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linux-stable/include/asm-s390/ptrace.h
Gerald Schaefer c1821c2e97 [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>
2007-02-05 21:18:17 +01:00

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/*
* include/asm-s390/ptrace.h
*
* S390 version
* Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
*/
#ifndef _S390_PTRACE_H
#define _S390_PTRACE_H
/*
* Offsets in the user_regs_struct. They are used for the ptrace
* system call and in entry.S
*/
#ifndef __s390x__
#define PT_PSWMASK 0x00
#define PT_PSWADDR 0x04
#define PT_GPR0 0x08
#define PT_GPR1 0x0C
#define PT_GPR2 0x10
#define PT_GPR3 0x14
#define PT_GPR4 0x18
#define PT_GPR5 0x1C
#define PT_GPR6 0x20
#define PT_GPR7 0x24
#define PT_GPR8 0x28
#define PT_GPR9 0x2C
#define PT_GPR10 0x30
#define PT_GPR11 0x34
#define PT_GPR12 0x38
#define PT_GPR13 0x3C
#define PT_GPR14 0x40
#define PT_GPR15 0x44
#define PT_ACR0 0x48
#define PT_ACR1 0x4C
#define PT_ACR2 0x50
#define PT_ACR3 0x54
#define PT_ACR4 0x58
#define PT_ACR5 0x5C
#define PT_ACR6 0x60
#define PT_ACR7 0x64
#define PT_ACR8 0x68
#define PT_ACR9 0x6C
#define PT_ACR10 0x70
#define PT_ACR11 0x74
#define PT_ACR12 0x78
#define PT_ACR13 0x7C
#define PT_ACR14 0x80
#define PT_ACR15 0x84
#define PT_ORIGGPR2 0x88
#define PT_FPC 0x90
/*
* A nasty fact of life that the ptrace api
* only supports passing of longs.
*/
#define PT_FPR0_HI 0x98
#define PT_FPR0_LO 0x9C
#define PT_FPR1_HI 0xA0
#define PT_FPR1_LO 0xA4
#define PT_FPR2_HI 0xA8
#define PT_FPR2_LO 0xAC
#define PT_FPR3_HI 0xB0
#define PT_FPR3_LO 0xB4
#define PT_FPR4_HI 0xB8
#define PT_FPR4_LO 0xBC
#define PT_FPR5_HI 0xC0
#define PT_FPR5_LO 0xC4
#define PT_FPR6_HI 0xC8
#define PT_FPR6_LO 0xCC
#define PT_FPR7_HI 0xD0
#define PT_FPR7_LO 0xD4
#define PT_FPR8_HI 0xD8
#define PT_FPR8_LO 0XDC
#define PT_FPR9_HI 0xE0
#define PT_FPR9_LO 0xE4
#define PT_FPR10_HI 0xE8
#define PT_FPR10_LO 0xEC
#define PT_FPR11_HI 0xF0
#define PT_FPR11_LO 0xF4
#define PT_FPR12_HI 0xF8
#define PT_FPR12_LO 0xFC
#define PT_FPR13_HI 0x100
#define PT_FPR13_LO 0x104
#define PT_FPR14_HI 0x108
#define PT_FPR14_LO 0x10C
#define PT_FPR15_HI 0x110
#define PT_FPR15_LO 0x114
#define PT_CR_9 0x118
#define PT_CR_10 0x11C
#define PT_CR_11 0x120
#define PT_IEEE_IP 0x13C
#define PT_LASTOFF PT_IEEE_IP
#define PT_ENDREGS 0x140-1
#define GPR_SIZE 4
#define CR_SIZE 4
#define STACK_FRAME_OVERHEAD 96 /* size of minimum stack frame */
#else /* __s390x__ */
#define PT_PSWMASK 0x00
#define PT_PSWADDR 0x08
