From 748e4f3d702def1a4bff191e0cf93b6a05340f01 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Fri, 10 May 2024 07:41:34 +0000
Subject: [PATCH] add gpio led uart
---
kernel/arch/x86/kernel/aperture_64.c | 25 +++++++++++++++----------
1 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/kernel/arch/x86/kernel/aperture_64.c b/kernel/arch/x86/kernel/aperture_64.c
index 93426c5..294ed43 100644
--- a/kernel/arch/x86/kernel/aperture_64.c
+++ b/kernel/arch/x86/kernel/aperture_64.c
@@ -270,18 +270,23 @@
}
early_param("gart_fix_e820", parse_gart_mem);
+/*
+ * With kexec/kdump, if the first kernel doesn't shut down the GART and the
+ * second kernel allocates a different GART region, there might be two
+ * overlapping GART regions present:
+ *
+ * - the first still used by the GART initialized in the first kernel.
+ * - (sub-)set of it used as normal RAM by the second kernel.
+ *
+ * which leads to memory corruptions and a kernel panic eventually.
+ *
+ * This can also happen if the BIOS has forgotten to mark the GART region
+ * as reserved.
+ *
+ * Try to update the e820 map to mark that new region as reserved.
+ */
void __init early_gart_iommu_check(void)
{
- /*
- * in case it is enabled before, esp for kexec/kdump,
- * previous kernel already enable that. memset called
- * by allocate_aperture/__alloc_bootmem_nopanic cause restart.
- * or second kernel have different position for GART hole. and new
- * kernel could use hole as RAM that is still used by GART set by
- * first kernel
- * or BIOS forget to put that in reserved.
- * try to update e820 to make that region as reserved.
- */
u32 agp_aper_order = 0;
int i, fix, slot, valid_agp = 0;
u32 ctl;
--
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