[PATCH v7 0/7] Relocate U-Boot in the last bank
Ilias Apalodimas
ilias.apalodimas at linaro.org
Tue Jun 23 15:20:01 CEST 2026
On Tue, 23 Jun 2026 at 16:13, Christophe Leroy (CS GROUP)
<chleroy at kernel.org> wrote:
>
> Hi,
>
> Le 17/06/2026 à 09:48, Ilias Apalodimas a écrit :
> > Hi all, this is v7 of [1][2][3][4][5][6]!
> >
> > There was a discussion recently on the mailing lists regarding our
> > management of memory above ram_top [0]. The tl;dr is that we have two problems.
> >
> > The first one is that U-Boot always relocates to the top of the first available
> > bank unless there's special board code to sidestep that. The second is we don't
> > successfully deal with devices that can only do 32-bit DMA.
> >
> > This patch series deals with the first problem by adding a Kconfig option
> > allowing platforms to relocate to the top of the last discovered bank.
> >
> > It's worth noting that this is easily testable with QEMU
>
> Following discussion on patch 1/7 in v5, I boot tested this v7 series on
> one of my powerpc boards. It could start Linux kernel v7.0 without any
> problem.
>
> FWIW,
>
> Tested-by: Christophe Leroy (CS GROUP) <chleroy at kernel.org>
Thanks Cristophe!
/Ilias
>
> Christophe
>
> >
> > qemu-system-aarch64 -m 8192 -smp 2 -nographic -cpu cortex-a57 \
> > -machine virt,secure=off \
> > -bios u-boot.bin \
> > -device virtio-rng-pci \
> > -drive id=os,if=none,file="$image" \
> > -device virtio-blk-device,drive=os \
> > -object memory-backend-ram,id=ram0,size=4G \
> > -object memory-backend-ram,id=ram1,size=4G \
> > -numa node,memdev=ram0 \
> > -numa node,memdev=ram1
> >
> > # RELOC_ADDR_TOP not set
> > Hit any key to stop autoboot: 0
> > => bdinfo
> > [...]
> > relocaddr = 0x000000013f66c000
> > reloc off = 0x000000013f66c000
> > [...]
> > lmb_dump_all:
> > memory.count = 0x1
> > memory[0] [0x40000000-0x23fffffff], 0x200000000 bytes, flags: none
> > reserved.count = 0x2
> > reserved[0] [0x13d507000-0x13d509fff], 0x3000 bytes, flags: no-notify, no-overwrite
> > reserved[1] [0x13d50aff0-0x23fffffff], 0x102af5010 bytes, flags: no-overwrite
> > devicetree = board
> > [...]
> > TLB addr = 0x000000013ffe0000
> > irq_sp = 0x000000013e50aff0
> > sp start = 0x000000013e50aff0
> > Early malloc usage: e88 / 2000
> > =>
> >
> > # RELOC_ADDR_TOP enabled
> >
> > => bdinfo
> > [...]
> > relocaddr = 0x000000023f66c000
> > reloc off = 0x000000023f66c000
> > [...]
> > lmb_dump_all:
> > memory.count = 0x1
> > memory[0] [0x40000000-0x23fffffff], 0x200000000 bytes, flags: none
> > reserved.count = 0x2
> > reserved[0] [0x23d507000-0x23d509fff], 0x3000 bytes, flags: no-notify, no-overwrite
> > reserved[1] [0x23d50aff0-0x23fffffff], 0x2af5010 bytes, flags: no-overwrite
> > devicetree = board
> > [...]
> > TLB addr = 0x000000023ffe0000
> > irq_sp = 0x000000023e50aff0
> > sp start = 0x000000023e50aff0
> > Early malloc usage: e88 / 2000
> > =>
> >
> > [1] https://lore.kernel.org/u-boot/20260403090109.3564638-1-ilias.apalodimas@linaro.org/
> > [2] https://lore.kernel.org/u-boot/CAC_iWj+JmwW6gDmUf76OX0WiW+RQy-DA2STs+ROHH-i0AbGJ2A@mail.gmail.com/T/#t
> > [3] https://lore.kernel.org/u-boot/20260427100832.581887-1-ilias.apalodimas@linaro.org/
> > [4] https://lore.kernel.org/u-boot/20260515135245.45067-1-ilias.apalodimas@linaro.org/
> > [5] https://lore.kernel.org/u-boot/20260604073719.48723-1-ilias.apalodimas@linaro.org/
> > [6] https://lore.kernel.org/u-boot/20260609131611.46399-1-ilias.apalodimas@linaro.org/
> >
> > Marek, I've kept your r-b on patch #5 since the changes seem minor and won't
> > affect anything for now
> >
> > Changes since v6:
> > - Mention QEMU on patch #6
> > - Remove redundant depends on EXPERT
> > - Rebase on top of -next
> >
> > Changes since v5:
> > - Call board_get_usable_ram_top() with mon_len until we decide what's best
> > for the common code (mon_len is what we used up to now)
> > - Address some comments from Simon on the documentation
> > - Reduce ram_top as well as ram_size when CONFIG_SYS_MEM_TOP_HIDE is defined
> >
> > Changes since v4:
> > - Use CONFIG_VAL instead of IS_ENABLED for SYS_MEM_TOP_HIDE
> > - Fix RPi4 hang
> >
> > Changes since v3:
> > - Use (aligned) gd->mon_len for the get_mem_top() size argument instead of 0.
