[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [Patch 1/3 v2] x86/irq: local_irq_restore() should not blindly popf
local_irq_restore() should only be concerned with possibly changing the interrupt flag. A blind popf could corrupt other system flags. While playing in this area, fixup an opencoded use of X86_EFLAGS_IF. Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> CC: Keir Fraser <keir@xxxxxxx> CC: Jan Beulich <JBeulich@xxxxxxxx> --- This is rather more RFC. It boots and runs VMs, so I am fairly sure it is functionally correct, but I cant help feeling there might be a neater way to do the inline assembly. Suggestions welcome. --- xen/include/asm-x86/system.h | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/xen/include/asm-x86/system.h b/xen/include/asm-x86/system.h index 6ab7d56..ff52671 100644 --- a/xen/include/asm-x86/system.h +++ b/xen/include/asm-x86/system.h @@ -3,6 +3,7 @@ #include <xen/lib.h> #include <xen/bitops.h> +#include <asm/processor.h> #define read_segment_register(name) \ ({ u16 __sel; \ @@ -159,15 +160,19 @@ static always_inline unsigned long __cmpxchg( #define local_irq_restore(x) \ ({ \ BUILD_BUG_ON(sizeof(x) != sizeof(long)); \ - asm volatile ( "push" __OS " %0 ; popf" __OS \ - : : "g" (x) : "memory", "cc" ); \ + asm volatile ( \ + "pushf" __OS "\n\t" \ + "and" __OS " %0, (%%" __OP "sp)\n\t" \ + "orw %1, (%%" __OP "sp)\n\t" \ + "popf" __OS "\n\t" : : "g" ( ~X86_EFLAGS_IF ), \ + "g" ( x & X86_EFLAGS_IF ) ); \ }) static inline int local_irq_is_enabled(void) { unsigned long flags; local_save_flags(flags); - return !!(flags & (1<<9)); /* EFLAGS_IF */ + return !!(flags & X86_EFLAGS_IF); } #define BROKEN_ACPI_Sx 0x0001 -- 1.7.10.4 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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