6.13-stable review patch. If anyone has any objections, please let me know.
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From: Oliver Upton oliver.upton@linux.dev
commit f818227a2f3d1d4f26469347e428323d61cc83f0 upstream.
Perhaps unsurprisingly there are some platforms where the GTDT isn't quite right and the Platforms Timer array overflows the length of the overall table.
While the recently-added sanity checking isn't wrong, it makes it impossible to boot the kernel on offending platforms. Try to hobble along and limit the Platform Timer count to the bounds of the table.
Cc: Marc Zyngier maz@kernel.org Cc: Lorenzo Pieralisi lpieralisi@kernel.org Cc: Zheng Zengkai zhengzengkai@huawei.com Cc: stable@vger.kernel.org Fixes: 263e22d6bd1f ("ACPI: GTDT: Tighten the check for the array of platform timer structures") Signed-off-by: Oliver Upton oliver.upton@linux.dev Acked-by: Marc Zyngier maz@kernel.org Reviewed-by: Lorenzo Pieralisi lpieralisi@kernel.org Link: https://lore.kernel.org/r/20250128001749.3132656-1-oliver.upton@linux.dev Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/acpi/arm64/gtdt.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c index 3561553eff8b..70f8290b659d 100644 --- a/drivers/acpi/arm64/gtdt.c +++ b/drivers/acpi/arm64/gtdt.c @@ -163,7 +163,7 @@ int __init acpi_gtdt_init(struct acpi_table_header *table, { void *platform_timer; struct acpi_table_gtdt *gtdt; - int cnt = 0; + u32 cnt = 0;
gtdt = container_of(table, struct acpi_table_gtdt, header); acpi_gtdt_desc.gtdt = gtdt; @@ -188,13 +188,17 @@ int __init acpi_gtdt_init(struct acpi_table_header *table, cnt++;
if (cnt != gtdt->platform_timer_count) { + cnt = min(cnt, gtdt->platform_timer_count); + pr_err(FW_BUG "limiting Platform Timer count to %d\n", cnt); + } + + if (!cnt) { acpi_gtdt_desc.platform_timer = NULL; - pr_err(FW_BUG "invalid timer data.\n"); - return -EINVAL; + return 0; }
if (platform_timer_count) - *platform_timer_count = gtdt->platform_timer_count; + *platform_timer_count = cnt;
return 0; }