diff options
Diffstat (limited to 'include/asm-x86/lguest_hcall.h')
| -rw-r--r-- | include/asm-x86/lguest_hcall.h | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/include/asm-x86/lguest_hcall.h b/include/asm-x86/lguest_hcall.h index f948491eb56..9c5092b6aa9 100644 --- a/include/asm-x86/lguest_hcall.h +++ b/include/asm-x86/lguest_hcall.h @@ -18,12 +18,17 @@ #define LHCALL_LOAD_TLS 16 #define LHCALL_NOTIFY 17 +#define LGUEST_TRAP_ENTRY 0x1F + +#ifndef __ASSEMBLY__ +#include <asm/hw_irq.h> + /*G:031 First, how does our Guest contact the Host to ask for privileged * operations? There are two ways: the direct way is to make a "hypercall", * to make requests of the Host Itself. * * Our hypercall mechanism uses the highest unused trap code (traps 32 and - * above are used by real hardware interrupts). Seventeen hypercalls are + * above are used by real hardware interrupts). Fifteen hypercalls are * available: the hypercall number is put in the %eax register, and the * arguments (when required) are placed in %edx, %ebx and %ecx. If a return * value makes sense, it's returned in %eax. @@ -31,20 +36,15 @@ * Grossly invalid calls result in Sudden Death at the hands of the vengeful * Host, rather than returning failure. This reflects Winston Churchill's * definition of a gentleman: "someone who is only rude intentionally". */ -#define LGUEST_TRAP_ENTRY 0x1F - -#ifndef __ASSEMBLY__ -#include <asm/hw_irq.h> - static inline unsigned long hcall(unsigned long call, unsigned long arg1, unsigned long arg2, unsigned long arg3) { /* "int" is the Intel instruction to trigger a trap. */ asm volatile("int $" __stringify(LGUEST_TRAP_ENTRY) - /* The call is in %eax (aka "a"), and can be replaced */ + /* The call in %eax (aka "a") might be overwritten */ : "=a"(call) - /* The other arguments are in %eax, %edx, %ebx & %ecx */ + /* The arguments are in %eax, %edx, %ebx & %ecx */ : "a"(call), "d"(arg1), "b"(arg2), "c"(arg3) /* "memory" means this might write somewhere in memory. * This isn't true for all calls, but it's safe to tell |