On processors with deep write buffers, it is likely that many cycles
will pass between a CACHE instruction and the time the data actually
gets written out to DRAM. Add a SYNC instruction to ensure that the
buffers get emptied before the flush functions return.
Actual problem seen in the wild:
1) dma_alloc_coherent() allocates cached memory
2) memset() is called to clear the new pages
3) dma_cache_wback_inv() is called to flush the zero data out to memory
4) dma_alloc_coherent() returns an uncached (kseg1) pointer to the
freshly allocated pages
5) Caller writes data through the kseg1 pointer
6) Buffered writeback data finally gets flushed out to DRAM
7) Part of caller's data is inexplicably zeroed out
This patch adds SYNC between steps 3 and 4, which fixed the problem.
Signed-off-by: Kevin Cernekee <[email protected]>
---
arch/mips/mm/c-r4k.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index b4923a7..dc5d9c4 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -604,6 +604,7 @@ static void r4k_dma_cache_wback_inv(unsigned long addr, unsigned long size)
r4k_blast_scache();
else
blast_scache_range(addr, addr + size);
+ __sync();
return;
}
@@ -620,6 +621,7 @@ static void r4k_dma_cache_wback_inv(unsigned long addr, unsigned long size)
}
bc_wback_inv(addr, size);
+ __sync();
}
static void r4k_dma_cache_inv(unsigned long addr, unsigned long size)
@@ -647,6 +649,7 @@ static void r4k_dma_cache_inv(unsigned long addr, unsigned long size)
(addr + size - 1) & almask);
blast_inv_scache_range(addr, addr + size);
}
+ __sync();
return;
}
@@ -663,6 +666,7 @@ static void r4k_dma_cache_inv(unsigned long addr, unsigned long size)
}
bc_inv(addr, size);
+ __sync();
}
#endif /* CONFIG_DMA_NONCOHERENT */
--
1.7.0.4
pfn_valid() compares the PFN to max_mapnr:
__pfn >= min_low_pfn && __pfn < max_mapnr;
On HIGHMEM kernels, highend_pfn is used to set the value of max_mapnr.
Unfortunately, highend_pfn is left at zero if the system does not
actually have enough RAM to reach into the HIGHMEM range. This causes
pfn_valid() to always return false, and when debug checks are enabled
the kernel will fail catastrophically:
Memory: 22432k/32768k available (2249k kernel code, 10336k reserved, 653k data, 1352k init, 0k highmem)
NR_IRQS:128
kfree_debugcheck: out of range ptr 81c02900h.
Kernel bug detected[#1]:
Cpu 0
$ 0 : 00000000 10008400 00000034 00000000
$ 4 : 8003e160 802a0000 8003e160 00000000
$ 8 : 00000000 0000003e 00000747 00000747
...
On such a configuration, max_low_pfn should be used to set max_mapnr.
This was seen on 2.6.34.
Signed-off-by: Kevin Cernekee <[email protected]>
---
arch/mips/mm/init.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 2efcbd2..18183a4 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -370,7 +370,7 @@ void __init mem_init(void)
#ifdef CONFIG_DISCONTIGMEM
#error "CONFIG_HIGHMEM and CONFIG_DISCONTIGMEM dont work together yet"
#endif
- max_mapnr = highend_pfn;
+ max_mapnr = highend_pfn ? : max_low_pfn;
#else
max_mapnr = max_low_pfn;
#endif
--
1.7.0.4
Memory maps and addressing quirks are normally defined in <spaces.h>.
There are already three targets that need to override FIXADDR_TOP, and
others exist. This will be a cleaner approach than adding lots of
ifdefs in fixmap.h .
Signed-off-by: Kevin Cernekee <[email protected]>
---
arch/mips/include/asm/fixmap.h | 10 +---------
arch/mips/include/asm/mach-bcm63xx/spaces.h | 17 +++++++++++++++++
arch/mips/include/asm/mach-generic/spaces.h | 4 ++++
arch/mips/include/asm/mach-tx39xx/spaces.h | 17 +++++++++++++++++
arch/mips/include/asm/mach-tx49xx/spaces.h | 17 +++++++++++++++++
5 files changed, 56 insertions(+), 9 deletions(-)
create mode 100644 arch/mips/include/asm/mach-bcm63xx/spaces.h
create mode 100644 arch/mips/include/asm/mach-tx39xx/spaces.h
create mode 100644 arch/mips/include/asm/mach-tx49xx/spaces.h
diff --git a/arch/mips/include/asm/fixmap.h b/arch/mips/include/asm/fixmap.h
index 0b89b83..98bcc98 100644
--- a/arch/mips/include/asm/fixmap.h
+++ b/arch/mips/include/asm/fixmap.h
@@ -14,6 +14,7 @@
#define _ASM_FIXMAP_H
#include <asm/page.h>
+#include <spaces.h>
#ifdef CONFIG_HIGHMEM
#include <linux/threads.h>
#include <asm/kmap_types.h>
@@ -67,15 +68,6 @@ enum fixed_addresses {
* the start of the fixmap, and leave one page empty
* at the top of mem..
*/
-#ifdef CONFIG_BCM63XX
-#define FIXADDR_TOP ((unsigned long)(long)(int)0xff000000)
-#else
-#if defined(CONFIG_CPU_TX39XX) || defined(CONFIG_CPU_TX49XX)
-#define FIXADDR_TOP ((unsigned long)(long)(int)(0xff000000 - 0x20000))
-#else
-#define FIXADDR_TOP ((unsigned long)(long)(int)0xfffe0000)
-#endif
-#endif
#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
diff --git a/arch/mips/include/asm/mach-bcm63xx/spaces.h b/arch/mips/include/asm/mach-bcm63xx/spaces.h
new file mode 100644
index 0000000..61e750f
--- /dev/null
+++ b/arch/mips/include/asm/mach-bcm63xx/spaces.h
@@ -0,0 +1,17 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1994 - 1999, 2000, 03, 04 Ralf Baechle
+ * Copyright (C) 2000, 2002 Maciej W. Rozycki
+ * Copyright (C) 1990, 1999, 2000 Silicon Graphics, Inc.
+ */
+#ifndef _ASM_BCM63XX_SPACES_H
+#define _ASM_BCM63XX_SPACES_H
+
+#define FIXADDR_TOP ((unsigned long)(long)(int)0xff000000)
+
+#include <asm/mach-generic/spaces.h>
+
+#endif /* __ASM_BCM63XX_SPACES_H */
diff --git a/arch/mips/include/asm/mach-generic/spaces.h b/arch/mips/include/asm/mach-generic/spaces.h
index c9fa4b1..d7a9efd 100644
--- a/arch/mips/include/asm/mach-generic/spaces.h
+++ b/arch/mips/include/asm/mach-generic/spaces.h
@@ -82,4 +82,8 @@
#define PAGE_OFFSET (CAC_BASE + PHYS_OFFSET)
#endif
+#ifndef FIXADDR_TOP
+#define FIXADDR_TOP ((unsigned long)(long)(int)0xfffe0000)
+#endif
+
#endif /* __ASM_MACH_GENERIC_SPACES_H */
diff --git a/arch/mips/include/asm/mach-tx39xx/spaces.h b/arch/mips/include/asm/mach-tx39xx/spaces.h
new file mode 100644
index 0000000..151fe7a
--- /dev/null
+++ b/arch/mips/include/asm/mach-tx39xx/spaces.h
@@ -0,0 +1,17 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1994 - 1999, 2000, 03, 04 Ralf Baechle
+ * Copyright (C) 2000, 2002 Maciej W. Rozycki
+ * Copyright (C) 1990, 1999, 2000 Silicon Graphics, Inc.
