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authorJuergen Beisert <juergen@kreuzholzen.de>2007-07-22 11:12:38 +0200
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-22 11:03:38 -0700
commitf25f64ed5bd3c2932493681bdfdb483ea707da0a (patch)
tree17d5151d79cbb0b53ddde80157950a2788ac947f /include/asm-i386
parentbdda1561ffda764583a295229db66d94cf6038a3 (diff)
x86: Replace NSC/Cyrix specific chipset access macros by inlined functions.
Due to index register access ordering problems, when using macros a line like this fails (and does nothing): setCx86(CX86_CCR2, getCx86(CX86_CCR2) | 0x88); With inlined functions this line will work as expected. Note about a side effect: Seems on Geode GX1 based systems the "suspend on halt power saving feature" was never enabled due to this wrong macro expansion. With inlined functions it will be enabled, but this will stop the TSC when the CPU runs into a HLT instruction. Kernel output something like this: Clocksource tsc unstable (delta = -472746897 ns) This is the 3rd version of this patch. - Adding missed arch/i386/kernel/cpu/mtrr/state.c Thanks to Andres Salomon - Adding some big fat comments into the new header file Suggested by Andi Kleen AK: fixed x86-64 compilation Signed-off-by: Juergen Beisert <juergen@kreuzholzen.de> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/asm-i386')
-rw-r--r--include/asm-i386/processor-cyrix.h30
-rw-r--r--include/asm-i386/processor.h11
2 files changed, 30 insertions, 11 deletions
diff --git a/include/asm-i386/processor-cyrix.h b/include/asm-i386/processor-cyrix.h
new file mode 100644
index 00000000000..97568ada1f9
--- /dev/null
+++ b/include/asm-i386/processor-cyrix.h
@@ -0,0 +1,30 @@
+/*
+ * NSC/Cyrix CPU indexed register access. Must be inlined instead of
+ * macros to ensure correct access ordering
+ * Access order is always 0x22 (=offset), 0x23 (=value)
+ *
+ * When using the old macros a line like
+ * setCx86(CX86_CCR2, getCx86(CX86_CCR2) | 0x88);
+ * gets expanded to:
+ * do {
+ * outb((CX86_CCR2), 0x22);
+ * outb((({
+ * outb((CX86_CCR2), 0x22);
+ * inb(0x23);
+ * }) | 0x88), 0x23);
+ * } while (0);
+ *
+ * which in fact violates the access order (= 0x22, 0x22, 0x23, 0x23).
+ */
+
+static inline u8 getCx86(u8 reg)
+{
+ outb(reg, 0x22);
+ return inb(0x23);
+}
+
+static inline void setCx86(u8 reg, u8 data)
+{
+ outb(reg, 0x22);
+ outb(data, 0x23);
+}
diff --git a/include/asm-i386/processor.h b/include/asm-i386/processor.h
index 48a7f69bb76..3845fe72383 100644
--- a/include/asm-i386/processor.h
+++ b/include/asm-i386/processor.h
@@ -168,17 +168,6 @@ static inline void clear_in_cr4 (unsigned long mask)
write_cr4(cr4);
}
-/*
- * NSC/Cyrix CPU indexed register access macros
- */
-
-#define getCx86(reg) ({ outb((reg), 0x22); inb(0x23); })
-
-#define setCx86(reg, data) do { \
- outb((reg), 0x22); \
- outb((data), 0x23); \
-} while (0)
-
/* Stop speculative execution */
static inline void sync_core(void)
{