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tiny-printf: Handle formatting of %p with an extra Kconfig

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The formatting with %pa / %pap behaves like %x, which results in an
incorrect value being output. To improve this, a new fine-tuning
Kconfig SPL_USE_TINY_PRINTF_POINTER_SUPPORT for pointer formatting
has been added. If it is enabled, the output of %pa / %pap should
be correct, and if it is disabled, the pointer formatting is
completely unsupported. In addition to indicate unsupported formatting,
'?' will be output. This allows enabling pointer formatting only
when needed. For SPL_NET it is selected by default. Then it also
supports the formatting with %pm, %pM and %pI4.

In summery this level of %p support for tiny printf is possible now:

1) The standard tiny printf won't have support for pointer formatting.
   So it doesn't print misleading values for %pa, instead '?' will be
   output:
   %p   => ?
   %pa  => ?a
   %pap => ?ap

2) If SPL_USE_TINY_PRINTF_POINTER_SUPPORT is enabled or DEBUG is defined
   tiny printf supports formatting %p and %pa / %pap.

3) If SPL_NET is enabled the support of pointers is extended
   for %pm, %pM and %pI4.

Signed-off-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
This commit is contained in:
Christoph Niedermaier
2025-05-08 13:57:25 +02:00
committed by Tom Rini
parent 0a00637157
commit 1e24e84db4
3 changed files with 33 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
common/spl/Kconfig
View File

@@ -1123,6 +1123,7 @@ config SPL_DM_SPI_FLASH
config SPL_NET
bool "Support networking"
depends on !NET_LWIP
select SPL_USE_TINY_PRINTF_POINTER_SUPPORT if SPL_USE_TINY_PRINTF
help
Enable support for network devices (such as Ethernet) in SPL.
This permits SPL to load U-Boot over a network link rather than

8
lib/Kconfig
View File

@@ -253,6 +253,14 @@ config VPL_USE_TINY_PRINTF
The supported format specifiers are %c, %s, %u/%d and %x.
config SPL_USE_TINY_PRINTF_POINTER_SUPPORT
bool "Extend tiny printf with the pointer formatting %p"
depends on SPL_USE_TINY_PRINTF
help
This option enables the formatting of pointers %p. It supports
%p and %pa / %pap. If this option is selected by SPL_NET
it also supports the formatting with %pm, %pM and %pI4.
config PANIC_HANG
bool "Do not reset the system on fatal error"
help

48
lib/tiny-printf.c
View File

@@ -141,7 +141,7 @@ static void ip4_addr_string(struct printf_info *info, u8 *addr)
string(info, ip4_addr);
}
#endif
#endif /* CONFIG_SPL_NET */
/*
* Show a '%p' thing. A kernel extension is that the '%p' is followed
@@ -157,18 +157,14 @@ static void ip4_addr_string(struct printf_info *info, u8 *addr)
* decimal).
*/
static void __maybe_unused pointer(struct printf_info *info, const char *fmt,
void *ptr)
#if defined(CONFIG_SPL_USE_TINY_PRINTF_POINTER_SUPPORT) || defined(DEBUG)
static void pointer(struct printf_info *info, const char *fmt, void *ptr)
{
#ifdef DEBUG
unsigned long num = (uintptr_t)ptr;
unsigned long div;
#endif
switch (*fmt) {
#ifdef DEBUG
case 'a':
switch (fmt[1]) {
case 'p':
default:
@@ -176,7 +172,6 @@ static void __maybe_unused pointer(struct printf_info *info, const char *fmt,
break;
}
break;
#endif
#ifdef CONFIG_SPL_NET
case 'm':
return mac_address_string(info, ptr, false);
@@ -185,16 +180,22 @@ static void __maybe_unused pointer(struct printf_info *info, const char *fmt,
case 'I':
if (fmt[1] == '4')
return ip4_addr_string(info, ptr);
#else
case 'm':
case 'M':
case 'I':
out(info, '?');
return;
#endif
default:
break;
}
#ifdef DEBUG
div = 1UL << (sizeof(long) * 8 - 4);
for (; div; div /= 0x10)
div_out(info, &num, div);
#endif
}
#endif
static int _vprintf(struct printf_info *info, const char *fmt, va_list va)
{
@@ -269,21 +270,18 @@ static int _vprintf(struct printf_info *info, const char *fmt, va_list va)
div_out(info, &num, div);
}
break;
#if defined(CONFIG_SPL_USE_TINY_PRINTF_POINTER_SUPPORT) || defined(DEBUG)
case 'p':
if (CONFIG_IS_ENABLED(NET) ||
CONFIG_IS_ENABLED(NET_LWIP) || _DEBUG) {
pointer(info, fmt, va_arg(va, void *));
/*
* Skip this because it pulls in _ctype which is
* 256 bytes, and we don't generally implement
* pointer anyway
*/
while (isalnum(fmt[0]))
fmt++;
break;
}
islong = true;
fallthrough;
pointer(info, fmt, va_arg(va, void *));
/*
* Skip this because it pulls in _ctype which is
* 256 bytes, and we don't generally implement
* pointer anyway
*/
while (isalnum(fmt[0]))
fmt++;
break;
#endif
case 'x':
case 'X':
if (islong) {
@@ -310,7 +308,9 @@ static int _vprintf(struct printf_info *info, const char *fmt, va_list va)
break;
case '%':
out(info, '%');
break;
default:
out(info, '?');
break;
}