[PATCH 0/1] MR7905: krnl386: Set carry flag for unimplemented DPMI 0800h call (Physical Address Mapping)
According to the DPMI specification, when DPMI function 0800h (Physical Address Mapping) fails then the carry flag has to be set. For example if the application request for physical memory mapping via the DPMI 0800h call it is required to set carry flag to indicate failure. Otherwise application would be treated as successful operation in which case in BX:CX registers is stored linear address of the mapped memory to which application can access. Obviously on successful path if the BX:CX registers are not set then application would try to access random memory and crashes. SysToolsLib, WinIO or libpci are just few examples of 32-bit Windows libraries which issue this DPMI call via the kernel32.dll VxDCall() function and are expecting either the carry flag on the failure or the valid mapped address in BX:CX registers on success. As the wine does not implement this DPMI function, always sets the carry flag. Windows NTVDM DPMI host does not implement the DPMI function 0800h too and also always sets the carry flag. Tested and verified with a very simple gcc/djgpp application on Windows NT. So this also change aligns the wine behavior with the Windows NT. -- https://gitlab.winehq.org/wine/wine/-/merge_requests/7905
From: Pali Rohár <pali(a)kernel.org> According to the DPMI specification, when DPMI function 0800h (Physical Address Mapping) fails then the carry flag has to be set. For example if the application request for physical memory mapping via the DPMI 0800h call it is required to set carry flag to indicate failure. Otherwise application would be treated as successful operation in which case in BX:CX registers is stored linear address of the mapped memory to which application can access. Obviously on successful path if the BX:CX registers are not set then application would try to access random memory and crashes. SysToolsLib, WinIO or libpci are just few examples of 32-bit Windows libraries which issue this DPMI call via the kernel32.dll VxDCall() function and are expecting either the carry flag on the failure or the valid mapped address in BX:CX registers on success. As the wine does not implement this DPMI function, always sets the carry flag. Windows NTVDM DPMI host does not implement the DPMI function 0800h too and also always sets the carry flag. Tested and verified with a very simple gcc/djgpp application on Windows NT. So this also change aligns the wine behavior with the Windows NT. Signed-off-by: Pali Rohár <pali(a)kernel.org> --- dlls/krnl386.exe16/int31.c | 1 + 1 file changed, 1 insertion(+) diff --git a/dlls/krnl386.exe16/int31.c b/dlls/krnl386.exe16/int31.c index 0d13763451c..ac79f0f0624 100644 --- a/dlls/krnl386.exe16/int31.c +++ b/dlls/krnl386.exe16/int31.c @@ -625,6 +625,7 @@ void WINAPI DOSVM_Int31Handler( CONTEXT *context ) case 0x0800: /* Physical address mapping */ FIXME( "physical address mapping (0x%08lx) - unimplemented\n", MAKELONG(CX_reg(context),BX_reg(context)) ); + SET_CFLAG( context ); break; case 0x0900: /* Get and Disable Virtual Interrupt State */ -- GitLab https://gitlab.winehq.org/wine/wine/-/merge_requests/7905
This merge request was approved by Alex Henrie. -- https://gitlab.winehq.org/wine/wine/-/merge_requests/7905
participants (2)
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Alex Henrie (＠alexhenrie) -
Pali Rohár