Excerpts from Christophe Leroy's message of October 21, 2021 3:43 pm:
>
>
> Le 21/10/2021 à 05:54, Nicholas Piggin a écrit :
>> Introduce a new option CONFIG_PPC_64S_HASH_MMU, and make 64s hash
>> code depend on it.
>>
>> Signed-off-by: Nicholas Piggin <npig...@gmail.com>
>> ---
>> arch/powerpc/Kconfig | 2 +-
>> arch/powerpc/include/asm/book3s/64/mmu.h | 19 +++++++++--
>> .../include/asm/book3s/64/tlbflush-hash.h | 7 ++++
>> arch/powerpc/include/asm/book3s/pgtable.h | 4 +++
>> arch/powerpc/include/asm/mmu.h | 16 +++++++--
>> arch/powerpc/include/asm/mmu_context.h | 2 ++
>> arch/powerpc/include/asm/paca.h | 8 +++++
>> arch/powerpc/kernel/asm-offsets.c | 2 ++
>> arch/powerpc/kernel/dt_cpu_ftrs.c | 14 +++++---
>> arch/powerpc/kernel/entry_64.S | 4 +--
>> arch/powerpc/kernel/exceptions-64s.S | 16 +++++++++
>> arch/powerpc/kernel/mce.c | 2 +-
>> arch/powerpc/kernel/mce_power.c | 10 ++++--
>> arch/powerpc/kernel/paca.c | 18 ++++------
>> arch/powerpc/kernel/process.c | 13 +++----
>> arch/powerpc/kernel/prom.c | 2 ++
>> arch/powerpc/kernel/setup_64.c | 5 +++
>> arch/powerpc/kexec/core_64.c | 4 +--
>> arch/powerpc/kexec/ranges.c | 4 +++
>> arch/powerpc/mm/book3s64/Makefile | 15 ++++----
>> arch/powerpc/mm/book3s64/hugetlbpage.c | 2 ++
>> arch/powerpc/mm/book3s64/mmu_context.c | 34 +++++++++++++++----
>> arch/powerpc/mm/book3s64/radix_pgtable.c | 4 +++
>> arch/powerpc/mm/copro_fault.c | 2 ++
>> arch/powerpc/mm/ioremap.c | 13 ++++---
>> arch/powerpc/mm/pgtable.c | 10 ++++--
>> arch/powerpc/mm/ptdump/Makefile | 2 +-
>> arch/powerpc/platforms/Kconfig.cputype | 4 +++
>> arch/powerpc/platforms/powernv/idle.c | 2 ++
>> arch/powerpc/platforms/powernv/setup.c | 2 ++
>> arch/powerpc/platforms/pseries/lpar.c | 11 ++++--
>> arch/powerpc/platforms/pseries/lparcfg.c | 2 +-
>> arch/powerpc/platforms/pseries/mobility.c | 6 ++++
>> arch/powerpc/platforms/pseries/ras.c | 2 ++
>> arch/powerpc/platforms/pseries/reconfig.c | 2 ++
>> arch/powerpc/platforms/pseries/setup.c | 6 ++--
>> arch/powerpc/xmon/xmon.c | 8 +++--
>> drivers/misc/lkdtm/Makefile | 2 +-
>> drivers/misc/lkdtm/core.c | 2 +-
>> 39 files changed, 219 insertions(+), 64 deletions(-)
>
> I'm still unconfortable with the quantity of files impacted in that commit.
Hmm. Splitting it into N partial patches that have the same result
doesn't seem better to me. There's a few other little things that are
be better split out, but size of the patch will not shrink much.
>> diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h
>> b/arch/powerpc/include/asm/book3s/64/mmu.h
>> index c02f42d1031e..d94ebae386b6 100644
>> --- a/arch/powerpc/include/asm/book3s/64/mmu.h
>> +++ b/arch/powerpc/include/asm/book3s/64/mmu.h
>
>> @@ -193,8 +198,15 @@ static inline struct subpage_prot_table
>> *mm_ctx_subpage_prot(mm_context_t *ctx)
>> extern int mmu_linear_psize;
>> extern int mmu_virtual_psize;
>> extern int mmu_vmalloc_psize;
>> -extern int mmu_vmemmap_psize;
>> extern int mmu_io_psize;
>> +#else /* CONFIG_PPC_64S_HASH_MMU */
>> +#ifdef CONFIG_PPC_64K_PAGES
>
> Avoid nested #ifdefs and do
>
> #elif defined(CONFIG_PPC_64K_PAGES)
I sort of like the nesting because this is the !HASH block. But I don't
care much so I can do it your way if you prefer.
>> @@ -223,6 +226,13 @@ enum {
>> #ifdef CONFIG_E500
>> #define MMU_FTRS_ALWAYS MMU_FTR_TYPE_FSL_E
>> #endif
>> +#ifdef CONFIG_PPC_BOOK3S_64
>
> No need of this CONFIG_PPC_BOOK3S_64 ifdef, it is necessarily defined if
> either CONFIG_PPC_RADIX_MMU or CONFIG_PPC_64S_HASH_MMU is defined
Good point.
>> +#if defined(CONFIG_PPC_RADIX_MMU) && !defined(CONFIG_PPC_64S_HASH_MMU)
>> +#define MMU_FTRS_ALWAYS MMU_FTR_TYPE_RADIX
>> +#elif !defined(CONFIG_PPC_RADIX_MMU) && defined(CONFIG_PPC_64S_HASH_MMU)
>> +#define MMU_FTRS_ALWAYS MMU_FTR_HPTE_TABLE
>> +#endif
>> +#endif
>>
>> #ifndef MMU_FTRS_ALWAYS
>> #define MMU_FTRS_ALWAYS 0
>
>> diff --git a/arch/powerpc/kernel/exceptions-64s.S
>> b/arch/powerpc/kernel/exceptions-64s.S
>> index 046c99e31d01..65b695e9401e 100644
>> --- a/arch/powerpc/kernel/exceptions-64s.S
>> +++ b/arch/powerpc/kernel/exceptions-64s.S
>> @@ -1369,11 +1369,15 @@ EXC_COMMON_BEGIN(data_access_common)
>> addi r3,r1,STACK_FRAME_OVERHEAD
>> andis. r0,r4,DSISR_DABRMATCH@h
>> bne- 1f
>> +#ifdef CONFIG_PPC_64S_HASH_MMU
>> BEGIN_MMU_FTR_SECTION
>> bl do_hash_fault
>> MMU_FTR_SECTION_ELSE
>> bl do_page_fault
>> ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX)
>> +#else
>> + bl do_page_fault
>> +#endif
>
> Maybe we could always branch to do_page_fault() and get redirected to
> do_hash_fault() from do_page_fault() if BOOK3S64 && !radix_enabled() ?
Not trivial because of do_hash_fault().
A book3s_64_do_page_fault() raw hander which calls do_hash_fault or
do_page_fault if necessary, but that's less optimal and we already
have this gunk so might as well keep it.
>
> Another solution is to make it a GAS macro ?
For this I don't find it too bad. Another macro means another thing to
look up. Maybe if we had more callers but for now this isn't too
terrible.
>> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
>> index 7d4bcbc3124e..59b1a1833143 100644
>> --- a/arch/powerpc/kernel/setup_64.c
>> +++ b/arch/powerpc/kernel/setup_64.c
>> @@ -887,6 +887,8 @@ void __init setup_per_cpu_areas(void)
>> } else if (radix_enabled()) {
>> atom_size = PAGE_SIZE;
>> } else {
>> +#ifdef CONFIG_PPC_64S_HASH_MMU
>
> Use IS_ENABLED()
Can't because of mmu_linear_psize.
>> diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
>> index cd16b407f47e..ab105d33e0b0 100644
>> --- a/arch/powerpc/mm/pgtable.c
>> +++ b/arch/powerpc/mm/pgtable.c
>> @@ -81,9 +81,6 @@ static struct page *maybe_pte_to_page(pte_t pte)
>>
>> static pte_t set_pte_filter_hash(pte_t pte)
>> {
>> - if (radix_enabled())
>> - return pte;
>> -
>> pte = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
>> if (pte_looks_normal(pte) && !(cpu_has_feature(CPU_FTR_COHERENT_ICACHE)
>> ||
>> cpu_has_feature(CPU_FTR_NOEXECUTE))) {
>> @@ -112,6 +109,9 @@ static inline pte_t set_pte_filter(pte_t pte)
>> {
>> struct page *pg;
>>
>> + if (radix_enabled())
>> + return pte;
>> +
>> if (mmu_has_feature(MMU_FTR_HPTE_TABLE))
>> return set_pte_filter_hash(pte);
>>
>> @@ -144,6 +144,10 @@ static pte_t set_access_flags_filter(pte_t pte, struct
>> vm_area_struct *vma,
>> {
>> struct page *pg;
>>
>> +#ifdef CONFIG_PPC_BOOK3S_64
>> + return pte;
>> +#endif
>
> Aren't you changing the behaviour here for RADIX ?
No, 64s always has MMU_FTR_HPTE_TABLE until now. I should actually split
this change out.
> Anyway, can use IS_ENABLED()
Good point.
>
>> +
>> if (mmu_has_feature(MMU_FTR_HPTE_TABLE))
>> return pte;
>>
>> diff --git a/arch/powerpc/mm/ptdump/Makefile
>> b/arch/powerpc/mm/ptdump/Makefile
>> index 4050cbb55acf..b533caaf0910 100644
>> --- a/arch/powerpc/mm/ptdump/Makefile
>> +++ b/arch/powerpc/mm/ptdump/Makefile
>> @@ -10,5 +10,5 @@ obj-$(CONFIG_PPC_BOOK3S_64) += book3s64.o
>>
>> ifdef CONFIG_PTDUMP_DEBUGFS
>> obj-$(CONFIG_PPC_BOOK3S_32) += bats.o segment_regs.o
>> -obj-$(CONFIG_PPC_BOOK3S_64) += hashpagetable.o
>> +obj-$(CONFIG_PPC_64S_HASH_MMU) += hashpagetable.o
>> endif
>> diff --git a/arch/powerpc/platforms/Kconfig.cputype
>> b/arch/powerpc/platforms/Kconfig.cputype
>> index a208997ade88..01726e7f2c7f 100644
>> --- a/arch/powerpc/platforms/Kconfig.cputype
>> +++ b/arch/powerpc/platforms/Kconfig.cputype
>> @@ -105,6 +105,7 @@ config PPC_BOOK3S_64
>> select HAVE_MOVE_PMD
>> select HAVE_MOVE_PUD
>> select IRQ_WORK
>> + select PPC_64S_HASH_MMU
>
> Not needed
>
>> select PPC_MM_SLICES
>> select PPC_HAVE_KUEP
>> select PPC_HAVE_KUAP
>> @@ -364,6 +365,9 @@ config SPE
>>
>> If in doubt, say Y here.
>>
>> +config PPC_64S_HASH_MMU
>> + bool
>
> Add
> depends on PPC_BOOK3S_64
> default y
>
>> +
>> config PPC_RADIX_MMU
>> bool "Radix MMU Support"
>> depends on PPC_BOOK3S_64
>
>> diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
>> index dd8241c009e5..33de8d798c95 100644
>> --- a/arch/powerpc/xmon/xmon.c
>> +++ b/arch/powerpc/xmon/xmon.c
>> @@ -1160,9 +1160,11 @@ cmds(struct pt_regs *excp)
>> show_tasks();
>> break;
>> #ifdef CONFIG_PPC_BOOK3S
>> +#ifdef CONFIG_PPC_64S_HASH_MMU
>
> And BOOK3S/32 ???
Oops, good catch.
Thanks,
Nick
>
>> case 'u':
>> dump_segments();
>> break;
>> +#endif
>> #elif defined(CONFIG_44x)
>> case 'u':
>> dump_tlb_44x();
