Messages in this thread | | | Date | Thu, 27 Mar 2008 22:47:49 +0300 | From | Cyrill Gorcunov <> | Subject | processor flags |
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Hi Peter, Ingo
could you spend a few minutes on me? ;)
You know, I'm almost complete changing the vm86 flags with X86_EFLAGS_... but there is a hidden problem lays. Look, in vm86.h we have the definition
#ifdef CONFIG_VM86 #define VM_MASK 0x00020000 #else #define VM_MASK 0 /* ignored */ #endif
which has an indirect conditional compilation effect. For example, if we take a look on include/asm-x86/ptrace.h
static inline int v8086_mode(struct pt_regs *regs) { #ifdef CONFIG_X86_32 return (regs->flags & VM_MASK); #else return 0; /* No V86 mode support in long mode */ #endif }
so if we don't have CONFIG_VM86 defined this function *always* returning 0 so there I can't just change VM_MASK to X86_EFLAGS_VM.
Another piece of code from traps_32.c:do_general_protection
if (regs->flags & VM_MASK) goto gp_in_vm86;
so if we didn't set CONFIG_VM86 i think this part is just thrown out by gcc. So as we see, this VM_MASK original flag is not *just* a flag but also says gcc which part of code to compile.
And now I'm in confusion - the way of changing this code I see is the following:
- or use additional #ifdef CONFIG_VM86 in code where VM_MASK is used (that would be ugly IMHO) - rename VM_MASK to say X86_EFLAGS_VM86 with that #ifdef remained - rest VM_MASK as it is
How do you think?
- Cyrill -
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