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lib: utils: Mark only the largest region as reserved in FDT

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In commit 230278dcf, RX and RW regions were marked separately.
When the RW region grows (e.g. with more harts) and it isn't a
power-of-two, sbi_domain_memregion_init will upgrade the region
to the next power-of-two. This will make RX and RW both start
at the same base address, like so (with 64 harts):
Domain0 Region01 : 0x0000000080000000-0x000000008001ffff M: (R,X) S/U: ()
Domain0 Region02 : 0x0000000080000000-0x00000000800fffff M: (R,W) S/U: ()

This doesn't break the permission enforcement because of static
priorities in PMP but makes the kernel complain about the regions
overlapping each other. Like so:
[    0.000000] OF: reserved mem: OVERLAP DETECTED!
[    0.000000] mmode_resv0@80000000 (0x0000000080000000--0x0000000080020000) \
	overlaps with mmode_resv1@80000000 (0x0000000080000000--0x0000000080100000)

To fix this warning, among the multiple regions having same base
address but different sizes, add only the largest region as reserved
region during fdt fixup.

Fixes: 230278dcf (lib: sbi: Add separate entries for firmware RX and RW regions)
Signed-off-by: Himanshu Chauhan <hchauhan@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Himanshu Chauhan 2023-01-27 09:49:23 +05:30 committed by Anup Patel
parent 84d15f4f52
commit 199189bd1c
1 changed files with 30 additions and 4 deletions
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34
lib/utils/fdt/fdt_fixup.c
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@ -1,3 +1,4 @@
// SPDX-License-Identifier: BSD-2-Clause
/*
* fdt_fixup.c - Flat Device Tree parsing helper routines
@ -14,6 +15,7 @@
#include <sbi/sbi_hart.h>
#include <sbi/sbi_scratch.h>
#include <sbi/sbi_string.h>
#include <sbi/sbi_error.h>
#include <sbi_utils/fdt/fdt_fixup.h>
#include <sbi_utils/fdt/fdt_pmu.h>
#include <sbi_utils/fdt/fdt_helper.h>
@ -285,8 +287,10 @@ int fdt_reserved_memory_fixup(void *fdt)
struct sbi_domain_memregion *reg;
struct sbi_domain *dom = sbi_domain_thishart_ptr();
struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
unsigned long filtered_base[PMP_COUNT] = { 0 };
unsigned char filtered_order[PMP_COUNT] = { 0 };
unsigned long addr, size;
int err, parent, i;
int err, parent, i, j;
int na = fdt_address_cells(fdt, 0);
int ns = fdt_size_cells(fdt, 0);
@ -351,11 +355,33 @@ int fdt_reserved_memory_fixup(void *fdt)
if (reg->flags & SBI_DOMAIN_MEMREGION_SU_EXECUTABLE)
continue;
if (i > PMP_COUNT) {
sbi_printf("%s: Too many memory regions to fixup.\n",
__func__);
return SBI_ENOSPC;
}
addr = reg->base;
size = 1UL << reg->order;
fdt_resv_memory_update_node(fdt, addr, size, i, parent,
(sbi_hart_pmp_count(scratch)) ? false : true);
for (j = 0; j < i; j++) {
if (addr == filtered_base[j]
&& filtered_order[j] < reg->order) {
filtered_order[j] = reg->order;
goto next_entry;
}
}
filtered_base[i] = reg->base;
filtered_order[i] = reg->order;
i++;
next_entry:
}
for (j = 0; j < i; j++) {
addr = filtered_base[j];
size = 1UL << filtered_order[j];
fdt_resv_memory_update_node(fdt, addr, size, j, parent,
(sbi_hart_pmp_count(scratch))
? false : true);
}
return 0;