Re: [PATCH v2 1/1] sparc: fix accurate exception reporting in copy_{from,to}_user for M7

[John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>]

Hi Rainer,

On Thu, 2025-08-28 at 15:04 +0200, Michael Karcher wrote:
> Fixes 34060b8fffa7 ("arch/sparc: Add accurate exception reporting in M7memcpy")
> Signed-off-by: Michael Karcher <kernel@mkarcher.dialup.fu-berlin.de>
> ---
>  arch/sparc/lib/M7memcpy.S     | 20 ++++++++++----------
>  arch/sparc/lib/Memcpy_utils.S |  9 +++++++++
>  2 files changed, 19 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/sparc/lib/M7memcpy.S b/arch/sparc/lib/M7memcpy.S
> index cbd42ea7c3f7..99357bfa8e82 100644
> --- a/arch/sparc/lib/M7memcpy.S
> +++ b/arch/sparc/lib/M7memcpy.S
> @@ -696,16 +696,16 @@ FUNC_NAME:
>  	EX_LD_FP(LOAD(ldd, %o4+40, %f26), memcpy_retl_o2_plus_o5_plus_40)
>  	faligndata %f24, %f26, %f10
>  	EX_ST_FP(STORE(std, %f6, %o0+24), memcpy_retl_o2_plus_o5_plus_40)
> -	EX_LD_FP(LOAD(ldd, %o4+48, %f28), memcpy_retl_o2_plus_o5_plus_40)
> +	EX_LD_FP(LOAD(ldd, %o4+48, %f28), memcpy_retl_o2_plus_o5_plus_32)
>  	faligndata %f26, %f28, %f12
> -	EX_ST_FP(STORE(std, %f8, %o0+32), memcpy_retl_o2_plus_o5_plus_40)
> +	EX_ST_FP(STORE(std, %f8, %o0+32), memcpy_retl_o2_plus_o5_plus_32)
>  	add	%o4, 64, %o4
> -	EX_LD_FP(LOAD(ldd, %o4-8, %f30), memcpy_retl_o2_plus_o5_plus_40)
> +	EX_LD_FP(LOAD(ldd, %o4-8, %f30), memcpy_retl_o2_plus_o5_plus_24)
>  	faligndata %f28, %f30, %f14
> -	EX_ST_FP(STORE(std, %f10, %o0+40), memcpy_retl_o2_plus_o5_plus_40)
> -	EX_ST_FP(STORE(std, %f12, %o0+48), memcpy_retl_o2_plus_o5_plus_40)
> +	EX_ST_FP(STORE(std, %f10, %o0+40), memcpy_retl_o2_plus_o5_plus_24)
> +	EX_ST_FP(STORE(std, %f12, %o0+48), memcpy_retl_o2_plus_o5_plus_16)
>  	add	%o0, 64, %o0
> -	EX_ST_FP(STORE(std, %f14, %o0-8), memcpy_retl_o2_plus_o5_plus_40)
> +	EX_ST_FP(STORE(std, %f14, %o0-8), memcpy_retl_o2_plus_o5_plus_8)
>  	fsrc2	%f30, %f14
>  	bgu,pt	%xcc, .Lunalign_sloop
>  	 prefetch [%o4 + (8 * BLOCK_SIZE)], 20
> @@ -728,7 +728,7 @@ FUNC_NAME:
>  	add	%o4, 8, %o4
>  	faligndata %f0, %f2, %f16
>  	subcc	%o5, 8, %o5
> -	EX_ST_FP(STORE(std, %f16, %o0), memcpy_retl_o2_plus_o5)
> +	EX_ST_FP(STORE(std, %f16, %o0), memcpy_retl_o2_plus_o5_plus_8)
>  	fsrc2	%f2, %f0
>  	bgu,pt	%xcc, .Lunalign_by8
>  	 add	%o0, 8, %o0
> @@ -772,7 +772,7 @@ FUNC_NAME:
>  	subcc	%o5, 0x20, %o5
>  	EX_ST(STORE(stx, %o3, %o0 + 0x00), memcpy_retl_o2_plus_o5_plus_32)
>  	EX_ST(STORE(stx, %g2, %o0 + 0x08), memcpy_retl_o2_plus_o5_plus_24)
> -	EX_ST(STORE(stx, %g7, %o0 + 0x10), memcpy_retl_o2_plus_o5_plus_24)
> +	EX_ST(STORE(stx, %g7, %o0 + 0x10), memcpy_retl_o2_plus_o5_plus_16)
>  	EX_ST(STORE(stx, %o4, %o0 + 0x18), memcpy_retl_o2_plus_o5_plus_8)
>  	bne,pt	%xcc, 1b
>  	 add	%o0, 0x20, %o0
> @@ -804,12 +804,12 @@ FUNC_NAME:
>  	brz,pt	%o3, 2f
>  	 sub	%o2, %o3, %o2
>  
> -1:	EX_LD(LOAD(ldub, %o1 + 0x00, %g2), memcpy_retl_o2_plus_g1)
> +1:	EX_LD(LOAD(ldub, %o1 + 0x00, %g2), memcpy_retl_o2_plus_o3)
>  	add	%o1, 1, %o1
>  	subcc	%o3, 1, %o3
>  	add	%o0, 1, %o0
>  	bne,pt	%xcc, 1b
> -	 EX_ST(STORE(stb, %g2, %o0 - 0x01), memcpy_retl_o2_plus_g1_plus_1)
> +	 EX_ST(STORE(stb, %g2, %o0 - 0x01), memcpy_retl_o2_plus_o3_plus_1)
>  2:
>  	and	%o1, 0x7, %o3
>  	brz,pn	%o3, .Lmedium_noprefetch_cp
> diff --git a/arch/sparc/lib/Memcpy_utils.S b/arch/sparc/lib/Memcpy_utils.S
> index 64fbac28b3db..207343367bb2 100644
> --- a/arch/sparc/lib/Memcpy_utils.S
> +++ b/arch/sparc/lib/Memcpy_utils.S
> @@ -137,6 +137,15 @@ ENTRY(memcpy_retl_o2_plus_63_8)
>  	ba,pt	%xcc, __restore_asi
>  	 add	%o2, 8, %o0
>  ENDPROC(memcpy_retl_o2_plus_63_8)
> +ENTRY(memcpy_retl_o2_plus_o3)
> +	ba,pt	%xcc, __restore_asi
> +	 add	%o2, %o3, %o0
> +ENDPROC(memcpy_retl_o2_plus_o3)
> +ENTRY(memcpy_retl_o2_plus_o3_plus_1)
> +	add	%o3, 1, %o3
> +	ba,pt	%xcc, __restore_asi
> +	 add	%o2, %o3, %o0
> +ENDPROC(memcpy_retl_o2_plus_o3_plus_1)
>  ENTRY(memcpy_retl_o2_plus_o5)
>  	ba,pt	%xcc, __restore_asi
>  	 add	%o2, %o5, %o0

in the past, you reported stability issues with the Linux kernel when running
inside an LDOM on SPARC M7/M8. Could you verify whether the patch above fixes
these problems or whether at least they don't introduce regressions?

Thanks,
Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
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