From: Conor Dooley <mail@conchuod.ie> To: Palmer Dabbelt <palmer@dabbelt.com>, Conor.Dooley@microchip.com Cc: mick@ics.forth.gr, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Paul Walmsley <paul.walmsley@sifive.com>, aou@eecs.berkeley.edu Subject: Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region Date: Thu, 28 Apr 2022 22:58:19 +0100 [thread overview] Message-ID: <4eec9cb6-c80e-a5e5-995b-7568d568ad26@conchuod.ie> (raw) In-Reply-To: <mhng-525e0b77-f9af-4cba-a985-f8872835574e@palmer-ri-x1c9> On 28/04/2022 22:48, Palmer Dabbelt wrote: > On Thu, 24 Mar 2022 02:37:29 PDT (-0700), Conor.Dooley@microchip.com wrote: >> >> On 22/03/2022 13:28, Nick Kossifidis wrote: >>> In case the DTB provided by the bootloader/BootROM is before the kernel >>> image or outside /memory, we won't be able to access it through the >>> linear mapping, and get a segfault on setup_arch(). Currently OpenSBI >>> relocates DTB but that's not always the case (e.g. if FW_JUMP_FDT_ADDR >>> is not specified), and it's also not the most portable approach since >>> the default FW_JUMP_FDT_ADDR of the generic platform relocates the DTB >>> at a specific offset that may not be available. To avoid this situation >>> copy DTB so that it's visible through the linear mapping. >>> >>> Signed-off-by: Nick Kossifidis <mick@ics.forth.gr> >> >> Albeit in a backport, I tested this on a PolarFire SoC based board. >> So I guess, Tested-by: Conor Dooley <conor.dooley@microchip.com> > > My scripts don't pick these up unless they're on their own line, not sure if that's too conservative but it's on purpose. I just sort of stumbled into this one so it's in. Uhh, I checked and b4 doesn't pick it up either. I'm not overly concerned about getting "credit" for testing it, more interested in pointing out that it does solve a real issue that I have run into in case you were looking for incentive to apply it :) I realised immediately after sending that it was likely an invalid tag, but figured it'd serve that purpose either way. Thanks, Conor. > >> >> And a lot cleaner than using create_pgd_mapping in setup_vm_final to do it :) >> >> Thanks, >> Conor. >> >>> --- >>> arch/riscv/mm/init.c | 21 +++++++++++++++++++-- >>> 1 file changed, 19 insertions(+), 2 deletions(-) >>> >>> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c >>> index 0d588032d..697a9aed4 100644 >>> --- a/arch/riscv/mm/init.c >>> +++ b/arch/riscv/mm/init.c >>> @@ -206,8 +206,25 @@ static void __init setup_bootmem(void) >>> * early_init_fdt_reserve_self() since __pa() does >>> * not work for DTB pointers that are fixmap addresses >>> */ >>> - if (!IS_ENABLED(CONFIG_BUILTIN_DTB)) >>> - memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va)); >>> + if (!IS_ENABLED(CONFIG_BUILTIN_DTB)) { >>> + /* >>> + * In case the DTB is not located in a memory region we won't >>> + * be able to locate it later on via the linear mapping and >>> + * get a segfault when accessing it via __va(dtb_early_pa). >>> + * To avoid this situation copy DTB to a memory region. >>> + * Note that memblock_phys_alloc will also reserve DTB region. >>> + */ >>> + if (!memblock_is_memory(dtb_early_pa)) { >>> + size_t fdt_size = fdt_totalsize(dtb_early_va); >>> + phys_addr_t new_dtb_early_pa = memblock_phys_alloc(fdt_size, PAGE_SIZE); >>> + void *new_dtb_early_va = early_memremap(new_dtb_early_pa, fdt_size); >>> + >>> + memcpy(new_dtb_early_va, dtb_early_va, fdt_size); >>> + early_memunmap(new_dtb_early_va, fdt_size); >>> + _dtb_early_pa = new_dtb_early_pa; >>> + } else >>> + memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va)); >>> + } >>> early_init_fdt_scan_reserved_mem(); >>> dma_contiguous_reserve(dma32_phys_limit);
WARNING: multiple messages have this Message-ID (diff)
From: Conor Dooley <mail@conchuod.ie> To: Palmer Dabbelt <palmer@dabbelt.com>, Conor.Dooley@microchip.com Cc: mick@ics.forth.gr, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Paul Walmsley <paul.walmsley@sifive.com>, aou@eecs.berkeley.edu Subject: Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region Date: Thu, 28 Apr 2022 22:58:19 +0100 [thread overview] Message-ID: <4eec9cb6-c80e-a5e5-995b-7568d568ad26@conchuod.ie> (raw) In-Reply-To: <mhng-525e0b77-f9af-4cba-a985-f8872835574e@palmer-ri-x1c9> On 28/04/2022 22:48, Palmer Dabbelt wrote: > On Thu, 24 Mar 2022 02:37:29 PDT (-0700), Conor.Dooley@microchip.com wrote: >> >> On 22/03/2022 13:28, Nick Kossifidis wrote: >>> In case the DTB provided by the bootloader/BootROM is before the kernel >>> image or outside /memory, we won't be able to access it through the >>> linear mapping, and get a segfault on setup_arch(). Currently OpenSBI >>> relocates DTB but that's not always the case (e.g. if FW_JUMP_FDT_ADDR >>> is not specified), and it's also not the most portable approach since >>> the default FW_JUMP_FDT_ADDR of the generic platform relocates the DTB >>> at a specific offset that may not be available. To avoid this situation >>> copy DTB so that it's visible through the linear mapping. >>> >>> Signed-off-by: Nick Kossifidis <mick@ics.forth.gr> >> >> Albeit in a backport, I tested this on a PolarFire SoC based board. >> So I guess, Tested-by: Conor Dooley <conor.dooley@microchip.com> > > My scripts don't pick these up unless they're on their own line, not sure if that's too conservative but it's on purpose. I just sort of stumbled into this one so it's in. Uhh, I checked and b4 doesn't pick it up either. I'm not overly concerned about getting "credit" for testing it, more interested in pointing out that it does solve a real issue that I have run into in case you were looking for incentive to apply it :) I realised immediately after sending that it was likely an invalid tag, but figured it'd serve that purpose either way. Thanks, Conor. > >> >> And a lot cleaner than using create_pgd_mapping in setup_vm_final to do it :) >> >> Thanks, >> Conor. >> >>> --- >>> arch/riscv/mm/init.c | 21 +++++++++++++++++++-- >>> 1 file changed, 19 insertions(+), 2 deletions(-) >>> >>> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c >>> index 0d588032d..697a9aed4 100644 >>> --- a/arch/riscv/mm/init.c >>> +++ b/arch/riscv/mm/init.c >>> @@ -206,8 +206,25 @@ static void __init setup_bootmem(void) >>> * early_init_fdt_reserve_self() since __pa() does >>> * not work for DTB pointers that are fixmap addresses >>> */ >>> - if (!IS_ENABLED(CONFIG_BUILTIN_DTB)) >>> - memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va)); >>> + if (!IS_ENABLED(CONFIG_BUILTIN_DTB)) { >>> + /* >>> + * In case the DTB is not located in a memory region we won't >>> + * be able to locate it later on via the linear mapping and >>> + * get a segfault when accessing it via __va(dtb_early_pa). >>> + * To avoid this situation copy DTB to a memory region. >>> + * Note that memblock_phys_alloc will also reserve DTB region. >>> + */ >>> + if (!memblock_is_memory(dtb_early_pa)) { >>> + size_t fdt_size = fdt_totalsize(dtb_early_va); >>> + phys_addr_t new_dtb_early_pa = memblock_phys_alloc(fdt_size, PAGE_SIZE); >>> + void *new_dtb_early_va = early_memremap(new_dtb_early_pa, fdt_size); >>> + >>> + memcpy(new_dtb_early_va, dtb_early_va, fdt_size); >>> + early_memunmap(new_dtb_early_va, fdt_size); >>> + _dtb_early_pa = new_dtb_early_pa; >>> + } else >>> + memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va)); >>> + } >>> early_init_fdt_scan_reserved_mem(); >>> dma_contiguous_reserve(dma32_phys_limit); _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2022-04-28 21:58 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-03-22 13:28 [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region Nick Kossifidis 2022-03-22 13:28 ` Nick Kossifidis 2022-03-23 17:21 ` Conor Dooley 2022-03-23 17:21 ` Conor Dooley 2022-03-24 9:37 ` Conor.Dooley 2022-03-24 9:37 ` Conor.Dooley 2022-03-27 8:52 ` Nick Kossifidis 2022-03-27 8:52 ` Nick Kossifidis 2022-04-28 21:48 ` Palmer Dabbelt 2022-04-28 21:48 ` Palmer Dabbelt 2022-04-28 21:58 ` Conor Dooley [this message] 2022-04-28 21:58 ` Conor Dooley 2022-04-26 6:11 ` Nick Kossifidis 2022-04-26 6:11 ` Nick Kossifidis 2022-04-28 21:48 ` Palmer Dabbelt 2022-04-28 21:48 ` Palmer Dabbelt 2022-04-29 15:28 ` Palmer Dabbelt 2022-04-29 15:28 ` Palmer Dabbelt 2022-04-29 19:18 ` Nick Kossifidis 2022-04-29 19:18 ` Nick Kossifidis 2022-05-06 16:36 ` Palmer Dabbelt 2022-05-06 16:36 ` Palmer Dabbelt
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