Commit 885e78d7 authored by Uros Bizjak's avatar Uros Bizjak Committed by Wei Liu
Browse files

x86/hyperv: Remove ASM_CALL_CONSTRAINT with VMMCALL insn 



Unlike CALL instruction, VMMCALL does not push to the stack, so it's
OK to allow the compiler to insert it before the frame pointer gets
set up by the containing function. ASM_CALL_CONSTRAINT is for CALLs
that must be inserted after the frame pointer is set up, so it is
over-constraining here and can be removed.

Signed-off-by: default avatarUros Bizjak <ubizjak@gmail.com>
Tested-by: default avatarMichael Kelley <mhklinux@outlook.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent 834ef6aa

arch/x86/hyperv/ivm.c

+1 −1
Original line number Diff line number Diff line
@@ -392,7 +392,7 @@ u64 hv_snp_hypercall(u64 control, u64 param1, u64 param2) 


	register u64 __r8 asm("r8") = param2;

	asm volatile("vmmcall"

		     : "=a" (hv_status), ASM_CALL_CONSTRAINT,

		     : "=a" (hv_status),

		       "+c" (control), "+d" (param1), "+r" (__r8)

		     : : "cc", "memory", "r9", "r10", "r11");