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Make sure that BSS is initialized 

Since the STM is created as a stand-alone set of code, certain
compiler initializations are not included.  This patch ensures
that the BSS area is initialized to zero.  Also, the page tables
are moved to after the STM image

Signed-off-by: Eugene D. Myers <edmyers@tycho.nsa.gov>
This commit is contained in:
Eugene D. Myers 2020-12-09 10:49:31 -05:00
parent 0447a0fb3c
commit 5eda06e2e8
2 changed files with 27 additions and 29 deletions
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27
Stm/StmPkg/Core/Init/StmInit.c
View File

@ -1265,28 +1265,29 @@ LaunchBack (
**/
extern UINT64 _BSS_start, _BSS_end;
extern UINT64 _BSS_start, _BSS_end;
VOID
InitializeSmmMonitor (
IN X86_REGISTER *Register
)
{
UINT32 Index;
UINT64 MSEG;
UINT64 BSS_location;
UINT64 BSS_size;
UINT64 MSEG;
UINT64 BSS_location;
UINT64 BSS_size;
Index = GetIndexFromStack (Register);
if (Index == 0) {
// Initialize the BSS before anyone has a chance to use it
MSEG = (UINT64) AsmReadMsr64(IA32_SMM_MONITOR_CTL_MSR_INDEX) & 0xFFFFF000;
BSS_location = (UINT64) &_BSS_start | (UINT64) MSEG;
BSS_size = (UINT64)&_BSS_end - (UINT64) &_BSS_start;
ZeroMem ((void *)BSS_location, BSS_size);
AsmWbinvd(); // flush caches
// Initialize the BSS before anyone has a chance to use it
MSEG = (UINT64) AsmReadMsr64(IA32_SMM_MONITOR_CTL_MSR_INDEX) & 0xFFFFF000;
BSS_location = (UINT64) &_BSS_start | (UINT64) MSEG;
BSS_size = (UINT64)&_BSS_end - (UINT64) &_BSS_start;
ZeroMem ((void *)BSS_location, BSS_size);
AsmWbinvd(); // flush caches
// The build process should make sure "virtual address" is same as "file pointer to raw data",
// in final PE/COFF image, so that we can let StmLoad load binrary to memory directly.
// If no, GenStm tool will "load image". So here, we just need "relocate image"

29
Stm/StmPkg/Core/Stm.lds
View File

@ -38,8 +38,8 @@ SECTIONS
.StmSpecVerMajor ALIGN(2048) : {BYTE(1)}
.StmSpecVerMinor : {BYTE(0)}
.Reserved : {SHORT(0)}
/* page tables are after the Stm Image */
.StaticImageSize : {LONG( ((_StmImageEnd + 0xFFF) & 0xFFFFF000) )}
/* page tables are after the Stm Image */
.StaticImageSize : {LONG( ((_StmImageEnd + 0xFFF) & 0xFFFFF000) )}
.PerProcDynamicMemorySize : {LONG(SizeOfPerProcessorStack)}
.AdditionalDynamicMemorySize : {LONG(HeapSize + PageTableSize)}
@ -111,7 +111,6 @@ SECTIONS
.Attribute8 : {BYTE(0x93)}
.LimitHi8 : {BYTE(0xCF)}
.BaseHi8 : {BYTE(0)}
.fill3 : { FILL(0x0); . = ALIGN(0x1000);}
.text : {
@ -129,7 +128,7 @@ SECTIONS
*(.data.rel.ro.local)
} =0x0
. = ALIGN(0x20);
. = ALIGN(0x20);
_ElfRelocTablesStart = .;
.reloc : {
@ -137,9 +136,8 @@ SECTIONS
}
_ElfRelocTablesEnd = .;
_StmImageEnd = .;
. = ALIGN(0X1000);
. = ALIGN(0X1000);
.data : {
*(.data.*)
}
@ -150,24 +148,23 @@ SECTIONS
}
. = ALIGN(0x20);
_BSS_start = .;
_BSS_start = .;
.bss : {
*(.bss.*)
*(COMMON)
*(.bss)
*(.bss)
/* dummy */
/* LONG (0x12345678) */
}
_BSS_end = .;
_BSS_end = .;
. = ALIGN(0x20);
.edata : {
}
. = ALIGN(0x20);
}
. = ALIGN(0x20);
_StmImageEnd = .;
_StmImageEnd = .;
. = ALIGN(0x1000);
_StmPageTables = .;
. = . + 24K; /* 6 pages for STM page tables, filled by BIOS and/or SINIT */
. = ALIGN(0x1000);
_StmPageTables = .;
. = . + 24K; /* 6 pages for STM page tables, filled by BIOS and/or SINIT */
}