Messages in this thread | | | From | David Laight <> | Subject | RE: [PATCH v3 3/6] x86/gsseg: make asm_load_gs_index() take an u16 | Date | Fri, 14 Oct 2022 12:28:25 +0000 |
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From: Xin Li > Sent: 13 October 2022 21:02 > > From: "H. Peter Anvin (Intel)" <hpa@zytor.com> > > Let gcc know that only the low 16 bits of load_gs_index() argument > actually matter. It might allow it to create slightly better > code. However, do not propagate this into the prototypes of functions > that end up being paravirtualized, to avoid unnecessary changes.
Using u16 will almost always make the code worse. At some point the value has to be masked and/or extended to ensure an out of range value doesn't appear in a register.
David
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