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References: <20211129014007.286478-1-wefu@redhat.com> <20211129014007.286478-3-wefu@redhat.com>
 <CAJF2gTSOZfcAUed+DmfugWQ0=_nJgRdL1JzJgYdmrFoNXVWM9g@mail.gmail.com>
In-Reply-To: <CAJF2gTSOZfcAUed+DmfugWQ0=_nJgRdL1JzJgYdmrFoNXVWM9g@mail.gmail.com>
From:   Wei Fu <wefu@redhat.com>
Date:   Wed, 1 Dec 2021 11:03:29 +0800
Message-ID: <CA+YCwKnWPsDdROcEBXbjCe8RKQB9gsd4ynO0K4qyU8=YhYKB3A@mail.gmail.com>
Subject: Re: [PATCH V4 2/2] riscv: add RISC-V Svpbmt extension supports
To:     Guo Ren <guoren@kernel.org>
Cc:     Anup Patel <anup.patel@wdc.com>, atishp04@gmail.com,
        Palmer Dabbelt <palmer@dabbelt.com>,
        =?UTF-8?Q?Christoph_M=C3=BCllner?= <christoph.muellner@vrull.eu>,
        Philipp Tomsich <philipp.tomsich@vrull.eu>,
        Christoph Hellwig <hch@lst.de>,
        liush <liush@allwinnertech.com>,
        =?UTF-8?B?V2VpIFd1ICjlkLTkvJ8p?= <lazyparser@gmail.com>,
        Drew Fustini <drew@beagleboard.org>,
        linux-riscv <linux-riscv@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        taiten.peng@canonical.com,
        Aniket Ponkshe <aniket.ponkshe@canonical.com>,
        Heinrich Schuchardt <heinrich.schuchardt@canonical.com>,
        Gordan Markus <gordan.markus@canonical.com>,
        Guo Ren <guoren@linux.alibaba.com>,
        Arnd Bergmann <arnd@arndb.de>, Chen-Yu Tsai <wens@csie.org>,
        Maxime Ripard <maxime@cerno.tech>,
        Daniel Lustig <dlustig@nvidia.com>,
        Greg Favor <gfavor@ventanamicro.com>,
        Andrea Mondelli <andrea.mondelli@huawei.com>,
        Jonathan Behrens <behrensj@mit.edu>,
        "Xinhaoqu (Freddie)" <xinhaoqu@huawei.com>,
        Bill Huffman <huffman@cadence.com>,
        Nick Kossifidis <mick@ics.forth.gr>,
        Allen Baum <allen.baum@esperantotech.com>,
        Josh Scheid <jscheid@ventanamicro.com>,
        Richard Trauben <rtrauben@gmail.com>,
        Palmer Dabbelt <palmerdabbelt@google.com>,
        Atish Patra <atish.patra@wdc.com>
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Thanks for reminding me, Guo Ren. :-)
yes, I am working on the new version , yes, my bad, I am adding it in to my V5

On Tue, Nov 30, 2021 at 6:19 PM Guo Ren <guoren@kernel.org> wrote:
>
> Hi,
>
> We forgot fixmap, add below into your patch.
>
> diff --git a/arch/riscv/include/asm/fixmap.h b/arch/riscv/include/asm/fixmap.h
> index 54cbf07fb4e9..899b59bdb9eb 100644
> --- a/arch/riscv/include/asm/fixmap.h
> +++ b/arch/riscv/include/asm/fixmap.h
> @@ -43,8 +43,6 @@ enum fixed_addresses {
>         __end_of_fixed_addresses
>  };
>
> -#define FIXMAP_PAGE_IO         PAGE_KERNEL
> -
>  #define __early_set_fixmap     __set_fixmap
>
>  #define __late_set_fixmap      __set_fixmap
> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> index f3c9f9a1c1bb..9bb06384c57f 100644
> --- a/arch/riscv/include/asm/pgtable.h
> +++ b/arch/riscv/include/asm/pgtable.h
> @@ -126,6 +126,8 @@
>                                 | _PAGE_SHARE \
>                                 | _PAGE_SO)
>
> +#define PAGE_KERNEL_IO         __pgprot(_PAGE_IOREMAP)
>
> On Mon, Nov 29, 2021 at 9:41 AM <wefu@redhat.com> wrote:
> >
> > From: Wei Fu <wefu@redhat.com>
> >
> > This patch follows the standard pure RISC-V Svpbmt extension in
> > privilege spec to solve the non-coherent SOC dma synchronization
> > issues.
