Re: [RFC GIT PULL] "Nuke 386-DX/SX support" changes for v3.8
Le 12/12/12 19:04, Linus Torvalds a écrit : On Tue, Dec 11, 2012 at 3:10 AM, Ingo Molnar wrote: This tree removes ancient-386-CPUs support and thus zaps quite a bit of complexity: Btw, I think we should probably at least consider taking this one step further, and remove the dear old FPU emulation support too. Remove CONFIG_MATH_EMULATION and all of arch/x86/math-emu, along with a lot of small special cases. Or do people still use the 486SX? Yes, the RDC-R321x SoC which is supported by mainline actually needs Math emulation to properly work. Now, the math emulation hasn't been all that fundamentally problematic (compared to lack of xadd etc), but it does result in some complexities in exception handling and ptrace (grep for HAVE_HWFP or "hard_math" or a number of other magic things). None of which have likely been tested at all in the last ten years, so who knows if it actually *works* or not. Maybe somebody could try booting with "no387". Does it actually work? Ok, I could try that. -- Florian -- 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: [RFC GIT PULL] "Nuke 386-DX/SX support" changes for v3.8
On Wed, Dec 12, 2012 at 2:24 PM, H. Peter Anvin wrote: > > Well... it turns out to boot and run Red Hat 4.1 just fine (using qemu -cpu > 486 and the no387 option) once I changed /dev/hda1 to /dev/sda1. Ok. It sounds like the code actually works despite lack of testing, and it clearly hasn't been the same kind of maintenance pain and problem that the lack of cmpxchg and friends, so let's leave it alone. Thanks, Linus -- 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: [RFC GIT PULL] "Nuke 386-DX/SX support" changes for v3.8
On Mit, 2012-12-12 at 11:00 -0800, H. Peter Anvin wrote: [...] > There were a *bunch* of embedded 486 clones made, some still in > production as far as I know, and I wouldn't be surprised if some of them > lacked FPU. I guess we'll see. And there is an x86 emulator written in Javascript at http://www.bellard.org/jslinux/. http://www.bellard.org/jslinux/tech.html says that it (also) lacks an FPU. Bernd -- Bernd Petrovitsch Email : be...@petrovitsch.priv.at LUGA : http://www.luga.at -- 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: [RFC GIT PULL] "Nuke 386-DX/SX support" changes for v3.8
H. Peter Anvin zytor.com> writes: > On 12/12/2012 10:04 AM, Linus Torvalds wrote: > > Or do people still use the 486SX? > There were a *bunch* of embedded 486 clones made, some still in > production as far as I know, and I wouldn't be surprised if some of them > lacked FPU. I guess we'll see. This one is fairly recent: Bifferboard ⇒ http://bifferos.co.uk/ bye, //mirabilos -- 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: [RFC GIT PULL] "Nuke 386-DX/SX support" changes for v3.8
On 12/12/2012 11:00 AM, H. Peter Anvin wrote: It builds and boots, at least. I'm currently installing Red Hat 4.1 in a VM so I can test to see if it does anything more than that. It doesn't get in the way the same case the old 386 bits does, so I'm more reluctant to remove it, but it does touch a lot of paths. Well... it turns out to boot and run Red Hat 4.1 just fine (using qemu -cpu 486 and the no387 option) once I changed /dev/hda1 to /dev/sda1. I'm actually kind of impressed. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- 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: [RFC GIT PULL] "Nuke 386-DX/SX support" changes for v3.8
On 12/12/2012 10:04 AM, Linus Torvalds wrote: On Tue, Dec 11, 2012 at 3:10 AM, Ingo Molnar wrote: This tree removes ancient-386-CPUs support and thus zaps quite a bit of complexity: Btw, I think we should probably at least consider taking this one step further, and remove the dear old FPU emulation support too. Remove CONFIG_MATH_EMULATION and all of arch/x86/math-emu, along with a lot of small special cases. Or do people still use the 486SX? Now, the math emulation hasn't been all that fundamentally problematic (compared to lack of xadd etc), but it does result in some complexities in exception handling and ptrace (grep for HAVE_HWFP or "hard_math" or a number of other magic things). None of which have likely been tested at all in the last ten years, so who knows if it actually *works* or not. Maybe somebody could try booting with "no387". Does it actually work? It builds and boots, at least. I'm currently installing Red Hat 4.1 in a VM so I can test to see if it does anything more than that. It doesn't get in the way the same case the old 386 bits does, so I'm more reluctant to remove it, but it does touch a lot of paths. There were a *bunch* of embedded 486 clones made, some still in production as far as I know, and I wouldn't be surprised if some of them lacked FPU. I guess we'll see. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- 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: [RFC GIT PULL] "Nuke 386-DX/SX support" changes for v3.8
