diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2021-01-30 16:08:15 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-02-08 16:02:08 +0300 |
| commit | a4922f5442e7e6ce85da304e224d940edec2f1fb (patch) | |
| tree | e66d67c74cd372f72142ddf7c148504ebd5470ef /arch/powerpc/mm | |
| parent | 36f0114140eef53e931592b65bdf8bb61ffac1f8 (diff) | |
| download | linux-a4922f5442e7e6ce85da304e224d940edec2f1fb.tar.xz | |
powerpc/64s: move the hash fault handling logic to C
The fault handling still has some complex logic particularly around
hash table handling, in asm. Implement most of this in C.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-6-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/book3s64/hash_utils.c | 77 |
1 files changed, 49 insertions, 28 deletions
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index 73b06adb6eeb..e866cae57e2f 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -1512,16 +1512,40 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap, } EXPORT_SYMBOL_GPL(hash_page); -int __hash_page(unsigned long trap, unsigned long ea, unsigned long dsisr, - unsigned long msr) +int do_hash_fault(struct pt_regs *regs, unsigned long ea, unsigned long dsisr) { unsigned long access = _PAGE_PRESENT | _PAGE_READ; unsigned long flags = 0; - struct mm_struct *mm = current->mm; - unsigned int region_id = get_region_id(ea); + struct mm_struct *mm; + unsigned int region_id; + int err; + + if (unlikely(dsisr & (DSISR_BAD_FAULT_64S | DSISR_KEYFAULT))) + goto page_fault; + + /* + * If we are in an "NMI" (e.g., an interrupt when soft-disabled), then + * don't call hash_page, just fail the fault. This is required to + * prevent re-entrancy problems in the hash code, namely perf + * interrupts hitting while something holds H_PAGE_BUSY, and taking a + * hash fault. See the comment in hash_preload(). + * + * We come here as a result of a DSI at a point where we don't want + * to call hash_page, such as when we are accessing memory (possibly + * user memory) inside a PMU interrupt that occurred while interrupts + * were soft-disabled. We want to invoke the exception handler for + * the access, or panic if there isn't a handler. + */ + if (unlikely(in_nmi())) { + bad_page_fault(regs, ea, SIGSEGV); + return 0; + } + region_id = get_region_id(ea); if ((region_id == VMALLOC_REGION_ID) || (region_id == IO_REGION_ID)) mm = &init_mm; + else + mm = current->mm; if (dsisr & DSISR_NOHPTE) flags |= HPTE_NOHPTE_UPDATE; @@ -1537,13 +1561,31 @@ int __hash_page(unsigned long trap, unsigned long ea, unsigned long dsisr, * 2) user space access kernel space. */ access |= _PAGE_PRIVILEGED; - if ((msr & MSR_PR) || (region_id == USER_REGION_ID)) + if (user_mode(regs) || (region_id == USER_REGION_ID)) access &= ~_PAGE_PRIVILEGED; - if (trap == 0x400) + if (regs->trap == 0x400) access |= _PAGE_EXEC; - return hash_page_mm(mm, ea, access, trap, flags); + err = hash_page_mm(mm, ea, access, regs->trap, flags); + if (unlikely(err < 0)) { + // failed to instert a hash PTE due to an hypervisor error + if (user_mode(regs)) { + if (IS_ENABLED(CONFIG_PPC_SUBPAGE_PROT) && err == -2) + _exception(SIGSEGV, regs, SEGV_ACCERR, ea); + else + _exception(SIGBUS, regs, BUS_ADRERR, ea); + } else { + bad_page_fault(regs, ea, SIGBUS); + } + err = 0; + + } else if (err) { +page_fault: + err = do_page_fault(regs, ea, dsisr); + } + + return err; } #ifdef CONFIG_PPC_MM_SLICES @@ -1843,27 +1885,6 @@ void flush_hash_range(unsigned long number, int local) } } -/* - * low_hash_fault is called when we the low level hash code failed - * to instert a PTE due to an hypervisor error - */ -void low_hash_fault(struct pt_regs *regs, unsigned long address, int rc) -{ - enum ctx_state prev_state = exception_enter(); - - if (user_mode(regs)) { -#ifdef CONFIG_PPC_SUBPAGE_PROT - if (rc == -2) - _exception(SIGSEGV, regs, SEGV_ACCERR, address); - else -#endif - _exception(SIGBUS, regs, BUS_ADRERR, address); - } else - bad_page_fault(regs, address, SIGBUS); - - exception_exit(prev_state); -} - long hpte_insert_repeating(unsigned long hash, unsigned long vpn, unsigned long pa, unsigned long rflags, unsigned long vflags, int psize, int ssize) |