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57d7f939e7
Bit 0x100 of a page table, segment table of region table entry can be used to disallow code execution for the virtual addresses associated with the entry. There is one tricky bit, the system call to return from a signal is part of the signal frame written to the user stack. With a non-executable stack this would stop working. To avoid breaking things the protection fault handler checks the opcode that caused the fault for 0x0a77 (sys_sigreturn) and 0x0aad (sys_rt_sigreturn) and injects a system call. This is preferable to the alternative solution with a stub function in the vdso because it works for vdso=off and statically linked binaries as well. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
35 lines
840 B
C
35 lines
840 B
C
#ifndef _S390_CACHEFLUSH_H
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#define _S390_CACHEFLUSH_H
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/* Caches aren't brain-dead on the s390. */
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#include <asm-generic/cacheflush.h>
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#define SET_MEMORY_RO 1UL
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#define SET_MEMORY_RW 2UL
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#define SET_MEMORY_NX 4UL
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#define SET_MEMORY_X 8UL
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int __set_memory(unsigned long addr, int numpages, unsigned long flags);
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static inline int set_memory_ro(unsigned long addr, int numpages)
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{
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return __set_memory(addr, numpages, SET_MEMORY_RO);
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}
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static inline int set_memory_rw(unsigned long addr, int numpages)
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{
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return __set_memory(addr, numpages, SET_MEMORY_RW);
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}
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static inline int set_memory_nx(unsigned long addr, int numpages)
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{
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return __set_memory(addr, numpages, SET_MEMORY_NX);
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}
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static inline int set_memory_x(unsigned long addr, int numpages)
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{
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return __set_memory(addr, numpages, SET_MEMORY_X);
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}
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#endif /* _S390_CACHEFLUSH_H */
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