On 09/24/15 at 02:06pm, Ard Biesheuvel wrote:
> On 23 September 2015 at 23:06, Dave Young <dyoung@xxxxxxxxxx> wrote:
> > On 09/09/15 at 10:08am, Ard Biesheuvel wrote:
> >> Version 2.5 of the UEFI spec introduces a new configuration table
> >> called the 'EFI Properties table'. Currently, it is only used to
> >> convey whether the Memory Protection feature is enabled, which splits
> >> PE/COFF images into separate code and data memory regions.
> >>
> >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> >> ---
> >> drivers/firmware/efi/efi.c | 32 ++++++++++++++++++--------------
> >> include/linux/efi.h | 13 +++++++++++++
> >> 2 files changed, 31 insertions(+), 14 deletions(-)
> >>
> >> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> >> index d6144e3b97c5..5cbb8d31da33 100644
> >> --- a/drivers/firmware/efi/efi.c
> >> +++ b/drivers/firmware/efi/efi.c
> >> @@ -26,20 +26,21 @@
> >> #include <linux/platform_device.h>
> >>
> >> struct efi __read_mostly efi = {
> >> - .mps = EFI_INVALID_TABLE_ADDR,
> >> - .acpi = EFI_INVALID_TABLE_ADDR,
> >> - .acpi20 = EFI_INVALID_TABLE_ADDR,
> >> - .smbios = EFI_INVALID_TABLE_ADDR,
> >> - .smbios3 = EFI_INVALID_TABLE_ADDR,
> >> - .sal_systab = EFI_INVALID_TABLE_ADDR,
> >> - .boot_info = EFI_INVALID_TABLE_ADDR,
> >> - .hcdp = EFI_INVALID_TABLE_ADDR,
> >> - .uga = EFI_INVALID_TABLE_ADDR,
> >> - .uv_systab = EFI_INVALID_TABLE_ADDR,
> >> - .fw_vendor = EFI_INVALID_TABLE_ADDR,
> >> - .runtime = EFI_INVALID_TABLE_ADDR,
> >> - .config_table = EFI_INVALID_TABLE_ADDR,
> >> - .esrt = EFI_INVALID_TABLE_ADDR,
> >> + .mps = EFI_INVALID_TABLE_ADDR,
> >> + .acpi = EFI_INVALID_TABLE_ADDR,
> >> + .acpi20 = EFI_INVALID_TABLE_ADDR,
> >> + .smbios = EFI_INVALID_TABLE_ADDR,
> >> + .smbios3 = EFI_INVALID_TABLE_ADDR,
> >> + .sal_systab = EFI_INVALID_TABLE_ADDR,
> >> + .boot_info = EFI_INVALID_TABLE_ADDR,
> >> + .hcdp = EFI_INVALID_TABLE_ADDR,
> >> + .uga = EFI_INVALID_TABLE_ADDR,
> >> + .uv_systab = EFI_INVALID_TABLE_ADDR,
> >> + .fw_vendor = EFI_INVALID_TABLE_ADDR,
> >> + .runtime = EFI_INVALID_TABLE_ADDR,
> >> + .config_table = EFI_INVALID_TABLE_ADDR,
> >> + .esrt = EFI_INVALID_TABLE_ADDR,
> >> + .properties_table = EFI_INVALID_TABLE_ADDR,
> >> };
> >> EXPORT_SYMBOL(efi);
> >>
> >> @@ -105,6 +106,8 @@ static ssize_t systab_show(struct kobject *kobj,
> >> str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
> >> if (efi.uga != EFI_INVALID_TABLE_ADDR)
> >> str += sprintf(str, "UGA=0x%lx\n", efi.uga);
> >> + if (efi.properties_table != EFI_INVALID_TABLE_ADDR)
> >> + str += sprintf(str, "PROP=0x%lx\n", efi.properties_table);
> >
> > Hello, Ard and Matt
> >
>
> Hi Dave,
>
> > I ramdomly read some of mails in linux-efi@, sorry for joining the discussion late.
> >
> > The sysfs file systab abuses sysfs policy about one value one file. For what we
> > have done we will have to maintain it, but I think we should not add more entries
> > to the file any more. Previously I thought to send a patch to add some code comment
> > to avoid later patches doing such modifications, but I hesitated if I should send
> > it, later I'm busy on something else..
> >
>
> While I agree that we should not be abusing this policy in the first
> place, changing the semantics of 'systab' to mean 'all configuration
> tables we knew about at some random point in the past' rather than
> 'all configuration tables passed by the firmware' is even worse imo.
Hmm, I have already put several of them out of systab like 'runtime', if you do not
like it, how about re-adding all table entries under /sys/firmware/efi as standalone
files, at the same time keep original systab there only for compatibility purpose.
Thanks
Dave
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