diff options
author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2018-04-19 12:34:00 +0530 |
---|---|---|
committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-05-03 22:32:25 +1000 |
commit | ea678ac627e01daf5b4f1da24bf1d0c500e10898 (patch) | |
tree | 3fc26b7a742114a8c6b79bc2a6490c40c86afaa5 /arch/powerpc/kernel/setup_64.c | |
parent | 6da6c0db5316275015e8cc2959f12a17584aeb64 (diff) |
powerpc64/ftrace: Add a field in paca to disable ftrace in unsafe code paths
We have some C code that we call into from real mode where we cannot
take any exceptions. Though the C functions themselves are mostly safe,
if these functions are traced, there is a possibility that we may take
an exception. For instance, in certain conditions, the ftrace code uses
WARN(), which uses a 'trap' to do its job.
For such scenarios, introduce a new field in paca 'ftrace_enabled',
which is checked on ftrace entry before continuing. This field can then
be set to zero to disable/pause ftrace, and set to a non-zero value to
resume ftrace.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/setup_64.c')
-rw-r--r-- | arch/powerpc/kernel/setup_64.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index b78f142a4148..313136006d1c 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -252,6 +252,9 @@ static void cpu_ready_for_interrupts(void) /* Set IR and DR in PACA MSR */ get_paca()->kernel_msr = MSR_KERNEL; + + /* We are now ok to enable ftrace */ + get_paca()->ftrace_enabled = 1; } unsigned long spr_default_dscr = 0; |