Linus Torvalds 577e6a7fd5 x86: inline the 'rep movs' in user copies for the FSRM case ... This does the same thing for the user copies as commit 0db7058e8e ("x86/clear_user: Make it faster") did for clear_user(). In other words, it inlines the "rep movs" case when X86_FEATURE_FSRM is set, avoiding the function call entirely. In order to do that, it makes the calling convention for the out-of-line case ("copy_user_generic_unrolled") match the 'rep movs' calling convention, although it does also end up clobbering a number of additional registers. Also, to simplify code sharing in the low-level assembly with the __copy_user_nocache() function (that uses the normal C calling convention), we end up with a kind of mixed return value for the low-level asm code: it will return the result in both %rcx (to work as an alternative for the 'rep movs' case), _and_ in %rax (for the nocache case). We could avoid this by wrapping __copy_user_nocache() callers in an inline asm, but since the cost is just an extra register copy, it's probably not worth it. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2023-04-18 17:05:28 -07:00
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asm	x86: inline the 'rep movs' in user copies for the FSRM case	2023-04-18 17:05:28 -07:00
uapi/asm	KVM/riscv changes for 6.3	2023-02-15 12:33:28 -05:00