Messages in this thread | | | From | Wei Fu <> | Date | Fri, 3 Dec 2021 17:12:10 +0800 | Subject | Re: [PATCH V4 2/2] riscv: add RISC-V Svpbmt extension supports |
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Hi Anup,
On Wed, Dec 1, 2021 at 2:19 PM Anup Patel <anup@brainfault.org> wrote: > > On Wed, Dec 1, 2021 at 10:35 AM Wei Fu <wefu@redhat.com> wrote: > > > > Hi, Jisheng Zhang, > > > > On Mon, Nov 29, 2021 at 9:44 PM Jisheng Zhang <jszhang@kernel.org> wrote: > > > > > > On Mon, 29 Nov 2021 09:40:07 +0800 > > > 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) > > > > > > IIRC, Christoph suggested a CONFIG_RISCV_SVPBMT when reviewing v3. What > > > about that idea? > > > > Yes, sorry for missing it, yes, I think we can have something like this > > > > config ARCH_HAS_RISCV_SVPBMT > > bool > > default n > > > > any platform which needs this support, can just > > > > select ARCH_HAS_RISCV_SVPBMT > > > > and which is the best name? ARCH_HAS_RISCV_SVPBMT or just ARCH_HAS_SVPBMT ? > > > > > > > > > + 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) > > > > > > can we remove this function currently? Instead, directly call > > > mmu_supports_svpbmt()? > > > > > > > +{ > > > > + 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; > > > > > > Added the structure for all RV64 including NOMMU case and those platforms > > > which doen't want SVPBMT at all, I believe Christoph's CONFIG_RISCV_SVPBMT > > > suggestion can solve this problem. > > > > see ARCH_HAS_RISCV_SVPBMT above . :-) > > This config option will not align with the goal of having a unified > kernel image which works on HW with/without Svpmbt. > > Better to explore code patching approaches which have zero > overhead.
Sure, I think Heiko has some Idea about code patching , and I will wait for his new patches for this mechanism
> > Regards, > Anup > > > > > > > > > > +EXPORT_SYMBOL(__svpbmt); > > > > +#endif > > > > > > > > > _______________________________________________ > > linux-riscv mailing list > > linux-riscv@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-riscv >
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