Re: [PATCH v3] powerpc/inst: add PPC_TLBILX_LPID

[Nick Desaulniers]

On Thu, Aug 3, 2023 at 11:47 AM Christophe Leroy
<christophe.leroy@xxxxxxxxxx> wrote:
>
>
>
> Le 03/08/2023 à 20:33, Nick Desaulniers a écrit :
> > 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>
>
> Not sure why you changed the order of #includes , nevertheless

Habit to sort; can drop if maintaining git blame is more important
than cleaning that up.

>
> Reviewed-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
>
> > ---
> > Changes in v3:
> > - left comment @ https://github.com/linuxppc/issues/issues/350#issuecomment-1664417212
> > - restore PPC_RAW_TLBILX previous definition
> > - fix comment style
> > - Link to v2: https://lore.kernel.org/r/20230803-ppc_tlbilxlpid-v2-1-211ffa1df194@xxxxxxxxxx
> >
> > Changes in v2:
> > - add 2 missing tabs to PPC_RAW_TLBILX_LPID
> > - Link to v1: https://lore.kernel.org/r/20230803-ppc_tlbilxlpid-v1-1-84a1bc5cf963@xxxxxxxxxx
> > ---
> >   arch/powerpc/include/asm/ppc-opcode.h |  2 ++
> >   arch/powerpc/kvm/e500mc.c             | 11 ++++++++---
> >   2 files changed, 10 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
> > index ef6972aa33b9..005601243dda 100644
> > --- a/arch/powerpc/include/asm/ppc-opcode.h
> > +++ b/arch/powerpc/include/asm/ppc-opcode.h
> > @@ -397,6 +397,7 @@
> >   #define PPC_RAW_RFCI                        (0x4c000066)
> >   #define PPC_RAW_RFDI                        (0x4c00004e)
> >   #define PPC_RAW_RFMCI                       (0x4c00004c)
> > +#define PPC_RAW_TLBILX_LPID          (0x7c000024)
> >   #define PPC_RAW_TLBILX(t, a, b)             (0x7c000024 | __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))
> > @@ -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..7c09c000c330 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 +93,11 @@ 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,



-- 
Thanks,
~Nick Desaulniers