> > Using !0 will properly factor in reserved regions before calculating the
> > reloc address
> > - Call board_get_usable_ram_top() regardless of the config option so
> > boards can tweak the address eventually
> > - Don't rely on the fact that banks are populated in ascending order
> > - Updated the Kconfig description wrt 32-bit boundaries
> > - Fixed array comment in include/init.h
> > - Don't carry Marek's patches. We can resend those once we have actual users
> >
> > Changes since v2:
> > - Rename bi_dram to dram apart from moving it to gd
> > - Adjusted a Kconfig description and a commit message on patch #6
> > - Use get_mem_top() instead of calculating the top address adding the
> > dram bank info. That function will account for the reserved memory regions
> > and exclude them
> > - Collected Tested/Reviewed-by tags
> >
> > Changes since v1:
> > - Rebased and added Marek's cleanup patches
> > - Remove the ifdefery on patch #6 in favor of 'if (CONFIG_IS_ENABLED)'
> > - Added a warning on the Kconfig message about breaking devices that
> > can't DMA to high memory
> > - Added depends on EXPERT for relocatiing to the last bank
> > - Using %llx instead of %llX on debug prints
> > - Removed 2 remaining comments of bd->bi_dram[]
> > - Collected Tested/Reviewed-by tags
> >
> > Ilias Apalodimas (7):
> > treewide: move bi_dram[] from bd to gd
> > common: move ram_base calculation to independent INITCALL()
> > common: Clean up setup_dest_addr()
> > rpi: Add a local get_effective_memsize()
> > common: Add an option to relocate on ram top
> > configs: Enable RELOC_ADDR_TOP on arm64 QEMU
> > doc: Add a warning about using RELOC_ADDR_TOP
> >
> > Kconfig | 13 ++
> > api/api_platform.c | 4 +-
> > arch/arm/cpu/armv8/cache_v8.c | 6 +-
> > arch/arm/cpu/armv8/fsl-layerscape/cpu.c | 118 +++++++++---------
> > arch/arm/lib/bootm-fdt.c | 5 +-
> > arch/arm/lib/bootm.c | 4 +-
> > arch/arm/lib/cache-cp15.c | 9 +-
> > arch/arm/lib/image.c | 2 +-
> > arch/arm/mach-airoha/an7581/init.c | 8 +-
> > arch/arm/mach-apple/board.c | 4 +-
> > arch/arm/mach-davinci/misc.c | 4 +-
> > arch/arm/mach-imx/ele_ahab.c | 7 +-
> > arch/arm/mach-imx/imx8/ahab.c | 7 +-
> > arch/arm/mach-imx/imx8/cpu.c | 44 +++----
> > arch/arm/mach-imx/imx8m/soc.c | 24 ++--
> > arch/arm/mach-imx/imx8ulp/soc.c | 20 +--
> > arch/arm/mach-imx/imx9/scmi/soc.c | 24 ++--
> > arch/arm/mach-imx/imx9/soc.c | 24 ++--
> > arch/arm/mach-imx/mx5/mx53_dram.c | 8 +-
> > arch/arm/mach-imx/spl.c | 4 +-
> > arch/arm/mach-k3/k3-ddr.c | 4 +-
> > arch/arm/mach-mvebu/alleycat5/cpu.c | 4 +-
> > arch/arm/mach-mvebu/armada3700/cpu.c | 10 +-
> > arch/arm/mach-mvebu/armada8k/dram.c | 10 +-
> > arch/arm/mach-mvebu/dram.c | 6 +-
> > arch/arm/mach-omap2/am33xx/board.c | 4 +-
> > arch/arm/mach-omap2/omap-cache.c | 5 +-
> > arch/arm/mach-omap2/omap3/emif4.c | 8 +-
> > arch/arm/mach-omap2/omap3/sdrc.c | 8 +-
> > arch/arm/mach-owl/soc.c | 4 +-
> > arch/arm/mach-renesas/memmap-gen3.c | 8 +-
> > arch/arm/mach-renesas/memmap-rzg2l.c | 4 +-
> > arch/arm/mach-rockchip/rk3588/rk3588.c | 8 +-
> > arch/arm/mach-rockchip/sdram.c | 42 +++----
> > arch/arm/mach-snapdragon/board.c | 16 +--
> > arch/arm/mach-socfpga/board.c | 5 +-
> > arch/arm/mach-socfpga/misc_arria10.c | 7 +-
> > .../mach-stm32mp/cmd_stm32prog/stm32prog.c | 4 +-
> > arch/arm/mach-stm32mp/stm32mp1/cpu.c | 7 +-
> > arch/arm/mach-tegra/board2.c | 14 +--
> > arch/arm/mach-tegra/cboot.c | 4 +-
> > arch/arm/mach-uniphier/dram_init.c | 6 +-
> > arch/arm/mach-uniphier/fdt-fixup.c | 8 +-
> > arch/arm/mach-versal-net/cpu.c | 8 +-
> > arch/arm/mach-versal/cpu.c | 16 +--
> > arch/arm/mach-versal2/cpu.c | 7 +-
> > arch/arm/mach-zynqmp/cpu.c | 8 +-
> > arch/mips/mach-octeon/dram.c | 4 +-
> > arch/riscv/cpu/k1/dram.c | 12 +-
> > arch/sandbox/cpu/spl.c | 4 +-
> > arch/x86/cpu/coreboot/sdram.c | 4 +-
> > arch/x86/cpu/efi/payload.c | 4 +-
> > arch/x86/cpu/efi/sdram.c | 4 +-
> > arch/x86/cpu/intel_common/mrc.c | 4 +-
> > arch/x86/cpu/ivybridge/sdram_nop.c | 4 +-
> > arch/x86/cpu/qemu/dram.c | 8 +-
> > arch/x86/cpu/quark/dram.c | 4 +-
> > arch/x86/cpu/slimbootloader/sdram.c | 4 +-
> > arch/x86/cpu/tangier/sdram.c | 4 +-
> > arch/x86/lib/bootm.c | 5 +-
> > arch/x86/lib/fsp/fsp_dram.c | 18 +--
> > board/CZ.NIC/turris_1x/turris_1x.c | 42 +++----
> > board/armltd/corstone1000/corstone1000.c | 4 +-
> > board/armltd/integrator/integrator.c | 4 +-
> > board/armltd/total_compute/total_compute.c | 6 +-
> > board/armltd/vexpress/vexpress_common.c | 8 +-
> > board/atmel/common/video_display.c | 2 +-
> > .../sam9x60_curiosity/sam9x60_curiosity.c | 2 +-
> > .../sam9x75_curiosity/sam9x75_curiosity.c | 2 +-
> > .../atmel/sama5d27_som1_ek/sama5d27_som1_ek.c | 2 +-
> > .../sama5d27_wlsom1_ek/sama5d27_wlsom1_ek.c | 2 +-
> > .../sama5d29_curiosity/sama5d29_curiosity.c | 2 +-
> > .../atmel/sama5d2_xplained/sama5d2_xplained.c | 2 +-
> > .../sama7d65_curiosity/sama7d65_curiosity.c | 2 +-
> > .../sama7g54_curiosity/sama7g54_curiosity.c | 2 +-
> > board/axiado/scm3005/scm3005.c | 4 +-
> > board/broadcom/bcmns3/ns3.c | 4 +-
> > board/compulab/cm_fx6/cm_fx6.c | 28 ++---
> > board/elgin/elgin_rv1108/elgin_rv1108.c | 4 +-
> > board/esd/meesc/meesc.c | 4 +-
> > board/friendlyarm/nanopi2/board.c | 10 +-
> > board/ge/mx53ppd/mx53ppd.c | 8 +-
> > board/hisilicon/hikey/hikey.c | 24 ++--
> > board/hisilicon/hikey960/hikey960.c | 4 +-
> > board/hisilicon/poplar/poplar.c | 4 +-
> > board/k+p/kp_imx53/kp_imx53.c | 4 +-
> > board/keymile/pg-wcom-ls102xa/ddr.c | 4 +-
> > board/kontron/sl28/sl28.c | 4 +-
> > board/kontron/sl28/spl_atf.c | 6 +-
> > board/liebherr/btt/btt.c | 2 +-
> > board/menlo/m53menlo/m53menlo.c | 8 +-
> > board/nuvoton/arbel_evb/arbel_evb.c | 26 ++--
> > board/nxp/imxrt1020-evk/imxrt1020-evk.c | 2 +-
> > board/nxp/imxrt1050-evk/imxrt1050-evk.c | 2 +-
> > board/nxp/imxrt1170-evk/imxrt1170-evk.c | 2 +-
> > board/nxp/ls1021aqds/ddr.c | 4 +-
> > board/nxp/ls1028a/ls1028a.c | 10 +-
> > board/nxp/ls1043aqds/ls1043aqds.c | 8 +-
> > board/nxp/ls1043ardb/ls1043ardb.c | 8 +-
