Messages in this thread | | | From | Ard Biesheuvel <> | Date | Thu, 9 Sep 2021 13:29:11 +0200 | Subject | Re: [PATCH v2] ARM: decompress: Use /memreserve/ DTS nodes when validating memory |
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On Tue, 7 Sept 2021 at 16:57, Bert Vermeulen <bert@biot.com> wrote: > > If the bootloader needs the start of memory to be preserved, for example > because it dropped the Trusted Firmware blob there, this chunk of memory > shouldn't be used by the kernel. > > To avoid adding yet another SoC-specific text offset to arch/arm/Makefile, > this patch allows for a /memreserve/ entry in the DTS to mark off the > memory chunk instead. > > Signed-off-by: Bert Vermeulen <bert@biot.com>
Thanks for working on this - I hope this will allow us to phase out at least some of the existing text_offset hacks too.
Acked-by: Ard Biesheuvel <ardb@kernel.org>
> --- > arch/arm/boot/compressed/fdt_check_mem_start.c | 15 ++++++++++++++- > 1 file changed, 14 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/boot/compressed/fdt_check_mem_start.c b/arch/arm/boot/compressed/fdt_check_mem_start.c > index 62450d824c3c..1d47de1e860b 100644 > --- a/arch/arm/boot/compressed/fdt_check_mem_start.c > +++ b/arch/arm/boot/compressed/fdt_check_mem_start.c > @@ -64,7 +64,7 @@ uint32_t fdt_check_mem_start(uint32_t mem_start, const void *fdt) > uint32_t addr_cells, size_cells, base; > uint32_t fdt_mem_start = 0xffffffff; > const fdt32_t *reg, *endp; > - uint64_t size, end; > + uint64_t rsvaddr, size, end; > const char *type; > int offset, len; > > @@ -74,6 +74,19 @@ uint32_t fdt_check_mem_start(uint32_t mem_start, const void *fdt) > if (fdt_magic(fdt) != FDT_MAGIC) > return mem_start; > > + for (offset = fdt_off_mem_rsvmap(fdt); ; offset += 16) { > + rsvaddr = get_val(fdt + offset, 2); > + size = get_val(fdt + offset + 8, 2); > + > + if (!rsvaddr && !size) > + break; > + > + end = rsvaddr + size; > + if (mem_start >= rsvaddr && mem_start <= end) > + /* Relocate past reserved block */ > + mem_start = round_up(end, SZ_2M); > + } > + > /* There may be multiple cells on LPAE platforms */ > addr_cells = get_cells(fdt, "#address-cells"); > size_cells = get_cells(fdt, "#size-cells"); > -- > 2.25.1 >
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