From: Willy Tarreau > Sent: 24 October 2021 18:28 > > After re-checking in the spec and comparing stack offsets with glibc, > The last pushed argument must be 16-byte aligned (i.e. aligned before the > call) so that in the callee esp+4 is multiple of 16, so the principle is > the 32-bit equivalent to what Ammar fixed for x86_64. It's possible that > 32-bit code using SSE2 or MMX could have been affected. In addition the > frame pointer ought to be zero at the deepest level. > ... > /* startup code */ > +/* > + * i386 System V ABI mandates: > + * 1) last pushed argument must be 16-byte aligned. > + * 2) The deepest stack frame should be set to zero I'm pretty sure that the historic SYSV i386 ABI only every required 4-byte alignment for the stack. At some point it got 'randomly' changed to 16-byte. I don't think this happened until after compiler support for SSE2 intrinsics was added. ISTR the NetBSD found that it was gcc that moved the goalposts. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
