#include "tests.h"
#include "machine.h"
#include "thread.h"
#include "map.h"
#include "debug.h"
int test__thread_mg_share(int subtest __maybe_unused)
{
struct machines machines;
struct machine *machine;
/* thread group */
struct thread *leader;
struct thread *t1, *t2, *t3;
struct map_groups *mg;
/* other process */
struct thread *other, *other_leader;
struct map_groups *other_mg;
/*
* This test create 2 processes abstractions (struct thread)
* with several threads and checks they properly share and
* maintain map groups info (struct map_groups).
*
* thread group (pid: 0, tids: 0, 1, 2, 3)
* other group (pid: 4, tids: 4, 5)
*/
machines__init(&machines);
machine = &machines.host;
/* create process with 4 threads */
leader = machine__findnew_thread(machine, 0, 0);
t1 = machine__findnew_thread(machine, 0, 1);
t2 = machine__findnew_thread(machine, 0, 2);
t3 = machine__findnew_thread(machine, 0, 3);
/* and create 1 separated process, without thread leader */
other = machine__findnew_thread(machine, 4, 5);
TEST_ASSERT_VAL("failed to create threads",
leader && t1 && t2 && t3 && other);
mg = leader->mg;
TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&mg->refcnt), 4);
/* test the map groups pointer is shared */
TEST_ASSERT_VAL("map groups don't match", mg == t1->mg);
TEST_ASSERT_VAL("map groups don't match", mg == t2->mg);
TEST_ASSERT_VAL("map groups don't match", mg == t3->mg);
/*
* Verify the other leader was created by previous call.
* It should have shared map groups with no change in
* refcnt.
*/
other_leader = machine__find_thread(machine, 4, 4);
TEST_ASSERT_VAL("failed to find other leader", other_leader);
/*
* Ok, now that all the rbtree related operations were done,
* lets remove all of them from there so that we can do the
* refcounting tests.
*/
machine__remove_thread(machine, leader);
machine__remove_thread(machine, t1);
machine__remove_thread(machine, t2);
machine__remove_thread(machine, t3);
machine__remove_thread(machine, other);
machine__remove_thread(machine, other_leader);
other_mg = other->mg;
TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&other_mg->refcnt), 2);
TEST_ASSERT_VAL("map groups don't match", other_mg == other_leader->mg);
/* release thread group */
thread__put(leader);
TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&mg->refcnt), 3);
thread__put(t1);
TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&mg->refcnt), 2);
thread__put(t2);
TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&mg->refcnt), 1);
thread__put(t3);
/* release other group */
thread__put(other_leader);
TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&other_mg->refcnt), 1);
thread__put(other);
machines__exit(&machines);
return 0;
}
' value=''/>
efi/fdt: Avoid FDT manipulation after ExitBootServices()
Some AArch64 UEFI implementations disable the MMU in ExitBootServices(),
after which unaligned accesses to RAM are no longer supported.
Commit:
abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel")
fixed an issue in the memory map handling of the stub FDT code, but
inadvertently created an issue with such firmware, by moving some
of the FDT manipulation to after the invocation of ExitBootServices().
Given that the stub's libfdt implementation uses the ordinary, accelerated
string functions, which rely on hardware handling of unaligned accesses,
manipulating the FDT with the MMU off may result in alignment faults.
So fix the situation by moving the update_fdt_memmap() call into the
callback function invoked by efi_exit_boot_services() right before it
calls the ExitBootServices() UEFI service (which is arguably a better
place for it anyway)
Note that disabling the MMU in ExitBootServices() is not compliant with
the UEFI spec, and carries great risk due to the fact that switching from
cached to uncached memory accesses halfway through compiler generated code
(i.e., involving a stack) can never be done in a way that is architecturally
safe.
Fixes: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel")
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Riku Voipio <riku.voipio@linaro.org>
Cc: <stable@vger.kernel.org>
Cc: mark.rutland@arm.com
Cc: linux-efi@vger.kernel.org
Cc: matt@codeblueprint.co.uk
Cc: leif.lindholm@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1485971102-23330-2-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>