Commit 029d9252 authored by Michael Ellerman's avatar Michael Ellerman
Browse files

powerpc/mm: Mark __init memory no-execute when STRICT_KERNEL_RWX=y 



Currently even with STRICT_KERNEL_RWX we leave the __init text marked
executable after init, which is bad.

Add a hook to mark it NX (no-execute) before we free it, and implement
it for radix and hash.

Note that we use __init_end as the end address, not _einittext,
because overlaps_kernel_text() uses __init_end, because there are
additional executable sections other than .init.text between
__init_begin and __init_end.

Tested on radix and hash with:

  0:mon> p $__init_begin
  *** 400 exception occurred

Fixes: 1e0fc9d1 ("powerpc/Kconfig: Enable STRICT_KERNEL_RWX for some configs")
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent fa7f9189

arch/powerpc/include/asm/book3s/64/hash.h

+1 −0
Original line number Diff line number Diff line
@@ -91,6 +91,7 @@ static inline int hash__pgd_bad(pgd_t pgd) 
}

#ifdef CONFIG_STRICT_KERNEL_RWX

extern void hash__mark_rodata_ro(void);

extern void hash__mark_initmem_nx(void);

#endif



extern void hpte_need_flush(struct mm_struct *mm, unsigned long addr,

arch/powerpc/include/asm/book3s/64/pgtable.h

+1 −0
Original line number Diff line number Diff line
@@ -1192,5 +1192,6 @@ static inline const int pud_pfn(pud_t pud) 
	BUILD_BUG();

	return 0;

}



#endif /* __ASSEMBLY__ */

#endif /* _ASM_POWERPC_BOOK3S_64_PGTABLE_H_ */

arch/powerpc/include/asm/book3s/64/radix.h

+1 −0
Original line number Diff line number Diff line
@@ -118,6 +118,7 @@ 


#ifdef CONFIG_STRICT_KERNEL_RWX

extern void radix__mark_rodata_ro(void);

extern void radix__mark_initmem_nx(void);

#endif



static inline unsigned long __radix_pte_update(pte_t *ptep, unsigned long clr,

arch/powerpc/include/asm/pgtable.h

+7 −0
Original line number Diff line number Diff line
@@ -80,6 +80,13 @@ unsigned long vmalloc_to_phys(void *vmalloc_addr); 


void pgtable_cache_add(unsigned shift, void (*ctor)(void *));

void pgtable_cache_init(void);



#ifdef CONFIG_STRICT_KERNEL_RWX

void mark_initmem_nx(void);

#else

static inline void mark_initmem_nx(void) { }

#endif



#endif /* __ASSEMBLY__ */



#endif /* _ASM_POWERPC_PGTABLE_H */

arch/powerpc/mm/mem.c

+1 −0
Original line number Diff line number Diff line
@@ -402,6 +402,7 @@ void __init mem_init(void) 
void free_initmem(void)

{

	ppc_md.progress = ppc_printk_progress;

	mark_initmem_nx();

	free_initmem_default(POISON_FREE_INITMEM);

}

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