On Sun, 2023-06-25 at 02:40 +0800, WANG Xuerui wrote:
> From: WANG Xuerui <git@xxxxxxxxxx>
>
> The invtlb instruction has been supported by upstream LoongArch
> toolchains from day one, so ditch the raw opcode trickery and just use
> plain inline asm for it.
>
> While at it, also make the invtlb asm statements barriers, for proper
> modeling of the side effects.
>
> The signature of the other more specific invtlb wrappers contain unused
> arguments right now, but these are not removed right away in order for
> the patch to be focused. In the meantime, assertions are added to ensure
> no accidental misuse happens before the refactor. (The more specific
> wrappers cannot re-use the generic invtlb wrapper, because the ISA
> manual says $zero shall be used in case a particular op does not take
> the respective argument: re-using the generic wrapper would mean losing
> control over the register usage.)
>
> Signed-off-by: WANG Xuerui <git@xxxxxxxxxx>
> ---
> arch/loongarch/include/asm/tlb.h | 39 ++++++++++++++++----------------
> 1 file changed, 19 insertions(+), 20 deletions(-)
>
> diff --git a/arch/loongarch/include/asm/tlb.h b/arch/loongarch/include/asm/tlb.h
> index 0dc9ee2b05d2..15750900540c 100644
> --- a/arch/loongarch/include/asm/tlb.h
> +++ b/arch/loongarch/include/asm/tlb.h
> @@ -88,52 +88,51 @@ enum invtlb_ops {
> INVTLB_GID_ADDR = 0x16,
> };
>
> -/*
> - * invtlb op info addr
> - * (0x1 << 26) | (0x24 << 20) | (0x13 << 15) |
> - * (addr << 10) | (info << 5) | op
> - */
> static inline void invtlb(u32 op, u32 info, u64 addr)
Oh, technically these wrappers should be __always_inline, not only
inline because they don't work at all if not inlined. Should we change
them to __always_inline in this patch by the way?
> {
> + BUILD_BUG_ON(!__builtin_constant_p(op));
Hmm, I guess it's redundant. If op is not a compile-time constant, it
won't satisfy the "i" constraint then the compiler will complain anyway.
> __asm__ __volatile__(
> - "parse_r addr,%0\n\t"
> - "parse_r info,%1\n\t"
> - ".word ((0x6498000) | (addr << 10) | (info << 5) | %2)\n\t"
> - :
> - : "r"(addr), "r"(info), "i"(op)
> + "invtlb %0, %1, %2\n\t"
> :
> + : "i"(op), "r"(info), "r"(addr)
> + : "memory"
> );
> }
Likewise for other wrappers.
/* snip */
--
Xi Ruoyao <xry111@xxxxxxxxxxx>
School of Aerospace Science and Technology, Xidian University