> >
> > Here is the svpbmt PTE format:
> > | 63 | 62-61 | 60-8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
> >   N     MT     RSW    D   A   G   U   X   W   R   V
> >         ^
> >
> > Of the Reserved bits [63:54] in a leaf PTE, the high bit is already
> > allocated (as the N bit), so bits [62:61] are used as the MT (aka
> > MemType) field. This field specifies one of three memory types that
> > are close equivalents (or equivalent in effect) to the three main x86
> > and ARMv8 memory types - as shown in the following table.
> >
> > RISC-V
> > Encoding &
> > MemType     RISC-V Description
> > ----------  ------------------------------------------------
> > 00 - PMA    Normal Cacheable, No change to implied PMA memory type
> > 01 - NC     Non-cacheable, idempotent, weakly-ordered Main Memory
> > 10 - IO     Non-cacheable, non-idempotent, strongly-ordered I/O memory
> > 11 - Rsvd   Reserved for future standard use
> >
> > The standard protection_map[] needn't be modified because the "PMA"
> > type keeps the highest bits zero. And the whole modification is
> > limited in the arch/riscv/* and using a global variable
> > (__svpbmt) as _PAGE_MASK/IO/NOCACHE for pgprot_noncached
> > (&writecombine) in pgtable.h. We also add _PAGE_CHG_MASK to filter
> > PFN than before.
> >
> > Enable it in devicetree - (Add "riscv,svpbmt" in the mmu of cpu node)
> >  - mmu:
> >      riscv,svpmbt
> >
> > Signed-off-by: Wei Fu <wefu@redhat.com>
> > Co-developed-by: Liu Shaohua <liush@allwinnertech.com>
> > Signed-off-by: Liu Shaohua <liush@allwinnertech.com>
> > Co-developed-by: Guo Ren <guoren@kernel.org>
> > Signed-off-by: Guo Ren <guoren@kernel.org>
> > Cc: Palmer Dabbelt <palmerdabbelt@google.com>
> > Cc: Christoph Hellwig <hch@lst.de>
> > Cc: Anup Patel <anup.patel@wdc.com>
> > Cc: Arnd Bergmann <arnd@arndb.de>
> > Cc: Atish Patra <atish.patra@wdc.com>
> > Cc: Drew Fustini <drew@beagleboard.org>
> > Cc: Wei Fu <wefu@redhat.com>
> > Cc: Wei Wu <lazyparser@gmail.com>
> > Cc: Chen-Yu Tsai <wens@csie.org>
> > Cc: Maxime Ripard <maxime@cerno.tech>
> > Cc: Daniel Lustig <dlustig@nvidia.com>
> > Cc: Greg Favor <gfavor@ventanamicro.com>
> > Cc: Andrea Mondelli <andrea.mondelli@huawei.com>
> > Cc: Jonathan Behrens <behrensj@mit.edu>
> > Cc: Xinhaoqu (Freddie) <xinhaoqu@huawei.com>
> > Cc: Bill Huffman <huffman@cadence.com>
> > Cc: Nick Kossifidis <mick@ics.forth.gr>
> > Cc: Allen Baum <allen.baum@esperantotech.com>
> > Cc: Josh Scheid <jscheid@ventanamicro.com>
> > Cc: Richard Trauben <rtrauben@gmail.com>
> > ---
> >  arch/riscv/include/asm/fixmap.h       |  2 +-
> >  arch/riscv/include/asm/pgtable-64.h   | 21 ++++++++++++---
> >  arch/riscv/include/asm/pgtable-bits.h | 39 +++++++++++++++++++++++++--
> >  arch/riscv/include/asm/pgtable.h      | 39 ++++++++++++++++++++-------
> >  arch/riscv/kernel/cpufeature.c        | 35 ++++++++++++++++++++++++
> >  arch/riscv/mm/init.c                  |  5 ++++
> >  6 files changed, 126 insertions(+), 15 deletions(-)
> >
> > diff --git a/arch/riscv/include/asm/fixmap.h b/arch/riscv/include/asm/fixmap.h
> > index 54cbf07fb4e9..5acd99d08e74 100644
> > --- a/arch/riscv/include/asm/fixmap.h
> > +++ b/arch/riscv/include/asm/fixmap.h
> > @@ -43,7 +43,7 @@ enum fixed_addresses {
> >         __end_of_fixed_addresses
> >  };
> >
