On Mon, 8 Dec 2014 23:15:32 +0200
"Michael S. Tsirkin" <m...@redhat.com> wrote:
> On Mon, Dec 08, 2014 at 04:08:03PM +0000, Igor Mammedov wrote:
> > According to ACPI spec NameSeg shorter than 4 characters
> > must be padded up to 4 characters with "_" symbol.
> > ACPI 5.0: 20.2.2 "Name Objects Encoding"
> >
> > Do it in build_append_nameseg() so that caller shouldn't know
> > or care about it.
> >
> > Signed-off-by: Igor Mammedov <imamm...@redhat.com>
>
> To me just doing it right in callers seems just as easy, but
> I guess you disagree :)
That means, author MUST know about padding, if he/she doesn't
or forget about it that would introduce error usually resulting
in BSOD. This patch allows to avoid such mistakes.
>
> > ---
> > hw/i386/acpi-build.c | 18 +++++++++++++-----
> > 1 file changed, 13 insertions(+), 5 deletions(-)
> >
> > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> > index f5ec66a..a8b7a2b 100644
> > --- a/hw/i386/acpi-build.c
> > +++ b/hw/i386/acpi-build.c
> > @@ -292,6 +292,8 @@ static inline void build_append_array(GArray *array,
> > GArray *val)
> > g_array_append_vals(array, val->data, val->len);
> > }
> >
> > +#define ACPI_NAMESEG_LEN 4
> > +
> > static void GCC_FMT_ATTR(2, 3)
> > build_append_nameseg(GArray *array, const char *format, ...)
> > {
> > @@ -299,13 +301,19 @@ build_append_nameseg(GArray *array, const char
> > *format, ...)
> > char s[] = "XXXX";
> > int len;
> > va_list args;
> > + const char padding = '_';
> >
> > va_start(args, format);
> > len = vsnprintf(s, sizeof s, format, args);
> > va_end(args);
> >
> > - assert(len == 4);
> > + g_assert(len <= ACPI_NAMESEG_LEN);
>
> I'm not sure when is g_assert preferable to assert.
> What's the motivation here?
>
>
> > +
> > g_array_append_vals(array, s, len);
> > + while (len != ACPI_NAMESEG_LEN) {
> > + g_array_append_val(array, padding);
> > + ++len;
> > + }
>
> Easier
>
> /* Pad up to 4 characters if necessary. */
> g_array_append_vals(array, "____", 4 - len);
>
>
>
> > }
> >
> > /* 5.4 Definition Block Encoding */
> > @@ -846,7 +854,7 @@ static void build_pci_bus_end(PCIBus *bus, void
> > *bus_state)
> >
> > if (bus->parent_dev) {
> > op = 0x82; /* DeviceOp */
> > - build_append_nameseg(bus_table, "S%.02X_",
> > + build_append_nameseg(bus_table, "S%.02X",
> > bus->parent_dev->devfn);
> > build_append_byte(bus_table, 0x08); /* NameOp */
> > build_append_nameseg(bus_table, "_SUN");
> > @@ -966,7 +974,7 @@ static void build_pci_bus_end(PCIBus *bus, void
> > *bus_state)
> > build_append_int(notify, 0x1U << i);
> > build_append_byte(notify, 0x00); /* NullName */
> > build_append_byte(notify, 0x86); /* NotifyOp */
> > - build_append_nameseg(notify, "S%.02X_", PCI_DEVFN(i, 0));
> > + build_append_nameseg(notify, "S%.02X", PCI_DEVFN(i, 0));
> > build_append_byte(notify, 0x69); /* Arg1Op */
> >
> > /* Pack it up */
> > @@ -1023,7 +1031,7 @@ static void build_pci_bus_end(PCIBus *bus, void
> > *bus_state)
> > if (bus->parent_dev) {
> > build_append_byte(parent->notify_table, '^'); /*
> > ParentPrefixChar */
> > build_append_byte(parent->notify_table, 0x2E); /*
> > DualNamePrefix */
> > - build_append_nameseg(parent->notify_table, "S%.02X_",
> > + build_append_nameseg(parent->notify_table, "S%.02X",
> > bus->parent_dev->devfn);
> > build_append_nameseg(parent->notify_table, "PCNT");
> > }
> > @@ -1093,7 +1101,7 @@ build_ssdt(GArray *table_data, GArray *linker,
> > GArray *sb_scope = build_alloc_array();
> > uint8_t op = 0x10; /* ScopeOp */
> >
> > - build_append_nameseg(sb_scope, "_SB_");
> > + build_append_nameseg(sb_scope, "_SB");
> >
> > /* build Processor object for each processor */
> > for (i = 0; i < acpi_cpus; i++) {
> > --
> > 1.8.3.1
