Re: [edk2-devel] [PATCH v4 2/6] UefiCpuPkg/CpuExceptionHandlerLib: Use single SEC/PEI version
Reviewed-by: Ray Ni
> -Original Message-
> From: Ard Biesheuvel
> Sent: Monday, April 3, 2023 10:29 PM
> To: devel@edk2.groups.io
> Cc: Ard Biesheuvel ; Ni, Ray ; Andrew
> Fish ; Kinney, Michael D ;
> Liu, Zhiguang ; Rebecca Cran
> ; Tom Lendacky ;
> Marvin Häuser
> Subject: [PATCH v4 2/6] UefiCpuPkg/CpuExceptionHandlerLib: Use single
> SEC/PEI version
>
> Currently, we use the non-Xcode5 version of ExceptionHandlerAsm.nasm
> only for the SEC and PEI phases, and this version was not compatible
> with the XCODE or LLD linkers, which do not permit absolute relocations
> in read-only sections.
>
> Given that SEC and PEI code typically executes in place from flash and
> does not use page alignment for sections, we can simply emit the code
> carrying the absolute symbol references into the .data segment instead.
> This works around the linker's objections, and the resulting image will
> be mapped executable in its entirety anyway. Since this is only needed
> for XCODE, let's make this change conditionally using a preprocessor
> macro.
>
> Let's rename the .nasm file to reflect the fact that is used for the
> SecPei flavor of this library only, and while at it, remove some
> unnecessary absolute references.
>
> Also update the Xcode specific version of this library, and use this
> source file instead. This is necesessary, as the Xcode specific version
> modifies its own code at runtime, which is not permitted in SEC or PEI.
> Note that this also removes CET support from the Xcode5 specific build
> of the SEC/PEI version of this library, but this is not needed this
> early in any case, and this aligns it with other toolchains, which use
> this version of the library, which does not have CET support either.
>
> 1. Change for non-XCODE SecPeiCpuExceptionHandlerLib:
> . Use SecPeiExceptionHandlerAsm.nasm (renamed from
> ExceptionHandlerAsm.nasm)
> . Removed some unnecessary absolute references
> (32 IDT stubs are still in .text.)
>
> 2. Change for XCODE SecPeiCpuExceptionHandlerLib:
> . Use SecPeiExceptionHandlerAsm.nasm instead of
> Xcode5ExceptionHandlerAsm.nasm
> . CET logic is not in SecPeiExceptionHandlerAsm.nasm (but aligns to
> non-XCODE lib instance)
> . Fixed a bug that does runtime fixup in TEXT section in SPI flash.
> . Emitted the code carrying the absolute symbol references into the
> .data which XCODE or LLD linkers allow.
> . Then fixup can be done by other build tools such as GenFv if the code
> runs in SPI flash, or by PE coff loader if the code is loaded to
> memory.
>
> Signed-off-by: Ard Biesheuvel
> ---
>
> UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib
> .inf | 4 +++-
>
> UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/{ExceptionHandlerAsm.na
> sm => SecPeiExceptionHandlerAsm.nasm} | 12
>
> UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHa
> ndlerLib.inf | 4 +++-
> 3 files changed, 14 insertions(+), 6 deletions(-)
>
> diff --git
> a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandler
> Lib.inf
> b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandler
> Lib.inf
> index df44371fe018e06d..e7b1144f694183b7 100644
> ---
> a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandler
> Lib.inf
> +++
> b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandler
> Lib.inf
> @@ -28,7 +28,7 @@ [Sources.Ia32]
>Ia32/ArchInterruptDefs.h
>
>
>
> [Sources.X64]
>
> - X64/ExceptionHandlerAsm.nasm
>
> + X64/SecPeiExceptionHandlerAsm.nasm
>
>X64/ArchExceptionHandler.c
>
>X64/ArchInterruptDefs.h
>
>
>
> @@ -58,3 +58,5 @@ [Pcd]
> [FeaturePcd]
>
>gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmStackGuard##
> CONSUMES
>
>
>
> +[BuildOptions]
>
> + XCODE:*_*_X64_NASM_FLAGS = -D NO_ABSOLUTE_RELOCS_IN_TEXT
>
> diff --git
> a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.n
> asm
> b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/SecPeiExceptionHandler
> Asm.nasm
> similarity index 94%
> rename from
> UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nas
> m
> rename to
> UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/SecPeiExceptionHandlerA
> sm.nasm
> index aaf8d622e6f3b8f1..5c7a59c99d3210f1 100644
> ---
> a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.n
> asm
> +++
> b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/SecPeiExceptionHandler
> Asm.nasm
> @@ -27,7 +27,9 @@ extern ASM_PFX(CommonExceptionHandler)
> SECTION .data
>
>
>
> DEFAULT REL
>
> +%ifndef NO_ABSOLUTE_RELOCS_IN_TEXT
>
> SECTION .text
>
> +%endif
>
>
>
> ALIGN 8
>
>
>
> @@ -51,6 +53,9 @@ HookAfterStubHeaderBegin:
> pushrax
>
> mov rax, HookAfterStubHeaderEnd
>
> jmp rax
>
> +
>
> +SECTION .text
>
> +
>
> HookAfterStubHeaderEnd:
>
> mov rax, rsp
>
> and sp, 0xfff0; make sure 16-byte
[edk2-devel] [PATCH v4 2/6] UefiCpuPkg/CpuExceptionHandlerLib: Use single SEC/PEI version
Currently, we use the non-Xcode5 version of ExceptionHandlerAsm.nasm
only for the SEC and PEI phases, and this version was not compatible
with the XCODE or LLD linkers, which do not permit absolute relocations
in read-only sections.