+ */
+#ifndef _ASM_TX39XX_SPACES_H
+#define _ASM_TX39XX_SPACES_H
+
+#define FIXADDR_TOP ((unsigned long)(long)(int)0xfefe0000)
+
+#include <asm/mach-generic/spaces.h>
+
+#endif /* __ASM_TX39XX_SPACES_H */
diff --git a/arch/mips/include/asm/mach-tx49xx/spaces.h b/arch/mips/include/asm/mach-tx49xx/spaces.h
new file mode 100644
index 0000000..0cb10a6
--- /dev/null
+++ b/arch/mips/include/asm/mach-tx49xx/spaces.h
@@ -0,0 +1,17 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1994 - 1999, 2000, 03, 04 Ralf Baechle
+ * Copyright (C) 2000, 2002 Maciej W. Rozycki
+ * Copyright (C) 1990, 1999, 2000 Silicon Graphics, Inc.
+ */
+#ifndef _ASM_TX49XX_SPACES_H
+#define _ASM_TX49XX_SPACES_H
+
+#define FIXADDR_TOP ((unsigned long)(long)(int)0xfefe0000)
+
+#include <asm/mach-generic/spaces.h>
+
+#endif /* __ASM_TX49XX_SPACES_H */
--
1.7.0.4
The MIPS DMA coherency functions do not work properly (i.e. kernel oops)
when HIGHMEM pages are passed in as arguments. Use kmap_atomic() to
temporarily map high pages for cache maintenance operations.
Tested on a 2.6.37-rc1 1GB HIGHMEM SMP no-alias system.
Signed-off-by: Dezhong Diao <[email protected]>
Signed-off-by: Kevin Cernekee <[email protected]>
---
arch/mips/mm/dma-default.c | 114 ++++++++++++++++++++++++++------------------
1 files changed, 68 insertions(+), 46 deletions(-)
diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
index 4fc1a0f..1e20758 100644
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -15,18 +15,18 @@
#include <linux/scatterlist.h>
#include <linux/string.h>
#include <linux/gfp.h>
+#include <linux/highmem.h>
#include <asm/cache.h>
#include <asm/io.h>
#include <dma-coherence.h>
-static inline unsigned long dma_addr_to_virt(struct device *dev,
+static inline struct page *dma_addr_to_page(struct device *dev,
dma_addr_t dma_addr)
{
- unsigned long addr = plat_dma_addr_to_phys(dev, dma_addr);
-
- return (unsigned long)phys_to_virt(addr);
+ return pfn_to_page(
+ plat_dma_addr_to_phys(dev, dma_addr) >> PAGE_SHIFT);
}
/*
@@ -148,20 +148,20 @@ static void mips_dma_free_coherent(struct device *dev, size_t size, void *vaddr,
free_pages(addr, get_order(size));
}
-static inline void __dma_sync(unsigned long addr, size_t size,
+static inline void __dma_sync_virtual(void *addr, size_t size,
enum dma_data_direction direction)
{
switch (direction) {
case DMA_TO_DEVICE:
- dma_cache_wback(addr, size);
+ dma_cache_wback((unsigned long)addr, size);
break;
case DMA_FROM_DEVICE:
- dma_cache_inv(addr, size);
+ dma_cache_inv((unsigned long)addr, size);
break;
case DMA_BIDIRECTIONAL:
- dma_cache_wback_inv(addr, size);
+ dma_cache_wback_inv((unsigned long)addr, size);
break;
default:
@@ -169,12 +169,49 @@ static inline void __dma_sync(unsigned long addr, size_t size,
}
}
+/*
+ * A single sg entry may refer to multiple physically contiguous
+ * pages. But we still need to process highmem pages individually.
+ * If highmem is not configured then the bulk of this loop gets
+ * optimized out.
