On 7/26/22 19:32, Sean Christopherson wrote:
On Tue, Jul 26, 2022, Paolo Bonzini wrote:
The "BIT" macro cannot be used in top-level assembly statements
(it can be used in functions through the "i" constraint). To
avoid having to hard-code EFLAGS.AC being bit 18, define the
constants for CR0, CR4 and EFLAGS bits in terms of new macros
for just the bit number.
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
...
diff --git a/x86/smap.c b/x86/smap.c
index 0994c29..3f63ee1 100644
--- a/x86/smap.c
+++ b/x86/smap.c
@@ -39,7 +39,7 @@ asm ("pf_tss:\n"
#endif
"add $"S", %"R "sp\n"
#ifdef __x86_64__
- "orl $" xstr(X86_EFLAGS_AC) ", 2*"S"(%"R "sp)\n" // set EFLAGS.AC and retry
I don't understand, this compiles cleanly on both gcc and clang, and generates the
correct code. What am I missing?
I saw a failure on older binutils where 1UL is not accepted by the
assembler.
An alternative is to have some kind of __ASSEMBLY__ symbol as in Linux.
Paolo
