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irqchip/gic-v3: Don't register a redistributor that was never counted

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gic_acpi_match_gicc() counts only the enabled GICCs with a non-zero
gicr_base_address, and that count sizes redist_regs[], but
gic_acpi_parse_madt_gicc() registers every enabled one. On a MADT with
no GICR entries, an enabled GICC with a zero GICR base therefore makes
gic_acpi_register_redist() write a struct redist_region past the end of
the array.

Commit fa2dabe572 ("irqchip/gic-v3: Don't return errors from
gic_acpi_match_gicc()") removed the check that kept the two consistent.
Its message says such entries are still caught by gic_populate_rdist(),
but that runs from gic_cpu_init(), after the write.

Skip the entry instead, and mark the CPU's redistributor broken as the
online-capable path does, so that gic_check_rdist() rejects the CPU.
gic_starting_cpu() runs past cpuhp's last failure point, so without the
mark the CPU would come online with its redistributor and CPU interface
unconfigured. With an ITS, its_cpu_init() would then dereference a NULL
rd_base.

Fixes: fa2dabe572 ("irqchip/gic-v3: Don't return errors from gic_acpi_match_gicc()")
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://patch.msgid.link/20260925085000.753400-4-fuad.tabba@linux.dev
This commit is contained in:
Fuad Tabba 2026-09-25 09:50:00 +01:00 committed by Thomas Gleixner
parent d09b36d8e0
commit 6a21693b97
1 changed files with 11 additions and 0 deletions
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11
drivers/irqchip/irq-gic-v3.c
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@ -2344,6 +2344,17 @@ gic_acpi_parse_madt_gicc(union acpi_subtable_headers *header,
return 0;
}
/* Not counted by gic_acpi_match_gicc(), so there is no slot for it */
if (!gicc->gicr_base_address) {
int cpu = get_cpu_for_acpi_id(gicc->uid);
pr_warn(FW_BUG "GICC entry with ACPI UID %u has no GICR base address, CPU kept offline\n",
gicc->uid);
if (cpu >= 0)
cpumask_set_cpu(cpu, &broken_rdists);
return 0;
}
redist_base = ioremap(gicc->gicr_base_address, size);
if (!redist_base)
return -ENOMEM;