From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Boyd Subject: Re: [PATCH v4 1/3] amr64: map FDT as RW for early_init_dt_scan() Date: Thu, 23 May 2019 17:04:18 -0700 Message-ID: <5ce73503.1c69fb81.5f889.1d84@mx.google.com> References: <20190519160446.320-1-hsinyi@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20190519160446.320-1-hsinyi@chromium.org> Sender: linux-kernel-owner@vger.kernel.org To: linux-arm-kernel@lists.infradead.org Cc: Rob Herring , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Frank Rowand , Catalin Marinas , Will Deacon , Andrew Morton , Mike Rapoport , Ard Biesheuvel , Miles Chen , Hsin-Yi Wang , James Morse , Andrew Murray , Mark Rutland , Jun Yao , Yu Zhao , Robin Murphy , Laura Abbott , Kees Cook List-Id: devicetree@vger.kernel.org Quoting Hsin-Yi Wang (2019-05-19 09:04:44) > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index a170c6369a68..29648e86f7e5 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -940,12 +940,12 @@ void *__init __fixmap_remap_fdt(phys_addr_t dt_phys= , int *size, pgprot_t prot) > return dt_virt; > } > =20 > -void *__init fixmap_remap_fdt(phys_addr_t dt_phys) > +void *__init fixmap_remap_fdt(phys_addr_t dt_phys, pgprot_t prot) > { > void *dt_virt; > int size; > =20 > - dt_virt =3D __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO); > + dt_virt =3D __fixmap_remap_fdt(dt_phys, &size, prot); > if (!dt_virt) > return NULL; > =20 Sorry, I'm still confused why we want to call memblock_reserve() again. Why not avoid it? diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h index 67ef25d037ea..d0d9de9da5c1 100644 --- a/arch/arm64/include/asm/mmu.h +++ b/arch/arm64/include/asm/mmu.h @@ -137,7 +137,7 @@ extern void init_mem_pgprot(void); extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, unsigned long virt, phys_addr_t size, pgprot_t prot, bool page_mappings_only); -extern void *fixmap_remap_fdt(phys_addr_t dt_phys); +extern void *__fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t p= rot); extern void mark_linear_text_alias_ro(void); =20 #define INIT_MM_CONTEXT(name) \ diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c index b09b6f75f759..0701c2cf1534 100644 --- a/arch/arm64/kernel/kaslr.c +++ b/arch/arm64/kernel/kaslr.c @@ -65,9 +65,6 @@ static __init const u8 *kaslr_get_cmdline(void *fdt) return default_cmdline; } =20 -extern void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size, - pgprot_t prot); - /* * This routine will be executed with the kernel mapped at its default vir= tual * address, and if it returns successfully, the kernel will be remapped, a= nd diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 413d566405d1..3e97354566ff 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -181,9 +181,13 @@ static void __init smp_build_mpidr_hash(void) =20 static void __init setup_machine_fdt(phys_addr_t dt_phys) { - void *dt_virt =3D fixmap_remap_fdt(dt_phys); + int size; + void *dt_virt =3D __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL); const char *name; =20 + if (dt_virt) + memblock_reserve(dt_phys, size); + if (!dt_virt || !early_init_dt_scan(dt_virt)) { pr_crit("\n" "Error: invalid device tree blob at physical address %pa (virtual addre= ss 0x%p)\n" @@ -195,6 +199,9 @@ static void __init setup_machine_fdt(phys_addr_t dt_phy= s) cpu_relax(); } =20 + /* Early fixups are done, map the FDT as read-only now */ + __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO); + name =3D of_flat_dt_get_machine_name(); if (!name) return; diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index a170c6369a68..ddf6086cd9dd 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -940,19 +940,6 @@ void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, i= nt *size, pgprot_t prot) return dt_virt; } =20 -void *__init fixmap_remap_fdt(phys_addr_t dt_phys) -{ - void *dt_virt; - int size; - - dt_virt =3D __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO); - if (!dt_virt) - return NULL; - - memblock_reserve(dt_phys, size); - return dt_virt; -} - int __init arch_ioremap_pud_supported(void) { /* only 4k granule supports level 1 block mappings */