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author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2018-03-07 19:06:45 +0530 |
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committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-04-04 15:23:09 +1000 |
commit | f2ed480fa4d7f95b190279722690df8d4a396b3e (patch) | |
tree | 74abb74702e3e68cfc46392cc2247d46833d03e8 /arch/powerpc | |
parent | b9ee31e100e73075431faaf7af2ee0fbfd6e624b (diff) | |
download | op-kernel-dev-f2ed480fa4d7f95b190279722690df8d4a396b3e.zip op-kernel-dev-f2ed480fa4d7f95b190279722690df8d4a396b3e.tar.gz |
powerpc/mm/keys: Update documentation and remove unnecessary check
Adds more code comments. We also remove an unnecessary pkey check
after we check for pkey error in this patch.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc')
-rw-r--r-- | arch/powerpc/mm/fault.c | 28 | ||||
-rw-r--r-- | arch/powerpc/mm/pkeys.c | 11 |
2 files changed, 16 insertions, 23 deletions
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 866446c..c01d627 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -297,7 +297,12 @@ static bool access_error(bool is_write, bool is_exec, if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))) return true; - + /* + * We should ideally do the vma pkey access check here. But in the + * fault path, handle_mm_fault() also does the same check. To avoid + * these multiple checks, we skip it here and handle access error due + * to pkeys later. + */ return false; } @@ -518,25 +523,16 @@ good_area: #ifdef CONFIG_PPC_MEM_KEYS /* - * if the HPTE is not hashed, hardware will not detect - * a key fault. Lets check if we failed because of a - * software detected key fault. + * we skipped checking for access error due to key earlier. + * Check that using handle_mm_fault error return. */ if (unlikely(fault & VM_FAULT_SIGSEGV) && - !arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, - is_exec, 0)) { - /* - * The PGD-PDT...PMD-PTE tree may not have been fully setup. - * Hence we cannot walk the tree to locate the PTE, to locate - * the key. Hence let's use vma_pkey() to get the key; instead - * of get_mm_addr_key(). - */ + !arch_vma_access_permitted(vma, is_write, is_exec, 0)) { + int pkey = vma_pkey(vma); - if (likely(pkey)) { - up_read(&mm->mmap_sem); - return bad_key_fault_exception(regs, address, pkey); - } + up_read(&mm->mmap_sem); + return bad_key_fault_exception(regs, address, pkey); } #endif /* CONFIG_PPC_MEM_KEYS */ diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index 328737b..0eafdf01 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -119,18 +119,15 @@ int pkey_initialize(void) #else os_reserved = 0; #endif + initial_allocation_mask = ~0x0; + pkey_amr_uamor_mask = ~0x0ul; + pkey_iamr_mask = ~0x0ul; /* - * Bits are in LE format. NOTE: 1, 0 are reserved. + * key 0, 1 are reserved. * key 0 is the default key, which allows read/write/execute. * key 1 is recommended not to be used. PowerISA(3.0) page 1015, * programming note. */ - initial_allocation_mask = ~0x0; - - /* register mask is in BE format */ - pkey_amr_uamor_mask = ~0x0ul; - pkey_iamr_mask = ~0x0ul; - for (i = 2; i < (pkeys_total - os_reserved); i++) { initial_allocation_mask &= ~(0x1 << i); pkey_amr_uamor_mask &= ~(0x3ul << pkeyshift(i)); |