+ */
+static inline void __dma_sync(struct page *page,
+ unsigned long offset, size_t size, enum dma_data_direction direction)
+{
+ size_t left = size;
+
+ do {
+ size_t len = left;
+
+ if (PageHighMem(page)) {
+ void *addr;
+
+ if (offset + len > PAGE_SIZE) {
+ if (offset >= PAGE_SIZE) {
+ page += offset >> PAGE_SHIFT;
+ offset &= ~PAGE_MASK;
+ }
+ len = PAGE_SIZE - offset;
+ }
+
+ addr = kmap_atomic(page);
+ __dma_sync_virtual(addr + offset, len, direction);
+ kunmap_atomic(addr);
+ } else
+ __dma_sync_virtual(page_address(page) + offset,
+ size, direction);
+ offset = 0;
+ page++;
+ left -= len;
+ } while (left);
+}
+
static void mips_dma_unmap_page(struct device *dev, dma_addr_t dma_addr,
size_t size, enum dma_data_direction direction, struct dma_attrs *attrs)
{
if (cpu_is_noncoherent_r10000(dev))
- __dma_sync(dma_addr_to_virt(dev, dma_addr), size,
- direction);
+ __dma_sync(dma_addr_to_page(dev, dma_addr),
+ dma_addr & ~PAGE_MASK, size, direction);
plat_unmap_dma_mem(dev, dma_addr, size, direction);
}
@@ -185,13 +222,11 @@ static int mips_dma_map_sg(struct device *dev, struct scatterlist *sg,
int i;
for (i = 0; i < nents; i++, sg++) {
- unsigned long addr;
-
- addr = (unsigned long) sg_virt(sg);
- if (!plat_device_is_coherent(dev) && addr)
- __dma_sync(addr, sg->length, direction);
- sg->dma_address = plat_map_dma_mem(dev,
- (void *)addr, sg->length);
+ if (!plat_device_is_coherent(dev))
+ __dma_sync(sg_page(sg), sg->offset, sg->length,
+ direction);
+ sg->dma_address = plat_map_dma_mem_page(dev, sg_page(sg)) +
+ sg->offset;
}
return nents;
@@ -201,30 +236,23 @@ static dma_addr_t mips_dma_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size, enum dma_data_direction direction,
struct dma_attrs *attrs)
{
- unsigned long addr;
-
- addr = (unsigned long) page_address(page) + offset;
-
if (!plat_device_is_coherent(dev))
- __dma_sync(addr, size, direction);
+ __dma_sync(page, offset, size, direction);
- return plat_map_dma_mem(dev, (void *)addr, size);
+ return plat_map_dma_mem_page(dev, page) + offset;
}
static void mips_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
int nhwentries, enum dma_data_direction direction,
struct dma_attrs *attrs)
{
- unsigned long addr;
int i;
for (i = 0; i < nhwentries; i++, sg++) {
if (!plat_device_is_coherent(dev) &&
- direction != DMA_TO_DEVICE) {
- addr = (unsigned long) sg_virt(sg);
- if (addr)
- __dma_sync(addr, sg->length, direction);
- }
+ direction != DMA_TO_DEVICE)
+ __dma_sync(sg_page(sg), sg->offset, sg->length,
+ direction);
plat_unmap_dma_mem(dev, sg->dma_address, sg->length, direction);
}
}
@@ -232,24 +260,18 @@ static void mips_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
static void mips_dma_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle, size_t size, enum dma_data_direction direction)
{
- if (cpu_is_noncoherent_r10000(dev)) {
- unsigned long addr;
-
- addr = dma_addr_to_virt(dev, dma_handle);
- __dma_sync(addr, size, direction);
- }
+ if (cpu_is_noncoherent_r10000(dev))
+ __dma_sync(dma_addr_to_page(dev, dma_handle),
+ dma_handle & ~PAGE_MASK, size, direction);
}
static void mips_dma_sync_single_for_device(struct device *dev,
dma_addr_t dma_handle, size_t size, enum dma_data_direction direction)