#define PT_GPR0 0x10
#define PT_GPR1 0x18
#define PT_GPR2 0x20
#define PT_GPR3 0x28
#define PT_GPR4 0x30
#define PT_GPR5 0x38
#define PT_GPR6 0x40
#define PT_GPR7 0x48
#define PT_GPR8 0x50
#define PT_GPR9 0x58
#define PT_GPR10 0x60
#define PT_GPR11 0x68
#define PT_GPR12 0x70
#define PT_GPR13 0x78
#define PT_GPR14 0x80
#define PT_GPR15 0x88
#define PT_ACR0 0x90
#define PT_ACR1 0x94
#define PT_ACR2 0x98
#define PT_ACR3 0x9C
#define PT_ACR4 0xA0
#define PT_ACR5 0xA4
#define PT_ACR6 0xA8
#define PT_ACR7 0xAC
#define PT_ACR8 0xB0
#define PT_ACR9 0xB4
#define PT_ACR10 0xB8
#define PT_ACR11 0xBC
#define PT_ACR12 0xC0
#define PT_ACR13 0xC4
#define PT_ACR14 0xC8
#define PT_ACR15 0xCC
#define PT_ORIGGPR2 0xD0
#define PT_FPC 0xD8
#define PT_FPR0 0xE0
#define PT_FPR1 0xE8
#define PT_FPR2 0xF0
#define PT_FPR3 0xF8
#define PT_FPR4 0x100
#define PT_FPR5 0x108
#define PT_FPR6 0x110
#define PT_FPR7 0x118
#define PT_FPR8 0x120
#define PT_FPR9 0x128
#define PT_FPR10 0x130
#define PT_FPR11 0x138
#define PT_FPR12 0x140
#define PT_FPR13 0x148
#define PT_FPR14 0x150
#define PT_FPR15 0x158
#define PT_CR_9 0x160
#define PT_CR_10 0x168
#define PT_CR_11 0x170
#define PT_IEEE_IP 0x1A8
#define PT_LASTOFF PT_IEEE_IP
#define PT_ENDREGS 0x1B0-1
#define GPR_SIZE 8
#define CR_SIZE 8
#define STACK_FRAME_OVERHEAD 160 /* size of minimum stack frame */
#endif /* __s390x__ */
#define NUM_GPRS 16
#define NUM_FPRS 16
#define NUM_CRS 16
#define NUM_ACRS 16
#define FPR_SIZE 8
#define FPC_SIZE 4
#define FPC_PAD_SIZE 4 /* gcc insists on aligning the fpregs */
#define ACR_SIZE 4
#define PTRACE_OLDSETOPTIONS 21
#ifndef __ASSEMBLY__
#include <linux/stddef.h>
#include <linux/types.h>
typedef union
{
float f;
double d;
__u64 ui;
struct
{
__u32 hi;
__u32 lo;
} fp;
} freg_t;
typedef struct
{
__u32 fpc;
freg_t fprs[NUM_FPRS];
} s390_fp_regs;
#define FPC_EXCEPTION_MASK 0xF8000000
#define FPC_FLAGS_MASK 0x00F80000
#define FPC_DXC_MASK 0x0000FF00
#define FPC_RM_MASK 0x00000003
#define FPC_VALID_MASK 0xF8F8FF03
/* this typedef defines how a Program Status Word looks like */
typedef struct
{
unsigned long mask;
unsigned long addr;
} __attribute__ ((aligned(8))) psw_t;
#ifndef __s390x__
#define PSW_MASK_PER 0x40000000UL
#define PSW_MASK_DAT 0x04000000UL
#define PSW_MASK_IO 0x02000000UL
#define PSW_MASK_EXT 0x01000000UL
#define PSW_MASK_KEY 0x00F00000UL
#define PSW_MASK_MCHECK 0x00040000UL
#define PSW_MASK_WAIT 0x00020000UL
#define PSW_MASK_PSTATE 0x00010000UL
#define PSW_MASK_ASC 0x0000C000UL
#define PSW_MASK_CC 0x00003000UL
