Re: Microblaze arch/microblaze/kernel/head.S: redundant code?
Hi, On 10/31/2014 04:15 PM, Adrian McMenamin wrote: > Looking at this code at line 78 (in 3.17 kernel) it has: > > mfs r1, rmsr > msrclr r8, 0 > cmpu r8, r8, r1 > > But as far as I can see the result of that comparison is never used - the > comments state it is to test if the msrclr instruction is enabled. r8 is used when machine_early_init() is called. r8 is 4th register which is used for passing args based on Microblaze reference manual. Thanks, Michal -- Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91 w: www.monstr.eu p: +42-0-721842854 Maintainer of Linux kernel - Microblaze cpu - http://www.monstr.eu/fdt/ Maintainer of Linux kernel - Xilinx Zynq ARM architecture Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform signature.asc Description: OpenPGP digital signature
arch/microblaze/kernel/head.S: redundant code?
Looking at this code at line 78 (in 3.17 kernel) it has: mfs r1, rmsr msrclr r8, 0 cmpu r8, r8, r1 But as far as I can see the result of that comparison is never used - the comments state it is to test if the msrclr instruction is enabled. Haven't posted a patch because I am using the code to understand how to write my own boot code for a very specific Microblaze application - but perhaps someone with real expertise could look and/or tell me I'm wrong? Cheers Adrian (apologies to Michal Simek for getting this twice) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
arch/microblaze/kernel/head.S: redundant code?
Looking at this code at line 78 (in 3.17 kernel) it has: mfs r1, rmsr msrclr r8, 0 cmpu r8, r8, r1 But as far as I can see the result of that comparison is never used - the comments state it is to test if the msrclr instruction is enabled. Haven't posted a patch because I am using the code to understand how to write my own boot code for a very specific Microblaze application - but perhaps someone with real expertise could look and/or tell me I'm wrong? Cheers Adrian (apologies to Michal Simek for getting this twice) -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: Microblaze arch/microblaze/kernel/head.S: redundant code?
Hi, On 10/31/2014 04:15 PM, Adrian McMenamin wrote: Looking at this code at line 78 (in 3.17 kernel) it has: mfs r1, rmsr msrclr r8, 0 cmpu r8, r8, r1 But as far as I can see the result of that comparison is never used - the comments state it is to test if the msrclr instruction is enabled. r8 is used when machine_early_init() is called. r8 is 4th register which is used for passing args based on Microblaze reference manual. Thanks, Michal -- Michal Simek, Ing. (M.Eng), OpenPGP - KeyID: FE3D1F91 w: www.monstr.eu p: +42-0-721842854 Maintainer of Linux kernel - Microblaze cpu - http://www.monstr.eu/fdt/ Maintainer of Linux kernel - Xilinx Zynq ARM architecture Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform signature.asc Description: OpenPGP digital signature
