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Subject[PATCH -v2 08/13] x86: if kernel .text .data .bss are not marked as E820_RAM, complain and fix
Date
From: Jacob Shin <jacob.shin@amd.com>

There could be cases where user supplied memmap=exactmap memory
mappings do not mark the region where the kernel .text .data and
.bss reside as E820_RAM, as reported here:

https://lkml.org/lkml/2012/8/14/86

Handle it by complaining, and adding the range back into the e820.

Signed-off-by: Jacob Shin <jacob.shin@amd.com>
---
arch/x86/kernel/setup.c | 14 ++++++++++++++
1 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index c30c78c..587dcd9 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -831,6 +831,20 @@ void __init setup_arch(char **cmdline_p)
insert_resource(&iomem_resource, &data_resource);
insert_resource(&iomem_resource, &bss_resource);

+ /*
+ * Complain if .text .data and .bss are not marked as E820_RAM and
+ * attempt to fix it by adding the range. We may have a confused BIOS,
+ * or the user may have incorrectly supplied it via memmap=exactmap. If
+ * we really are running on top non-RAM, we will crash later anyways.
+ */
+ if (!e820_all_mapped(code_resource.start, __pa(__brk_limit), E820_RAM)) {
+ pr_warn(".text .data .bss are not marked as E820_RAM!\n");
+
+ e820_add_region(code_resource.start,
+ __pa(__brk_limit) - code_resource.start + 1,
+ E820_RAM);
+ }
+
trim_bios_range();
#ifdef CONFIG_X86_32
if (ppro_with_ram_bug()) {
--
1.7.7


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