mirror of
https://github.com/FEX-Emu/linux.git
synced 2024-12-21 08:53:41 +00:00
78be3706b2
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). This is Chris' [RFC PATCH 15/33] move segment checks to subarch, except rather than using #define USER_MODE_MASK which depends on a config option, we use Zach's more flexible approach of assuming ring 3 == userspace. I also used "get_kernel_rpl()" over "get_kernel_cs()" because I think it reads better in the code... 1) Remove the hardcoded 3 and introduce #define SEGMENT_RPL_MASK 3 2) Add a get_kernel_rpl() macro, and don't assume it's zero. And: 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: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Andi Kleen <ak@suse.de>
36 lines
747 B
C
36 lines
747 B
C
/*
|
|
* linux/arch/i386/mm/extable.c
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/spinlock.h>
|
|
#include <asm/uaccess.h>
|
|
|
|
int fixup_exception(struct pt_regs *regs)
|
|
{
|
|
const struct exception_table_entry *fixup;
|
|
|
|
#ifdef CONFIG_PNPBIOS
|
|
if (unlikely(SEGMENT_IS_PNP_CODE(regs->xcs)))
|
|
{
|
|
extern u32 pnp_bios_fault_eip, pnp_bios_fault_esp;
|
|
extern u32 pnp_bios_is_utter_crap;
|
|
pnp_bios_is_utter_crap = 1;
|
|
printk(KERN_CRIT "PNPBIOS fault.. attempting recovery.\n");
|
|
__asm__ volatile(
|
|
"movl %0, %%esp\n\t"
|
|
"jmp *%1\n\t"
|
|
: : "g" (pnp_bios_fault_esp), "g" (pnp_bios_fault_eip));
|
|
panic("do_trap: can't hit this");
|
|
}
|
|
#endif
|
|
|
|
fixup = search_exception_tables(regs->eip);
|
|
if (fixup) {
|
|
regs->eip = fixup->fixup;
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|