On Mon, Nov 10, 2008 at 05:24:34PM -0600, Hollis Blanchard wrote:
>The current CHIP11 errata truncates the device tree memory node, and subtracts
>(hardcoded) 4096 bytes. This breaks kernels with larger PAGE_SIZE, since the
>bootmem allocator assumes that total memory is a multiple of PAGE_SIZE.
>
>Instead, use a device tree memory reservation to reserve only the 256 bytes
>actually affected by the errata, leaving the total memory size unaltered.
>
>Signed-off-by: Hollis Blanchard <[EMAIL PROTECTED]>
>
>---
>
>Using large pages results in a huge performance improvement for KVM, and this
>patch is required to make Ilya's large page patch work. David and/or Josh,
>please apply.
The patch looks fine to me, and once David acks the fdt parts I'll apply
for -next. I'll try to do some testing later today as well, since I have
one of the boards with the Errata.
josh
>
>diff --git a/arch/powerpc/boot/4xx.c b/arch/powerpc/boot/4xx.c
>--- a/arch/powerpc/boot/4xx.c
>+++ b/arch/powerpc/boot/4xx.c
>@@ -21,7 +21,7 @@
> #include "reg.h"
> #include "dcr.h"
>
>-static unsigned long chip_11_errata(unsigned long memsize)
>+static void chip_11_errata(unsigned long memsize)
> {
> unsigned long pvr;
>
>@@ -31,13 +31,11 @@ static unsigned long chip_11_errata(unsi
> case 0x40000850:
> case 0x400008d0:
> case 0x200008d0:
>- memsize -= 4096;
>+ fdt_add_mem_rsv(fdt, memsize - 256, 256);
> break;
> default:
> break;
> }
>-
>- return memsize;
> }
>
> /* Read the 4xx SDRAM controller to get size of system memory. */
>@@ -53,7 +51,7 @@ void ibm4xx_sdram_fixup_memsize(void)
> memsize += SDRAM_CONFIG_BANK_SIZE(bank_config);
> }
>
>- memsize = chip_11_errata(memsize);
>+ chip_11_errata(memsize);
> dt_fixup_memory(0, memsize);
> }
>
>@@ -219,7 +217,7 @@ void ibm4xx_denali_fixup_memsize(void)
> bank = 4; /* 4 banks */
>
> memsize = cs * (1 << (col+row)) * bank * dpath;
>- memsize = chip_11_errata(memsize);
>+ chip_11_errata(memsize);
> dt_fixup_memory(0, memsize);
> }
>
>diff --git a/arch/powerpc/boot/libfdt-wrapper.c
>b/arch/powerpc/boot/libfdt-wrapper.c
>--- a/arch/powerpc/boot/libfdt-wrapper.c
>+++ b/arch/powerpc/boot/libfdt-wrapper.c
>@@ -51,7 +51,7 @@
> #define devp_offset_find(devp) (((int)(devp))-1)
> #define devp_offset(devp) (devp ? ((int)(devp))-1 : 0)
>
>-static void *fdt;
>+void *fdt;
> static void *buf; /* = NULL */
>
> #define EXPAND_GRANULARITY 1024
>diff --git a/arch/powerpc/boot/ops.h b/arch/powerpc/boot/ops.h
>--- a/arch/powerpc/boot/ops.h
>+++ b/arch/powerpc/boot/ops.h
>@@ -14,6 +14,7 @@
> #include <stddef.h>
> #include "types.h"
> #include "string.h"
>+#include "libfdt_env.h"
>
> #define COMMAND_LINE_SIZE 512
> #define MAX_PATH_LEN 256
>@@ -32,6 +33,9 @@ struct platform_ops {
> void * (*vmlinux_alloc)(unsigned long size);
> };
> extern struct platform_ops platform_ops;
>+
>+/* The device tree itself. Should almost always be accessed via dt_ops. */
>+extern void *fdt;
>
> /* Device Tree operations */
> struct dt_ops {
>@@ -98,6 +102,8 @@ void dt_get_reg_format(void *node, u32 *
> void dt_get_reg_format(void *node, u32 *naddr, u32 *nsize);
> int dt_get_virtual_reg(void *node, void **addr, int nres);
>
>+int fdt_add_mem_rsv(void *fdt, uint64_t address, uint64_t size);
>+
> static inline void *finddevice(const char *name)
> {
> return (dt_ops.finddevice) ? dt_ops.finddevice(name) : NULL;
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