[patch 26/32] SPARC64: Fix two bugs wrt. kernel 4MB TSB.

Chris Wright
2007-06-08T07:21:37Z

[-- Attachment #1: sparc64-fix-two-bugs-wrt.-kernel-4mb-tsb.patch --]
[-- Type: text/plain, Size: 3444 bytes --]

-stable review patch. If anyone has any objections, please let us know.
---------------------

From: David Miller <davem@davemloft.net>

1) The TSB lookup was not using the correct hash mask.

2) It was not aligned on a boundary equal to it's size,
which is required by the sun4v Hypervisor.

wasn't having it's return value checked, and that bug will be fixed up
as well in a subsequent changeset.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

---
arch/sparc64/kernel/head.S | 31 ++++++++++++++++++++++++++-----
arch/sparc64/mm/init.c | 7 +++++--
include/asm-sparc64/tsb.h | 2 +-
3 files changed, 32 insertions(+), 8 deletions(-)

--- linux-2.6.20.13.orig/arch/sparc64/kernel/head.S
+++ linux-2.6.20.13/arch/sparc64/kernel/head.S
@@ -653,33 +653,54 @@ setup_tba:
restore
sparc64_boot_end:

-#include "ktlb.S"
-#include "tsb.S"
#include "etrap.S"
#include "rtrap.S"
#include "winfixup.S"
#include "entry.S"
#include "sun4v_tlb_miss.S"
#include "sun4v_ivec.S"
+#include "ktlb.S"
+#include "tsb.S"

/*
* The following skip makes sure the trap table in ttable.S is aligned
* on a 32K boundary as required by the v9 specs for TBA register.
*
* We align to a 32K boundary, then we have the 32K kernel TSB,
- * then the 32K aligned trap table.
+ * the 64K kernel 4MB TSB, and then the 32K aligned trap table.
*/
1:
.skip 0x4000 + _start - 1b

+! 0x0000000000408000
+
.globl swapper_tsb
swapper_tsb:
.skip (32 * 1024)

-! 0x0000000000408000
-
+ .globl swapper_4m_tsb
+swapper_4m_tsb:
+ .skip (64 * 1024)
+
+! 0x0000000000420000
+
+ /* Some care needs to be exercised if you try to move the
+ * location of the trap table relative to other things. For
+ * one thing there are br* instructions in some of the
+ * trap table entires which branch back to code in ktlb.S
+ * Those instructions can only handle a signed 16-bit
+ * displacement.
+ *
+ * There is a binutils bug (bugzilla #4558) which causes
+ * the relocation overflow checks for such instructions to
+ * not be done correctly. So bintuils will not notice the
+ * error and will instead write junk into the relocation and
+ * you'll have an unbootable kernel.
+ */
#include "ttable.S"

+! 0x0000000000428000
+
#include "systbls.S"

.data
--- linux-2.6.20.13.orig/arch/sparc64/mm/init.c
+++ linux-2.6.20.13/arch/sparc64/mm/init.c
@@ -60,8 +60,11 @@ unsigned long kern_linear_pte_xor[2] __r
unsigned long kpte_linear_bitmap[KPTE_BITMAP_BYTES / sizeof(unsigned long)];

#ifndef CONFIG_DEBUG_PAGEALLOC
-/* A special kernel TSB for 4MB and 256MB linear mappings. */
-struct tsb swapper_4m_tsb[KERNEL_TSB4M_NENTRIES];
+/* A special kernel TSB for 4MB and 256MB linear mappings.
+ * Space is allocated for this right after the trap table
+ * in arch/sparc64/kernel/head.S
+ */
+extern struct tsb swapper_4m_tsb[KERNEL_TSB4M_NENTRIES];
#endif

#define MAX_BANKS 32
--- linux-2.6.20.13.orig/include/asm-sparc64/tsb.h
+++ linux-2.6.20.13/include/asm-sparc64/tsb.h
@@ -271,7 +271,7 @@ extern struct tsb_phys_patch_entry __tsb
#define KERN_TSB4M_LOOKUP_TL1(TAG, REG1, REG2, REG3, REG4, OK_LABEL) \
sethi %hi(swapper_4m_tsb), REG1; \
or REG1, %lo(swapper_4m_tsb), REG1; \
- and TAG, (KERNEL_TSB_NENTRIES - 1), REG2; \
+ and TAG, (KERNEL_TSB4M_NENTRIES - 1), REG2; \
sllx REG2, 4, REG2; \
add REG1, REG2, REG2; \
KTSB_LOAD_QUAD(REG2, REG3); \

--