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linux-next/arch/s390/include/asm/ptrace.h

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/*
* S390 version
* Copyright IBM Corp. 1999, 2000
* Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
*/
#ifndef _S390_PTRACE_H
#define _S390_PTRACE_H
#include <uapi/asm/ptrace.h>
#ifndef __ASSEMBLY__
[S390] noexec protection This provides a noexec protection on s390 hardware. Our hardware does not have any bits left in the pte for a hw noexec bit, so this is a different approach using shadow page tables and a special addressing mode that allows separate address spaces for code and data. As a special feature of our "secondary-space" addressing mode, separate page tables can be specified for the translation of data addresses (storage operands) and instruction addresses. The shadow page table is used for the instruction addresses and the standard page table for the data addresses. The shadow page table is linked to the standard page table by a pointer in page->lru.next of the struct page corresponding to the page that contains the standard page table (since page->private is not really private with the pte_lock and the page table pages are not in the LRU list). Depending on the software bits of a pte, it is either inserted into both page tables or just into the standard (data) page table. Pages of a vma that does not have the VM_EXEC bit set get mapped only in the data address space. Any try to execute code on such a page will cause a page translation exception. The standard reaction to this is a SIGSEGV with two exceptions: the two system call opcodes 0x0a77 (sys_sigreturn) and 0x0aad (sys_rt_sigreturn) are allowed. They are stored by the kernel to the signal stack frame. Unfortunately, the signal return mechanism cannot be modified to use an SA_RESTORER because the exception unwinding code depends on the system call opcode stored behind the signal stack frame. This feature requires that user space is executed in secondary-space mode and the kernel in home-space mode, which means that the addressing modes need to be switched and that the noexec protection only works for user space. After switching the addressing modes, we cannot use the mvcp/mvcs instructions anymore to copy between kernel and user space. A new mvcos instruction has been added to the z9 EC/BC hardware which allows to copy between arbitrary address spaces, but on older hardware the page tables need to be walked manually. Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-02-06 04:18:17 +08:00
extern long psw_kernel_bits;
extern long psw_user_bits;
/*
* The pt_regs struct defines the way the registers are stored on
* the stack during a system call.
*/
struct pt_regs
{
unsigned long args[1];
psw_t psw;
unsigned long gprs[NUM_GPRS];
unsigned long orig_gpr2;
unsigned int int_code;
unsigned long int_parm_long;
};
/*
* Program event recording (PER) register set.
*/
struct per_regs {
unsigned long control; /* PER control bits */
unsigned long start; /* PER starting address */
unsigned long end; /* PER ending address */
};
/*
* PER event contains information about the cause of the last PER exception.
*/
struct per_event {
unsigned short cause; /* PER code, ATMID and AI */
unsigned long address; /* PER address */
unsigned char paid; /* PER access identification */
};
/*
* Simplified per_info structure used to decode the ptrace user space ABI.
*/
struct per_struct_kernel {
unsigned long cr9; /* PER control bits */
unsigned long cr10; /* PER starting address */
unsigned long cr11; /* PER ending address */
unsigned long bits; /* Obsolete software bits */
unsigned long starting_addr; /* User specified start address */
unsigned long ending_addr; /* User specified end address */
unsigned short perc_atmid; /* PER trap ATMID */
unsigned long address; /* PER trap instruction address */
unsigned char access_id; /* PER trap access identification */
};
#define PER_EVENT_MASK 0xEB000000UL
#define PER_EVENT_BRANCH 0x80000000UL
#define PER_EVENT_IFETCH 0x40000000UL
#define PER_EVENT_STORE 0x20000000UL
#define PER_EVENT_STORE_REAL 0x08000000UL
#define PER_EVENT_TRANSACTION_END 0x02000000UL
#define PER_EVENT_NULLIFICATION 0x01000000UL
#define PER_CONTROL_MASK 0x00e00000UL
#define PER_CONTROL_BRANCH_ADDRESS 0x00800000UL
#define PER_CONTROL_SUSPENSION 0x00400000UL
#define PER_CONTROL_ALTERATION 0x00200000UL
/*
* These are defined as per linux/ptrace.h, which see.
*/
#define arch_has_single_step() (1)
#define user_mode(regs) (((regs)->psw.mask & PSW_MASK_PSTATE) != 0)
#define instruction_pointer(regs) ((regs)->psw.addr & PSW_ADDR_INSN)
#define user_stack_pointer(regs)((regs)->gprs[15])
#define profile_pc(regs) instruction_pointer(regs)
Audit: push audit success and retcode into arch ptrace.h The audit system previously expected arches calling to audit_syscall_exit to supply as arguments if the syscall was a success and what the return code was. Audit also provides a helper AUDITSC_RESULT which was supposed to simplify things by converting from negative retcodes to an audit internal magic value stating success or failure. This helper was wrong and could indicate that a valid pointer returned to userspace was a failed syscall. The fix is to fix the layering foolishness. We now pass audit_syscall_exit a struct pt_reg and it in turns calls back into arch code to collect the return value and to determine if the syscall was a success or failure. We also define a generic is_syscall_success() macro which determines success/failure based on if the value is < -MAX_ERRNO. This works for arches like x86 which do not use a separate mechanism to indicate syscall failure. We make both the is_syscall_success() and regs_return_value() static inlines instead of macros. The reason is because the audit function must take a void* for the regs. (uml calls theirs struct uml_pt_regs instead of just struct pt_regs so audit_syscall_exit can't take a struct pt_regs). Since the audit function takes a void* we need to use static inlines to cast it back to the arch correct structure to dereference it. The other major change is that on some arches, like ia64, MIPS and ppc, we change regs_return_value() to give us the negative value on syscall failure. THE only other user of this macro, kretprobe_example.c, won't notice and it makes the value signed consistently for the audit functions across all archs. In arch/sh/kernel/ptrace_64.c I see that we were using regs[9] in the old audit code as the return value. But the ptrace_64.h code defined the macro regs_return_value() as regs[3]. I have no idea which one is correct, but this patch now uses the regs_return_value() function, so it now uses regs[3]. For powerpc we previously used regs->result but now use the regs_return_value() function which uses regs->gprs[3]. regs->gprs[3] is always positive so the regs_return_value(), much like ia64 makes it negative before calling the audit code when appropriate. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: H. Peter Anvin <hpa@zytor.com> [for x86 portion] Acked-by: Tony Luck <tony.luck@intel.com> [for ia64] Acked-by: Richard Weinberger <richard@nod.at> [for uml] Acked-by: David S. Miller <davem@davemloft.net> [for sparc] Acked-by: Ralf Baechle <ralf@linux-mips.org> [for mips] Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> [for ppc]
2012-01-04 03:23:06 +08:00
static inline long regs_return_value(struct pt_regs *regs)
{
return regs->gprs[2];
}
int regs_query_register_offset(const char *name);
const char *regs_query_register_name(unsigned int offset);
unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset);
unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n);
static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
{
return regs->gprs[15] & PSW_ADDR_INSN;
}
#endif /* __ASSEMBLY__ */
#endif /* _S390_PTRACE_H */