#define PSW_MASK_PM 0x00000F00UL
#define PSW_ADDR_AMODE 0x80000000UL
#define PSW_ADDR_INSN 0x7FFFFFFFUL
#define PSW_BASE_BITS 0x00080000UL
#define PSW_DEFAULT_KEY (((unsigned long) PAGE_DEFAULT_ACC) << 20)
#define PSW_ASC_PRIMARY 0x00000000UL
#define PSW_ASC_ACCREG 0x00004000UL
#define PSW_ASC_SECONDARY 0x00008000UL
#define PSW_ASC_HOME 0x0000C000UL
#else /* __s390x__ */
#define PSW_MASK_PER 0x4000000000000000UL
#define PSW_MASK_DAT 0x0400000000000000UL
#define PSW_MASK_IO 0x0200000000000000UL
#define PSW_MASK_EXT 0x0100000000000000UL
#define PSW_MASK_KEY 0x00F0000000000000UL
#define PSW_MASK_MCHECK 0x0004000000000000UL
#define PSW_MASK_WAIT 0x0002000000000000UL
#define PSW_MASK_PSTATE 0x0001000000000000UL
#define PSW_MASK_ASC 0x0000C00000000000UL
#define PSW_MASK_CC 0x0000300000000000UL
#define PSW_MASK_PM 0x00000F0000000000UL
#define PSW_ADDR_AMODE 0x0000000000000000UL
#define PSW_ADDR_INSN 0xFFFFFFFFFFFFFFFFUL
#define PSW_BASE_BITS 0x0000000180000000UL
#define PSW_BASE32_BITS 0x0000000080000000UL
#define PSW_DEFAULT_KEY (((unsigned long) PAGE_DEFAULT_ACC) << 52)
#define PSW_ASC_PRIMARY 0x0000000000000000UL
#define PSW_ASC_ACCREG 0x0000400000000000UL
#define PSW_ASC_SECONDARY 0x0000800000000000UL
#define PSW_ASC_HOME 0x0000C00000000000UL
extern long psw_user32_bits;
#endif /* __s390x__ */
extern long psw_kernel_bits;
extern long psw_user_bits;
/* This macro merges a NEW PSW mask specified by the user into
the currently active PSW mask CURRENT, modifying only those
bits in CURRENT that the user may be allowed to change: this
is the condition code and the program mask bits. */
#define PSW_MASK_MERGE(CURRENT,NEW) \
(((CURRENT) & ~(PSW_MASK_CC|PSW_MASK_PM)) | \
((NEW) & (PSW_MASK_CC|PSW_MASK_PM)))
/*
* The s390_regs structure is used to define the elf_gregset_t.
*/
typedef struct
{
psw_t psw;
unsigned long gprs[NUM_GPRS];
unsigned int acrs[NUM_ACRS];
unsigned long orig_gpr2;
} s390_regs;
#ifdef __KERNEL__
#include <asm/setup.h>
#include <asm/page.h>
/*
* 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 short ilc;
unsigned short trap;
};
#endif
/*
* Now for the program event recording (trace) definitions.
*/
typedef struct
{
unsigned long cr[3];
} per_cr_words;
#define PER_EM_MASK 0xE8000000UL
typedef struct
{
#ifdef __s390x__
unsigned : 32;
#endif /* __s390x__ */
unsigned em_branching : 1;
unsigned em_instruction_fetch : 1;
/*
* Switching on storage alteration automatically fixes
* the storage alteration event bit in the users std.
