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alistair23-linux/arch/arm/mm
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Will Deacon 40ee068ec0 ARM: 8465/1: mm: keep reserved ASIDs in sync with mm after multiple rollovers 
Under some unusual context-switching patterns, it is possible to end up
with multiple threads from the same mm running concurrently with
different ASIDs:

1. CPU x schedules task t with mm p containing ASID a and generation g
   This task doesn't block and the CPU doesn't context switch.
   So:
     * per_cpu(active_asid, x) = {g,a}
     * p->context.id = {g,a}

2. Some other CPU generates an ASID rollover. The global generation is
   now (g + 1). CPU x is still running t, with no context switch and
   so per_cpu(reserved_asid, x) = {g,a}

3. CPU y schedules task t', which shares mm p with t. The generation
   mismatches, so we take the slowpath and hit the reserved ASID from
   CPU x. p is then updated so that p->context.id = {g + 1,a}

4. CPU y schedules some other task u, which has an mm != p.

5. Some other CPU generates *another* CPU rollover. The global
   generation is now (g + 2). CPU x is still running t, with no context
   switch and so per_cpu(reserved_asid, x) = {g,a}.

6. CPU y once again schedules task t', but now *fails* to hit the
   reserved ASID from CPU x because of the generation mismatch. This
   results in a new ASID being allocated, despite the fact that t is
   still running on CPU x with the same mm.

Consequently, TLBIs (e.g. as a result of CoW) will not be synchronised
between the two threads.

This patch fixes the problem by updating all of the matching reserved
ASIDs when we hit on the slowpath (i.e. in step 3 above). This keeps
the reserved ASIDs in-sync with the mm and avoids the problem.