Given that SEC and PEI code typically executes in place from flash and
does not use page alignment for sections, we can simply emit the code
carrying the absolute symbol references into the .data segment instead.
This works around the linker's objections, and the resulting image will
be mapped executable in its entirety anyway. Since this is only needed
for XCODE, let's make this change conditionally using a preprocessor
macro.
Let's rename the .nasm file to reflect the fact that is used for the
SecPei flavor of this library only, and while at it, remove some
unnecessary absolute references.
Also update the Xcode specific version of this library, and use this
source file instead. This is necesessary, as the Xcode specific version
modifies its own code at runtime, which is not permitted in SEC or PEI.
Note that this also removes CET support from the Xcode5 specific build
of the SEC/PEI version of this library, but this is not needed this
early in any case, and this aligns it with other toolchains, which use
this version of the library, which does not have CET support either.
1. Change for non-XCODE SecPeiCpuExceptionHandlerLib:
. Use SecPeiExceptionHandlerAsm.nasm (renamed from
ExceptionHandlerAsm.nasm)
. Removed some unnecessary absolute references
(32 IDT stubs are still in .text.)
2. Change for XCODE SecPeiCpuExceptionHandlerLib:
. Use SecPeiExceptionHandlerAsm.nasm instead of
Xcode5ExceptionHandlerAsm.nasm
. CET logic is not in SecPeiExceptionHandlerAsm.nasm (but aligns to
non-XCODE lib instance)
. Fixed a bug that does runtime fixup in TEXT section in SPI flash.
. Emitted the code carrying the absolute symbol references into the
.data which XCODE or LLD linkers allow.
. Then fixup can be done by other build tools such as GenFv if the code
runs in SPI flash, or by PE coff loader if the code is loaded to
memory.
Signed-off-by: Ard Biesheuvel
---
UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf
| 4 +++-
UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/{ExceptionHandlerAsm.nasm =>
SecPeiExceptionHandlerAsm.nasm} | 12
UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHandlerLib.inf
| 4 +++-
3 files changed, 14 insertions(+), 6 deletions(-)
diff --git
a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf
b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf
index df44371fe018e06d..e7b1144f694183b7 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf
@@ -28,7 +28,7 @@ [Sources.Ia32]
Ia32/ArchInterruptDefs.h
[Sources.X64]
- X64/ExceptionHandlerAsm.nasm
+ X64/SecPeiExceptionHandlerAsm.nasm
X64/ArchExceptionHandler.c
X64/ArchInterruptDefs.h
@@ -58,3 +58,5 @@ [Pcd]
[FeaturePcd]
gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmStackGuard## CONSUMES
+[BuildOptions]
+ XCODE:*_*_X64_NASM_FLAGS = -D NO_ABSOLUTE_RELOCS_IN_TEXT
diff --git
a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm
b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/SecPeiExceptionHandlerAsm.nasm
similarity index 94%
rename from
UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm
rename to
UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/SecPeiExceptionHandlerAsm.nasm
index aaf8d622e6f3b8f1..5c7a59c99d3210f1 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm
+++
b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/SecPeiExceptionHandlerAsm.nasm
@@ -27,7 +27,9 @@ extern ASM_PFX(CommonExceptionHandler)
SECTION .data
DEFAULT REL
+%ifndef NO_ABSOLUTE_RELOCS_IN_TEXT
SECTION .text
+%endif
ALIGN 8
@@ -51,6 +53,9 @@ HookAfterStubHeaderBegin:
pushrax
mov rax, HookAfterStubHeaderEnd
jmp rax
+
+SECTION .text
+
HookAfterStubHeaderEnd:
mov rax, rsp
and sp, 0xfff0; make sure 16-byte aligned for exception
context
@@ -276,8 +281,7 @@ DrFinish:
; and make sure RSP is 16-byte aligned
;
sub rsp, 4 * 8 + 8
-mov rax, ASM_PFX(CommonExceptionHandler)
-callrax
+callASM_PFX(CommonExceptionHandler)
add rsp, 4 * 8 + 8
cli
@@ -384,10 +388,10 @@ DoIret:
; comments here for definition of address map
global ASM_PFX(AsmGetTemplateAddressMap)
ASM_PFX(AsmGetTemplateAddressMap):
-mov rax, AsmIdtVectorBegin
+lea rax, [AsmIdtVectorBegin]
mov qword [rcx], rax
mov qword [rcx + 0x8], (AsmIdtVectorEnd - AsmIdtVectorBegin) / 32
-mov rax, HookAfterStubHeaderBegin
+lea rax, [HookAfterStubH
