On 04/30/19 03:30, Michael D Kinney wrote: > Add gEfiMdePkgTokenSpaceGuid.PcdSpeculationBarrierType that > uses the PCD type FixedAtBuild. This performs a build time > selection for the type of speculation barrier to use in the > BaseLib function SpeculationBarrier(). The recommended > speculation barrier for x86 is LFENCE and this is the default > value for this PCD. x86 CPUs that do not support LFENCE must > select one of the other supported values which includes CPUID > and nothing. > > Cc: Liming Gao <liming....@intel.com> > Signed-off-by: Michael D Kinney <michael.d.kin...@intel.com> > --- > MdePkg/MdePkg.dec | 9 +++++++++ > MdePkg/MdePkg.uni | 8 ++++++++ > 2 files changed, 17 insertions(+) > > diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec > index e2ea8fff66..28d4a966c2 100644 > --- a/MdePkg/MdePkg.dec > +++ b/MdePkg/MdePkg.dec > @@ -2062,6 +2062,15 @@ [PcdsFixedAtBuild] > # @Prompt Enable control flow enforcement. > > gEfiMdePkgTokenSpaceGuid.PcdControlFlowEnforcementPropertyMask|0x0|UINT32|0x30001017 > > + ## Indicates the type of instruction sequence to use for a speculation > + # barrier. The default instruction sequence is LFENCE.<BR><BR> > + # 0x00 - No operation.<BR> > + # 0x01 - LFENCE (IA32/X64).<BR> > + # 0x02 - CPUID (IA32/X64).<BR> > + # Other - reserved > + # @Prompt Speculation Barrier Type. > + gEfiMdePkgTokenSpaceGuid.PcdSpeculationBarrierType|0x01|UINT8|0x30001018 > + > [PcdsFixedAtBuild,PcdsPatchableInModule] > ## Indicates the maximum length of unicode string used in the following > # BaseLib functions: StrLen(), StrSize(), StrCmp(), StrnCmp(), StrCpy(), > StrnCpy()<BR><BR>
In MdePkg.dec, we have: - [Includes.X64] - [LibraryClasses.X64] - [Guids.X64] but no PCD declarations that are architecture-specific. Is that intentional? Because, this PCD could be a good candidate for "IA32/X64 only". (Looking at the next patch too.) But, that's just my curiosity. Reviewed-by: Laszlo Ersek <ler...@redhat.com> Thanks Laszlo > diff --git a/MdePkg/MdePkg.uni b/MdePkg/MdePkg.uni > index c359bb4b5b..5c1fa24065 100644 > --- a/MdePkg/MdePkg.uni > +++ b/MdePkg/MdePkg.uni > @@ -149,6 +149,14 @@ > > " BIT0 - SMM CET Shadow Stack is enabled.<BR>\n" > > " Other - reserved" > > +#string STR_gEfiMdePkgTokenSpaceGuid_PcdSpeculationBarrierType_PROMPT > #language en-US "Speculation Barrier Type." > + > +#string STR_gEfiMdePkgTokenSpaceGuid_PcdSpeculationBarrierType_HELP > #language en-US "Indicates the type of instruction sequence to use for a > speculation.barrier. The default instruction sequence is LFENCE.<BR><BR>\n" > + > "0x00 - No operation.<BR>\n" > + > "0x01 - LFENCE (IA32/X64).<BR>\n" > + > "0x02 - CPUID (IA32/X64).<BR>\n" > + > "Other - reserved" > + > #string STR_gEfiMdePkgTokenSpaceGuid_PcdMaximumAsciiStringLength_PROMPT > #language en-US "Maximum Length of Ascii String" > > #string STR_gEfiMdePkgTokenSpaceGuid_PcdMaximumAsciiStringLength_HELP > #language en-US "Sets the maximum number of ASCII characters used for string > functions. This affects the following BaseLib functions: AsciiStrLen(), > AsciiStrSize(), AsciiStrCmp(), AsciiStrnCmp(), AsciiStrCpy(), AsciiStrnCpy(). > <BR><BR>\n" > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#39845): https://edk2.groups.io/g/devel/message/39845 Mute This Topic: https://groups.io/mt/31415900/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
