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From:   Zong Li <zong.li@sifive.com>
Date:   Thu, 2 Jan 2020 11:49:43 +0800
Message-ID: <CANXhq0rHOj6_UetWEnvNw4TzwWR9tzWTAJysxqknPN1Ng1Pu8A@mail.gmail.com>
Subject: Re: [PATCH 2/2] riscv: mm: use __pa_symbol for kernel symbols
To:     Anup Patel <anup@brainfault.org>
Cc:     Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        linux-riscv <linux-riscv@lists.infradead.org>,
        "linux-kernel@vger.kernel.org List" <linux-kernel@vger.kernel.org>
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Sender: linux-kernel-owner@vger.kernel.org
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On Thu, Jan 2, 2020 at 11:32 AM Anup Patel <anup@brainfault.org> wrote:
>
> On Thu, Jan 2, 2020 at 8:42 AM Zong Li <zong.li@sifive.com> wrote:
> >
> > __pa_symbol is the marcro that should be used for kernel symbols. It is
> > also a pre-requisite for DEBUG_VIRTUAL which will do bounds checking.
> >
> > Signed-off-by: Zong Li <zong.li@sifive.com>
> > ---
> >  arch/riscv/mm/init.c | 12 ++++++------
> >  1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> > index 69f6678db7f3..965a8cf4829c 100644
> > --- a/arch/riscv/mm/init.c
> > +++ b/arch/riscv/mm/init.c
> > @@ -99,13 +99,13 @@ static void __init setup_initrd(void)
> >                 pr_info("initrd not found or empty");
> >                 goto disable;
> >         }
> > -       if (__pa(initrd_end) > PFN_PHYS(max_low_pfn)) {
> > +       if (__pa_symbol(initrd_end) > PFN_PHYS(max_low_pfn)) {
> >                 pr_err("initrd extends beyond end of memory");
> >                 goto disable;
> >         }
> >
> >         size = initrd_end - initrd_start;
> > -       memblock_reserve(__pa(initrd_start), size);
> > +       memblock_reserve(__pa_symbol(initrd_start), size);
> >         initrd_below_start_ok = 1;
> >
> >         pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",
> > @@ -124,8 +124,8 @@ void __init setup_bootmem(void)
> >  {
> >         struct memblock_region *reg;
> >         phys_addr_t mem_size = 0;
> > -       phys_addr_t vmlinux_end = __pa(&_end);
> > -       phys_addr_t vmlinux_start = __pa(&_start);
> > +       phys_addr_t vmlinux_end = __pa_symbol(&_end);
> > +       phys_addr_t vmlinux_start = __pa_symbol(&_start);
> >
> >         /* Find the memory region containing the kernel */
> >         for_each_memblock(memory, reg) {
> > @@ -445,7 +445,7 @@ static void __init setup_vm_final(void)
> >
> >         /* Setup swapper PGD for fixmap */
> >         create_pgd_mapping(swapper_pg_dir, FIXADDR_START,
> > -                          __pa(fixmap_pgd_next),
> > +                          __pa_symbol(fixmap_pgd_next),
> >                            PGDIR_SIZE, PAGE_TABLE);
> >
> >         /* Map all memory banks */
> > @@ -474,7 +474,7 @@ static void __init setup_vm_final(void)
> >         clear_fixmap(FIX_PMD);
> >
> >         /* Move to swapper page table */
> > -       csr_write(CSR_SATP, PFN_DOWN(__pa(swapper_pg_dir)) | SATP_MODE);
> > +       csr_write(CSR_SATP, PFN_DOWN(__pa_symbol(swapper_pg_dir)) | SATP_MODE);
> >         local_flush_tlb_all();
> >  }
> >  #else
> > --
> > 2.24.1
> >
>
> Overall looks good to me.
>
> Reviewed-by: Anup Patel <anup@brainfault.org>
>
> I have not tried this patch but can you confirm that
> __pa_symbol() works fine even when DEBUG_VIRTUAL=n

Yes, it works fine through original way when DEBUG_VIRTUAL is not set.

>
> Regards,
> Anup