{
plat_extra_sync_for_device(dev);
- if (!plat_device_is_coherent(dev)) {
- unsigned long addr;
-
- addr = dma_addr_to_virt(dev, dma_handle);
- __dma_sync(addr, size, direction);
- }
+ if (!plat_device_is_coherent(dev))
+ __dma_sync(dma_addr_to_page(dev, dma_handle),
+ dma_handle & ~PAGE_MASK, size, direction);
}
static void mips_dma_sync_sg_for_cpu(struct device *dev,
@@ -260,8 +282,8 @@ static void mips_dma_sync_sg_for_cpu(struct device *dev,
/* Make sure that gcc doesn't leave the empty loop body. */
for (i = 0; i < nelems; i++, sg++) {
if (cpu_is_noncoherent_r10000(dev))
- __dma_sync((unsigned long)page_address(sg_page(sg)),
- sg->length, direction);
+ __dma_sync(sg_page(sg), sg->offset, sg->length,
+ direction);
}
}
@@ -273,8 +295,8 @@ static void mips_dma_sync_sg_for_device(struct device *dev,
/* Make sure that gcc doesn't leave the empty loop body. */
for (i = 0; i < nelems; i++, sg++) {
if (!plat_device_is_coherent(dev))
- __dma_sync((unsigned long)page_address(sg_page(sg)),
- sg->length, direction);
+ __dma_sync(sg_page(sg), sg->offset, sg->length,
+ direction);
}
}
@@ -295,7 +317,7 @@ void mips_dma_cache_sync(struct device *dev, void *vaddr, size_t size,
plat_extra_sync_for_device(dev);
if (!plat_device_is_coherent(dev))
- __dma_sync((unsigned long)vaddr, size, direction);
+ __dma_sync_virtual(vaddr, size, direction);
}
static struct dma_map_ops mips_default_dma_map_ops = {
--
1.7.0.4
BMIPS4350/4380/5000 CMT/SMT all use SW INT0/INT1 for inter-thread
signaling.
Signed-off-by: Kevin Cernekee <[email protected]>
---
arch/mips/kernel/irq_cpu.c | 14 ++++++--------
1 files changed, 6 insertions(+), 8 deletions(-)
diff --git a/arch/mips/kernel/irq_cpu.c b/arch/mips/kernel/irq_cpu.c
index 0262abe..70d4736 100644
--- a/arch/mips/kernel/irq_cpu.c
+++ b/arch/mips/kernel/irq_cpu.c
@@ -107,14 +107,12 @@ void __init mips_cpu_irq_init(void)
clear_c0_status(ST0_IM);
clear_c0_cause(CAUSEF_IP);
- /*
- * Only MT is using the software interrupts currently, so we just
- * leave them uninitialized for other processors.
- */
- if (cpu_has_mipsmt)
- for (i = irq_base; i < irq_base + 2; i++)
- set_irq_chip_and_handler(i, &mips_mt_cpu_irq_controller,
- handle_percpu_irq);
+ /* Software interrupts are used for MT/CMT IPI */
+ for (i = irq_base; i < irq_base + 2; i++)
+ set_irq_chip_and_handler(i, cpu_has_mipsmt ?
+ &mips_mt_cpu_irq_controller :
+ &mips_cpu_irq_controller,
+ handle_percpu_irq);
for (i = irq_base + 2; i < irq_base + 8; i++)
set_irq_chip_and_handler(i, &mips_cpu_irq_controller,
--
1.7.0.4
Consider the following test case:
write_c0_compare(read_c0_count());
Even if the counter doesn't increment during execution, this might not
generate an interrupt until the counter wraps around. The CPU may
perform the comparison each time CP0 COUNT increments, not when CP0
COMPARE is written.
If mips_next_event() is called with a very small delta, and CP0 COUNT
increments during the calculation of "cnt += delta", it is possible
that CP0 COMPARE will be written with the current value of CP0 COUNT.
If this is detected, the function should return -ETIME, to indicate
that the interrupt might not have actually gotten scheduled.
