does there root fs for i386?

[youxiaojie]

1. does there root fs for i386? I see there is only kernel.
2. you say 3.7 kernel need some patch to build and run, where is the patch?
   thanks!

[marmolak]

Hello.

1. Kernel image have initramfs which contains userspace.

2. Parches are here:
   i386 boot:
   31fb571
   33cf6cb
   f4e2e35
   afd2218
   ef4b585
   floppy:
   6d52c3a
   9ce80f9
   emulator: 7bfd7f7

[youxiaojie]

thanks. I saw there is an i486-emu, is it emulate some instruction missing in 386? if so why it could not emulate cmpxchg?
2.
if I revert the commit of dropping 386 support, should I get some more recent kernel? 3.8 3.9 3.16....

http://lkml.kernel.org/r/1354132230-21854-3-git-send-email-hpa@linux.intel.com
3. I hope to put rootfs on hd, so I can use ssh telenet, turn it as serial terminal. is there way to make rootfs?

[marmolak]

Hello.

1. cmpxchg is emulated only for user space, not for kernel space.
   I don't know how to handle CPU exception from within kernel.

2. I think that this should be possible somewhere around 3.8.0 kernel but even 3.7.x (with latest patches?) kernel have some issues with compilation for i386.

3. You can compile kernel without initramfs and then create rootfs manually.
   Maybe I will add some tools to generate rootfs but primary, this distribution is for a netboot. But you can start experimenting with syslinux etc.

[youxiaojie]

-#ifndef CONFIG_X86_CMPXCHG
-/*
- * Building a kernel capable running on 80386. It may be necessary to
- * simulate the cmpxchg on the 80386 CPU. For that purpose we define
- * a function for each of the sizes we support.
- */
-
-extern unsigned long cmpxchg_386_u8(volatile void *, u8, u8);
-extern unsigned long cmpxchg_386_u16(volatile void *, u16, u16);
-extern unsigned long cmpxchg_386_u32(volatile void *, u32, u32);
-
-static inline unsigned long cmpxchg_386(volatile void *ptr, unsigned long old,
-					unsigned long new, int size)
-{
-	switch (size) {
-	case 1:
-		return cmpxchg_386_u8(ptr, old, new);
-	case 2:
-		return cmpxchg_386_u16(ptr, old, new);
-	case 4:
-		return cmpxchg_386_u32(ptr, old, new);
-	}
-	return old;
-}
-
-#define cmpxchg(ptr, o, n)						\
-({									\
-	__typeof__(*(ptr)) __ret;					\
-	if (likely(boot_cpu_data.x86 > 3))				\
-		__ret = (__typeof__(*(ptr)))__cmpxchg((ptr),		\
-				(unsigned long)(o), (unsigned long)(n),	\
-				sizeof(*(ptr)));			\
-	else								\
-		__ret = (__typeof__(*(ptr)))cmpxchg_386((ptr),		\
-				(unsigned long)(o), (unsigned long)(n),	\
-				sizeof(*(ptr)));			\
-	__ret;								\
-})
-#define cmpxchg_local(ptr, o, n)					\
-({									\
-	__typeof__(*(ptr)) __ret;					\
-	if (likely(boot_cpu_data.x86 > 3))				\
-		__ret = (__typeof__(*(ptr)))__cmpxchg_local((ptr),	\
-				(unsigned long)(o), (unsigned long)(n),	\
-				sizeof(*(ptr)));			\
-	else								\
-		__ret = (__typeof__(*(ptr)))cmpxchg_386((ptr),		\
-				(unsigned long)(o), (unsigned long)(n),	\
-				sizeof(*(ptr)));			\
-	__ret;								\
-})
-#endif

thanks. you mean even the original kernel with CONFIG_CMPXCHG CONFIG_XADD will not run correctly?

cmpxchg, xadd, bswap instruction emulator/simulator - currently I'm not able to force gcc to not emit them.

does it the fault of higher version gcc?

[jszigetvari]

Hello, another future Pocket 386 user here.
I don't want to kidnap this issue, but the topic is somewhat similar to what I would like to ask.

I understand this project currently aims at providing a kernel, with a userland in initramfs.
On the other hand, how could one build a limited userspace (similarly with busybox), to have it installed on a CF card and use it as a more permanent installation on said machine?
Also, one would need an additional bootloader to load the kernel. I guess lilo would be sufficient for the task, but how would I get it installed in a version that doesn't use any post i386 code? I would probably have to build such a binary first.

[marmolak]

Hello, another future Pocket 386 user here. I don't want to kidnap this issue, but the topic is somewhat similar to what I would like to ask.

I understand this project currently aims at providing a kernel, with a userland in initramfs. On the other hand, how could one build a limited userspace (similarly with busybox), to have it installed on a CF card and use it as a more permanent installation on said machine? Also, one would need an additional bootloader to load the kernel. I guess lilo would be sufficient for the task, but how would I get it installed in a version that doesn't use any post i386 code? I would probably have to build such a binary first.

Hello. Looks like I will need to try recompile syslinux or similar (not sure about state of LILO) and try to create small fs image. This linux distro has been build as a experiment with net booting (success!) so maybe it's time to move on and create bootable filesystem image :).

[jszigetvari]

Sounds great. Let me know if I can help with testing it (when it gets there).