On 1/19/24 05:56, Nhi Pham wrote: > From: Laszlo Ersek <ler...@redhat.com> > > The current dependency evaluator violates the memory access permission > when patching depex grammar directly in the read-only depex memory area. > > Laszlo pointed out the optimization issue in the thread (1) "Memory > Attribute for depex section" and provided suggested patch to remove the > perf optimization. > > In my testing, removing the optimization does not make significant perf > reduction. That makes sense that StandaloneMM dispatcher only searches > in MM protocol database and does not depend on UEFI/DXE protocol > database. Also, we don't have many protocols in StandaloneMM like > UEFI/DXE. > > From Laszlo, > > "The patch removes the EFI_DEP_REPLACE_TRUE handling altogether, plus it > CONST-ifies the Iterator pointer (which points into the DEPEX section), > so that the compiler catch any possible accesses at *build time* that > would write to the write-protected DEPEX memory area." > > (1) https://edk2.groups.io/g/devel/message/113531 > > Signed-off-by: Nhi Pham <n...@os.amperecomputing.com> > --- > StandaloneMmPkg/Core/Dependency.c | 37 ++++---------------- > 1 file changed, 7 insertions(+), 30 deletions(-) > > diff --git a/StandaloneMmPkg/Core/Dependency.c > b/StandaloneMmPkg/Core/Dependency.c > index 440fe3e45238..2bcb07d34666 100644 > --- a/StandaloneMmPkg/Core/Dependency.c > +++ b/StandaloneMmPkg/Core/Dependency.c > @@ -13,16 +13,6 @@ > > #include "StandaloneMmCore.h" > > -/// > -/// EFI_DEP_REPLACE_TRUE - Used to dynamically patch the dependency > expression > -/// to save time. A EFI_DEP_PUSH is evaluated one an > -/// replaced with EFI_DEP_REPLACE_TRUE. If PI spec's > Vol 2 > -/// Driver Execution Environment Core Interface use > 0xff > -/// as new DEPEX opcode. EFI_DEP_REPLACE_TRUE should > be > -/// defined to a new value that is not conflicting > with PI spec. > -/// > -#define EFI_DEP_REPLACE_TRUE 0xff > - > /// > /// Define the initial size of the dependency expression evaluation stack > /// > @@ -170,12 +160,12 @@ MmIsSchedulable ( > IN EFI_MM_DRIVER_ENTRY *DriverEntry > ) > { > - EFI_STATUS Status; > - UINT8 *Iterator; > - BOOLEAN Operator; > - BOOLEAN Operator2; > - EFI_GUID DriverGuid; > - VOID *Interface; > + EFI_STATUS Status; > + CONST UINT8 *Iterator; > + BOOLEAN Operator; > + BOOLEAN Operator2; > + EFI_GUID DriverGuid; > + VOID *Interface; > > Operator = FALSE; > Operator2 = FALSE; > @@ -253,8 +243,7 @@ MmIsSchedulable ( > Status = PushBool (FALSE); > } else { > DEBUG ((DEBUG_DISPATCH, " PUSH GUID(%g) = TRUE\n", &DriverGuid)); > - *Iterator = EFI_DEP_REPLACE_TRUE; > - Status = PushBool (TRUE); > + Status = PushBool (TRUE); > } > > if (EFI_ERROR (Status)) { > @@ -356,18 +345,6 @@ MmIsSchedulable ( > DEBUG ((DEBUG_DISPATCH, " RESULT = %a\n", Operator ? "TRUE" : > "FALSE")); > return Operator; > > - case EFI_DEP_REPLACE_TRUE: > - CopyMem (&DriverGuid, Iterator + 1, sizeof (EFI_GUID)); > - DEBUG ((DEBUG_DISPATCH, " PUSH GUID(%g) = TRUE\n", &DriverGuid)); > - Status = PushBool (TRUE); > - if (EFI_ERROR (Status)) { > - DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n")); > - return FALSE; > - } > - > - Iterator += sizeof (EFI_GUID); > - break; > - > default: > DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unknown opcode)\n")); > goto Done;
looks good to me, thanks! (Can't give an R-b or A-b for a patch that was originally written by me, just confirming that the code and commit message look good.) -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#114047): https://edk2.groups.io/g/devel/message/114047 Mute This Topic: https://groups.io/mt/103824815/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/leave/9847357/21656/1706620634/xyzzy [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
