff);
+ q = put_dec_helper4(p, q);
+ p += 4;
+
+ q += 7671 * d3 + 9496 * d2 + 6 * d1;
+ q = put_dec_helper4(p, q);
+ p += 4;
+
+ q += 4749 * d3 + 42 * d2;
+ q = put_dec_helper4(p, q);
+ p += 4;
+
+ q += 281 * d3;
+ q = put_dec_helper4(p, q);
+ p += 4;
+
+ put_dec_full4(p, q);
+ p += 4;
+
+ /* strip off the extra 0's we printed */
+ while (p > buf && p[-1] == '0')
+ --p;
+
+ return p - buf;
+}
+
#define ZEROPAD 1 /* pad with zero */
#define SIGN 2 /* unsigned/signed long */
#define PLUS 4 /* show plus */
@@ -36,13 +113,7 @@ static int skip_atoi(const char **s)
#define SMALL 32 /* Must be 32 == 0x20 */
#define SPECIAL 64 /* 0x */
-#define __do_div(n, base) ({ \
-int __res; \
-__res = ((unsigned long) n) % (unsigned) base; \
-n = ((unsigned long) n) / (unsigned) base; \
-__res; })
-
-static char *number(char *str, long num, int base, int size, int precision,
+static char *number(char *str, long long num, int base, int size, int precision,
int type)
{
/* we are called with base 8, 10 or 16, only, thus don't need "G..." */
@@ -57,8 +128,6 @@ static char *number(char *str, long num,
locase = (type & SMALL);
if (type & LEFT)
type &= ~ZEROPAD;
- if (base < 2 || base > 16)
- return NULL;
c = (type & ZEROPAD) ? '0' : ' ';
sign = 0;
if (type & SIGN) {
@@ -83,9 +152,28 @@ static char *number(char *str, long num,
i = 0;
if (num == 0)
tmp[i++] = '0';
- else
- while (num != 0)
- tmp[i++] = (digits[__do_div(num, base)] | locase);
+ else {
+ switch (base) {
+ case 10:
+ i += put_dec(&tmp[i], num);
+ break;
+ case 8:
+ while (num != 0) {
+ tmp[i++] = '0' + (num & 07);
+ num = (unsigned long long)num >> 3;
+ }
+ break;
+ case 16:
+ while (num != 0) {
+ tmp[i++] = digits[num & 0xf] | locase;
+ num = (unsigned long long)num >> 4;
+ }
+ break;
+ default:
+ unreachable();
+ }
+ }
+
if (i > precision)
precision = i;
size -= precision;
@@ -117,7 +205,7 @@ static char *number(char *str, long num,
int vsprintf(char *buf, const char *fmt, va_list args)
{
int len;
- unsigned long num;
+ unsigned long long num;
int i, base;
char *str;
const char *s;
@@ -127,7 +215,7 @@ int vsprintf(char *buf, const char *fmt,
int field_width; /* width of output field */
int precision; /* min. # of digits for integers; max
number of chars for from string */
- int qualifier; /* 'h' or 'l' for integer fields */
+ int qualifier; /* 'h', 'hh', 'l' or 'll' for integer fields */
for (str = buf; *fmt; ++fmt) {
if (*fmt != '%') {
@@ -191,6 +279,10 @@ int vsprintf(char *buf, const char *fmt,
if (*fmt == 'h' || *fmt == 'l') {
qualifier = *fmt;
++fmt;
+ if (qualifier == *fmt) {
+ qualifier -= 'a'-'A';
+ ++fmt;
+ }
}
/* default base */
@@ -260,16 +352,40 @@ int vsprintf(char *buf, const char *fmt,
--fmt;
continue;
}
- if (qualifier == 'l') {
- num = va_arg(args, unsigned long);
- } else if (qualifier == 'h') {
- num = (unsigned short)va_arg(args, int);
- if (flags & SIGN)
- num = (short)num;
- } else if (flags & SIGN) {
- num = va_arg(args, int);
+ if (flags & SIGN) {
+ switch (qualifier) {
+ case 'L':
+ num = va_arg(args, long long);
+ break;
+ case 'l':
+ num = va_arg(args, long);
+ break;
+ case 'h':
+ num = (short)va_arg(args, int);
+ break;
+ case 'H':
+ num = (signed char)va_arg(args, int);
+ break;
+ default:
+ num = va_arg(args, int);
+ }
} else {
- num = va_arg(args, unsigned int);
+ switch (qualifier) {
+ case 'L':
+ num = va_arg(args, unsigned long long);
+ break;
+ case 'l':
+ num = va_arg(args, unsigned long);
+ break;
+ case 'h':
+ num = (unsigned short)va_arg(args, int);
+ break;
+ case 'H':
+ num = (unsigned char)va_arg(args, int);
+ break;
+ default:
+ num = va_arg(args, unsigned int);
+ }
}
str = number(str, num, base, field_width, precision, flags);
}