Re: [PATCH V10 12/22] LoongArch: Add memory management

[Huacai Chen <chenhuacai@gmail.com>]

Hi, Xuerui,

On Sun, May 15, 2022 at 5:42 PM WANG Xuerui <kernel@xen0n.name> wrote:
>
> Hi,
>
> Compared to other areas, I'm not that familiar with mm in general, so
> this review may not be as in-depth as I'd like. Still...
>
> On 5/14/22 16:03, Huacai Chen wrote:
> > Add memory management support for LoongArch, including: cache and tlb
> > management, page fault handling and ioremap/mmap support.
> >
> > Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> > ---
> >   arch/loongarch/include/asm/cache.h        |  13 +
> >   arch/loongarch/include/asm/cacheflush.h   |  80 ++++
> >   arch/loongarch/include/asm/cacheops.h     |  37 ++
> >   arch/loongarch/include/asm/fixmap.h       |  13 +
> >   arch/loongarch/include/asm/hugetlb.h      |  79 ++++
> >   arch/loongarch/include/asm/page.h         | 113 +++++
> >   arch/loongarch/include/asm/pgalloc.h      | 103 +++++
> >   arch/loongarch/include/asm/pgtable-bits.h | 131 ++++++
> >   arch/loongarch/include/asm/pgtable.h      | 532 ++++++++++++++++++++++
> >   arch/loongarch/include/asm/shmparam.h     |  12 +
> >   arch/loongarch/include/asm/sparsemem.h    |  23 +
> >   arch/loongarch/include/asm/tlb.h          | 216 +++++++++
> >   arch/loongarch/include/asm/tlbflush.h     |  35 ++
> >   arch/loongarch/include/asm/vmalloc.h      |   4 +
> >   arch/loongarch/mm/cache.c                 | 140 ++++++
> >   arch/loongarch/mm/extable.c               |  22 +
> >   arch/loongarch/mm/fault.c                 | 261 +++++++++++
> >   arch/loongarch/mm/hugetlbpage.c           |  87 ++++
> >   arch/loongarch/mm/init.c                  | 165 +++++++
> >   arch/loongarch/mm/ioremap.c               |  27 ++
> >   arch/loongarch/mm/maccess.c               |  10 +
> >   arch/loongarch/mm/mmap.c                  | 125 +++++
> >   arch/loongarch/mm/page.S                  |  84 ++++
> >   arch/loongarch/mm/pgtable.c               | 130 ++++++
> >   arch/loongarch/mm/tlb.c                   | 282 ++++++++++++
> >   arch/loongarch/mm/tlbex.S                 | 477 +++++++++++++++++++
> >   26 files changed, 3201 insertions(+)
> >   create mode 100644 arch/loongarch/include/asm/cache.h
> >   create mode 100644 arch/loongarch/include/asm/cacheflush.h
> >   create mode 100644 arch/loongarch/include/asm/cacheops.h
> >   create mode 100644 arch/loongarch/include/asm/fixmap.h
> >   create mode 100644 arch/loongarch/include/asm/hugetlb.h
> >   create mode 100644 arch/loongarch/include/asm/page.h
> >   create mode 100644 arch/loongarch/include/asm/pgalloc.h
> >   create mode 100644 arch/loongarch/include/asm/pgtable-bits.h
> >   create mode 100644 arch/loongarch/include/asm/pgtable.h
