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
H. Peter Anvin hpa at 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 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
On Wed, Dec 12, 2012 at 2:24 PM, H. Peter Anvin h...@zytor.com 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
Le 12/12/12 19:04, Linus Torvalds a écrit : On Tue, Dec 11, 2012 at 3:10 AM, Ingo Molnar mi...@kernel.org 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 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/
Re: [RFC GIT PULL] Nuke 386-DX/SX support changes for v3.8
On Tue, Dec 11, 2012 at 3:10 AM, Ingo Molnar mi...@kernel.org 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/
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 mi...@kernel.org 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 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/
