2018-05-29 19:21:09

by Mathieu Malaterre

Subject: [PATCH] powerpc/prom: Fix %u/%llx usage since prom_printf() change

In commit eae5f709a4d7 ("powerpc: Add __printf verification to
prom_printf") __printf attribute was added to prom_printf(), which
means GCC started warning about type/format mismatches. As part of that
commit we changed some "%lx" formats to "%llx" where the type is
actually unsigned long long.

Unfortunately prom_printf() doesn't know how to print "%llx", it just
prints a literal "lx", eg:

reserved memory map:
lx - lx
lx - lx

prom_printf() also doesn't know how to print "%u" (only "%lu"), it just
print a literal "u", eg:

Max number of cores passed to firmware: u (NR_CPUS = 2048)

instead of:

Max number of cores passed to firmware: 2048 (NR_CPUS = 2048)

This commit adds support for the missing formatters.

Fixes: eae5f709a4d7 ("powerpc: Add __printf verification to prom_printf")
Reported-by: Michael Ellerman <[email protected]>
Reported-by: Stephen Rothwell <[email protected]>
Signed-off-by: Mathieu Malaterre <[email protected]>
---
I've reviewed all formatters added in eae5f709a4d7 and only %u and %llx were
actually missing (eg. llu or lld are not used)

arch/powerpc/kernel/prom_init.c | 72 +++++++++++++++++++++++++++--------------
1 file changed, 48 insertions(+), 24 deletions(-)

diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index 4d62f561f272..2c04516fe274 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -301,6 +301,9 @@ static void __init prom_print(const char *msg)
}


+/* both prom_print_hex & prom_print_dec takes an unsigned long as input so that
+ * we do not need __udivdi3 or __umoddi3 on 32bits
+ */
static void __init prom_print_hex(unsigned long val)
{
int i, nibbles = sizeof(val)*2;
@@ -341,6 +344,7 @@ static void __init prom_printf(const char *format, ...)
va_list args;
unsigned long v;
long vs;
+ int n = 0;

va_start(args, format);
for (p = format; *p != 0; p = q) {
@@ -359,6 +363,10 @@ static void __init prom_printf(const char *format, ...)
++q;
if (*q == 0)
break;
+ while (*q == 'l') {
+ ++q;
+ ++n;
+ }
switch (*q) {
case 's':
++q;
@@ -367,39 +375,55 @@ static void __init prom_printf(const char *format, ...)
break;
case 'x':
++q;
- v = va_arg(args, unsigned long);
+ switch (n) {
+ case 0:
+ v = va_arg(args, unsigned int);
+ break;
+ case 1:
+ v = va_arg(args, unsigned long);
+ break;
+ case 2:
+ default:
+ v = va_arg(args, unsigned long long);
+ break;
+ }
prom_print_hex(v);
break;
- case 'd':
+ case 'u':
++q;
- vs = va_arg(args, int);
- if (vs < 0) {
- prom_print("-");
- vs = -vs;
+ switch (n) {
+ case 0:
+ v = va_arg(args, unsigned int);
+ break;
+ case 1:
+ v = va_arg(args, unsigned long);
+ break;
+ case 2:
+ default:
+ v = va_arg(args, unsigned long long);
+ break;
}
- prom_print_dec(vs);
+ prom_print_dec(v);
break;
- case 'l':
+ case 'd':
++q;
- if (*q == 0)
+ switch (n) {
+ case 0:
+ vs = va_arg(args, int);
break;
- else if (*q == 'x') {
- ++q;
- v = va_arg(args, unsigned long);
- prom_print_hex(v);
- } else if (*q == 'u') { /* '%lu' */
- ++q;
- v = va_arg(args, unsigned long);
- prom_print_dec(v);
- } else if (*q == 'd') { /* %ld */
- ++q;
+ case 1:
vs = va_arg(args, long);
- if (vs < 0) {
- prom_print("-");
- vs = -vs;
- }
- prom_print_dec(vs);
+ break;
+ case 2:
+ default:
+ vs = va_arg(args, long long);
+ break;
+ }
+ if (vs < 0) {
+ prom_print("-");
+ vs = -vs;
}
+ prom_print_dec(vs);
break;
}
}
--
2.11.0

2018-06-01 15:57:02

by Michael Ellerman

Subject: Re: powerpc/prom: Fix %u/%llx usage since prom_printf() change

On Tue, 2018-05-29 at 19:20:01 UTC, Mathieu Malaterre wrote:
> In commit eae5f709a4d7 ("powerpc: Add __printf verification to
> prom_printf") __printf attribute was added to prom_printf(), which
> means GCC started warning about type/format mismatches. As part of that
> commit we changed some "%lx" formats to "%llx" where the type is
> actually unsigned long long.
>
> Unfortunately prom_printf() doesn't know how to print "%llx", it just
> prints a literal "lx", eg:
>
> reserved memory map:
> lx - lx
> lx - lx
>
> prom_printf() also doesn't know how to print "%u" (only "%lu"), it just
> print a literal "u", eg:
>
> Max number of cores passed to firmware: u (NR_CPUS = 2048)
>
> instead of:
>
> Max number of cores passed to firmware: 2048 (NR_CPUS = 2048)
>
> This commit adds support for the missing formatters.
>
> Fixes: eae5f709a4d7 ("powerpc: Add __printf verification to prom_printf")
> Reported-by: Michael Ellerman <[email protected]>
> Reported-by: Stephen Rothwell <[email protected]>
> Signed-off-by: Mathieu Malaterre <[email protected]>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/8af1da40669609707303eecdb857f4

cheers