From: Oliver Upton Date: Tue, 28 Jan 2025 00:17:49 +0000 (+0000) Subject: ACPI: GTDT: Relax sanity checking on Platform Timers array count X-Git-Tag: v6.14-rc3~30^2~2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f818227a2f3d1d4f26469347e428323d61cc83f0;p=thirdparty%2Fkernel%2Flinux.git ACPI: GTDT: Relax sanity checking on Platform Timers array count 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 Cc: Lorenzo Pieralisi Cc: Zheng Zengkai Cc: stable@vger.kernel.org Fixes: 263e22d6bd1f ("ACPI: GTDT: Tighten the check for the array of platform timer structures") Signed-off-by: Oliver Upton Acked-by: Marc Zyngier Reviewed-by: Lorenzo Pieralisi Link: https://lore.kernel.org/r/20250128001749.3132656-1-oliver.upton@linux.dev Signed-off-by: Will Deacon --- diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c index 3561553eff8b5..70f8290b659de 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; }