> On Oct 31, 2014, at 12:38 PM, Jordan Justen <[email protected]> wrote: > > Andrew, > > Back in February 2011, you added this assembly file to (apparently) > work around a gdb bug. Do you think it is still required? (Did the bug > get fixed?) >
It is not a bug. It is how the stack unwind logic works in gdb/lldb. For clang the default is to emit frame pointers, so this means you can always walk the stack frame. So for example an exception handler lib can print the stack trace for the exception. > It seems like we ought to be able to use C here, and, in my opinion, > less assembly is generally better than more. :) > It is probably possible to adjust the stack frame in the C code to be compatible. Thanks, Andrew Fish > Thanks, > > -Jordan > > On Mon, Jul 11, 2011 at 8:01 PM, <[email protected]> wrote: >> Revision: 12007 >> http://edk2.svn.sourceforge.net/edk2/?rev=12007&view=rev >> Author: andrewfish >> Date: 2011-07-12 03:01:34 +0000 (Tue, 12 Jul 2011) >> >> Log Message: >> ----------- >> MdePkg: Fix X64 clang compile issues. >> >> Fixed issues with X64 clang, and also make StackSwitch push a zero on the >> new stack to prevent a stack unwind into memory that is no longer valid. >> >> signed-off-by: andrewfish >> reviewed-by: lgao4 >> reviewed-by: mdkinney >> >> Modified Paths: >> -------------- >> trunk/edk2/MdePkg/Library/BaseLib/BaseLib.inf >> trunk/edk2/MdePkg/Library/BaseLib/X64/SwitchStack.S >> trunk/edk2/MdePkg/Library/BaseLib/X64/Thunk16.S >> trunk/edk2/MdePkg/Library/BasePeCoffLib/BasePeCoff.c >> >> Added Paths: >> ----------- >> trunk/edk2/MdePkg/Library/BaseLib/Ia32/InternalSwitchStack.S >> >> Modified: trunk/edk2/MdePkg/Library/BaseLib/BaseLib.inf >> =================================================================== >> --- trunk/edk2/MdePkg/Library/BaseLib/BaseLib.inf 2011-07-12 02:57:30 >> UTC (rev 12006) >> +++ trunk/edk2/MdePkg/Library/BaseLib/BaseLib.inf 2011-07-12 03:01:34 >> UTC (rev 12007) >> @@ -277,7 +277,9 @@ >> Ia32/DisableCache.S | GCC >> >> Ia32/DivS64x64Remainder.c >> - Ia32/InternalSwitchStack.c >> + Ia32/InternalSwitchStack.c | MSFT >> + Ia32/InternalSwitchStack.c | INTEL >> + Ia32/InternalSwitchStack.S | GCC >> Ia32/Non-existing.c >> Unaligned.c >> X86WriteIdtr.c >> >> Added: trunk/edk2/MdePkg/Library/BaseLib/Ia32/InternalSwitchStack.S >> =================================================================== >> --- trunk/edk2/MdePkg/Library/BaseLib/Ia32/InternalSwitchStack.S >> (rev 0) >> +++ trunk/edk2/MdePkg/Library/BaseLib/Ia32/InternalSwitchStack.S >> 2011-07-12 03:01:34 UTC (rev 12007) >> @@ -0,0 +1,48 @@ >> +#------------------------------------------------------------------------------ >> +# >> +# Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR> >> +# Portions copyright (c) 2011, Apple Inc. All rights reserved. >> +# This program and the accompanying materials >> +# are licensed and made available under the terms and conditions of the BSD >> License >> +# which accompanies this distribution. The full text