Messages in this thread Patch in this message | | | Subject | Re: [RFC][PATCH] printk: Add %pb to print bitmaps | From | Peter Zijlstra <> | Date | Wed, 09 May 2012 15:59:07 +0200 |
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On Wed, 2012-05-09 at 15:44 +0200, Peter Zijlstra wrote: > On Wed, 2012-05-09 at 15:36 +0200, Ingo Molnar wrote: > > * Peter Zijlstra <peterz@infradead.org> wrote: > > > > > @@ -857,15 +860,19 @@ int kptr_restrict __read_mostly; > > > * correctness of the format string and va_list arguments. > > > * - 'K' For a kernel pointer that should be hidden from unprivileged users > > > * - 'NF' For a netdev_features_t > > > + * - 'b' For a bitmap, consumes 2 args, second is int > > > > hm, won't the second arg confuse gcc's printf format checker? > > > Ah, yes, I suppose I could abuse something like %*pb. Let me try that.
I guess I should use %.*pb and keep the field_width in case someone manages to actually make bitmap_scnlistprintf() conform to it. The precision is unused anyway.
The current implementation limits both (field_width and precision) to s16, which will limit us to printing 32Kb bitmaps. If need arises we could increase printf_spec size I guess.
--- lib/vsprintf.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index abbabec..6eb30a9 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -25,6 +25,9 @@ #include <linux/kallsyms.h> #include <linux/uaccess.h> #include <linux/ioport.h> +#include <linux/bitmap.h> +#include <linux/cpumask.h> +#include <linux/numa.h> #include <net/addrconf.h> #include <asm/page.h> /* for PAGE_SIZE */ @@ -857,6 +860,9 @@ int kptr_restrict __read_mostly; * correctness of the format string and va_list arguments. * - 'K' For a kernel pointer that should be hidden from unprivileged users * - 'NF' For a netdev_features_t + * - 'b' For a bitmap; %.*pb is required and the precision is used as bitmap length + * - 'bc' For a cpumask + * - 'bn' For a nodemask * * Note: The difference between 'S' and 'F' is that on ia64 and ppc64 * function pointers are really function descriptors, which contain a @@ -941,6 +947,26 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, return netdev_feature_string(buf, end, ptr, spec); } break; + case 'b': + { + int bits, len; + + switch (fmt[1]) { + case 'c': + bits = nr_cpumask_bits; + break; + case 'n': + bits = MAX_NUMNODES; + break; + default: + bits = spec->precision; + break; + } + + len = bitmap_scnlistprintf(buf, end - buf, ptr, bits); + + return buf + len; + } } spec.flags |= SMALL; if (spec.field_width == -1) { @@ -1175,6 +1201,9 @@ int format_decode(const char *fmt, struct printf_spec *spec) * %pI6c print an IPv6 address as specified by RFC 5952 * %pU[bBlL] print a UUID/GUID in big or little endian using lower or upper * case. + * %.*pb print a bitmap list using the precision as bitmap length + * %pbc print a cpumask bitmap + * %pbn print a nodemask bitmap * %n is ignored * * The return value is the number of characters which would
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