mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-26 22:24:09 +08:00
f95d47caae
This patch is the meat of the PDA change. This patch makes several related changes: 1: Most significantly, %gs is now used in the kernel. This means that on entry, the old value of %gs is saved away, and it is reloaded with __KERNEL_PDA. 2: entry.S constructs the stack in the shape of struct pt_regs, and this is passed around the kernel so that the process's saved register state can be accessed. Unfortunately struct pt_regs doesn't currently have space for %gs (or %fs). This patch extends pt_regs to add space for gs (no space is allocated for %fs, since it won't be used, and it would just complicate the code in entry.S to work around the space). 3: Because %gs is now saved on the stack like %ds, %es and the integer registers, there are a number of places where it no longer needs to be handled specially; namely context switch, and saving/restoring the register state in a signal context. 4: And since kernel threads run in kernel space and call normal kernel code, they need to be created with their %gs == __KERNEL_PDA. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Chuck Ebbert <76306.1226@compuserve.com> Cc: Zachary Amsden <zach@vmware.com> Cc: Jan Beulich <jbeulich@novell.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org>
60 lines
1.4 KiB
C
60 lines
1.4 KiB
C
#ifndef _I386_PTRACE_H
|
|
#define _I386_PTRACE_H
|
|
|
|
#include <asm/ptrace-abi.h>
|
|
|
|
/* this struct defines the way the registers are stored on the
|
|
stack during a system call. */
|
|
|
|
struct pt_regs {
|
|
long ebx;
|
|
long ecx;
|
|
long edx;
|
|
long esi;
|
|
long edi;
|
|
long ebp;
|
|
long eax;
|
|
int xds;
|
|
int xes;
|
|
/* int xfs; */
|
|
int xgs;
|
|
long orig_eax;
|
|
long eip;
|
|
int xcs;
|
|
long eflags;
|
|
long esp;
|
|
int xss;
|
|
};
|
|
|
|
#ifdef __KERNEL__
|
|
|
|
#include <asm/vm86.h>
|
|
#include <asm/segment.h>
|
|
|
|
struct task_struct;
|
|
extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code);
|
|
|
|
/*
|
|
* user_mode_vm(regs) determines whether a register set came from user mode.
|
|
* This is true if V8086 mode was enabled OR if the register set was from
|
|
* protected mode with RPL-3 CS value. This tricky test checks that with
|
|
* one comparison. Many places in the kernel can bypass this full check
|
|
* if they have already ruled out V8086 mode, so user_mode(regs) can be used.
|
|
*/
|
|
static inline int user_mode(struct pt_regs *regs)
|
|
{
|
|
return (regs->xcs & SEGMENT_RPL_MASK) == USER_RPL;
|
|
}
|
|
static inline int user_mode_vm(struct pt_regs *regs)
|
|
{
|
|
return ((regs->xcs & SEGMENT_RPL_MASK) | (regs->eflags & VM_MASK)) >= USER_RPL;
|
|
}
|
|
|
|
#define instruction_pointer(regs) ((regs)->eip)
|
|
#define regs_return_value(regs) ((regs)->eax)
|
|
|
|
extern unsigned long profile_pc(struct pt_regs *regs);
|
|
#endif /* __KERNEL__ */
|
|
|
|
#endif
|