similar to: [PATCH 4/21] i386 Broken bios common

Andrew Morton's fix for PnP BIOS. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-rc1/drivers/pnp/pnpbios/bioscalls.c =================================================================== --- linux-2.6.14-rc1.orig/drivers/pnp/pnpbios/bioscalls.c 2005-08-28 16:41:01.000000000 -0700 +++ linux-2.6.14-rc1/drivers/pnp/pnpbios/bioscalls.c 2005-09-28 13:13:42.000000000 -0700

Andrew Morton's fix for PnP BIOS. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-rc1/drivers/pnp/pnpbios/bioscalls.c =================================================================== --- linux-2.6.14-rc1.orig/drivers/pnp/pnpbios/bioscalls.c 2005-08-28 16:41:01.000000000 -0700 +++ linux-2.6.14-rc1/drivers/pnp/pnpbios/bioscalls.c 2005-09-28 13:13:42.000000000 -0700

Add an accessor function for getting the per-CPU gdt. Callee must already have the CPU. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-rc1/include/asm-i386/desc.h =================================================================== --- linux-2.6.14-rc1.orig/include/asm-i386/desc.h 2005-09-20 14:49:10.000000000 -0700 +++ linux-2.6.14-rc1/include/asm-i386/desc.h

Add an accessor function for getting the per-CPU gdt. Callee must already have the CPU. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-rc1/include/asm-i386/desc.h =================================================================== --- linux-2.6.14-rc1.orig/include/asm-i386/desc.h 2005-09-20 14:49:10.000000000 -0700 +++ linux-2.6.14-rc1/include/asm-i386/desc.h

I discovered an even more subtle problem; the PnP BIOS code is saving the %fs and %gs segments in inline assembler, yet it also uses the same hack for patching in a fake real mode selector for the BIOS data area. Note that the protected mode selector 0x40 overlaps the user TLS area in the GDT; this means that badly timed PnP BIOS calls could come in, save %fs, come back, and restore %fs -- to

I discovered an even more subtle problem; the PnP BIOS code is saving the %fs and %gs segments in inline assembler, yet it also uses the same hack for patching in a fake real mode selector for the BIOS data area. Note that the protected mode selector 0x40 overlaps the user TLS area in the GDT; this means that badly timed PnP BIOS calls could come in, save %fs, come back, and restore %fs -- to

Index: linux-2.6.13/include/asm-i386/desc.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/desc.h 2005-08-08 17:15:56.000000000 -0700 +++ linux-2.6.13/include/asm-i386/desc.h 2005-08-08 17:16:07.000000000 -0700 @@ -21,6 +21,8 @@ extern struct desc_struct cpu_gdt_table[GDT_ENTRIES]; DECLARE_PER_CPU(struct desc_struct,

Index: linux-2.6.13/include/asm-i386/desc.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/desc.h 2005-08-08 17:15:56.000000000 -0700 +++ linux-2.6.13/include/asm-i386/desc.h 2005-08-08 17:16:07.000000000 -0700 @@ -21,6 +21,8 @@ extern struct desc_struct cpu_gdt_table[GDT_ENTRIES]; DECLARE_PER_CPU(struct desc_struct,

Add an accessor function for getting the per-CPU gdt. Callee must already have the CPU. Patch-base: 2.6.13-rc5-mm1 Patch-keys: i386 desc xen Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.13/include/asm-i386/desc.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/desc.h 2005-08-09 20:17:21.000000000 -0700 +++

Add an accessor function for getting the per-CPU gdt. Callee must already have the CPU. Patch-base: 2.6.13-rc5-mm1 Patch-keys: i386 desc xen Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.13/include/asm-i386/desc.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/desc.h 2005-08-09 20:17:21.000000000 -0700 +++

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

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:

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:

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

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: