[PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Nick Kossifidis]

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>
---
 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);
-- 
2.34.1

[PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Nick Kossifidis]

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>
---
 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);
-- 
2.34.1


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Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Conor Dooley]

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.

Ran into the same issue & have been carrying a hack for it, this looks 
*a lot* cleaner. I'll dig out the offending configuration tomorrow and 
try to give you a tested-by.
Thanks,
Conor.

> 
> Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
> ---
>   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);

Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Conor Dooley]

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.

Ran into the same issue & have been carrying a hack for it, this looks 
*a lot* cleaner. I'll dig out the offending configuration tomorrow and 
try to give you a tested-by.
Thanks,
Conor.

> 
> Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
> ---
>   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);

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Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Conor.Dooley]

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>

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);

Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Conor.Dooley]

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>

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);
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Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Nick Kossifidis]

Στις 2022-03-24 11:37, Conor.Dooley@microchip.com έγραψε:
> 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>
> 
> And a lot cleaner than using create_pgd_mapping in setup_vm_final to do 
> it :)
> 
> Thanks,
> Conor.
> 

Thanks !

Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Nick Kossifidis]

Στις 2022-03-24 11:37, Conor.Dooley@microchip.com έγραψε:
> 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>
> 
> And a lot cleaner than using create_pgd_mapping in setup_vm_final to do 
> it :)
> 
> Thanks,
> Conor.
> 

Thanks !

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Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Palmer Dabbelt]

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.

> 
> 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);

Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Palmer Dabbelt]

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.

> 
> 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);

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Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Conor Dooley]

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);

Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Conor Dooley]

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);

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Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Nick Kossifidis]

Hello Palmer,

Any updates on this ?

Regards,
Nick

On 3/22/22 15:28, 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>
> ---
>   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);

Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Nick Kossifidis]

Hello Palmer,

Any updates on this ?

Regards,
Nick

On 3/22/22 15:28, 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>
> ---
>   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);


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Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Palmer Dabbelt]

On Mon, 25 Apr 2022 23:11:23 PDT (-0700), mick@ics.forth.gr wrote:
> Hello Palmer,
>
> Any updates on this ?

Sorry about that, it's on fixes.

>
> Regards,
> Nick
>
> On 3/22/22 15:28, 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>
>> ---
>>   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);

Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Palmer Dabbelt]

On Mon, 25 Apr 2022 23:11:23 PDT (-0700), mick@ics.forth.gr wrote:
> Hello Palmer,
>
> Any updates on this ?

Sorry about that, it's on fixes.

>
> Regards,
> Nick
>
> On 3/22/22 15:28, 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>
>> ---
>>   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);

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Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Palmer Dabbelt]

On Thu, 28 Apr 2022 14:48:14 PDT (-0700), Palmer Dabbelt wrote:
> On Mon, 25 Apr 2022 23:11:23 PDT (-0700), mick@ics.forth.gr wrote:
>> Hello Palmer,
>>
>> Any updates on this ?
>
> Sorry about that, it's on fixes.

Not sure if I just wasn't paying attention yesterday or if I'm grumpier 
this morning, but that "RISC-V-fixes: " prefix is just a bit too odd -- 
I know we've got a split between "RISC-V" and "riscv" so maybe it 
doesn't matter, but even that is kind of ugly.

I re-wrote it, but I'm going to let it round trip through linux-next so 
I'll send it up next time.

Sorry, I know this happened twice recently but I'll try not to make a 
habit of it.

>
>>
>> Regards,
>> Nick
>>
>> On 3/22/22 15:28, 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>
>>> ---
>>>   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);

Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Palmer Dabbelt]

On Thu, 28 Apr 2022 14:48:14 PDT (-0700), Palmer Dabbelt wrote:
> On Mon, 25 Apr 2022 23:11:23 PDT (-0700), mick@ics.forth.gr wrote:
>> Hello Palmer,
>>
>> Any updates on this ?
>
> Sorry about that, it's on fixes.

Not sure if I just wasn't paying attention yesterday or if I'm grumpier 
this morning, but that "RISC-V-fixes: " prefix is just a bit too odd -- 
I know we've got a split between "RISC-V" and "riscv" so maybe it 
doesn't matter, but even that is kind of ugly.

I re-wrote it, but I'm going to let it round trip through linux-next so 
I'll send it up next time.

Sorry, I know this happened twice recently but I'll try not to make a 
habit of it.