of the license may be >> found at >> +# http://opensource.org/licenses/bsd-license.php. >> +# >> +# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, >> +# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR >> IMPLIED. >> +# >> +# Module Name: >> +# >> +# InternalSwitchStack.S >> +# >> +# Abstract: >> +# >> +# Implementation of a stack switch on IA-32. >> +# >> +#------------------------------------------------------------------------------ >> + >> +ASM_GLOBAL ASM_PFX(InternalSwitchStack) >> + >> +#------------------------------------------------------------------------------ >> +# VOID >> +# EFIAPI >> +# InternalSwitchStack ( >> +# IN SWITCH_STACK_ENTRY_POINT EntryPoint, >> +# IN VOID *Context1, OPTIONAL >> +# IN VOID *Context2, OPTIONAL >> +# IN VOID *NewStack >> +# ); >> +#------------------------------------------------------------------------------ >> +ASM_PFX(InternalSwitchStack): >> + pushl %ebp >> + movl %esp, %ebp >> + >> + movl 20(%ebp), %esp # switch stack >> + subl $8, %esp >> + >> + movl 16(%ebp), %eax >> + movl %eax, 4(%esp) >> + movl 12(%ebp), %eax >> + movl %eax, (%esp) >> + pushl $0 # keeps gdb from unwinding stack >> + jmp *8(%ebp) # call and never return >> + >> >> Modified: trunk/edk2/MdePkg/Library/BaseLib/X64/SwitchStack.S >> =================================================================== >> --- trunk/edk2/MdePkg/Library/BaseLib/X64/SwitchStack.S 2011-07-12 02:57:30 >> UTC (rev 12006) >> +++ trunk/edk2/MdePkg/Library/BaseLib/X64/SwitchStack.S 2011-07-12 03:01:34 >> UTC (rev 12007) >> @@ -37,7 +37,10 @@ >> #------------------------------------------------------------------------------ >> ASM_GLOBAL ASM_PFX(InternalSwitchStack) >> ASM_PFX(InternalSwitchStack): >> - mov %rcx, %rax >> + pushq %rbp >> + movq %rsp, %rbp >> + >> + mov %rcx, %rax // Shift registers for new call >> mov %rdx, %rcx >> mov %r8, %rdx >> # >> @@ -45,4 +48,5 @@ >> # in case the callee wishes to spill them. >> # >> lea -0x20(%r9), %rsp >> - call *%rax >> + pushq $0 // stop gdb stack unwind >> + jmp *%rax // call EntryPoint () >> >> Modified: trunk/edk2/MdePkg/Library/BaseLib/X64/Thunk16.S >> =================================================================== >> --- trunk/edk2/MdePkg/Library/BaseLib/X64/Thunk16.S 2011-07-12 02:57:30 >> UTC (rev 12006) >> +++ trunk/edk2/MdePkg/Library/BaseLib/X64/Thunk16.S 2011-07-12 03:01:34 >> UTC (rev 12007) >> @@ -49,13 +49,18 @@ >> .set IA32_REGS_SIZE, 56 >> >> .data >> + >> +.set Lm16Size, ASM_PFX(InternalAsmThunk16) - ASM_PFX(m16Start) >> +ASM_PFX(m16Size): .word Lm16Size >> +.set LmThunk16Attr, L_ThunkAttr - ASM_PFX(m16Start) >> +ASM_PFX(mThunk16Attr): .word LmThunk16Attr >> +.set Lm16Gdt, ASM_PFX(NullSeg) - ASM_PFX(m16Start) >> +ASM_PFX(m16Gdt): .word Lm16Gdt >> +.set Lm16GdtrBase, _16GdtrBase - ASM_PFX(m16Start) >> +ASM_PFX(m16GdtrBase): .word Lm16GdtrBase >> +.set LmTransition, _EntryPoint - ASM_PFX(m16Start) >> +ASM_PFX(mTransition): .word LmTransition >> >> -ASM_PFX(m16Size): .word