Re: [PATCH 2/2] riscv: mm: use __pa_symbol for kernel symbols

From: Anup Patel <anup@brainfault.org>
To: Zong Li <zong.li@sifive.com>
Cc: linux-riscv <linux-riscv@lists.infradead.org>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	"linux-kernel@vger.kernel.org List"
	<linux-kernel@vger.kernel.org>,
	Paul Walmsley <paul.walmsley@sifive.com>
Subject: Re: [PATCH 2/2] riscv: mm: use __pa_symbol for kernel symbols
Date: Thu, 2 Jan 2020 09:01:58 +0530	[thread overview]
Message-ID: <CAAhSdy0sp_=nwAKxphA8of4UV_NfxHE-KXyTPekmHkieq_XyVw@mail.gmail.com> (raw)
In-Reply-To: <20200102031240.44484-3-zong.li@sifive.com>

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

Regards,
Anup