From: Chad Reese <kreese@caviumnetworks.com>
To: Ralf Baechle <ralf@linux-mips.org>
Cc: ddaney@caviumnetworks.com, linux-mips@linux-mips.org,
Tomaso Paoletti <tpaoletti@caviumnetworks.com>,
Paul Gortmaker <Paul.Gortmaker@windriver.com>
Subject: Re: [PATCH 35/37] Set c0 status for ST0_KX on Cavium OCTEON.
Date: Sun, 26 Oct 2008 18:33:44 -0700 [thread overview]
Message-ID: <49051A78.8080601@caviumnetworks.com> (raw)
In-Reply-To: <20081026124821.GN25297@linux-mips.org>
>> -#ifdef CONFIG_64BIT
>> +#if defined(CONFIG_64BIT) || defined(CONFIG_CPU_CAVIUM_OCTEON)
>> + /*
>> + * Note: We always set ST0_KX on Octeon since IO addresses are at
>> + * 64bit addresses. Keep in mind this also moves the TLB handler.
>> + */
>> setup_c0_status ST0_KX 0
>
> That's a bit odd - on 64-bit kernels KX would be set anyway and on 32-bit
> kernels would be corrupted by exceptions or interrupts, so 64-bit
> addresses are not safe to use on 32-bit kernels for most part.
>
> 32-bit virtual addresses mapped to a non-compat address otoh will work fine
> without KX set.
>
> Ralf
The Octeon IO space regions are significantly larger than a 32bit kernel
could tlb map easily. The entire range takes 49 bits to address. As a
not particularly clean, but working alternative, we enable 64bit
addressing in the kernel and used XKPHYS to access IO. Every access was
surrounded by a local_irq_save/local_irq_restore. Since this is ugly to
the extreme, maybe we should drop being able to boot a 32bit kernel on
Octeon until something better is worked out.
Chad
next prev parent reply other threads:[~2008-10-26 18:34 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-24 0:56 [PATCH 00/37] Add Cavium OCTEON processor support ddaney
2008-10-24 0:56 ` [PATCH 01/37] Add Cavium OCTEON processor support files to arch/mips/cavium-octeon ddaney
2008-10-24 0:56 ` [PATCH 02/37] Add Cavium OCTEON files to arch/mips/include/asm/mach-cavium-octeon ddaney
2008-10-24 0:56 ` [PATCH 03/37] Add Cavium OCTEON processor support files to arch/mips/kernel ddaney
2008-10-24 0:56 ` [PATCH 04/37] Add Cavium OCTEON processor support files to arch/mips/mm ddaney
2008-10-24 0:56 ` [PATCH 05/37] Add Cavium OCTEON processor support files to and arch/mips/cavium-octeon/executive ddaney
2008-10-24 0:56 ` [PATCH 06/37] Add Cavium OCTEON processor CSR definitions ddaney
2008-10-24 0:56 ` [PATCH 07/37] Don't assume boot CPU is CPU0 if MIPS_DISABLE_BOOT_CPU_ZERO set ddaney
2008-10-24 0:56 ` [PATCH 08/37] For Cavium OCTEON handle hazzards as per the R10000 handling ddaney
2008-10-24 10:46 ` Sergei Shtylyov
2008-10-24 0:56 ` [PATCH 09/37] Enable mips32 style bitops for Cavium OCTEON ddaney
2008-10-24 0:56 ` [PATCH 10/37] Cavium OCTEON: Set hwrena and lazily restore CP2 state ddaney
2008-10-24 0:56 ` [PATCH 11/37] Cavium OCTEON: ebase isn't just CAC_BASE ddaney
2008-10-24 19:56 ` Maciej W. Rozycki
2008-10-24 20:12 ` David Daney
2008-10-24 0:56 ` [PATCH 12/37] Add Cavium OCTEON to arch/mips/Kconfig ddaney
2008-10-24 0:56 ` [PATCH 13/37] Add Cavium OCTEON processor constants ddaney
2008-10-24 0:56 ` [PATCH 14/37] Rewrite cpu_to_name so it has one statement per line ddaney
2008-10-24 0:56 ` [PATCH 15/37] Probe for Cavium OCTEON CPUs ddaney
2008-10-24 0:56 ` [PATCH 16/37] MIPS: Hook Cavium OCTEON cache init into cache.c ddaney
2008-10-24 0:56 ` [PATCH 17/37] cavium: Hook Cavium specifics into main arch/mips dir ddaney
2008-10-24 0:56 ` [PATCH 18/37] Cavium OCTEON modify core io.h macros to account for the Octeon Errata Core-301 ddaney
2008-10-24 0:56 ` [PATCH 19/37] Cavium OCTEON: increase MAX_DMA address ddaney
2008-10-24 0:56 ` [PATCH 20/37] Cavium OCTEON: add in icache and dcache error functions ddaney
2008-10-24 0:56 ` [PATCH 21/37] Cavium OCTEON: Add cop2/cvmseg state entries to processor.h ddaney
2008-10-24 0:56 ` [PATCH 22/37] Add Cavium OCTEON specific registers to ptrace.h and asm-offsets.c ddaney
2008-10-24 0:56 ` [PATCH 23/37] Add SMP_ICACHE_FLUSH for the Cavium CPU family ddaney
2008-10-24 0:56 ` [PATCH 24/37] Cavium OCTEON: PT vs MFC0 reorder, multiplier state preservation ddaney
2008-10-24 0:56 ` [PATCH 25/37] Add Cavium OCTEON irq hazard in asmmacro.h ddaney
2008-10-24 0:56 ` [PATCH 26/37] Compute branch returns for Cavium OCTEON specific branch instructions ddaney
2008-10-24 0:56 ` [PATCH 27/37] Add Cavium OCTEON slot into proper tlb category ddaney
2008-10-24 0:56 ` [PATCH 28/37] Cavium OCTEON FPU EMU exception as TLB exception ddaney
2008-10-24 10:39 ` Sergei Shtylyov
2008-10-24 13:11 ` Paul Gortmaker
2008-10-24 17:01 ` David Daney
2008-10-24 0:56 ` [PATCH 29/37] Don't clobber spinlocks in 8250 ddaney
2008-10-24 20:12 ` Maciej W. Rozycki
2008-10-24 20:16 ` David Daney
2008-10-24 0:56 ` [PATCH 30/37] Generic 8250 serial driver changes to support future OCTEON serial patches ddaney
2008-10-24 0:56 ` [PATCH 31/37] Allow port type to be specified when calling serial8250_register_port ddaney
2008-10-24 0:56 ` [PATCH 32/37] Allow port type to specify bugs that are not probed for ddaney
2008-10-24 0:56 ` [PATCH 33/37] 8250 serial driver changes for Cavium OCTEON ddaney
2008-10-24 0:56 ` [PATCH 34/37] Adjust the dma-common.c platform hooks ddaney
2008-10-24 0:56 ` [PATCH 35/37] Set c0 status for ST0_KX on Cavium OCTEON ddaney
2008-10-26 12:48 ` Ralf Baechle
2008-10-27 1:33 ` Chad Reese [this message]
2008-10-26 18:51 ` Maciej W. Rozycki
2008-10-26 22:33 ` Ralf Baechle
2008-10-24 0:57 ` [PATCH 36/37] Cavium OCTEON: pmd_none - use pmd_val() in pmd_val() ddaney
2008-10-24 13:00 ` Paul Gortmaker
2008-10-24 15:55 ` David Daney
2008-10-24 15:12 ` Sergei Shtylyov
2008-10-24 0:57 ` [PATCH 37/37] Add defconfig for Cavium OCTEON ddaney
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