> > board/nxp/ls1046afrwy/ls1046afrwy.c | 8 +-
> > board/nxp/ls1046aqds/ls1046aqds.c | 8 +-
> > board/nxp/ls1046ardb/ls1046ardb.c | 8 +-
> > board/nxp/ls1088a/ls1088a.c | 6 +-
> > board/nxp/ls2080aqds/ls2080aqds.c | 14 +--
> > board/nxp/ls2080ardb/ls2080ardb.c | 14 +--
> > board/nxp/lx2160a/lx2160a.c | 6 +-
> > board/phytec/phycore_am62x/phycore-am62x.c | 26 ++--
> > board/phytec/phycore_am64x/phycore-am64x.c | 18 +--
> > board/phytium/durian/durian.c | 4 +-
> > board/phytium/pe2201/pe2201.c | 4 +-
> > board/raspberrypi/rpi/rpi.c | 12 +-
> > board/renesas/common/rcar64-common.c | 6 +-
> > board/renesas/genmai/genmai.c | 4 +-
> > board/renesas/sparrowhawk/sparrowhawk.c | 8 +-
> > board/ronetix/pm9261/pm9261.c | 4 +-
> > board/ronetix/pm9263/pm9263.c | 4 +-
> > board/ronetix/pm9g45/pm9g45.c | 4 +-
> > board/samsung/arndale/arndale.c | 4 +-
> > board/samsung/common/board.c | 6 +-
> > board/samsung/exynos-mobile/exynos-mobile.c | 4 +-
> > board/samsung/goni/goni.c | 12 +-
> > board/samsung/smdkc100/smdkc100.c | 4 +-
> > board/samsung/smdkv310/smdkv310.c | 16 +--
> > board/siemens/iot2050/board.c | 16 +--
> > board/socionext/developerbox/developerbox.c | 6 +-
> > board/st/stih410-b2260/board.c | 4 +-
> > board/ste/stemmy/stemmy.c | 4 +-
> > board/ti/dra7xx/evm.c | 8 +-
> > board/ti/ks2_evm/board.c | 4 +-
> > board/toradex/colibri_imx7/colibri_imx7.c | 8 +-
> > board/toradex/verdin-am62/verdin-am62.c | 2 +-
> > board/toradex/verdin-am62p/verdin-am62p.c | 2 +-
> > board/traverse/ten64/ten64.c | 6 +-
> > board/xilinx/zynq/cmds.c | 6 +-
> > board/xilinx/zynqmp/zynqmp.c | 4 +-
> > boot/image-board.c | 2 +-
> > boot/image-fdt.c | 4 +-
> > cmd/bdinfo.c | 12 +-
> > cmd/ti/ddr4.c | 8 +-
> > cmd/ufetch.c | 4 +-
> > common/board_f.c | 71 ++++++++---
> > common/init/handoff.c | 10 +-
> > configs/qemu_arm64_defconfig | 1 +
> > doc/develop/memory.rst | 9 ++
> > drivers/bootcount/bootcount_ram.c | 4 +-
> > drivers/ddr/altera/sdram_agilex.c | 4 +-
> > drivers/ddr/altera/sdram_agilex5.c | 18 +--
> > drivers/ddr/altera/sdram_agilex7m.c | 4 +-
> > drivers/ddr/altera/sdram_arria10.c | 12 +-
> > drivers/ddr/altera/sdram_n5x.c | 4 +-
> > drivers/ddr/altera/sdram_s10.c | 4 +-
> > drivers/ddr/altera/sdram_soc64.c | 28 ++---
> > drivers/mmc/mvebu_mmc.c | 4 +-
> > drivers/net/mvgbe.c | 4 +-
> > drivers/pci/pci-uclass.c | 8 +-
> > drivers/usb/host/ehci-marvell.c | 4 +-
> > drivers/video/meson/meson_vpu.c | 8 +-
> > drivers/video/sunxi/sunxi_de2.c | 2 +-
> > drivers/video/sunxi/sunxi_display.c | 2 +-
> > include/asm-generic/global_data.h | 7 ++
> > include/asm-generic/u-boot.h | 4 -
> > include/configs/m53menlo.h | 4 +-
> > include/configs/mx53cx9020.h | 4 +-
> > include/configs/mx53loco.h | 4 +-
> > include/configs/mx53ppd.h | 4 +-
> > include/fdtdec.h | 7 +-
> > include/init.h | 2 +-
> > lib/fdtdec.c | 23 ++--
> > lib/lmb.c | 19 ++-
> > test/cmd/bdinfo.c | 7 +-
> > 170 files changed, 785 insertions(+), 728 deletions(-)
> >
> > --
> > 2.43.0
> >
>
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