* H. Peter Anvin <hpa@xxxxxxxxx> wrote: > On 08/03/2009 08:11 AM, Akinobu Mita wrote: > >>>> > >> OK, I spotted the following error, which certainly would explain a crash on > >> an APM machine: > >> > >> /* data */ > >> - [GDT_ENTRY_APMBIOS_BASE+2] = { { { 0x0000ffff, 0x00409200 } } > >> }, > >> + [GDT_ENTRY_APMBIOS_BASE+2] = GDT_ENTRY_INIT(0x409a, 0, 0xffff), > > > > Oops, I really should have checked the binary because the compiler should > > generate same code with this patch. > > > > Well, it doesn't even on the best of days, because the last hunk changes > a dynamic initializer to a strange mix between static and dynamic: > > -static struct desc_struct bad_bios_desc; > +static struct desc_struct bad_bios_desc = GDT_ENTRY_INIT(0x4092, 0, 0); > > /* > * At some point we want to use this stack frame pointer to unwind > @@ -476,9 +476,6 @@ void pnpbios_calls_init(union > pnp_bios_install_struct *header) > pnp_bios_callpoint.offset = header->fields.pm16offset; > pnp_bios_callpoint.segment = PNP_CS16; > > - bad_bios_desc.a = 0; > - bad_bios_desc.b = 0x00409200; > - > set_desc_base(&bad_bios_desc, (unsigned long)__va(0x40UL << 4)); > set_desc_limit(&bad_bios_desc, 4095 - (0x40 << 4)); > > This is about at strange as it comes; I think we could simply do: > > GDT_ENTRY_INIT(0x4092, (unsigned long)__va(0x400UL), 4095-0x400); > > Although perhaps the 4095 should really be PAGE_SIZE-1... I've removed the patch for now - please resubmit when fixed. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html