>
>>
>> Regards,
>> Nick
>>
>> On 3/22/22 15:28, 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>
>>> ---
>>>   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);

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Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Nick Kossifidis]

Στις 2022-04-29 18:28, Palmer Dabbelt έγραψε:
> On Thu, 28 Apr 2022 14:48:14 PDT (-0700), Palmer Dabbelt wrote:
>> On Mon, 25 Apr 2022 23:11:23 PDT (-0700), mick@ics.forth.gr wrote:
>>> Hello Palmer,
>>> 
>>> Any updates on this ?
>> 
>> Sorry about that, it's on fixes.
> 
> Not sure if I just wasn't paying attention yesterday or if I'm
> grumpier this morning, but that "RISC-V-fixes: " prefix is just a bit
> too odd -- I know we've got a split between "RISC-V" and "riscv" so
> maybe it doesn't matter, but even that is kind of ugly.
> 
> I re-wrote it, but I'm going to let it round trip through linux-next
> so I'll send it up next time.
> 
> Sorry, I know this happened twice recently but I'll try not to make a
> habit of it.
> 

Don't worry about it, just let me know what works better for you, would 
"[PATCH -fixes] riscv:" be ok next time ?

Regards,
Nick

Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Nick Kossifidis]

Στις 2022-04-29 18:28, Palmer Dabbelt έγραψε:
> On Thu, 28 Apr 2022 14:48:14 PDT (-0700), Palmer Dabbelt wrote:
>> On Mon, 25 Apr 2022 23:11:23 PDT (-0700), mick@ics.forth.gr wrote:
>>> Hello Palmer,
>>> 
>>> Any updates on this ?
>> 
>> Sorry about that, it's on fixes.
> 
> Not sure if I just wasn't paying attention yesterday or if I'm
> grumpier this morning, but that "RISC-V-fixes: " prefix is just a bit
> too odd -- I know we've got a split between "RISC-V" and "riscv" so
> maybe it doesn't matter, but even that is kind of ugly.
> 
> I re-wrote it, but I'm going to let it round trip through linux-next
> so I'll send it up next time.
> 
> Sorry, I know this happened twice recently but I'll try not to make a
> habit of it.
> 

Don't worry about it, just let me know what works better for you, would 
"[PATCH -fixes] riscv:" be ok next time ?

Regards,
Nick

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Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Palmer Dabbelt]

On Fri, 29 Apr 2022 12:18:14 PDT (-0700), mick@ics.forth.gr wrote:
> Στις 2022-04-29 18:28, Palmer Dabbelt έγραψε:
>> On Thu, 28 Apr 2022 14:48:14 PDT (-0700), Palmer Dabbelt wrote:
>>> On Mon, 25 Apr 2022 23:11:23 PDT (-0700), mick@ics.forth.gr wrote:
>>>> Hello Palmer,
>>>>
>>>> Any updates on this ?
>>>
>>> Sorry about that, it's on fixes.
>>
>> Not sure if I just wasn't paying attention yesterday or if I'm
>> grumpier this morning, but that "RISC-V-fixes: " prefix is just a bit
>> too odd -- I know we've got a split between "RISC-V" and "riscv" so
>> maybe it doesn't matter, but even that is kind of ugly.
>>
>> I re-wrote it, but I'm going to let it round trip through linux-next
>> so I'll send it up next time.
>>
>> Sorry, I know this happened twice recently but I'll try not to make a
>> habit of it.
>>
>
> Don't worry about it, just let me know what works better for you, would
> "[PATCH -fixes] riscv:" be ok next time ?

That's generally how folks do it, but I just look for "fix" anywhere in 
the subject line.

Re: [PATCH] RISC-V-fixes: relocate DTB if it's outside memory region

[Palmer Dabbelt]

On Fri, 29 Apr 2022 12:18:14 PDT (-0700), mick@ics.forth.gr wrote:
> Στις 2022-04-29 18:28, Palmer Dabbelt έγραψε:
>> On Thu, 28 Apr 2022 14:48:14 PDT (-0700), Palmer Dabbelt wrote:
>>> On Mon, 25 Apr 2022 23:11:23 PDT (-0700), mick@ics.forth.gr wrote:
>>>> Hello Palmer,
>>>>
>>>> Any updates on this ?
>>>
>>> Sorry about that, it's on fixes.
>>
>> Not sure if I just wasn't paying attention yesterday or if I'm
>> grumpier this morning, but that "RISC-V-fixes: " prefix is just a bit
>> too odd -- I know we've got a split between "RISC-V" and "riscv" so
>> maybe it doesn't matter, but even that is kind of ugly.
>>
>> I re-wrote it, but I'm going to let it round trip through linux-next
>> so I'll send it up next time.
>>
>> Sorry, I know this happened twice recently but I'll try not to make a
>> habit of it.
>>
>
> Don't worry about it, just let me know what works better for you, would
> "[PATCH -fixes] riscv:" be ok next time ?

That's generally how folks do it, but I just look for "fix" anywhere in 
the subject line.

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