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c1821c2e97
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>
186 lines
4.2 KiB
C
186 lines
4.2 KiB
C
/*
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* include/asm-s390/setup.h
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*
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* S390 version
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* Copyright IBM Corp. 1999,2006
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*/
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#ifndef _ASM_S390_SETUP_H
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#define _ASM_S390_SETUP_H
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#define COMMAND_LINE_SIZE 896
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#ifdef __KERNEL__
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#include <asm/types.h>
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#define PARMAREA 0x10400
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#define MEMORY_CHUNKS 16 /* max 0x7fff */
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#define IPL_PARMBLOCK_ORIGIN 0x2000
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#ifndef __ASSEMBLY__
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#ifndef __s390x__
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#define IPL_DEVICE (*(unsigned long *) (0x10404))
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#define INITRD_START (*(unsigned long *) (0x1040C))
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#define INITRD_SIZE (*(unsigned long *) (0x10414))
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#else /* __s390x__ */
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#define IPL_DEVICE (*(unsigned long *) (0x10400))
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#define INITRD_START (*(unsigned long *) (0x10408))
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#define INITRD_SIZE (*(unsigned long *) (0x10410))
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#endif /* __s390x__ */
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#define COMMAND_LINE ((char *) (0x10480))
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#define CHUNK_READ_WRITE 0
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#define CHUNK_READ_ONLY 1
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struct mem_chunk {
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unsigned long addr;
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unsigned long size;
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unsigned long type;
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};
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extern struct mem_chunk memory_chunk[];
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#ifdef CONFIG_S390_SWITCH_AMODE
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extern unsigned int switch_amode;
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#else
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#define switch_amode (0)
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#endif
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#ifdef CONFIG_S390_EXEC_PROTECT
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extern unsigned int s390_noexec;
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#else
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#define s390_noexec (0)
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#endif
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/*
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* Machine features detected in head.S
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*/
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extern unsigned long machine_flags;
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#define MACHINE_IS_VM (machine_flags & 1)
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#define MACHINE_IS_P390 (machine_flags & 4)
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#define MACHINE_HAS_MVPG (machine_flags & 16)
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#define MACHINE_HAS_IDTE (machine_flags & 128)
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#define MACHINE_HAS_DIAG9C (machine_flags & 256)
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#ifndef __s390x__
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#define MACHINE_HAS_IEEE (machine_flags & 2)
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#define MACHINE_HAS_CSP (machine_flags & 8)
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#define MACHINE_HAS_DIAG44 (1)
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#define MACHINE_HAS_MVCOS (0)
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#else /* __s390x__ */
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#define MACHINE_HAS_IEEE (1)
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#define MACHINE_HAS_CSP (1)
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#define MACHINE_HAS_DIAG44 (machine_flags & 32)
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#define MACHINE_HAS_MVCOS (machine_flags & 512)
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#endif /* __s390x__ */
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#define MACHINE_HAS_SCLP (!MACHINE_IS_P390)
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/*
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* Console mode. Override with conmode=
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*/
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extern unsigned int console_mode;
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extern unsigned int console_devno;
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extern unsigned int console_irq;
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extern char vmhalt_cmd[];
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extern char vmpoff_cmd[];
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#define CONSOLE_IS_UNDEFINED (console_mode == 0)
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#define CONSOLE_IS_SCLP (console_mode == 1)
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#define CONSOLE_IS_3215 (console_mode == 2)
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#define CONSOLE_IS_3270 (console_mode == 3)
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#define SET_CONSOLE_SCLP do { console_mode = 1; } while (0)
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#define SET_CONSOLE_3215 do { console_mode = 2; } while (0)
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#define SET_CONSOLE_3270 do { console_mode = 3; } while (0)
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struct ipl_list_hdr {
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u32 len;
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u8 reserved1[3];
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u8 version;
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u32 blk0_len;
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u8 pbt;
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u8 flags;
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u16 reserved2;
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} __attribute__((packed));
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struct ipl_block_fcp {
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u8 reserved1[313-1];
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u8 opt;
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u8 reserved2[3];
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u16 reserved3;
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u16 devno;
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u8 reserved4[4];
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u64 wwpn;
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u64 lun;
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u32 bootprog;
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u8 reserved5[12];
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u64 br_lba;
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u32 scp_data_len;
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u8 reserved6[260];
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u8 scp_data[];
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} __attribute__((packed));
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struct ipl_block_ccw {
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u8 load_param[8];
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u8 reserved1[84];
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u8 reserved2[2];
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u16 devno;
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u8 vm_flags;
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u8 reserved3[3];
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u32 vm_parm_len;
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} __attribute__((packed));
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struct ipl_parameter_block {
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struct ipl_list_hdr hdr;
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union {
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struct ipl_block_fcp fcp;
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struct ipl_block_ccw ccw;
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} ipl_info;
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} __attribute__((packed));
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#define IPL_PARM_BLK_FCP_LEN (sizeof(struct ipl_list_hdr) + \
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sizeof(struct ipl_block_fcp))
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#define IPL_PARM_BLK_CCW_LEN (sizeof(struct ipl_list_hdr) + \
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sizeof(struct ipl_block_ccw))
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#define IPL_MAX_SUPPORTED_VERSION (0)
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/*
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* IPL validity flags and parameters as detected in head.S
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*/
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extern u32 ipl_flags;
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extern u16 ipl_devno;
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void do_reipl(void);
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enum {
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IPL_DEVNO_VALID = 1,
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IPL_PARMBLOCK_VALID = 2,
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};
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#define IPL_PARMBLOCK_START ((struct ipl_parameter_block *) \
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IPL_PARMBLOCK_ORIGIN)
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#define IPL_PARMBLOCK_SIZE (IPL_PARMBLOCK_START->hdr.len)
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#else /* __ASSEMBLY__ */
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#ifndef __s390x__
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#define IPL_DEVICE 0x10404
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#define INITRD_START 0x1040C
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#define INITRD_SIZE 0x10414
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#else /* __s390x__ */
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#define IPL_DEVICE 0x10400
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#define INITRD_START 0x10408
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#define INITRD_SIZE 0x10410
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#endif /* __s390x__ */
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#define COMMAND_LINE 0x10480
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#endif /* __ASSEMBLY__ */
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#endif /* __KERNEL__ */
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#endif /* _ASM_S390_SETUP_H */
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