On 09/26/18 11:34, Ni, Ruiyu wrote: > On 9/26/2018 5:05 PM, Laszlo Ersek wrote: >> Hi, >> >> On 09/25/18 21:48, Laszlo Ersek wrote: >>> Currently, "gcc-4.8.5-28.el7_5.1.x86_64" generates the following code >>> for >>> me, from the XADD inline assembly added to "X64/GccInline.c" in commit >>> 17634d026f96: >>> >>>> 0000000000004383 <InternalSyncIncrement>: >>>> UINT32 >>>> EFIAPI >>>> InternalSyncIncrement ( >>>> IN volatile UINT32 *Value >>>> ) >>>> { >>>> 4383: 55 push %rbp >>>> 4384: 48 89 e5 mov %rsp,%rbp >>>> 4387: 48 83 ec 10 sub $0x10,%rsp >>>> 438b: 48 89 4d 10 mov %rcx,0x10(%rbp) >>>> UINT32 Result; >>>> >>>> __asm__ __volatile__ ( >>>> 438f: 48 8b 55 10 mov 0x10(%rbp),%rdx >>>> 4393: 48 8b 45 10 mov 0x10(%rbp),%rax >>>> 4397: b8 01 00 00 00 mov $0x1,%eax >>>> 439c: f0 0f c1 00 lock xadd %eax,(%rax) >>>> 43a0: ff c0 inc %eax >>>> 43a2: 89 45 fc mov %eax,-0x4(%rbp) >>>> : "m" (*Value) // %2 >>>> : "memory", >>>> "cc" >>>> ); >>>> >>>> return Result; >>>> 43a5: 8b 45 fc mov -0x4(%rbp),%eax >>>> } >>>> 43a8: c9 leaveq >>>> 43a9: c3 retq >>>> >>> >>> The MOV $0X1,%EAX instruction corrupts the address of Value in %RAX >>> before >>> we reach the XADD instruction. In fact, it makes no sense for XADD to >>> use >>> %EAX as source operand and (%RAX) as destination operand at the same >>> time. >> >> may I get a fast review for this patch, please? The regression from >> commit 17634d026f96 prevents OVMF from booting. > > Sure. Reviewed-by: Ruiyu Ni <ruiyu...@intel.com>
Thanks, Ray! Commit 8a94eb9283fa. Laszlo _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel