On Wed, Aug 17, 2022 at 01:42:34PM +0200, Ahmad Fatoum wrote: > v1 -> v2: > - fold misplaced hunk changing %u added in [01/10] into 0x%x in > [02/10] directly into [01/10] (Ulrich) > - Correct typo in commit message (Sascha) > > When setting up page tables, barebox marks all the address space as > eXecute Never and uncached, except for the memory banks. If we happen to > have secure memory, this is andequate as speculative execution may read > from secure memory or even attempt to execute it leading to spurious > data aborts. The way around this so far was either having OP-TEE in SRAM > (which normally isn't a barebox memory bank) or having it at the end of > DRAM, but adjusting size, so it's not covered by a memory bank. > > This adds a generic solution to the issue. We already request the SDRAM > regions described by the reserved memory entries in the DT. We go a step > further and mark them as IORESOURCE_BUSY, which we can then evaluat in > the MMU setup code to map these regions uncached and eXecute Never. > > There has been previous attempts by Rouven to achieve this, the latest > being: > > https://lore.barebox.org/barebox/20210803094418.475609-1-r.czerwinski@xxxxxxxxxxxxxx/ > > While this series tries to achieve the same end goal, it goes about it > in a different manner: We don't use FDT fixup table to tell us what to > nstead have both the FDT fixup table and the /reserved-memory child > nodes feed into the barebox request_sdram_region allocator and then > use to apply caching attributes. > > Note that this doesn't yet solve all problems. For example, PPA secure > monitor installation on Layerscape may happen with CONFIG_MMU_EARLY=y, > in which case barebox in EL2 may speculate into the secure memory > before any device tree reserved-memory settings are considered. For this > reason, both early MMU and normal MMU setup must be aware of the > reserved memory regions. The original patch set by Rouven used FDT > parsing in PBL to achieve this, but this is omitted here to limit > scope of the patch series. Instead we only handle the CONFIG_OPTEE_SIZE > case out-of-the-box. > > Ahmad Fatoum (9): > resource: add flags parameter to __request_region > common: allow requesting SDRAM regions with custom flags > memory: define reserve_sdram_region helper > init: define new postmem_initcall() > of: reserved-mem: reserve regions prior to mmu_initcall() > ARM: mmu64: map reserved regions uncached > ARM: mmu: define attrs_uncached_mem() helper > ARM: early-mmu: don't cache/prefetch OPTEE_SIZE bytes from end of > memory > commands: iomem: point out [R]eserved regions > > Rouven Czerwinski (1): > ARM: mmu: use reserve mem entries to modify maps Applied, thanks Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
