From 8cff0ac21658fedd4598e9904dd0c518bdaf5856 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 25 Aug 2026 11:49:25 +0200 Subject: [PATCH] s390/pai: Reduce excessive debug feature size The pai debug feature is registered with 256 areas, where each area contains 32 pages. This sums up to a total of 32MiB. The code does not use any debug exceptions, which means that 255 of those areas are never used. In addition all existing debug feature calls have a lower level (5) than the default level (3). This in turn means that without user interaction the debug feature is unused. Reduce the number of areas to 1, and also reduce the number of pages for the remaining area to 1. Since user interaction is required, the user can also increase the size of the remaining area, instead of wasting memory by default. This reduces the total size of the debug feature to 4KiB. Fixes: a3f8423622ef ("s390/pai_crypto: Add PAI crypto characteristics table for parameters") Reviewed-by: Thomas Richter Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens --- arch/s390/kernel/perf_pai.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/kernel/perf_pai.c b/arch/s390/kernel/perf_pai.c index 05f74d74fad1..5c18c8b82ab7 100644 --- a/arch/s390/kernel/perf_pai.c +++ b/arch/s390/kernel/perf_pai.c @@ -1242,7 +1242,7 @@ static int __init paipmu_setup(void) static int __init pai_init(void) { /* Setup s390dbf facility */ - paidbg = debug_register("pai", 32, 256, 128); + paidbg = debug_register("pai", 1, 1, 128); if (!paidbg) { pr_err("Registration of s390dbf pai failed\n"); return -ENOMEM;