On Tue, Dec 11, 2012 at 3:10 AM, Ingo Molnar wrote: > > This tree removes ancient-386-CPUs support and thus zaps quite a > bit of complexity: Btw, I think we should probably at least consider taking this one step further, and remove the dear old FPU emulation support too. Remove CONFIG_MATH_EMULATION and all of arch/x86/math-emu, along with a lot of small special cases. Or do people still use the 486SX? Now, the math emulation hasn't been all that fundamentally problematic (compared to lack of xadd etc), but it does result in some complexities in exception handling and ptrace (grep for HAVE_HWFP or "hard_math" or a number of other magic things). None of which have likely been tested at all in the last ten years, so who knows if it actually *works* or not. Maybe somebody could try booting with "no387". Does it actually work? Linus -- 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/
[RFC GIT PULL] "Nuke 386-DX/SX support" changes for v3.8
Linus, Please consider pulling the latest x86-nuke386-for-linus git tree from: git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-nuke386-for-linus HEAD: 11af32b69ef7ee64c7d8848cad71a6f3749d9e37 x86, 386 removal: Document Nx586 as a 386 and thus unsupported This tree removes ancient-386-CPUs support and thus zaps quite a bit of complexity: 24 files changed, 56 insertions(+), 425 deletions(-) ... which complexity has plagued us with extra work whenever we wanted to change SMP primitives, for years. Unfortunately there's a nostalgic cost: your old original 386 DX33 system from early 1991 won't be able to boot modern Linux kernels anymore. Sniff. Thanks, Ingo --> H. Peter Anvin (9): x86, 386 removal: Remove CONFIG_M386 from Kconfig x86, 386 removal: Remove CONFIG_CMPXCHG x86, 386 removal: Remove CONFIG_XADD x86, 386 removal: Remove CONFIG_BSWAP x86, 386 removal: Remove CONFIG_INVLPG x86, 386 removal: Remove CONFIG_X86_WP_WORKS_OK x86, 386 removal: Remove CONFIG_X86_POPAD_OK x86, cleanups: Simplify sync_core() in the case of no CPUID x86, 386 removal: Document Nx586 as a 386 and thus unsupported arch/x86/Kconfig | 11 ++ arch/x86/Kconfig.cpu | 73 +++ arch/x86/Makefile_32.cpu | 1 - arch/x86/include/asm/atomic.h | 16 - arch/x86/include/asm/cmpxchg_32.h | 55 - arch/x86/include/asm/cpufeature.h | 6 arch/x86/include/asm/futex.h | 12 --- arch/x86/include/asm/local.h | 18 +- arch/x86/include/asm/module.h | 2 -- arch/x86/include/asm/percpu.h | 3 -- arch/x86/include/asm/processor.h | 33 -- arch/x86/include/asm/swab.h | 29 ++-- arch/x86/include/asm/tlbflush.h | 3 -- arch/x86/include/asm/uaccess.h| 42 -- arch/x86/kernel/cpu/amd.c | 3 -- arch/x86/kernel/cpu/bugs.c| 41 ++ arch/x86/kernel/cpu/intel.c | 4 --- arch/x86/lib/Makefile | 1 - arch/x86/lib/cmpxchg.c| 54 - arch/x86/lib/usercopy_32.c| 57 -- arch/x86/mm/init_32.c | 5 +-- arch/x86/mm/tlb.c | 8 ++--- arch/x86/um/Kconfig | 2 +- arch/x86/xen/Kconfig | 2 +- 24 files changed, 56 insertions(+), 425 deletions(-) delete mode 100644 arch/x86/lib/cmpxchg.c diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 46c3bff..631b298 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -69,8 +69,8 @@ config X86 select HAVE_PERF_USER_STACK_DUMP select HAVE_DEBUG_KMEMLEAK select ANON_INODES - select HAVE_ALIGNED_STRUCT_PAGE if SLUB && !M386 - select HAVE_CMPXCHG_LOCAL if !M386 + select HAVE_ALIGNED_STRUCT_PAGE if SLUB + select HAVE_CMPXCHG_LOCAL select HAVE_CMPXCHG_DOUBLE select HAVE_ARCH_KMEMCHECK select HAVE_USER_RETURN_NOTIFIER @@ -171,13 +171,8 @@ config ARCH_MAY_HAVE_PC_FDC def_bool y depends on ISA_DMA_API -config RWSEM_GENERIC_SPINLOCK - def_bool y - depends on !X86_XADD - config RWSEM_XCHGADD_ALGORITHM def_bool y - depends on X86_XADD config GENERIC_CALIBRATE_DELAY def_bool y @@ -1100,7 +1095,7 @@ config HIGHMEM4G config HIGHMEM64G bool "64GB" - depends on !M386 && !M486 + depends on !M486 select X86_PAE ---help--- Select this if you have a 32-bit processor and more than 4 diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu index f3b86d0..c026cca 100644 --- a/arch/x86/Kconfig.cpu +++ b/arch/x86/Kconfig.cpu @@ -4,23 +4,24 @@ choice default M686 if X86_32 default GENERIC_CPU if X86_64 -config M386 - bool "386" - depends on X86_32 && !UML +config M486 + bool "486" + depends on X86_32 ---help--- - This is the processor type of your CPU. This information is used for - optimizing purposes. In order to compile a kernel that can run on - all x86 CPU types (albeit not optimally fast), you can specify - "386" here. + This is the processor type of your CPU. This information is + used for optimizing purposes. In order to compile a kernel + that can run on all supported x86 CPU types (albeit not + optimally fast), you can specify "486" here. + + Note that the 386 is no longer supported, this includes + AMD/Cyrix/Intel 386DX/DXL/SL/SLC/SX, Cyrix/TI 486DLC/DLC2, + UMC 486SX-S and the NexGen Nx586. The kernel will not necessarily run on earlier architectures than the one you have chosen, e.g. a Pentium optimized kernel will run on a PPro, but not necessarily on a i486. Here are the settings
