From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from qw-out-2122.google.com (qw-out-2122.google.com [74.125.92.25]) by ozlabs.org (Postfix) with ESMTP id 5C5BFDDDF8 for ; Tue, 11 Nov 2008 23:54:28 +1100 (EST) Received: by qw-out-2122.google.com with SMTP id 9so1679144qwb.15 for ; Tue, 11 Nov 2008 04:54:26 -0800 (PST) Date: Tue, 11 Nov 2008 07:52:18 -0500 From: Josh Boyer To: Hollis Blanchard Subject: Re: [PATCH] [v2] powerpc/4xx: work around CHIP11 errata in a more PAGE_SIZE-friendly way Message-ID: <20081111125218.GA2266@yoda.jdub.homelinux.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: Josh Boyer Cc: linuxppc-dev@ozlabs.org, yanok@emcraft.com, kvm-ppc@vger.kernel.org, dwg@au1.ibm.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 > >--- > >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 > #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; >_______________________________________________ >Linuxppc-dev mailing list >Linuxppc-dev@ozlabs.org >https://ozlabs.org/mailman/listinfo/linuxppc-dev