> > -#define FIXMAP_PAGE_IO         PAGE_KERNEL
> > +#define FIXMAP_PAGE_IO         PAGE_IOREMAP
> >
> >  #define __early_set_fixmap     __set_fixmap
> >
> > diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h
> > index 228261aa9628..16d251282b1d 100644
> > --- a/arch/riscv/include/asm/pgtable-64.h
> > +++ b/arch/riscv/include/asm/pgtable-64.h
> > @@ -59,14 +59,29 @@ static inline void pud_clear(pud_t *pudp)
> >         set_pud(pudp, __pud(0));
> >  }
> >
> > +static inline unsigned long _chg_of_pmd(pmd_t pmd)
> > +{
> > +       return (pmd_val(pmd) & _PAGE_CHG_MASK);
> > +}
> > +
> > +static inline unsigned long _chg_of_pud(pud_t pud)
> > +{
> > +       return (pud_val(pud) & _PAGE_CHG_MASK);
> > +}
> > +
> > +static inline unsigned long _chg_of_pte(pte_t pte)
> > +{
> > +       return (pte_val(pte) & _PAGE_CHG_MASK);
> > +}
> > +
> >  static inline pmd_t *pud_pgtable(pud_t pud)
> >  {
> > -       return (pmd_t *)pfn_to_virt(pud_val(pud) >> _PAGE_PFN_SHIFT);
> > +       return (pmd_t *)pfn_to_virt(_chg_of_pud(pud) >> _PAGE_PFN_SHIFT);
> >  }
> >
> >  static inline struct page *pud_page(pud_t pud)
> >  {
> > -       return pfn_to_page(pud_val(pud) >> _PAGE_PFN_SHIFT);
> > +       return pfn_to_page(_chg_of_pud(pud) >> _PAGE_PFN_SHIFT);
> >  }
> >
> >  static inline pmd_t pfn_pmd(unsigned long pfn, pgprot_t prot)
> > @@ -76,7 +91,7 @@ static inline pmd_t pfn_pmd(unsigned long pfn, pgprot_t prot)
> >
> >  static inline unsigned long _pmd_pfn(pmd_t pmd)
> >  {
> > -       return pmd_val(pmd) >> _PAGE_PFN_SHIFT;
> > +       return _chg_of_pmd(pmd) >> _PAGE_PFN_SHIFT;
> >  }
> >
> >  #define mk_pmd(page, prot)    pfn_pmd(page_to_pfn(page), prot)
> > diff --git a/arch/riscv/include/asm/pgtable-bits.h b/arch/riscv/include/asm/pgtable-bits.h
> > index 2ee413912926..e5b0fce4ddc5 100644
> > --- a/arch/riscv/include/asm/pgtable-bits.h
> > +++ b/arch/riscv/include/asm/pgtable-bits.h
> > @@ -7,7 +7,7 @@
> >  #define _ASM_RISCV_PGTABLE_BITS_H
> >
> >  /*
> > - * PTE format:
> > + * rv32 PTE format:
> >   * | XLEN-1  10 | 9             8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
> >   *       PFN      reserved for SW   D   A   G   U   X   W   R   V
> >   */
> > @@ -24,6 +24,40 @@
> >  #define _PAGE_DIRTY     (1 << 7)    /* Set by hardware on any write */
> >  #define _PAGE_SOFT      (1 << 8)    /* Reserved for software */
> >
> > +#if !defined(__ASSEMBLY__) && defined(CONFIG_64BIT)
> > +/*
> > + * rv64 PTE format:
> > + * | 63 | 62 61 | 60 54 | 53  10 | 9             8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
> > + *   N      MT     RSV    PFN      reserved for SW   D   A   G   U   X   W   R   V
> > + * [62:61] Memory Type definitions:
> > + *  00 - PMA    Normal Cacheable, No change to implied PMA memory type
> > + *  01 - NC     Non-cacheable, idempotent, weakly-ordered Main Memory
> > + *  10 - IO     Non-cacheable, non-idempotent, strongly-ordered I/O memory
> > + *  11 - Rsvd   Reserved for future standard use
> > + */
> > +#define _SVPBMT_PMA            0UL
> > +#define _SVPBMT_NC             (1UL << 61)
> > +#define _SVPBMT_IO             (1UL << 62)
> > +#define _SVPBMT_MASK           (_SVPBMT_NC | _SVPBMT_IO)
> > +
> > +extern struct __svpbmt_struct {
> > +       unsigned long mask;
> > +       unsigned long pma;
