forked from luck/tmp_suning_uos_patched
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
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#define _I386_PTRACE_H
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#include <asm/ptrace-abi.h>
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/* this struct defines the way the registers are stored on the
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stack during a system call. */
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struct pt_regs {
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long ebx;
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long ecx;
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long edx;
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long esi;
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long edi;
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long ebp;
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long eax;
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int xds;
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int xes;
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/* int xfs; */
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int xgs;
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long orig_eax;
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long eip;
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int xcs;
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long eflags;
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long esp;
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int xss;
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};
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#ifdef __KERNEL__
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#include <asm/vm86.h>
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#include <asm/segment.h>
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struct task_struct;
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extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code);
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/*
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* user_mode_vm(regs) determines whether a register set came from user mode.
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* This is true if V8086 mode was enabled OR if the register set was from
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* protected mode with RPL-3 CS value. This tricky test checks that with
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* one comparison. Many places in the kernel can bypass this full check
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* if they have already ruled out V8086 mode, so user_mode(regs) can be used.
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*/
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static inline int user_mode(struct pt_regs *regs)
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{
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return (regs->xcs & SEGMENT_RPL_MASK) == USER_RPL;
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}
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static inline int user_mode_vm(struct pt_regs *regs)
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{
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return ((regs->xcs & SEGMENT_RPL_MASK) | (regs->eflags & VM_MASK)) >= USER_RPL;
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}
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#define instruction_pointer(regs) ((regs)->eip)
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#define regs_return_value(regs) ((regs)->eax)
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extern unsigned long profile_pc(struct pt_regs *regs);
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#endif /* __KERNEL__ */
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#endif
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