From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Rapoport Subject: Re: [PATCH v6 1/3] arm64: map FDT as RW for early_init_dt_scan() Date: Thu, 13 Jun 2019 14:44:44 +0300 Message-ID: <20190613114443.GA25164@rapoport-lnx> References: <20190612043258.166048-1-hsinyi@chromium.org> <20190612043258.166048-2-hsinyi@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20190612043258.166048-2-hsinyi@chromium.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Hsin-Yi Wang Cc: Mark Rutland , devicetree@vger.kernel.org, Yu Zhao , Kees Cook , Ard Biesheuvel , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, Stephen Boyd , Jun Yao , Miles Chen , Rob Herring , James Morse , Andrew Murray , Andrew Morton , Laura Abbott , Frank Rowand , linux-arm-kernel@lists.infradead.org, Robin Murphy List-Id: devicetree@vger.kernel.org On Wed, Jun 12, 2019 at 12:32:58PM +0800, Hsin-Yi Wang wrote: > Currently in arm64, FDT is mapped to RO before it's passed to > early_init_dt_scan(). However, there might be some codes > (eg. commit "fdt: add support for rng-seed") that need to modify FDT > during init. Map FDT to RO after early fixups are done. > > Signed-off-by: Hsin-Yi Wang > Reviewed-by: Stephen Boyd Reviewed-by: Mike Rapoport > --- > change log v5->v6: > * no change. > --- > arch/arm64/include/asm/mmu.h | 2 +- > arch/arm64/kernel/kaslr.c | 5 +---- > arch/arm64/kernel/setup.c | 9 ++++++++- > arch/arm64/mm/mmu.c | 15 +-------------- > 4 files changed, 11 insertions(+), 20 deletions(-) > > diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h > index 67ef25d037ea..27f6f17aae36 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 prot); > extern void mark_linear_text_alias_ro(void); > > #define INIT_MM_CONTEXT(name) \ > diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c > index 06941c1fe418..92bb53460401 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; > } > > -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 virtual > * address, and if it returns successfully, the kernel will be remapped, and > @@ -96,7 +93,7 @@ u64 __init kaslr_early_init(u64 dt_phys) > * attempt at mapping the FDT in setup_machine() > */ > early_fixmap_init(); > - fdt = __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL); > + fdt = fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL); > if (!fdt) > return 0; > > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c > index 413d566405d1..6a7050319b5b 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) > > static void __init setup_machine_fdt(phys_addr_t dt_phys) > { > - void *dt_virt = fixmap_remap_fdt(dt_phys); > + int size; > + void *dt_virt = fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL); > const char *name; > > + 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 address 0x%p)\n" > @@ -195,6 +199,9 @@ static void __init setup_machine_fdt(phys_addr_t dt_phys) > cpu_relax(); > } > > + /* Early fixups are done, map the FDT as read-only now */ > + fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO); > + > name = of_flat_dt_get_machine_name(); > if (!name) > return; > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 93ed0df4df79..5d01365a4333 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -887,7 +887,7 @@ void __set_fixmap(enum fixed_addresses idx, > } > } > > -void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) > +void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) > { > const u64 dt_virt_base = __fix_to_virt(FIX_FDT); > int offset; > @@ -940,19 +940,6 @@ void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) > return dt_virt; > } > > -void *__init fixmap_remap_fdt(phys_addr_t dt_phys) > -{ > - void *dt_virt; > - int size; > - > - dt_virt = __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) > { > /* > -- > 2.20.1 > -- Sincerely yours, Mike.