diff options
| author | David S. Miller <davem@davemloft.net> | 2014-05-07 08:27:37 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-08-14 04:42:36 +0400 |
| commit | 0de492190948948d0ff5d3ad8f7e1f0942f0379e (patch) | |
| tree | 164a94e70c11dd9a9cb2134a68cf81778e8af3d4 /arch/sparc | |
| parent | 86982cf46cf082ef705237b1ed7372ec772f3f8e (diff) | |
| download | linux-0de492190948948d0ff5d3ad8f7e1f0942f0379e.tar.xz | |
sparc64: Don't bark so loudly about 32-bit tasks generating 64-bit fault addresses.
[ Upstream commit e5c460f46ae7ee94831cb55cb980f942aa9e5a85 ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/sparc')
| -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 98a64f957ed5..1387acafc62c 100644 --- a/arch/sparc/mm/fault_64.c +++ b/arch/sparc/mm/fault_64.c @@ -282,18 +282,6 @@ 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) { struct mm_struct *mm = current->mm; @@ -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) { |