# HG changeset patch
# User Jimi Xenidis <jimix@xxxxxxxxxxxxxx>
# Node ID 276d39822a21da13dddd8bc409316105d2fa3838
# Parent 77373497916f9e24939bf4d9549ba7c67c02c73f
[XEN][POWERPC] go ultra conservative on CI IO routines
The following patch contains:
- Code that uses SLBIE for ERAT flush rather than TLBIE. Erratum #16
says to use SLBIE bit a TLBIE should do it and is "less
distruptive".
- Machine Check issues
- Track CI mode while cache is still enabled
- Use r7 to indicate that the IO is still pending while CI is on
- The right sync for the right reasons
Signed-off-by: Jimi Xenidis <jimix@xxxxxxxxxxxxxx>
---
xen/arch/powerpc/powerpc64/io.S | 65 ++++++++++++++++++++++++++++++----------
1 files changed, 50 insertions(+), 15 deletions(-)
diff -r 77373497916f -r 276d39822a21 xen/arch/powerpc/powerpc64/io.S
--- a/xen/arch/powerpc/powerpc64/io.S Sun Oct 01 20:40:44 2006 -0400
+++ b/xen/arch/powerpc/powerpc64/io.S Mon Oct 02 11:04:00 2006 -0400
@@ -23,6 +23,11 @@
#include <asm/processor.h>
#include <asm/percpu.h>
+/* There is no reason why I can't use a tlbie, which should be less
+ * "destructive" but useing SLBIE proves to be more stable result.
+ */
+#define INVALIDATE_ERAT_WITH_SLBIE
+
/* Xen runs in real mode (i.e. untranslated, MMU disabled). This avoids TLB
* flushes and also makes it easy to access all domains' memory. However, on
* PowerPC real mode accesses are cacheable, which is good for general
@@ -34,12 +39,14 @@
* make the access, then re-enable it...
*/
+#ifdef INVALIDATE_ERAT_WITH_SLBIE
/* Not all useful assemblers understand 'tlbiel'.
* 'addr' is a GPR containing the address being accessed.
*/
.macro tlbiel addr
.long 0x7c000224 | (\addr << 11)
.endm
+#endif
.macro DISABLE_DCACHE addr
mfmsr r8
@@ -48,29 +55,53 @@
ori r6, r6, MSR_EE
andc r5, r8, r6
mtmsr r5
+ sync
- /* set HID4.RM_CI */
+#ifdef INVALIDATE_ERAT_WITH_SLBIE
+ /* create an slbie entry for the io setting a high order bit
+ * to avoid any important SLBs */
+ extldi r0, \addr, 36, 0
+#endif
+ /* setup HID4.RM_CI */
mfspr r9, SPRN_HID4
li r6, 0x100
sldi r6, r6, 32
- or r5, r9, r6
- tlbiel \addr /* invalidate the ERAT entry */
- sync
- mtspr SPRN_HID4, r5
+ or r10, r9, r6
+
+ /* Mark the processor as "in CI mode" */
+ li r7,0
+ mfspr r5, SPRN_PIR
+ li r6, MCK_CPU_STAT_CI
+ /* store that we are in a CI routine */
+ stb r6, MCK_CPU_STAT_BASE(r5)
+ /* r7 = MCK_CPU_STAT_CI IO in progress */
+ mr r7, r5
+ lwsync
+
+ /* switch modes */
+ mtspr SPRN_HID4, r10
+ /* invalidate the ERAT entry */
+#ifdef INVALIDATE_ERAT_WITH_SLBIE
+ slbie r0
+#else
+ tlbiel \addr
+#endif
isync
- /* Mark the processor as "in CI mode" */
- mfspr r5, SPRN_PIR
- li r6, MCK_CPU_STAT_CI
- stb r6, MCK_CPU_STAT_BASE(r5)
- sync
.endm
.macro ENABLE_DCACHE addr
- /* re-zero HID4.RM_CI */
+ /* r7 = 0, IO is complete */
+ li r7, 0
+ lwsync
+ /* restore HID4.RM_CI */
+ mtspr SPRN_HID4, r9
+ /* invalidate the ERAT entry */
+#ifdef INVALIDATE_ERAT_WITH_SLBIE
+ slbie r0
+#else
tlbiel \addr /* invalidate the ERAT entry */
- sync
- mtspr SPRN_HID4, r9
+#endif
isync
/* Mark the processor as "out of CI mode" */
@@ -83,9 +114,13 @@
mtmsr r8
.endm
-/* The following assembly cannot use r8 or r9 since they hold original
- * values of msr and hid4 repectively
+/* The following assembly cannot use some registers since they hold original
+ * values of we need to keep
*/
+#undef r0
+#define r0 do_not_use_r0
+#undef r7
+#define r7 do_not_use_r7
#undef r8
#define r8 do_not_use_r8
#undef r9
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