Cc: <stable@vger.kernel.org>
Reported-by: Tony Thompson <anthony.thompson@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
 		2015-12-02 23:57:54 +00:00
..
Kconfig ARM: SoC platform updates for v4.4 2015-11-10 14:56:23 -08:00
Makefile ARM: uniphier: add outer cache support 2015-10-27 09:20:50 +09:00
abort-ev4.S ARM: entry: provide uaccess assembly macro hooks 2015-08-26 20:27:02 +01:00
abort-ev4t.S ARM: entry: data abort: tail-call the main data abort handler 2011-07-02 10:56:11 +01:00
abort-ev5t.S ARM: entry: provide uaccess assembly macro hooks 2015-08-26 20:27:02 +01:00
abort-ev5tj.S ARM: entry: provide uaccess assembly macro hooks 2015-08-26 20:27:02 +01:00
abort-ev6.S ARM: entry: provide uaccess assembly macro hooks 2015-08-26 20:27:02 +01:00
abort-ev7.S ARM: entry: provide uaccess assembly macro hooks 2015-08-26 20:27:02 +01:00
abort-lv4t.S ARM: entry: provide uaccess assembly macro hooks 2015-08-26 20:27:02 +01:00
abort-macro.S ARM: entry: provide uaccess assembly macro hooks 2015-08-26 20:27:02 +01:00
abort-nommu.S ARM: entry: data abort: tail-call the main data abort handler 2011-07-02 10:56:11 +01:00
alignment.c uaccess: reimplement probe_kernel_address() using probe_kernel_read() 2015-11-05 19:34:48 -08:00
cache-aurora-l2.h ARM: 7547/4: cache-l2x0: add support for Aurora L2 cache ctrl 2012-11-06 19:47:35 +00:00
cache-fa.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-feroceon-l2.c ARM: 8416/1: Feroceon: use of_iomap() to map register base 2015-08-18 14:00:30 +01:00
cache-l2x0.c ARM: 8395/1: l2c: Add support for the "arm,shared-override" property 2015-07-10 11:07:31 +01:00
cache-nop.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-tauros2.c ARM: convert printk(KERN_* to pr_* 2014-11-21 15:24:50 +00:00
cache-tauros3.h ARM: 7922/1: l2x0: add Marvell Tauros3 support 2013-12-29 12:32:47 +00:00
cache-uniphier.c ARM: uniphier: add outer cache support 2015-10-27 09:20:50 +09:00
cache-v4.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-v4wb.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-v4wt.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-v6.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-v7.S ARM: cache-v7: optimise test for Cortex A9 r0pX devices 2015-04-14 22:26:52 +01:00
cache-xsc3l2.c ARM: move CP15 definitions to separate header file 2012-03-28 18:30:01 +01:00
context.c ARM: 8465/1: mm: keep reserved ASIDs in sync with mm after multiple rollovers 2015-12-02 23:57:54 +00:00
copypage-fa.c arm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:14 +08:00
copypage-feroceon.c arm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:14 +08:00
copypage-v4mc.c Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-arm 2012-03-29 16:53:48 -07:00
copypage-v4wb.c arm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:14 +08:00
copypage-v4wt.c arm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:14 +08:00
copypage-v6.c ARM: 8236/1: mm: fix discard_old_kernel_data 2014-12-03 16:00:04 +00:00
copypage-xsc3.c arm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:14 +08:00
copypage-xscale.c Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-arm 2012-03-29 16:53:48 -07:00
dma-mapping.c mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd 2015-11-06 17:50:42 -08:00
dma.h ARM: reduce visibility of dmac_* functions 2015-08-01 22:25:04 +01:00
dump.c ARM: 8249/1: mm: dump: don't skip regions 2015-01-07 20:33:33 +00:00
extable.c ARM: 7876/1: clear Thumb-2 IT state on exception handling 2013-11-07 00:15:49 +00:00
fault-armv.c ARM: convert printk(KERN_* to pr_* 2014-11-21 15:24:50 +00:00
fault.c ARM: 8447/1: catch pending imprecise abort on unmask 2015-10-19 17:08:33 +01:00
fault.h ARM: 8447/1: catch pending imprecise abort on unmask 2015-10-19 17:08:33 +01:00
flush.c ARM: add soc memory barrier extension 2015-07-25 15:28:11 +01:00
fsr-2level.c ARM: LPAE: Move the FSR definitions to separate files 2011-12-08 10:30:37 +00:00
fsr-3level.c ARM: mm: Transparent huge page support for LPAE systems. 2013-06-04 16:52:38 +01:00
highmem.c kmap_atomic_to_page() has no users, remove it 2015-11-09 15:11:24 -08:00
hugetlbpage.c mm/hugetlb: reduce arch dependent code about huge_pmd_unshare 2015-06-24 17:49:41 -07:00
idmap.c ARM: 8152/1: Convert pr_warning to pr_warn 2014-09-26 14:39:53 +01:00
init.c of/fdt: split off FDT self reservation from memreserve processing 2015-06-02 16:31:25 +01:00
iomap.c arm/PCI: remove arch pci_flags definition 2012-02-23 20:18:56 -07:00
ioremap.c ARM: io: convert ioremap*() to functions 2015-07-03 17:06:56 +01:00
l2c-common.c ARM: outer cache: add WARN_ON() to outer_disable() 2014-05-30 00:47:23 +01:00
l2c-l2x0-resume.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
mm.h ARM: provide common method to clear bits in CPU control register 2014-06-02 09:20:11 +01:00
mmap.c mm: expose arch_mmap_rnd when available 2015-04-14 16:49:05 -07:00
mmu.c ARM: 8447/1: catch pending imprecise abort on unmask 2015-10-19 17:08:33 +01:00
nommu.c ARM: io: convert ioremap*() to functions 2015-07-03 17:06:56 +01:00
pabort-legacy.S ARM: entry: prefetch abort: tail-call the main prefetch abort handler 2011-07-02 10:56:10 +01:00
pabort-v6.S ARM: entry: prefetch abort: tail-call the main prefetch abort handler 2011-07-02 10:56:10 +01:00
pabort-v7.S ARM: entry: prefetch abort: tail-call the main prefetch abort handler 2011-07-02 10:56:10 +01:00
pageattr.c ARM: 8311/1: Don't use is_module_addr in setting page attributes 2015-03-18 10:13:46 +00:00
pgd.c ARM: domains: keep vectors in separate domain 2015-08-21 13:55:53 +01:00
proc-arm7tdmi.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm9tdmi.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm720.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm740.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm920.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm922.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm925.S ARM: 8349/1: arch/arm/mm/proc-arm925.S: remove dead #ifdef block 2015-05-03 23:22:27 +01:00
proc-arm926.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm940.S Merge branches 'misc', 'vdso' and 'fixes' into for-next 2015-04-14 22:28:25 +01:00
proc-arm946.S Merge branches 'misc', 'vdso' and 'fixes' into for-next 2015-04-14 22:28:25 +01:00
proc-arm1020.S ARM: 8348/1: remove comments on CPU_ARM1020_CPU_IDLE 2015-05-03 23:22:09 +01:00
proc-arm1020e.S ARM: 8348/1: remove comments on CPU_ARM1020_CPU_IDLE 2015-05-03 23:22:09 +01:00
proc-arm1022.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm1026.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-fa526.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-feroceon.S ARM: 8350/1: proc-feroceon: Fix feroceon_proc_info macro 2015-05-03 23:23:09 +01:00
proc-macros.S Merge branches 'misc', 'vdso' and 'fixes' into for-next 2015-04-14 22:28:25 +01:00
proc-mohawk.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-sa110.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-sa1100.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-syms.c ARM: modules: don't export cpu_set_pte_ext when !MMU 2013-03-26 09:55:34 +00:00
proc-v6.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-v7-2level.S Merge branches 'arnd-fixes', 'clk', 'misc', 'v7' and 'fixes' into for-next 2015-06-12 21:18:08 +01:00
proc-v7-3level.S ARM: redo TTBR setup code for LPAE 2015-06-01 23:48:19 +01:00
proc-v7.S ARM: invalidate L1 before enabling coherency 2015-07-17 15:08:40 +01:00
proc-v7m.S ARM: replace BSYM() with badr assembly macro 2015-05-08 17:33:50 +01:00
proc-xsc3.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-xscale.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
pv-fixup-asm.S ARM: re-implement physical address space switching 2015-06-01 23:46:33 +01:00
tcm.h ARM: 7694/1: ARM, TCM: initialize TCM in paging_init(), instead of setup_arch() 2013-04-17 16:53:24 +01:00
tlb-fa.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
tlb-v4.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
tlb-v4wb.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
tlb-v4wbi.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
tlb-v6.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
tlb-v7.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00