From: Jan Beulich Date: Fri, 30 Sep 2016 08:01:14 +0000 (+0200) Subject: x86emul: simplify LEAVE handling X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~261 X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=002e3ffb2156a135abbfb57374802922e162c5ae;p=xen.git x86emul: simplify LEAVE handling There's no 1-byte operand size case to take care of here, and there's no point doing the first writeback using dst fields - we can read rBP and write rSP directly. Signed-off-by: Jan Beulich Reviewed-by: Andrew Cooper --- diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c b/xen/arch/x86/x86_emulate/x86_emulate.c index b1b1883613..78b23a0caf 100644 --- a/xen/arch/x86/x86_emulate/x86_emulate.c +++ b/xen/arch/x86/x86_emulate/x86_emulate.c @@ -3171,21 +3171,16 @@ x86_emulate( case 0xc9: /* leave */ /* First writeback, to %%esp. */ - dst.type = OP_REG; dst.bytes = (mode_64bit() && (op_bytes == 4)) ? 8 : op_bytes; - dst.reg = (unsigned long *)&_regs.esp; - dst.val = _regs.ebp; - - /* Flush first writeback, since there is a second. */ switch ( dst.bytes ) { - case 1: *(uint8_t *)dst.reg = (uint8_t)dst.val; break; - case 2: *(uint16_t *)dst.reg = (uint16_t)dst.val; break; - case 4: *dst.reg = (uint32_t)dst.val; break; /* 64b: zero-ext */ - case 8: *dst.reg = dst.val; break; + case 2: *(uint16_t *)&_regs.esp = (uint16_t)_regs.ebp; break; + case 4: _regs.esp = (uint32_t)_regs.ebp; break; /* 64b: zero-ext */ + case 8: _regs.esp = _regs.ebp; break; } /* Second writeback, to %%ebp. */ + dst.type = OP_REG; dst.reg = (unsigned long *)&_regs.ebp; if ( (rc = read_ulong(x86_seg_ss, sp_post_inc(dst.bytes), &dst.val, dst.bytes, ctxt, ops)) )