diff options
| author | David S. Miller <davem@davemloft.net> | 2014-05-06 21:27:37 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-05-06 21:27:37 -0700 |
| commit | e5c460f46ae7ee94831cb55cb980f942aa9e5a85 (patch) | |
| tree | 5ba76a0a5386686445276b4345536492df60b787 /arch | |
| parent | 256cf4c438e60116785a83b060614c63c7477e84 (diff) | |
sparc64: Don't bark so loudly about 32-bit tasks generating 64-bit fault addresses.
This was found using Dave Jone's trinity tool.
When a user process which is 32-bit performs a load or a store, the
cpu chops off the top 32-bits of the effective address before
translating it.
This is because we run 32-bit tasks with the PSTATE_AM (address
masking) bit set.
We can't run the kernel with that bit set, so when the kernel accesses
userspace no address masking occurs.
Since a 32-bit process will have no mappings in that region we will
properly fault, so we don't try to handle this using access_ok(),
which can safely just be a NOP on sparc64.
Real faults from 32-bit processes should never generate such addresses
so a bug check was added long ago, and it barks in the logs if this
happens.
But it also barks when a kernel user access causes this condition, and
that _can_ happen. For example, if a pointer passed into a system call
is "0xfffffffc" and the kernel access 4 bytes offset from that pointer.
Just handle such faults normally via the exception entries.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/sparc/mm/fault_64.c | 16 |
1 files changed, 1 insertions, 15 deletions
diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c index a8ff0d1a3b6..4ced3fc6613 100644 --- a/arch/sparc/mm/fault_64.c +++ b/arch/sparc/mm/fault_64.c @@ -281,18 +281,6 @@ static void noinline __kprobes bogus_32bit_fault_tpc(struct pt_regs *regs) show_regs(regs); } -static void noinline __kprobes bogus_32bit_fault_address(struct pt_regs *regs, - unsigned long addr) -{ - static int times; - - if (times++ < 10) - printk(KERN_ERR "FAULT[%s:%d]: 32-bit process " - "reports 64-bit fault address [%lx]\n", - current->comm, current->pid, addr); - show_regs(regs); -} - asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs) { enum ctx_state prev_state = exception_enter(); @@ -322,10 +310,8 @@ asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs) goto intr_or_no_mm; } } - if (unlikely((address >> 32) != 0)) { - bogus_32bit_fault_address(regs, address); + if (unlikely((address >> 32) != 0)) goto intr_or_no_mm; - } } if (regs->tstate & TSTATE_PRIV) { |