> > +       unsigned long nocache;
> > +       unsigned long io;
> > +} __svpbmt __cacheline_aligned;
> > +
> > +#define _PAGE_MASK             __svpbmt.mask
> > +#define _PAGE_PMA              __svpbmt.pma
> > +#define _PAGE_NOCACHE          __svpbmt.nocache
> > +#define _PAGE_IO               __svpbmt.io
> > +#else
> > +#define _PAGE_MASK             0
> > +#define _PAGE_PMA              0
> > +#define _PAGE_NOCACHE          0
> > +#define _PAGE_IO               0
> > +#endif /* !__ASSEMBLY__ && CONFIG_64BIT */
> > +
> >  #define _PAGE_SPECIAL   _PAGE_SOFT
> >  #define _PAGE_TABLE     _PAGE_PRESENT
> >
> > @@ -38,7 +72,8 @@
> >  /* Set of bits to preserve across pte_modify() */
> >  #define _PAGE_CHG_MASK  (~(unsigned long)(_PAGE_PRESENT | _PAGE_READ | \
> >                                           _PAGE_WRITE | _PAGE_EXEC |    \
> > -                                         _PAGE_USER | _PAGE_GLOBAL))
> > +                                         _PAGE_USER | _PAGE_GLOBAL |   \
> > +                                         _PAGE_MASK))
> >  /*
> >   * when all of R/W/X are zero, the PTE is a pointer to the next level
> >   * of the page table; otherwise, it is a leaf PTE.
> > diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> > index bf204e7c1f74..0f7a6541015f 100644
> > --- a/arch/riscv/include/asm/pgtable.h
> > +++ b/arch/riscv/include/asm/pgtable.h
> > @@ -138,7 +138,8 @@
> >                                 | _PAGE_PRESENT \
> >                                 | _PAGE_ACCESSED \
> >                                 | _PAGE_DIRTY \
> > -                               | _PAGE_GLOBAL)
> > +                               | _PAGE_GLOBAL \
> > +                               | _PAGE_PMA)
> >
> >  #define PAGE_KERNEL            __pgprot(_PAGE_KERNEL)
> >  #define PAGE_KERNEL_READ       __pgprot(_PAGE_KERNEL & ~_PAGE_WRITE)
> > @@ -148,11 +149,9 @@
> >
> >  #define PAGE_TABLE             __pgprot(_PAGE_TABLE)
> >
> > -/*
> > - * The RISC-V ISA doesn't yet specify how to query or modify PMAs, so we can't
> > - * change the properties of memory regions.
> > - */
> > -#define _PAGE_IOREMAP _PAGE_KERNEL
> > +#define _PAGE_IOREMAP  ((_PAGE_KERNEL & ~_PAGE_MASK) | _PAGE_IO)
> > +
> > +#define PAGE_IOREMAP           __pgprot(_PAGE_IOREMAP)
> >
> >  extern pgd_t swapper_pg_dir[];
> >
> > @@ -232,12 +231,12 @@ static inline unsigned long _pgd_pfn(pgd_t pgd)
> >
> >  static inline struct page *pmd_page(pmd_t pmd)
> >  {
> > -       return pfn_to_page(pmd_val(pmd) >> _PAGE_PFN_SHIFT);
> > +       return pfn_to_page(_chg_of_pmd(pmd) >> _PAGE_PFN_SHIFT);
> >  }
> >
> >  static inline unsigned long pmd_page_vaddr(pmd_t pmd)
> >  {
> > -       return (unsigned long)pfn_to_virt(pmd_val(pmd) >> _PAGE_PFN_SHIFT);
> > +       return (unsigned long)pfn_to_virt(_chg_of_pmd(pmd) >> _PAGE_PFN_SHIFT);
> >  }
> >
> >  static inline pte_t pmd_pte(pmd_t pmd)
> > @@ -253,7 +252,7 @@ static inline pte_t pud_pte(pud_t pud)
> >  /* Yields the page frame number (PFN) of a page table entry */
> >  static inline unsigned long pte_pfn(pte_t pte)
> >  {
> > -       return (pte_val(pte) >> _PAGE_PFN_SHIFT);
> > +       return (_chg_of_pte(pte) >> _PAGE_PFN_SHIFT);
> >  }
> >
> >  #define pte_page(x)     pfn_to_page(pte_pfn(x))
> > @@ -492,6 +491,28 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