ASM_PFX(InternalAsmThunk16) - >> ASM_PFX(m16Start) >> -ASM_PFX(mThunk16Attr): .word _ThunkAttr - ASM_PFX(m16Start) >> -ASM_PFX(m16Gdt): .word ASM_PFX(NullSeg) - ASM_PFX(m16Start) >> -ASM_PFX(m16GdtrBase): .word _16GdtrBase - ASM_PFX(m16Start) >> -ASM_PFX(mTransition): .word _EntryPoint - ASM_PFX(m16Start) >> - >> .text >> >> ASM_PFX(m16Start): >> @@ -91,7 +96,7 @@ >> .byte 0x1e # push ds >> .byte 0x66,0x60 # pushad >> .byte 0x66,0xba # mov edx, imm32 >> -_ThunkAttr: .space 4 >> +L_ThunkAttr: .space 4 >> testb $THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15, %dl >> jz L_1 >> movl $0x15cd2401,%eax # mov ax, 2401h & int 15h >> @@ -120,7 +125,7 @@ >> .byte 0x66,0x2e,0x89,0x87 # mov cs:[bx + (L_64Eip - L_Base)], >> eax >> .word L_64Eip - L_Base >> .byte 0x66,0xb8 # mov eax, imm32 >> -SavedCr4: .space 4 >> +L_SavedCr4: .long 0 >> movq %rax, %cr4 >> # >> # rdi in the instruction below is indeed bx in 16-bit code >> @@ -133,15 +138,15 @@ >> orb $1,%ah >> wrmsr >> .byte 0x66,0xb8 # mov eax, imm32 >> -SavedCr0: .space 4 >> +L_SavedCr0: .long >> movq %rax, %cr0 >> .byte 0x66,0xea # jmp far cs:L_64Bit >> -L_64Eip: .space 4 >> -SavedCs: .space 2 >> +L_64Eip: .long 0 >> +L_SavedCs: .space 2 >> L_64BitCode: >> .byte 0x90 >> .byte 0x67,0xbc # mov esp, imm32 >> -SavedSp: .space 4 # restore stack >> +L_SavedSp: .long # restore stack >> nop >> ret >> >> @@ -258,19 +263,20 @@ >> popq %rcx >> rep >> movsl # copy RegSet >> - lea (SavedCr4 - ASM_PFX(m16Start))(%rdx), %ecx >> + lea (L_SavedCr4 - ASM_PFX(m16Start))(%rdx), %ecx >> movl %edx,%eax # eax <- transition code address >> andl $0xf,%edx >> shll $12,%eax # segment address in high order 16 >> bits >> - lea (ASM_PFX(BackFromUserCode) - ASM_PFX(m16Start))(%rdx), %ax >> + .set LBackFromUserCodeDelta, ASM_PFX(BackFromUserCode) - >> ASM_PFX(m16Start) >> + lea (LBackFromUserCodeDelta)(%rdx), %ax >> stosl # [edi] <- return address of user >> code >> sgdt 0x60(%rsp) # save GDT stack in argument space >> movzwq 0x60(%rsp), %r10 # r10 <- GDT limit >> - lea ((ASM_PFX(InternalAsmThunk16) - SavedCr4) + 0xf)(%rcx), %r11 >> + lea ((ASM_PFX(InternalAsmThunk16) - L_SavedCr4) + 0xf)(%rcx), %r11 >> andq $0xfffffffffffffff0, %r11 # r11 <- 16-byte aligned shadowed >> GDT table in real mode buffer >> >> - movw %r10w, (SavedGdt - SavedCr4)(%rcx) # save the limit of >> shadowed GDT table >> - movq %r11, (SavedGdt - SavedCr4 + 0x2)(%rcx) # save the base >> address of shadowed GDT table >> + movw %r10w, (SavedGdt - L_SavedCr4)(%rcx) # save the limit of >> shadowed GDT table >> + movq %r11, (SavedGdt - L_SavedCr4 + 0x2)(%rcx) # save the base >> address of shadowed GDT table >> >> movq 0x62(%rsp) ,%rsi # rsi <- the original GDT base >> address >> xchg %r10, %rcx # save rcx to r10 and initialize rcx >> to be the limit of GDT table >> @@ -283,7 +289,8 @@ >> >> sidt 0x50(%rsp) >> movq %cr0, %rax >> - movl %eax, (SavedCr0 - SavedCr4)(%rcx) >> + .set LSavedCrDelta, L_SavedCr0 - L_SavedCr4 >> + movl %eax, (LSavedCrDelta)(%rcx) >> andl $0x7ffffffe,%eax # clear PE, PG bits >> movq %cr4, %rbp >> movl %ebp, (%rcx) # save CR4 in SavedCr4 >> @@ -291,17 +298,18 @@ >> movl %r8d, %esi # esi <- 16-bit stack segment >> .byte 0x6a, DATA32 >> popq %rdx >> - lgdt (_16Gdtr - SavedCr4)(%rcx) >> + lgdt (_16Gdtr - L_SavedCr4)(%rcx) >> movl %edx,%ss >> pushfq >> lea -8(%rdx), %edx >> lea L_RetFromRealMode(%rip), %r8 >> pushq %r8 >> movl %cs, %r8d >> - movw %r8w, (SavedCs - SavedCr4)(%rcx) >> - movl %esp, (SavedSp - SavedCr4)(%rcx) >> - .byte 0xff, 0x69 # jmp (_EntryPoint - >> SavedCr4)(%rcx) >> - .byte _EntryPoint - SavedCr4 >> + movw %r8w, (L_SavedCs - L_SavedCr4)(%rcx) >> + movl %esp, (L_SavedSp - L_SavedCr4)(%rcx) >> + .byte 0xff, 0x69 # jmp (_EntryPoint - >> L_SavedCr4)(%rcx) >> + .set Ltemp1, _EntryPoint - L_SavedCr4 >> + .byte Ltemp1 >> L_RetFromRealMode: >> popfq >> lgdt 0x60(%rsp) # restore protected mode GDTR >> >> Modified: trunk/edk2/MdePkg/Library/BasePeCoffLib/BasePeCoff.c >> =================================================================== >> --- trunk/edk2/MdePkg/Library/BasePeCoffLib/BasePeCoff.c 2011-07-12 >> 02:57:30 UTC (rev 12006) >> +++ trunk/edk2/MdePkg/Library/BasePeCoffLib/BasePeCoff.c 2011-07-12 >> 03:01:34 UTC (rev 12007) >> @@ -829,6 +829,7 @@ >> EFI_IMAGE_RESOURCE_DIRECTORY_ENTRY *ResourceDirectoryEntry; >> EFI_IMAGE_RESOURCE_DIRECTORY_STRING *ResourceDirectoryString; >> EFI_IMAGE_RESOURCE_DATA_ENTRY *ResourceDataEntry; >> + CHAR16 *String; >> >> >> ASSERT (ImageContext != NULL); >> @@ -1209,11 +1210,12 @@ >> for (Index = 0; Index < ResourceDirectory->NumberOfNamedEntries; >> Index++) { >> if (ResourceDirectoryEntry->u1.s.NameIsString) { >> ResourceDirectoryString = (EFI_IMAGE_RESOURCE_DIRECTORY_STRING >> *) (Base + ResourceDirectoryEntry->u1.s.NameOffset); >> + String = &ResourceDirectoryString->String[0]; >> >> if (ResourceDirectoryString->Length == 3 && >> - ResourceDirectoryString->String[0] == L'H' && >> - ResourceDirectoryString->String[1] == L'I' && >> - ResourceDirectoryString->String[2] == L'I') { >> + String[0] == L'H' && >> + String[1] == L'I' && >> + String[2] == L'I') { >> // >> // Resource Type "HII" found >> // >> >> >> This was sent by the SourceForge.net collaborative development platform, the >> world's largest Open Source development site. >> >> ------------------------------------------------------------------------------ >> All of the data generated in your IT infrastructure is seriously valuable. >> Why? It contains a definitive record of application performance, security >> threats, fraudulent activity, and more. Splunk takes this data and makes >> sense of it. IT sense. And common sense. >> http://p.sf.net/sfu/splunk-d2d-c2 >> _______________________________________________ >> edk2-commits mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/edk2-commits ------------------------------------------------------------------------------ _______________________________________________ edk2-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/edk2-devel