Signed-off-by: Kevin Cernekee <[email protected]>
---
arch/mips/kernel/cevt-r4k.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/mips/kernel/cevt-r4k.c b/arch/mips/kernel/cevt-r4k.c
index 2f4d7a9..98c5a97 100644
--- a/arch/mips/kernel/cevt-r4k.c
+++ b/arch/mips/kernel/cevt-r4k.c
@@ -32,7 +32,7 @@ static int mips_next_event(unsigned long delta,
cnt = read_c0_count();
cnt += delta;
write_c0_compare(cnt);
- res = ((int)(read_c0_count() - cnt) > 0) ? -ETIME : 0;
+ res = ((int)(read_c0_count() - cnt) >= 0) ? -ETIME : 0;
return res;
}
--
1.7.0.4
BCM4710 uses the BMIPS32 core (like BCM6345), not the MIPS 4Kc core as
was previously believed.
Signed-off-by: Kevin Cernekee <[email protected]>
Tested-by: Alexandros C. Couloumbis <[email protected]>
---
arch/mips/include/asm/cpu.h | 4 ++--
arch/mips/kernel/cpu-probe.c | 7 ++-----
2 files changed, 4 insertions(+), 7 deletions(-)
diff --git a/arch/mips/include/asm/cpu.h b/arch/mips/include/asm/cpu.h
index 06d59dc..8687753 100644
--- a/arch/mips/include/asm/cpu.h
+++ b/arch/mips/include/asm/cpu.h
@@ -111,8 +111,8 @@
* These are the PRID's for when 23:16 == PRID_COMP_BROADCOM
*/
-#define PRID_IMP_BMIPS4KC 0x4000
-#define PRID_IMP_BMIPS32 0x8000
+#define PRID_IMP_BMIPS32_REV4 0x4000
+#define PRID_IMP_BMIPS32_REV8 0x8000
#define PRID_IMP_BMIPS3300 0x9000
#define PRID_IMP_BMIPS3300_ALT 0x9100
#define PRID_IMP_BMIPS3300_BUG 0x0000
diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 71620e1..68dae7b 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -905,7 +905,8 @@ static inline void cpu_probe_broadcom(struct cpuinfo_mips *c, unsigned int cpu)
{
decode_configs(c);
switch (c->processor_id & 0xff00) {
- case PRID_IMP_BMIPS32:
+ case PRID_IMP_BMIPS32_REV4:
+ case PRID_IMP_BMIPS32_REV8:
c->cputype = CPU_BMIPS32;
__cpu_name[cpu] = "Broadcom BMIPS32";
break;
@@ -933,10 +934,6 @@ static inline void cpu_probe_broadcom(struct cpuinfo_mips *c, unsigned int cpu)
__cpu_name[cpu] = "Broadcom BMIPS5000";
c->options |= MIPS_CPU_ULRI;
break;
- case PRID_IMP_BMIPS4KC:
- c->cputype = CPU_4KC;
- __cpu_name[cpu] = "MIPS 4Kc";
- break;
}
}
--
1.7.0.4
On Tue, Nov 23, 2010 at 10:26:44AM -0800, Kevin Cernekee wrote:
> write_c0_compare(read_c0_count());
>
> Even if the counter doesn't increment during execution, this might not
> generate an interrupt until the counter wraps around. The CPU may
> perform the comparison each time CP0 COUNT increments, not when CP0
> COMPARE is written.
>
> If mips_next_event() is called with a very small delta, and CP0 COUNT
> increments during the calculation of "cnt += delta", it is possible
> that CP0 COMPARE will be written with the current value of CP0 COUNT.
> If this is detected, the function should return -ETIME, to indicate
> that the interrupt might not have actually gotten scheduled.
Good catch - though on real hardware it should be theoretical as the
minimum timer interval is 300ns. So it should only be trigerable on
a very slow system like a hardware emulator or maybe if a software
emulator like qemu gets rescheduled between the update and the read-back.
Applied,
Ralf
Applied as well.
Thanks,
Ralf