[PATCH 1/6] Add new mtrr_add_unaligned function

[Thomas Schlichter]

This function creates multiple MTRR entries for unaligned memory regions.

Signed-off-by: Thomas Schlichter <thomas.schlichter@xxxxxx>
---
 arch/x86/include/asm/mtrr.h     |    8 ++++++++
 arch/x86/kernel/cpu/mtrr/main.c |   30 ++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/mtrr.h b/arch/x86/include/asm/mtrr.h
index 4365ffd..2e0d99d 100644
--- a/arch/x86/include/asm/mtrr.h
+++ b/arch/x86/include/asm/mtrr.h
@@ -116,6 +116,9 @@ extern int mtrr_add(unsigned long base, unsigned long size,
 		    unsigned int type, bool increment);
 extern int mtrr_add_page(unsigned long base, unsigned long size,
 			 unsigned int type, bool increment);
+extern void mtrr_add_unaligned(unsigned long base, unsigned long size,
+			       unsigned int type, bool increment,
+			       int *mtrr_usage);
 extern int mtrr_del(int reg, unsigned long base, unsigned long size);
 extern int mtrr_del_page(int reg, unsigned long base, unsigned long size);
 extern void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi);
@@ -146,6 +149,11 @@ static inline int mtrr_add_page(unsigned long base, unsigned long size,
 {
     return -ENODEV;
 }
+static inline void mtrr_add_unaligned(unsigned long base, unsigned long size,
+				      unsigned int type, bool increment,
+				      int *mtrr_usage)
+{
+}
 static inline int mtrr_del(int reg, unsigned long base, unsigned long size)
 {
     return -ENODEV;
diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index 84e83de..5bf769b 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -487,6 +487,36 @@ int mtrr_add(unsigned long base, unsigned long size, unsigned int type,
 }
 EXPORT_SYMBOL(mtrr_add);
 
+void mtrr_add_unaligned(unsigned long base, unsigned long size,
+			unsigned int type, bool increment, int *mtrr_usage)
+{
+	int i;
+	unsigned long ptr1, ptr2, end = base + size;
+
+	// round down size to next power ot two
+	size = __rounddown_pow_of_two(size);
+
+	// accordingly align pointers
+	ptr1 = ptr2 = (base + size - 1) & ~(size - 1);
+
+	while (size >= PAGE_SIZE) {
+		if (ptr1 + size <= end) {
+			i = mtrr_add(ptr1, size, type, increment);
+			if (i >= 0 && increment && mtrr_usage)
+				++mtrr_usage[i];
+			ptr1 += size;
+		}
+		if (base + size <= ptr2) {
+			ptr2 -= size;
+			i = mtrr_add(ptr2, size, type, increment);
+			if (i >= 0 && increment && mtrr_usage)
+				++mtrr_usage[i];
+		}
+		size >>= 1;
+	}
+}
+EXPORT_SYMBOL(mtrr_add_unaligned);
+
 /**
  * mtrr_del_page - delete a memory type region
  * @reg: Register returned by mtrr_add
-- 
1.6.5


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  charset="iso-8859-1";
  name="0002-Make-num_var_ranges-accessible-outside-MTRR-code.patch"
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Content-Disposition: inline;
	filename="0002-Make-num_var_ranges-accessible-outside-MTRR-code.patch"