similar to: [PATCH 1/21] i386 Pnp segments in segment h

It is impossible to have a zero length segment in descriptor tables using "normal" segments. One of many ways to properly protect segments to zero length is to map the base to an umapped page. Create a nicer way to do this, and stop subtracting 1 from the length passed to set_limit (note calling set limit with a zero limit does something very bad! - not anymore). Signed-off-by:

It is impossible to have a zero length segment in descriptor tables using "normal" segments. One of many ways to properly protect segments to zero length is to map the base to an umapped page. Create a nicer way to do this, and stop subtracting 1 from the length passed to set_limit (note calling set limit with a zero limit does something very bad! - not anymore). Signed-off-by:

PnP BIOS for x86 is part of drivers, so I missed it in the initial GDT page alignment patch. Kudos to Andrew for fixing that. Unfortunately, fixing the build introduced a kernel panic when trying to setup the as of yet unallocated GDTs for the APs. This fixes the problem by setting only the BSP's GDT, then copying the PnP segments back to the cpu_gdt_table template. Signed-off-by: Zachary

PnP BIOS for x86 is part of drivers, so I missed it in the initial GDT page alignment patch. Kudos to Andrew for fixing that. Unfortunately, fixing the build introduced a kernel panic when trying to setup the as of yet unallocated GDTs for the APs. This fixes the problem by setting only the BSP's GDT, then copying the PnP segments back to the cpu_gdt_table template. Signed-off-by: Zachary

PnP BIOS data, code, and 32-bit entry segments all have fixed limits as well; set them in the GDT rather than adding more code. It would be nice to add these fixups to the boot GDT rather than setting the GDT for each CPU; perhaps I can wiggle this in later, but getting it in before the subsys init looks tricky. Also, make some progress on deprecating the ugly Q_SET_SEL macros. Signed-off-by:

PnP BIOS data, code, and 32-bit entry segments all have fixed limits as well; set them in the GDT rather than adding more code. It would be nice to add these fixups to the boot GDT rather than setting the GDT for each CPU; perhaps I can wiggle this in later, but getting it in before the subsys init looks tricky. Also, make some progress on deprecating the ugly Q_SET_SEL macros. Signed-off-by:

Both the APM BIOS and PnP BIOS code use a segment hack to simulate real mode selector 0x40 (which points to the BIOS data area at 0x00400 in real mode). Several broken BIOSen use selector 0x40 as if they were running in real mode, which we make work by faking up selector 0x40 in the GDT to point to physical memory starting at 0x400. We limit the access to the remainder of this physical page

Both the APM BIOS and PnP BIOS code use a segment hack to simulate real mode selector 0x40 (which points to the BIOS data area at 0x00400 in real mode). Several broken BIOSen use selector 0x40 as if they were running in real mode, which we make work by faking up selector 0x40 in the GDT to point to physical memory starting at 0x400. We limit the access to the remainder of this physical page

Ancient inline assembler that manipulates descriptor tables is unreadable and has no type checking. Doing this in C actually generates better code, saves code space, and improves readability. The fact that you must cast descriptors to (char *) for the inline assembler to work properly caused me no end of grief working on these patches. Note that GCC does not generate rotations to utilize

Ancient inline assembler that manipulates descriptor tables is unreadable and has no type checking. Doing this in C actually generates better code, saves code space, and improves readability. The fact that you must cast descriptors to (char *) for the inline assembler to work properly caused me no end of grief working on these patches. Note that GCC does not generate rotations to utilize

Make GDT page aligned and page padded to support running inside of a hypervisor. This prevents false sharing of the GDT page with other hot data, which is not allowed in Xen, and causes performance problems in VMware. Rather than go back to the old method of statically allocating the GDT (which wastes unneded space for non-present CPUs), the GDT for APs is allocated dynamically. Signed-off-by:

Make GDT page aligned and page padded to support running inside of a hypervisor. This prevents false sharing of the GDT page with other hot data, which is not allowed in Xen, and causes performance problems in VMware. Rather than go back to the old method of statically allocating the GDT (which wastes unneded space for non-present CPUs), the GDT for APs is allocated dynamically. Signed-off-by:

In-Reply-To: <20060803002518.190834642@xensource.com> On Wed, 02 Aug 2006 17:25:13 -0700, Jeremy Fitzhardinge wrote: > We allow for the fact that the guest kernel may not run in ring 0. > This requires some abstraction in a few places when setting %cs or > checking privilege level (user vs kernel). I made some changes: a. Added some comments about the SEGMENT_IS_*_CODE() macros.

In-Reply-To: <20060803002518.190834642@xensource.com> On Wed, 02 Aug 2006 17:25:13 -0700, Jeremy Fitzhardinge wrote: > We allow for the fact that the guest kernel may not run in ring 0. > This requires some abstraction in a few places when setting %cs or > checking privilege level (user vs kernel). I made some changes: a. Added some comments about the SEGMENT_IS_*_CODE() macros.

Clean up of patch for letting kernel run other than ring 0: a. Add some comments about the SEGMENT_IS_*_CODE() macros. b. Add a USER_RPL macro. (Code was comparing a value to a mask in some places and to the magic number 3 in other places.) c. Add macros for table indicator field and use them. d. Change the entry.S tests for LDT stack segment to use the macros. Signed-off-by: Chuck Ebbert

Clean up of patch for letting kernel run other than ring 0: a. Add some comments about the SEGMENT_IS_*_CODE() macros. b. Add a USER_RPL macro. (Code was comparing a value to a mask in some places and to the magic number 3 in other places.) c. Add macros for table indicator field and use them. d. Change the entry.S tests for LDT stack segment to use the macros. Signed-off-by: Chuck Ebbert

I am trying to figure out how to create a PnP Gateway. What I understand it does is this. My server Ip: 192.168.100.1 Dhcp range 192.168.100.xxx/24 Sub 255.255.255.0 Gateway 192.168.100.1 What I am looing to do from what I understand is allow someone with a static ip of say like 1.1.1.1/24 and a gateway of 1.1.1..254 to connect to the network and access the network. Can someone point me where

Simple question. In the motherboard bios should PnP OS be enabled or disable on motherboard running Centos 4.x? Matt

The one remaining caller of set_limit, the PnP BIOS code, calls into the PnP BIOS, passing kernel parameters in and out. These parameteres may be passed from arbitrary kernel virtual memory, so they deserve strict protection to stop a bad BIOS from smashing beyond the object size. Unfortunately, the use of set_limit was badly botching this by setting the limit in terms of pages, when it really

HI: I try to let guest os to DHA(directly hardware acceess) physical network card, and also want to let rombios (which is not DHA) to initialize networks card''s pnp option Rom(the pnp option rom is DHA). however , I find the init program(offset by 3 from 55aa header signature) within option rom can not run properly ---- it cause stact underflow . and when retf form option rom ,system