ccbeed3a05
Impact: pt_regs changed, lazy gs handling made optional, add slight
overhead to SAVE_ALL, simplifies error_code path a bit
On x86_32, %gs hasn't been used by kernel and handled lazily. pt_regs
doesn't have place for it and gs is saved/loaded only when necessary.
In preparation for stack protector support, this patch makes lazy %gs
handling optional by doing the followings.
* Add CONFIG_X86_32_LAZY_GS and place for gs in pt_regs.
* Save and restore %gs along with other registers in entry_32.S unless
LAZY_GS. Note that this unfortunately adds "pushl $0" on SAVE_ALL
even when LAZY_GS. However, it adds no overhead to common exit path
and simplifies entry path with error code.
* Define different user_gs accessors depending on LAZY_GS and add
lazy_save_gs() and lazy_load_gs() which are noop if !LAZY_GS. The
lazy_*_gs() ops are used to save, load and clear %gs lazily.
* Define ELF_CORE_COPY_KERNEL_REGS() which always read %gs directly.
xen and lguest changes need to be verified.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
250 lines
5.3 KiB
C
250 lines
5.3 KiB
C
#ifndef _ASM_X86_PTRACE_H
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#define _ASM_X86_PTRACE_H
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#include <linux/compiler.h> /* For __user */
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#include <asm/ptrace-abi.h>
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#include <asm/processor-flags.h>
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#ifdef __KERNEL__
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#include <asm/segment.h>
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#endif
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#ifndef __ASSEMBLY__
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#ifdef __i386__
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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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#ifndef __KERNEL__
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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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#else /* __KERNEL__ */
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struct pt_regs {
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unsigned long bx;
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unsigned long cx;
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unsigned long dx;
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unsigned long si;
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unsigned long di;
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unsigned long bp;
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unsigned long ax;
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unsigned long ds;
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unsigned long es;
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unsigned long fs;
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unsigned long gs;
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unsigned long orig_ax;
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unsigned long ip;
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unsigned long cs;
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unsigned long flags;
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unsigned long sp;
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unsigned long ss;
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};
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#endif /* __KERNEL__ */
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#else /* __i386__ */
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#ifndef __KERNEL__
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struct pt_regs {
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unsigned long r15;
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unsigned long r14;
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unsigned long r13;
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unsigned long r12;
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unsigned long rbp;
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unsigned long rbx;
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/* arguments: non interrupts/non tracing syscalls only save upto here*/
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unsigned long r11;
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unsigned long r10;
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unsigned long r9;
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unsigned long r8;
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unsigned long rax;
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unsigned long rcx;
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unsigned long rdx;
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unsigned long rsi;
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unsigned long rdi;
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unsigned long orig_rax;
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/* end of arguments */
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/* cpu exception frame or undefined */
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unsigned long rip;
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unsigned long cs;
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unsigned long eflags;
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unsigned long rsp;
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unsigned long ss;
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/* top of stack page */
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};
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#else /* __KERNEL__ */
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struct pt_regs {
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unsigned long r15;
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unsigned long r14;
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unsigned long r13;
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unsigned long r12;
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unsigned long bp;
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unsigned long bx;
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/* arguments: non interrupts/non tracing syscalls only save upto here*/
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unsigned long r11;
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unsigned long r10;
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unsigned long r9;
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unsigned long r8;
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unsigned long ax;
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unsigned long cx;
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unsigned long dx;
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unsigned long si;
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unsigned long di;
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unsigned long orig_ax;
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/* end of arguments */
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/* cpu exception frame or undefined */
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unsigned long ip;
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unsigned long cs;
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unsigned long flags;
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unsigned long sp;
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unsigned long ss;
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/* top of stack page */
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};
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#endif /* __KERNEL__ */
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#endif /* !__i386__ */
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#ifdef __KERNEL__
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#include <linux/init.h>
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struct cpuinfo_x86;
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struct task_struct;
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extern unsigned long profile_pc(struct pt_regs *regs);
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extern unsigned long
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convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs);
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extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
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int error_code, int si_code);
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void signal_fault(struct pt_regs *regs, void __user *frame, char *where);
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extern long syscall_trace_enter(struct pt_regs *);
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extern void syscall_trace_leave(struct pt_regs *);
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static inline unsigned long regs_return_value(struct pt_regs *regs)
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{
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return regs->ax;
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}
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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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#ifdef CONFIG_X86_32
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return (regs->cs & SEGMENT_RPL_MASK) == USER_RPL;
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#else
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return !!(regs->cs & 3);
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#endif
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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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#ifdef CONFIG_X86_32
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return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >=
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USER_RPL;
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#else
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return user_mode(regs);
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#endif
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}
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static inline int v8086_mode(struct pt_regs *regs)
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{
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#ifdef CONFIG_X86_32
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return (regs->flags & X86_VM_MASK);
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#else
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return 0; /* No V86 mode support in long mode */
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#endif
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}
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/*
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* X86_32 CPUs don't save ss and esp if the CPU is already in kernel mode
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* when it traps. So regs will be the current sp.
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*
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* This is valid only for kernel mode traps.
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*/
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static inline unsigned long kernel_trap_sp(struct pt_regs *regs)
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{
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#ifdef CONFIG_X86_32
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return (unsigned long)regs;
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#else
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return regs->sp;
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#endif
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}
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static inline unsigned long instruction_pointer(struct pt_regs *regs)
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{
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return regs->ip;
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}
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static inline unsigned long frame_pointer(struct pt_regs *regs)
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{
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return regs->bp;
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}
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static inline unsigned long user_stack_pointer(struct pt_regs *regs)
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{
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return regs->sp;
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}
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/*
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* These are defined as per linux/ptrace.h, which see.
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*/
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#define arch_has_single_step() (1)
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extern void user_enable_single_step(struct task_struct *);
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extern void user_disable_single_step(struct task_struct *);
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extern void user_enable_block_step(struct task_struct *);
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#ifdef CONFIG_X86_DEBUGCTLMSR
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#define arch_has_block_step() (1)
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#else
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#define arch_has_block_step() (boot_cpu_data.x86 >= 6)
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#endif
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struct user_desc;
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extern int do_get_thread_area(struct task_struct *p, int idx,
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struct user_desc __user *info);
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extern int do_set_thread_area(struct task_struct *p, int idx,
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struct user_desc __user *info, int can_allocate);
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extern void x86_ptrace_untrace(struct task_struct *);
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extern void x86_ptrace_fork(struct task_struct *child,
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unsigned long clone_flags);
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#define arch_ptrace_untrace(tsk) x86_ptrace_untrace(tsk)
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#define arch_ptrace_fork(child, flags) x86_ptrace_fork(child, flags)
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#endif /* __KERNEL__ */
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#endif /* !__ASSEMBLY__ */
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#endif /* _ASM_X86_PTRACE_H */
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