> >   create mode 100644 arch/loongarch/include/asm/shmparam.h
> >   create mode 100644 arch/loongarch/include/asm/sparsemem.h
> >   create mode 100644 arch/loongarch/include/asm/tlb.h
> >   create mode 100644 arch/loongarch/include/asm/tlbflush.h
> >   create mode 100644 arch/loongarch/include/asm/vmalloc.h
> >   create mode 100644 arch/loongarch/mm/cache.c
> >   create mode 100644 arch/loongarch/mm/extable.c
> >   create mode 100644 arch/loongarch/mm/fault.c
> >   create mode 100644 arch/loongarch/mm/hugetlbpage.c
> >   create mode 100644 arch/loongarch/mm/init.c
> >   create mode 100644 arch/loongarch/mm/ioremap.c
> >   create mode 100644 arch/loongarch/mm/maccess.c
> >   create mode 100644 arch/loongarch/mm/mmap.c
> >   create mode 100644 arch/loongarch/mm/page.S
> >   create mode 100644 arch/loongarch/mm/pgtable.c
> >   create mode 100644 arch/loongarch/mm/tlb.c
> >   create mode 100644 arch/loongarch/mm/tlbex.S
> >
> (snip)
> > diff --git a/arch/loongarch/include/asm/tlb.h b/arch/loongarch/include/asm/tlb.h
> > new file mode 100644
> > index 000000000000..a9dda11c494b
> > --- /dev/null
> > +++ b/arch/loongarch/include/asm/tlb.h
> > @@ -0,0 +1,216 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> > + */
> > +#ifndef __ASM_TLB_H
> > +#define __ASM_TLB_H
> > +
> > +#include <linux/mm_types.h>
> > +#include <asm/cpu-features.h>
> > +#include <asm/loongarch.h>
> > +
> > +/*
> > + * TLB Invalidate Flush
> > + */
> > +static inline void tlbclr(void)
> > +{
> > +     __asm__ __volatile__("tlbclr");
> > +}
> > +
> > +static inline void tlbflush(void)
> > +{
> > +     __asm__ __volatile__("tlbflush");
> > +}
> > +
> > +/*
> > + * TLB R/W operations.
> > + */
> > +static inline void tlb_probe(void)
> > +{
> > +     __asm__ __volatile__("tlbsrch");
> > +}
> > +
> > +static inline void tlb_read(void)
> > +{
> > +     __asm__ __volatile__("tlbrd");
> > +}
> > +
> > +static inline void tlb_write_indexed(void)
> > +{
> > +     __asm__ __volatile__("tlbwr");
> > +}
> > +
> > +static inline void tlb_write_random(void)
> > +{
> > +     __asm__ __volatile__("tlbfill");
> > +}
> > +
> > +/*
> > + * Guest TLB Invalidate Flush
> > + */
> > +static inline void guest_tlbflush(void)
> > +{
> > +     __asm__ __volatile__(
> > +             ".word 0x6482401\n\t");
> > +}
>
> Do we want to add guest mm ops this early? KVM isn't part of initial
> bring-up. Leaving as-is would save some later work, though, and I'll
> leave the judgment to other reviewers as to whether to remove these. (My
> recommendation would of course be in favor of removal.)
>
> Plus it's interesting to see undocumented instruction words, this
> satisfies curiosity ;-)
>
> (Always better to properly support in binutils though.)
OK, they should be removed at present.

>
> > +
> > +/*
> > + * Guest TLB R/W operations.
> > + */
> > +static inline void guest_tlb_probe(void)
> > +{
> > +     __asm__ __volatile__(
> > +             ".word 0x6482801\n\t");
> > +}
> > +
> > +static inline void guest_tlb_read(void)
> > +{
> > +     __asm__ __volatile__(
> > +             ".word 0x6482c01\n\t");
> > +}
> > +
> > +static inline void guest_tlb_write_indexed(void)
> > +{
> > +     __asm__ __volatile__(
> > +             ".word 0x6483001\n\t");
> > +}
> > +
> > +static inline void guest_tlb_write_random(void)
> > +{
> > +     __asm__ __volatile__(
> > +             ".word 0x6483401\n\t");
> > +}
> > +
> > +enum invtlb_ops {
> > +     /* Invalid all tlb */
> > +     INVTLB_ALL = 0x0,
> > +     /* Invalid current tlb */
> > +     INVTLB_CURRENT_ALL = 0x1,
> > +     /* Invalid all global=1 lines in current tlb */
> > +     INVTLB_CURRENT_GTRUE = 0x2,
> > +     /* Invalid all global=0 lines in current tlb */
> > +     INVTLB_CURRENT_GFALSE = 0x3,
> > +     /* Invalid global=0 and matched asid lines in current tlb */
> > +     INVTLB_GFALSE_AND_ASID = 0x4,
> > +     /* Invalid addr with global=0 and matched asid in current tlb */
> > +     INVTLB_ADDR_GFALSE_AND_ASID = 0x5,
> > +     /* Invalid addr with global=1 or matched asid in current tlb */
> > +     INVTLB_ADDR_GTRUE_OR_ASID = 0x6,
> > +     /* Invalid matched gid in guest tlb */
> > +     INVGTLB_GID = 0x9,
> > +     /* Invalid global=1, matched gid in guest tlb */
> > +     INVGTLB_GID_GTRUE = 0xa,
> > +     /* Invalid global=0, matched gid in guest tlb */
> > +     INVGTLB_GID_GFALSE = 0xb,
> > +     /* Invalid global=0, matched gid and asid in guest tlb */
> > +     INVGTLB_GID_GFALSE_ASID = 0xc,
> > +     /* Invalid global=0 , matched gid, asid and addr in guest tlb */
> > +     INVGTLB_GID_GFALSE_ASID_ADDR = 0xd,
> > +     /* Invalid global=1 , matched gid, asid and addr in guest tlb */
> > +     INVGTLB_GID_GTRUE_ASID_ADDR = 0xe,
> > +     /* Invalid all gid gva-->gpa guest tlb */
> > +     INVGTLB_ALLGID_GVA_TO_GPA = 0x10,
> > +     /* Invalid all gid gpa-->hpa tlb */
> > +     INVTLB_ALLGID_GPA_TO_HPA = 0x11,
> > +     /* Invalid all gid tlb, including  gva-->gpa and gpa-->hpa */
> > +     INVTLB_ALLGID = 0x12,
> > +     /* Invalid matched gid gva-->gpa guest tlb */
> > +     INVGTLB_GID_GVA_TO_GPA = 0x13,
> > +     /* Invalid matched gid gpa-->hpa tlb */
> > +     INVTLB_GID_GPA_TO_HPA = 0x14,
> > +     /* Invalid matched gid tlb,including gva-->gpa and gpa-->hpa */
> > +     INVTLB_GID_ALL = 0x15,
> > +     /* Invalid matched gid and addr gpa-->hpa tlb */
> > +     INVTLB_GID_ADDR = 0x16,
> > +};
> > +
> > +/*
> > + * invtlb op info addr
> > + * (0x1 << 26) | (0x24 << 20) | (0x13 << 15) |
> > + * (addr << 10) | (info << 5) | op
> > + */
> > +static inline void invtlb(u32 op, u32 info, u64 addr)
> > +{
> > +     __asm__ __volatile__(
> > +             "parse_r addr,%0\n\t"
> > +             "parse_r info,%1\n\t"
> > +             ".word ((0x6498000) | (addr << 10) | (info << 5) | %2)\n\t"
> Isn't INVTLB already supported by binutils?
> > +             :
> > +             : "r"(addr), "r"(info), "i"(op)
> > +             :
> > +             );
> > +}
> > +
> > +static inline void invtlb_addr(u32 op, u32 info, u64 addr)
> > +{
> > +     __asm__ __volatile__(
> > +             "parse_r addr,%0\n\t"
> > +             ".word ((0x6498000) | (addr << 10) | (0 << 5) | %1)\n\t"
> > +             :
> > +             : "r"(addr), "i"(op)
> > +             :
> > +             );
> > +}
> > +
> > +static inline void invtlb_info(u32 op, u32 info, u64 addr)
> > +{
> > +     __asm__ __volatile__(
> > +             "parse_r info,%0\n\t"
> > +             ".word ((0x6498000) | (0 << 10) | (info << 5) | %1)\n\t"
> > +             :
> > +             : "r"(info), "i"(op)
> > +             :
> > +             );
> > +}
> > +
> > +static inline void invtlb_all(u32 op, u32 info, u64 addr)
> > +{
> > +     __asm__ __volatile__(
> > +             ".word ((0x6498000) | (0 << 10) | (0 << 5) | %0)\n\t"
> > +             :
> > +             : "i"(op)
> > +             :
> > +             );
> > +}
> > +
>
> (rest of patch snipped for brevity)
>
> Admittedly I didn't really look into the rest for correctness, only
> briefly checking code style. However as several people (me included)
> already used the port for heavy compilation loads, stresses and things
> like that, the code should be in good standing too.
>
> With the nits addressed:
>
> Reviewed-by: WANG Xuerui <git@xen0n.name>
Thanks for your review.

Huacai
>