*/
unsigned em_storage_alteration : 1;
unsigned em_gpr_alt_unused : 1;
unsigned em_store_real_address : 1;
unsigned : 3;
unsigned branch_addr_ctl : 1;
unsigned : 1;
unsigned storage_alt_space_ctl : 1;
unsigned : 21;
unsigned long starting_addr;
unsigned long ending_addr;
} per_cr_bits;
typedef struct
{
unsigned short perc_atmid;
unsigned long address;
unsigned char access_id;
} per_lowcore_words;
typedef struct
{
unsigned perc_branching : 1;
unsigned perc_instruction_fetch : 1;
unsigned perc_storage_alteration : 1;
unsigned perc_gpr_alt_unused : 1;
unsigned perc_store_real_address : 1;
unsigned : 3;
unsigned atmid_psw_bit_31 : 1;
unsigned atmid_validity_bit : 1;
unsigned atmid_psw_bit_32 : 1;
unsigned atmid_psw_bit_5 : 1;
unsigned atmid_psw_bit_16 : 1;
unsigned atmid_psw_bit_17 : 1;
unsigned si : 2;
unsigned long address;
unsigned : 4;
unsigned access_id : 4;
} per_lowcore_bits;
typedef struct
{
union {
per_cr_words words;
per_cr_bits bits;
} control_regs;
/*
* Use these flags instead of setting em_instruction_fetch
* directly they are used so that single stepping can be
* switched on & off while not affecting other tracing
*/
unsigned single_step : 1;
unsigned instruction_fetch : 1;
unsigned : 30;
/*
* These addresses are copied into cr10 & cr11 if single
* stepping is switched off
*/
unsigned long starting_addr;
unsigned long ending_addr;
union {
per_lowcore_words words;
per_lowcore_bits bits;
} lowcore;
} per_struct;
typedef struct
{
unsigned int len;
unsigned long kernel_addr;
unsigned long process_addr;
} ptrace_area;
/*
* S/390 specific non posix ptrace requests. I chose unusual values so
* they are unlikely to clash with future ptrace definitions.
*/
#define PTRACE_PEEKUSR_AREA 0x5000
#define PTRACE_POKEUSR_AREA 0x5001
#define PTRACE_PEEKTEXT_AREA 0x5002
#define PTRACE_PEEKDATA_AREA 0x5003
#define PTRACE_POKETEXT_AREA 0x5004
#define PTRACE_POKEDATA_AREA 0x5005
/*
* PT_PROT definition is loosely based on hppa bsd definition in
* gdb/hppab-nat.c
*/
#define PTRACE_PROT 21
typedef enum
{
ptprot_set_access_watchpoint,
ptprot_set_write_watchpoint,
ptprot_disable_watchpoint
} ptprot_flags;
typedef struct
{
unsigned long lowaddr;
unsigned long hiaddr;
ptprot_flags prot;
} ptprot_area;
/* Sequence of bytes for breakpoint illegal instruction. */
#define S390_BREAKPOINT {0x0,0x1}
#define S390_BREAKPOINT_U16 ((__u16)0x0001)
#define S390_SYSCALL_OPCODE ((__u16)0x0a00)
#define S390_SYSCALL_SIZE 2
/*
* The user_regs_struct defines the way the user registers are
* store on the stack for signal handling.
*/
struct user_regs_struct
{
psw_t psw;
unsigned long gprs[NUM_GPRS];
unsigned int acrs[NUM_ACRS];
unsigned long orig_gpr2;
s390_fp_regs fp_regs;
/*
* These per registers are in here so that gdb can modify them
* itself as there is no "official" ptrace interface for hardware
* watchpoints. This is the way intel does it.
*/
per_struct per_info;
unsigned long ieee_instruction_pointer;
/* Used to give failing instruction back to user for ieee exceptions */
};
#ifdef __KERNEL__
#define __ARCH_SYS_PTRACE 1
#define user_mode(regs) (((regs)->psw.mask & PSW_MASK_PSTATE) != 0)
#define instruction_pointer(regs) ((regs)->psw.addr & PSW_ADDR_INSN)
#define regs_return_value(regs)((regs)->gprs[2])
#define profile_pc(regs) instruction_pointer(regs)
extern void show_regs(struct pt_regs * regs);
#endif
static inline void
psw_set_key(unsigned int key)
{
asm volatile("spka 0(%0)" : : "d" (key));
}
#endif /* __ASSEMBLY__ */
#endif /* _S390_PTRACE_H */
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