Re: [PATCH] powerpc/inst: add PPC_TLBILX_LPID

[Nick Desaulniers]

On Thu, Aug 3, 2023 at 10:00 AM <ndesaulniers@xxxxxxxxxx> wrote:
>
> Clang didn't recognize the instruction tlbilxlpid. This was fixed in
> clang-18 [0] then backported to clang-17 [1].  To support clang-16 and
> older, rather than using that instruction bare in inline asm, add it to
> ppc-opcode.h and use that macro as is done elsewhere for other
> instructions.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1891
> Link: https://github.com/llvm/llvm-project/issues/64080
> Link: https://github.com/llvm/llvm-project/commit/53648ac1d0c953ae6d008864dd2eddb437a92468 [0]
> Link: https://github.com/llvm/llvm-project-release-prs/commit/0af7e5e54a8c7ac665773ac1ada328713e8338f5 [1]
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/llvm/202307211945.TSPcyOhh-lkp@xxxxxxxxx/
> Suggested-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> ---
>  arch/powerpc/include/asm/ppc-opcode.h |  4 +++-
>  arch/powerpc/kvm/e500mc.c             | 10 +++++++---
>  2 files changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
> index ef6972aa33b9..72f184e06bec 100644
> --- a/arch/powerpc/include/asm/ppc-opcode.h
> +++ b/arch/powerpc/include/asm/ppc-opcode.h
> @@ -397,7 +397,8 @@
>  #define PPC_RAW_RFCI                   (0x4c000066)
>  #define PPC_RAW_RFDI                   (0x4c00004e)
>  #define PPC_RAW_RFMCI                  (0x4c00004c)
> -#define PPC_RAW_TLBILX(t, a, b)                (0x7c000024 | __PPC_T_TLB(t) |  __PPC_RA0(a) | __PPC_RB(b))
> +#define PPC_RAW_TLBILX_LPID (0x7c000024)

^ missing two tabs.

I'm also having issues with b4 and my external mailer setting the From
header correctly.  To test up local modifications to b4, I'm going to
send a v2.

> +#define PPC_RAW_TLBILX(t, a, b)                (PPC_RAW_TLBILX_LPID | __PPC_T_TLB(t) | __PPC_RA0(a) | __PPC_RB(b))
>  #define PPC_RAW_WAIT_v203              (0x7c00007c)
>  #define PPC_RAW_WAIT(w, p)             (0x7c00003c | __PPC_WC(w) | __PPC_PL(p))
>  #define PPC_RAW_TLBIE(lp, a)           (0x7c000264 | ___PPC_RB(a) | ___PPC_RS(lp))
> @@ -616,6 +617,7 @@
>  #define PPC_TLBILX(t, a, b)    stringify_in_c(.long PPC_RAW_TLBILX(t, a, b))
>  #define PPC_TLBILX_ALL(a, b)   PPC_TLBILX(0, a, b)
>  #define PPC_TLBILX_PID(a, b)   PPC_TLBILX(1, a, b)
> +#define PPC_TLBILX_LPID                stringify_in_c(.long PPC_RAW_TLBILX_LPID)
>  #define PPC_TLBILX_VA(a, b)    PPC_TLBILX(3, a, b)
>  #define PPC_WAIT_v203          stringify_in_c(.long PPC_RAW_WAIT_v203)
>  #define PPC_WAIT(w, p)         stringify_in_c(.long PPC_RAW_WAIT(w, p))
> diff --git a/arch/powerpc/kvm/e500mc.c b/arch/powerpc/kvm/e500mc.c
> index d58df71ace58..dc054b8b5032 100644
> --- a/arch/powerpc/kvm/e500mc.c
> +++ b/arch/powerpc/kvm/e500mc.c
> @@ -16,10 +16,11 @@
>  #include <linux/miscdevice.h>
>  #include <linux/module.h>
>
> -#include <asm/reg.h>
>  #include <asm/cputable.h>
> -#include <asm/kvm_ppc.h>
>  #include <asm/dbell.h>
> +#include <asm/kvm_ppc.h>
> +#include <asm/ppc-opcode.h>
> +#include <asm/reg.h>
>
>  #include "booke.h"
>  #include "e500.h"
> @@ -92,7 +93,10 @@ void kvmppc_e500_tlbil_all(struct kvmppc_vcpu_e500 *vcpu_e500)
>
>         local_irq_save(flags);
>         mtspr(SPRN_MAS5, MAS5_SGS | get_lpid(&vcpu_e500->vcpu));
> -       asm volatile("tlbilxlpid");
> +       /* clang-17 and older could not assemble tlbilxlpid.
> +        * https://github.com/ClangBuiltLinux/linux/issues/1891
> +        */
> +       asm volatile (PPC_TLBILX_LPID);
>         mtspr(SPRN_MAS5, 0);
>         local_irq_restore(flags);
>  }
>
> ---
> base-commit: 7bafbd4027ae86572f308c4ddf93120c90126332
> change-id: 20230803-ppc_tlbilxlpid-cfdbf4fd4f7f
>
> Best regards,
> --
> Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
>


-- 
Thanks,
~Nick Desaulniers