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Message-Id: <1336501366-28617-4-git-send-email-jarkko.sakkinen@intel.com>
Date: Tue, 8 May 2012 21:22:26 +0300
From: Jarkko Sakkinen <jarkko.sakkinen@...el.com>
To: linux-kernel@...r.kernel.org
Cc: linux-kbuild@...r.kernel.org, Michal Marek <mmarek@...e.cz>,
Sam Ravnborg <sam@...nborg.org>,
Joseph Cihula <joseph.cihula@...el.com>,
Shane Wang <shane.wang@...el.com>, hpa@...ux.intel.com,
Jarkko Sakkinen <jarkko.sakkinen@...el.com>
Subject: [PATCH 03/23] x86, realmode: Relocator for realmode code
Implements relocator for real mode code that is called
as part of setup_arch(). Processes segment relocations
and linear relocations. Real-mode code is relocated to
a free hole below 1 MB.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...el.com>
---
arch/x86/include/asm/realmode.h | 26 +++++++++++++
arch/x86/kernel/Makefile | 1 +
arch/x86/kernel/realmode.c | 79 +++++++++++++++++++++++++++++++++++++++
arch/x86/kernel/setup.c | 2 +
4 files changed, 108 insertions(+)
create mode 100644 arch/x86/include/asm/realmode.h
create mode 100644 arch/x86/kernel/realmode.c
diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h
new file mode 100644
index 0000000..dc1bba5
--- /dev/null
+++ b/arch/x86/include/asm/realmode.h
@@ -0,0 +1,26 @@
+#ifndef _ARCH_X86_REALMODE_H
+#define _ARCH_X86_REALMODE_H
+
+#include <linux/types.h>
+#include <asm/io.h>
+
+/* This must match data at realmode.S */
+struct real_mode_header {
+ u32 text_start;
+ u32 ro_end;
+ u32 end;
+} __attribute__((__packed__));
+
+extern struct real_mode_header real_mode_header;
+extern unsigned char *real_mode_base;
+
+extern unsigned long init_rsp;
+extern unsigned long initial_code;
+extern unsigned long initial_gs;
+
+extern unsigned char real_mode_blob[];
+extern unsigned char real_mode_relocs[];
+
+extern void __init setup_real_mode(void);
+
+#endif /* _ARCH_X86_REALMODE_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 532d2e0..f9e19d4 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -36,6 +36,7 @@ obj-y += pci-iommu_table.o
obj-y += resource.o
obj-y += trampoline.o trampoline_$(BITS).o
+obj-y += realmode.o
obj-y += process.o
obj-y += i387.o xsave.o
obj-y += ptrace.o
diff --git a/arch/x86/kernel/realmode.c b/arch/x86/kernel/realmode.c
new file mode 100644
index 0000000..7415c42
--- /dev/null
+++ b/arch/x86/kernel/realmode.c
@@ -0,0 +1,79 @@
+#include <linux/io.h>
+#include <linux/memblock.h>
+
+#include <asm/cacheflush.h>
+#include <asm/pgtable.h>
+#include <asm/realmode.h>
+
+unsigned char *real_mode_base;
+struct real_mode_header real_mode_header;
+
+void __init setup_real_mode(void)
+{
+ phys_addr_t mem;
+ u16 real_mode_seg;
+ u32 *rel;
+ u32 count;
+ u32 *ptr;
+ u16 *seg;
+ int i;
+
+ struct real_mode_header *header =
+ (struct real_mode_header *) real_mode_blob;
+
+ size_t size = PAGE_ALIGN(header->end);
+
+ /* Has to be in very low memory so we can execute real-mode AP code. */
+ mem = memblock_find_in_range(0, 1<<20, size, PAGE_SIZE);
+ if (!mem)
+ panic("Cannot allocate trampoline\n");
+
+ real_mode_base = __va(mem);
+ memblock_reserve(mem, size);
+
+ printk(KERN_DEBUG "Base memory trampoline at [%p] %llx size %zu\n",
+ real_mode_base, (unsigned long long)mem, size);
+
+ memcpy(real_mode_base, real_mode_blob, size);
+
+ real_mode_seg = __pa(real_mode_base) >> 4;
+ rel = (u32 *) real_mode_relocs;
+
+ /* 16-bit segment relocations. */
+ count = rel[0];
+ rel = &rel[1];
+ for (i = 0; i < count; i++) {
+ seg = (u16 *) (real_mode_base + rel[i]);
+ *seg = real_mode_seg;
+ }
+
+ /* 32-bit linear relocations. */
+ count = rel[i];
+ rel = &rel[i + 1];
+ for (i = 0; i < count; i++) {
+ ptr = (u32 *) (real_mode_base + rel[i]);
+ *ptr += __pa(real_mode_base);
+ }
+
+ /* Copied header will contain relocated physical addresses. */
+ memcpy(&real_mode_header, real_mode_base,
+ sizeof(struct real_mode_header));
+}
+
+/*
+ * set_real_mode_permissions() gets called very early, to guarantee the
+ * availability of low memory. This is before the proper kernel page
+ * tables are set up, so we cannot set page permissions in that
+ * function. Thus, we use an arch_initcall instead.
+ */
+static int __init set_real_mode_permissions(void)
+{
+ size_t all_size =
+ PAGE_ALIGN(real_mode_header.end) -
+ __pa(real_mode_base);
+
+ set_memory_x((unsigned long) real_mode_base, all_size >> PAGE_SHIFT);
+ return 0;
+}
+
+arch_initcall(set_real_mode_permissions);
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 1a29015..56e4124 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -74,6 +74,7 @@
#include <asm/mtrr.h>
#include <asm/apic.h>
#include <asm/trampoline.h>
+#include <asm/realmode.h>
#include <asm/e820.h>
#include <asm/mpspec.h>
#include <asm/setup.h>
@@ -918,6 +919,7 @@ void __init setup_arch(char **cmdline_p)
max_pfn_mapped<<PAGE_SHIFT);
setup_trampolines();
+ setup_real_mode();
init_gbpages();
--
1.7.9.5
--
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