Someone could write 0 bytes to /proc/sgi_uv/ptc_statistics,
causing
optstr[count - 1] = '\0';
to write to who-knows-where.
(Andi Kleen noticed this need from a patch I sent for
similar code in the ia64 world (sn2_ptc_proc_write()).)
(count less than zero is not possible here, as count is unsigned)
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
v6: 6/19 close the security hole in uv_ptc_proc_write())
> Found a potential security hole while doing that:
> static ssize_t uv_ptc_proc_write(struct file *file, const char __user *user,
> size_t count, loff_t *data)
> if (copy_from_user(optstr, user, count))
> return -EFAULT;
>
> is count guaranteed to never be larger than 64?
is fixed below.
It adds tlb_uv.o to the Makefile.
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Cc: mingo@elte.hu
Signed-off-by: Ingo Molnar <mingo@elte.hu>
fix:
arch/x86/kernel/tlb_uv.c: In function ‘uv_table_bases_init':
arch/x86/kernel/tlb_uv.c:612: error: ‘bau_tabsp' undeclared (first use in this function)
arch/x86/kernel/tlb_uv.c:612: error: (Each undeclared identifier is reported only once
arch/x86/kernel/tlb_uv.c:612: error: for each function it appears in.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
TLB shootdown for SGI UV.
v1: 6/2 original
v2: 6/3 corrections/improvements per Ingo's review
v3: 6/4 split atomic operations off to a separate patch (Jeremy's review)
v4: 6/12 include <mach_apic.h> rather than <asm/mach-bigsmp/mach_apic.h>
(fixes a !SMP build problem that Ingo found)
fix the index on uv_table_bases[blade]
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
TLB shootdown for SGI UV.
Depends on patch (in tip/x86/irq):
x86-update-macros-used-by-uv-platform.patch Jack Steiner May 29
This patch provides the ability to flush TLB's in cpu's that are not on
the local node. The hardware mechanism for distributing the flush
messages is the UV's "broadcast assist unit".
The hook to intercept TLB shootdown requests is a 2-line change to
native_flush_tlb_others() (arch/x86/kernel/tlb_64.c).
This code has been tested on a hardware simulator. The real hardware
is not yet available.
The shootdown statistics are provided through /proc/sgi_uv/ptc_statistics.
The use of /sys was considered, but would have required the use of
many /sys files. The debugfs was also considered, but these statistics
should be available on an ongoing basis, not just for debugging.
Issues to be fixed later:
- The IRQ for the messaging interrupt is currently hardcoded as 200
(see UV_BAU_MESSAGE). It should be dynamically assigned in the future.
- The use of appropriate udelay()'s is untested, as they are a problem
in the simulator.
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cliff Wickman