> >         return ptep_test_and_clear_young(vma, address, ptep);
> >  }
> >
> > +#define pgprot_noncached pgprot_noncached
> > +static inline pgprot_t pgprot_noncached(pgprot_t _prot)
> > +{
> > +       unsigned long prot = pgprot_val(_prot);
> > +
> > +       prot &= ~_PAGE_MASK;
> > +       prot |= _PAGE_IO;
> > +
> > +       return __pgprot(prot);
> > +}
> > +
> > +#define pgprot_writecombine pgprot_writecombine
> > +static inline pgprot_t pgprot_writecombine(pgprot_t _prot)
> > +{
> > +       unsigned long prot = pgprot_val(_prot);
> > +
> > +       prot &= ~_PAGE_MASK;
> > +       prot |= _PAGE_NOCACHE;
> > +
> > +       return __pgprot(prot);
> > +}
> > +
> >  /*
> >   * THP functions
> >   */
> > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> > index d959d207a40d..fa7480cb8b87 100644
> > --- a/arch/riscv/kernel/cpufeature.c
> > +++ b/arch/riscv/kernel/cpufeature.c
> > @@ -8,6 +8,7 @@
> >
> >  #include <linux/bitmap.h>
> >  #include <linux/of.h>
> > +#include <linux/pgtable.h>
> >  #include <asm/processor.h>
> >  #include <asm/hwcap.h>
> >  #include <asm/smp.h>
> > @@ -59,6 +60,38 @@ bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit)
> >  }
> >  EXPORT_SYMBOL_GPL(__riscv_isa_extension_available);
> >
> > +static void __init mmu_supports_svpbmt(void)
> > +{
> > +#if defined(CONFIG_MMU) && defined(CONFIG_64BIT)
> > +       struct device_node *node;
> > +       const char *str;
> > +
> > +       for_each_of_cpu_node(node) {
> > +               if (of_property_read_string(node, "mmu-type", &str))
> > +                       continue;
> > +
> > +               if (!strncmp(str + 6, "none", 4))
> > +                       continue;
> > +
> > +               if (of_property_read_string(node, "mmu", &str))
> > +                       continue;
> > +
> > +               if (strncmp(str + 6, "svpmbt", 6))
> > +                       continue;
> > +       }
> > +
> > +       __svpbmt.pma            = _SVPBMT_PMA;
> > +       __svpbmt.nocache        = _SVPBMT_NC;
> > +       __svpbmt.io             = _SVPBMT_IO;
> > +       __svpbmt.mask           = _SVPBMT_MASK;
> > +#endif
> > +}
> > +
> > +static void __init mmu_supports(void)
> > +{
> > +       mmu_supports_svpbmt();
> > +}
> > +
> >  void __init riscv_fill_hwcap(void)
> >  {
> >         struct device_node *node;
> > @@ -67,6 +100,8 @@ void __init riscv_fill_hwcap(void)
> >         size_t i, j, isa_len;
> >         static unsigned long isa2hwcap[256] = {0};
> >
> > +       mmu_supports();
> > +
> >         isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;
> >         isa2hwcap['m'] = isa2hwcap['M'] = COMPAT_HWCAP_ISA_M;
> >         isa2hwcap['a'] = isa2hwcap['A'] = COMPAT_HWCAP_ISA_A;
> > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> > index 24b2b8044602..e4e658165ee1 100644
> > --- a/arch/riscv/mm/init.c
> > +++ b/arch/riscv/mm/init.c
> > @@ -854,3 +854,8 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
> >         return vmemmap_populate_basepages(start, end, node, NULL);
> >  }
> >  #endif
> > +
> > +#if defined(CONFIG_64BIT)
> > +struct __svpbmt_struct __svpbmt __ro_after_init;
> > +EXPORT_SYMBOL(__svpbmt);
> > +#endif
> > --
> > 2.25.4
> >
>
>
> --
> Best Regards
>  Guo Ren
>
> ML: https://lore.kernel.org/linux-csky/
>