Messages in this thread | | | Date | Sat, 16 Jul 2022 00:53:18 +0800 | From | Jisheng Zhang <> | Subject | Re: [PATCH v5 2/2] riscv: turn pgtable_l4|[l5]_enabled to static key for RV64 |
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On Fri, Jul 15, 2022 at 05:04:38PM +0200, Emil Renner Berthing wrote: > On Fri, 15 Jul 2022 at 15:59, Jisheng Zhang <jszhang@kernel.org> wrote: > > On a specific HW platform, pgtable_l4|[l5]_enabled won't change after > > boot, and the check sits at hot code path, this characteristic makes it > > suitable for optimization with static key. > > > > _pgtable_l4|[l5]_enabled is used very early during boot, even is used > > with MMU off, so the static key mechanism isn't ready. For this case, > > we use another static key _pgtable_lx_ready to indicate whether we > > have finalised pgtable_l4|[l5]_enabled or not, then fall back to > > _pgtable_l4|[l5]_enabled_early bool. > > > > Signed-off-by: Jisheng Zhang <jszhang@kernel.org> > > Reviewed-by: Anup Patel <anup@brainfault.org> > > --- > > arch/riscv/include/asm/pgalloc.h | 16 ++++---- > > arch/riscv/include/asm/pgtable-32.h | 3 ++ > > arch/riscv/include/asm/pgtable-64.h | 60 ++++++++++++++++++--------- > > arch/riscv/include/asm/pgtable.h | 5 +-- > > arch/riscv/kernel/cpu.c | 4 +- > > arch/riscv/mm/init.c | 64 ++++++++++++++++++----------- > > arch/riscv/mm/kasan_init.c | 16 ++++---- > > 7 files changed, 103 insertions(+), 65 deletions(-) > > > > diff --git a/arch/riscv/include/asm/pgalloc.h b/arch/riscv/include/asm/pgalloc.h > > index 947f23d7b6af..0280eeb4756f 100644 > > --- a/arch/riscv/include/asm/pgalloc.h > > +++ b/arch/riscv/include/asm/pgalloc.h > > @@ -41,7 +41,7 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd) > > > > static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4d, pud_t *pud) > > { > > - if (pgtable_l4_enabled) { > > + if (pgtable_l4_enabled()) { > > unsigned long pfn = virt_to_pfn(pud); > > > > set_p4d(p4d, __p4d((pfn << _PAGE_PFN_SHIFT) | _PAGE_TABLE)); > > @@ -51,7 +51,7 @@ static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4d, pud_t *pud) > > static inline void p4d_populate_safe(struct mm_struct *mm, p4d_t *p4d, > > pud_t *pud) > > { > > - if (pgtable_l4_enabled) { > > + if (pgtable_l4_enabled()) { > > unsigned long pfn = virt_to_pfn(pud); > > > > set_p4d_safe(p4d, > > @@ -61,7 +61,7 @@ static inline void p4d_populate_safe(struct mm_struct *mm, p4d_t *p4d, > > > > static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, p4d_t *p4d) > > { > > - if (pgtable_l5_enabled) { > > + if (pgtable_l5_enabled()) { > > unsigned long pfn = virt_to_pfn(p4d); > > > > set_pgd(pgd, __pgd((pfn << _PAGE_PFN_SHIFT) | _PAGE_TABLE)); > > @@ -71,7 +71,7 @@ static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, p4d_t *p4d) > > static inline void pgd_populate_safe(struct mm_struct *mm, pgd_t *pgd, > > p4d_t *p4d) > > { > > - if (pgtable_l5_enabled) { > > + if (pgtable_l5_enabled()) { > > unsigned long pfn = virt_to_pfn(p4d); > > > > set_pgd_safe(pgd, > > @@ -82,7 +82,7 @@ static inline void pgd_populate_safe(struct mm_struct *mm, pgd_t *pgd, > > #define pud_alloc_one pud_alloc_one > > static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr) > > { > > - if (pgtable_l4_enabled) > > + if (pgtable_l4_enabled()) > > return __pud_alloc_one(mm, addr); > > > > return NULL; > > @@ -91,7 +91,7 @@ static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr) > > #define pud_free pud_free > > static inline void pud_free(struct mm_struct *mm, pud_t *pud) > > { > > - if (pgtable_l4_enabled) > > + if (pgtable_l4_enabled()) > > __pud_free(mm, pud); > > } > > > > @@ -100,7 +100,7 @@ static inline void pud_free(struct mm_struct *mm, pud_t *pud) > > #define p4d_alloc_one p4d_alloc_one > > static inline p4d_t *p4d_alloc_one(struct mm_struct *mm, unsigned long addr) > > { > > - if (pgtable_l5_enabled) { > > + if (pgtable_l5_enabled()) { > > gfp_t gfp = GFP_PGTABLE_USER; > > > > if (mm == &init_mm) > > @@ -120,7 +120,7 @@ static inline void __p4d_free(struct mm_struct *mm, p4d_t *p4d) > > #define p4d_free p4d_free > > static inline void p4d_free(struct mm_struct *mm, p4d_t *p4d) > > { > > - if (pgtable_l5_enabled) > > + if (pgtable_l5_enabled()) > > __p4d_free(mm, p4d); > > } > > > > diff --git a/arch/riscv/include/asm/pgtable-32.h b/arch/riscv/include/asm/pgtable-32.h > > index 59ba1fbaf784..1ef52079179a 100644 > > --- a/arch/riscv/include/asm/pgtable-32.h > > +++ b/arch/riscv/include/asm/pgtable-32.h > > @@ -17,6 +17,9 @@ > > > > #define MAX_POSSIBLE_PHYSMEM_BITS 34 > > > > +#define pgtable_l5_enabled() 0 > > +#define pgtable_l4_enabled() 0 > > + > > /* > > * rv32 PTE format: > > * | XLEN-1 10 | 9 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 > > diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h > > index 5c2aba5efbd0..edfff00d8ca3 100644 > > --- a/arch/riscv/include/asm/pgtable-64.h > > +++ b/arch/riscv/include/asm/pgtable-64.h > > @@ -8,18 +8,38 @@ > > > > #include <linux/bits.h> > > #include <linux/const.h> > > +#include <linux/jump_label.h> > > #include <asm/errata_list.h> > > > > -extern bool pgtable_l4_enabled; > > -extern bool pgtable_l5_enabled; > > +extern bool _pgtable_l5_enabled_early; > > +extern bool _pgtable_l4_enabled_early; > > +extern struct static_key_false _pgtable_l5_enabled; > > +extern struct static_key_false _pgtable_l4_enabled; > > +extern struct static_key_false _pgtable_lx_ready; > > It amounts to the same, but I wonder if we ought to use the > DECLARE_STATIC_KEY_FALSE macro here.
Thanks for the hint, will send out a newer version soon. Before that, I will wait a bit for other review feedbacks.
Thanks
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