powerpc/mm: Move the DSISR_PROTFAULT sanity check (2865d08d) · Commits · 戴 / test

arch/powerpc/mm/fault.c

+42 −33

Original line number	Diff line number	Diff line
		@@ -239,6 +239,45 @@ static inline void cmo_account_page_fault(void)
		static inline void cmo_account_page_fault(void) { }
		#endif /* CONFIG_PPC_SMLPAR */

		#ifdef CONFIG_PPC_STD_MMU
		static void sanity_check_fault(bool is_write, unsigned long error_code)
		{
		/*
		* For hash translation mode, we should never get a
		* PROTFAULT. Any update to pte to reduce access will result in us
		* removing the hash page table entry, thus resulting in a DSISR_NOHPTE
		* fault instead of DSISR_PROTFAULT.
		*
		* A pte update to relax the access will not result in a hash page table
		* entry invalidate and hence can result in DSISR_PROTFAULT.
		* ptep_set_access_flags() doesn't do a hpte flush. This is why we have
		* the special !is_write in the below conditional.
		*
		* For platforms that doesn't supports coherent icache and do support
		* per page noexec bit, we do setup things such that we do the
		* sync between D/I cache via fault. But that is handled via low level
		* hash fault code (hash_page_do_lazy_icache()) and we should not reach
		* here in such case.
		*
		* For wrong access that can result in PROTFAULT, the above vma->vm_flags
		* check should handle those and hence we should fall to the bad_area
		* handling correctly.
		*
		* For embedded with per page exec support that doesn't support coherent
		* icache we do get PROTFAULT and we handle that D/I cache sync in
		* set_pte_at while taking the noexec/prot fault. Hence this is WARN_ON
		* is conditional for server MMU.
		*
		* For radix, we can get prot fault for autonuma case, because radix
		* page table will have them marked noaccess for user.
		*/
		if (!radix_enabled() && !is_write)
		WARN_ON_ONCE(error_code & DSISR_PROTFAULT);
		}
		#else
		static void sanity_check_fault(bool is_write, unsigned long error_code) { }
		#endif /* CONFIG_PPC_STD_MMU */

		/*
		* Define the correct "is_write" bit in error_code based
		* on the processor family
		@@ -306,6 +345,9 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
		return SIGBUS;
		}

		/* Additional sanity check(s) */
		sanity_check_fault(is_write, error_code);

		/*
		* The kernel should never take an execute fault nor should it
		* take a page fault to a kernel address.
		@@ -441,39 +483,6 @@ good_area:
		if (!(vma->vm_flags & (VM_READ \| VM_EXEC \| VM_WRITE)))
		return bad_area(regs, address);
		}
		#ifdef CONFIG_PPC_STD_MMU
		/*
		* For hash translation mode, we should never get a
		* PROTFAULT. Any update to pte to reduce access will result in us
		* removing the hash page table entry, thus resulting in a DSISR_NOHPTE
		* fault instead of DSISR_PROTFAULT.
		*
		* A pte update to relax the access will not result in a hash page table
		* entry invalidate and hence can result in DSISR_PROTFAULT.
		* ptep_set_access_flags() doesn't do a hpte flush. This is why we have
		* the special !is_write in the below conditional.
		*
		* For platforms that doesn't supports coherent icache and do support
		* per page noexec bit, we do setup things such that we do the
		* sync between D/I cache via fault. But that is handled via low level
		* hash fault code (hash_page_do_lazy_icache()) and we should not reach
		* here in such case.
		*
		* For wrong access that can result in PROTFAULT, the above vma->vm_flags
		* check should handle those and hence we should fall to the bad_area
		* handling correctly.
		*
		* For embedded with per page exec support that doesn't support coherent
		* icache we do get PROTFAULT and we handle that D/I cache sync in
		* set_pte_at while taking the noexec/prot fault. Hence this is WARN_ON
		* is conditional for server MMU.
		*
		* For radix, we can get prot fault for autonuma case, because radix
		* page table will have them marked noaccess for user.
		*/
		if (!radix_enabled() && !is_write)
		WARN_ON_ONCE(error_code & DSISR_PROTFAULT);
		#endif /* CONFIG_PPC_STD_MMU */

		/*
		* If for any reason at all we couldn't handle the fault,

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