於 四，2013-05-30 於 00:53 +0200，Jiri Kosina 提到：
> On Wed, 29 May 2013, Russ Anderson wrote:
>
> > > Yes, but this call is clearly happening way before ExitBootServices() --
> > > see the surrounding code, see for example this in efi_main():
> > >
> > > [ ... snip ... ]
> > > setup_efi_vars(boot_params);
> > >
> > > setup_efi_pci(boot_params);
> > >
> > > status = efi_call_phys3(sys_table->boottime->allocate_pool,
> > > EFI_LOADER_DATA, sizeof(*gdt),
> > > (void **)&gdt);
> > > if (status != EFI_SUCCESS) {
> > > efi_printk("Failed to alloc mem for gdt structure\n");
> > > goto fail;
> > > }
> > > [ ... snip ... ]
> >
> > Yes. Note the failing call is sys_table->runtime while all the
> > other calls are sys_table->boottime and seem to work. Not sure
> > why the sys_table->runtime call has a problem but it may be
> > a clue. Could something in the runtime path not be set up???
>
> That was my original idea early today as well. My understanding of the
> UEFI spec is admittedly limited, but afaics calling runtime method from
> boot environment should be a valid thing to do ... ?
QueryVariableInfo() is a runtime services, all runtime services should
available bother on boot time and runtime:
UEFI spec 2.3.1 P.109:
Runtime Services
Functions that are available before and after any call to
ExitBootServices(). These functions are described in Section 7.
>
> > > We are calling QueryVariableInfo() in setup_efi_vars(), and later on
> > > AllocatePool is being called (through boot table).
> >
> > On my system the QueryVariableInfo() call fails, so AllocatePool()
> > is not called in setup_efi_vars().
>
> But it's being called later on coming back to efi_main(). That was just a
> poor man's demonstration attempt why this code is running before
> ExitBootServices() has been called.
>
Yes, I agreed your point, the space information of
EFI_VARIABLE_BOOTSERVICE_ACCESS should still return by
QueryVariableInfo() because we call it before ExitBootServices():
arch/x86/boot/compressed/eboot.c
efi_main(void *handle, efi_system_table_t *_table, struct boot_params
*boot_params)
..
sys_table = _table;
/* Check if we were booted by the EFI firmware */
if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
goto fail;
boot_params->secure_boot = get_secure_boot(sys_table)
/* check does BIOS in secure boot mode */
setup_graphics(boot_params);
setup_efi_vars(boot_params);
/* Pass boot services variable info to runtime code, call QueryVariableInfo() */
...
status = exit_boot(boot_params, handle);
/* call ExitBootServices() */
...
Thanks a lot!
Joey Lee
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