| Message ID | 1470922605-27803-1-git-send-email-yamada.masahiro@socionext.com |
|---|---|
| State | New |
| Headers | show |
Hi Alex, 2016-08-11 22:50 GMT+09:00 Alexander Graf <agraf@suse.de>: > > > On 11.08.16 15:36, Masahiro Yamada wrote: >> As you see in arch/arm/include/asm/types.h, CONFIG_PHYS_64BIT >> determines the size of phys_addr_t. The ARM Large Physical Address >> Extension allows CPUs to access a physical address space larger than >> 4GB, so the physical address may not fit in 32bit long phys_addr_t. >> >> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> >> --- >> >> I did Buildman test, but not run-time test. >> >> Looks like bcm283x (RPI) is the only arch that selects ARMV7_LPAE, >> so I hope Stephen will check this patch. > > Well, the bcm2837 still only has a 32bit bus, so we can't actually make > use of addresses bigger than 32bits. > > I think it would make most sense to select PHYS_64BIT on whatever 32bit > SoC actually needs to accesses memory above 4GB. > > The main reason for having LPAE support for armv7 is not to support > higher addresses (we still map everything 1:1 usually), it's to allow > running in HYP mode which requires LPAE style page tables. Thanks for explaining this. Then, please forget about this patch. -- Best Regards Masahiro Yamada _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
diff --git a/arch/arm/cpu/armv7/Kconfig b/arch/arm/cpu/armv7/Kconfig index 0560178..1697e61 100644 --- a/arch/arm/cpu/armv7/Kconfig +++ b/arch/arm/cpu/armv7/Kconfig @@ -45,6 +45,7 @@ config ARMV7_PSCI_NR_CPUS config ARMV7_LPAE boolean "Use LPAE page table format" if EXPERT depends on CPU_V7 + select PHYS_64BIT default n ---help--- Say Y here to use the long descriptor page table format. This is
As you see in arch/arm/include/asm/types.h, CONFIG_PHYS_64BIT determines the size of phys_addr_t. The ARM Large Physical Address Extension allows CPUs to access a physical address space larger than 4GB, so the physical address may not fit in 32bit long phys_addr_t. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> --- I did Buildman test, but not run-time test. Looks like bcm283x (RPI) is the only arch that selects ARMV7_LPAE, so I hope Stephen will check this patch. arch/arm/cpu/armv7/Kconfig | 1 + 1 file changed, 1 insertion(+) -- 1.9.1 _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot