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| author | Heiko Carstens <hca@linux.ibm.com> | 2023-10-12 09:40:44 +0200 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2023-10-23 18:21:22 +0200 |
| commit | f67c2da9f1c2d56e3adab342fc39c00c0c5ec790 (patch) | |
| tree | 7ba036c152dcc105b2377e27bbf9f754bd535b14 /arch/s390 | |
| parent | s390/mm,fault: improve readability by using teid union (diff) | |
| download | linux-f67c2da9f1c2d56e3adab342fc39c00c0c5ec790.tar.xz linux-f67c2da9f1c2d56e3adab342fc39c00c0c5ec790.zip | |
s390/mm,fault: use get_kernel_nofault() to dereference in dump_pagetable()
The page table dumper uses get_kernel_nofault() to test if dereferencing
page table entries is possible. Use the result, which is the required page
table entry, instead of throwing it away and dereferencing a second time
without any safe guard.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/mm/fault.c | 45 |
1 files changed, 19 insertions, 26 deletions
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index bcaac0f939df..c37e28fbfbef 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -112,59 +112,52 @@ static __always_inline bool fault_is_write(struct pt_regs *regs) return false; } -static int bad_address(void *p) -{ - unsigned long dummy; - - return get_kernel_nofault(dummy, (unsigned long *)p); -} - static void dump_pagetable(unsigned long asce, unsigned long address) { - unsigned long *table = __va(asce & _ASCE_ORIGIN); + unsigned long entry, *table = __va(asce & _ASCE_ORIGIN); pr_alert("AS:%016lx ", asce); switch (asce & _ASCE_TYPE_MASK) { case _ASCE_TYPE_REGION1: table += (address & _REGION1_INDEX) >> _REGION1_SHIFT; - if (bad_address(table)) + if (get_kernel_nofault(entry, table)) goto bad; - pr_cont("R1:%016lx ", *table); - if (*table & _REGION_ENTRY_INVALID) + pr_cont("R1:%016lx ", entry); + if (entry & _REGION_ENTRY_INVALID) goto out; - table = __va(*table & _REGION_ENTRY_ORIGIN); + table = __va(entry & _REGION_ENTRY_ORIGIN); fallthrough; case _ASCE_TYPE_REGION2: table += (address & _REGION2_INDEX) >> _REGION2_SHIFT; - if (bad_address(table)) + if (get_kernel_nofault(entry, table)) goto bad; - pr_cont("R2:%016lx ", *table); - if (*table & _REGION_ENTRY_INVALID) + pr_cont("R2:%016lx ", entry); + if (entry & _REGION_ENTRY_INVALID) goto out; - table = __va(*table & _REGION_ENTRY_ORIGIN); + table = __va(entry & _REGION_ENTRY_ORIGIN); fallthrough; case _ASCE_TYPE_REGION3: table += (address & _REGION3_INDEX) >> _REGION3_SHIFT; - if (bad_address(table)) + if (get_kernel_nofault(entry, table)) goto bad; - pr_cont("R3:%016lx ", *table); - if (*table & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE)) + pr_cont("R3:%016lx ", entry); + if (entry & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE)) goto out; - table = __va(*table & _REGION_ENTRY_ORIGIN); + table = __va(entry & _REGION_ENTRY_ORIGIN); fallthrough; case _ASCE_TYPE_SEGMENT: table += (address & _SEGMENT_INDEX) >> _SEGMENT_SHIFT; - if (bad_address(table)) + if (get_kernel_nofault(entry, table)) goto bad; - pr_cont("S:%016lx ", *table); - if (*table & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE)) + pr_cont("S:%016lx ", entry); + if (entry & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE)) goto out; - table = __va(*table & _SEGMENT_ENTRY_ORIGIN); + table = __va(entry & _SEGMENT_ENTRY_ORIGIN); } table += (address & _PAGE_INDEX) >> _PAGE_SHIFT; - if (bad_address(table)) + if (get_kernel_nofault(entry, table)) goto bad; - pr_cont("P:%016lx ", *table); + pr_cont("P:%016lx ", entry); out: pr_cont("\n"); return; |