diff options
| author | Kevin Hilman <khilman@deeprootsystems.com> | 2013-03-28 22:54:40 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2013-04-03 17:00:01 +0100 |
| commit | b00884802043d9102ecc2abfdc37a7b35b30e52a (patch) | |
| tree | 634138ea0602f55374fb1d4a5fa453cce17c6683 /arch/arm/kernel | |
| parent | 4fd75911f6970478444eece952dacb2db9d1e5a5 (diff) | |
ARM: 7688/1: add support for context tracking subsystem
commit 91d1aa43 (context_tracking: New context tracking susbsystem)
generalized parts of the RCU userspace extended quiescent state into
the context tracking subsystem. Context tracking is then used
to implement adaptive tickless (a.k.a extended nohz)
To support the new context tracking subsystem on ARM, the user/kernel
boundary transtions need to be instrumented.
For exceptions and IRQs in usermode, the existing usr_entry macro is
used to instrument the user->kernel transition. For the return to
usermode path, the ret_to_user* path is instrumented. Using the
usr_entry macro, this covers interrupts in userspace, data abort and
prefetch abort exceptions in userspace as well as undefined exceptions
in userspace (which is where FP emulation and VFP are handled.)
For syscalls, the slow return path is covered by instrumenting the
ret_to_user path. In addition, the syscall entry point is
instrumented which covers the user->kernel transition for both fast
and slow syscalls, and an additional instrumentation point is added
for the fast syscall return path (ret_fast_syscall).
Cc: Mats Liljegren <mats.liljegren@enea.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel')
| -rw-r--r-- | arch/arm/kernel/entry-armv.S | 1 | ||||
| -rw-r--r-- | arch/arm/kernel/entry-common.S | 3 | ||||
| -rw-r--r-- | arch/arm/kernel/entry-header.S | 28 |
3 files changed, 32 insertions, 0 deletions
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index 0f82098c9bfe..2b1de1b2f132 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -396,6 +396,7 @@ ENDPROC(__pabt_svc) #ifdef CONFIG_IRQSOFF_TRACER bl trace_hardirqs_off #endif + ct_user_exit save = 0 .endm .macro kuser_cmpxchg_check diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 3248cde504ed..469e82b3f757 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -41,6 +41,7 @@ ret_fast_syscall: /* perform architecture specific actions before user return */ arch_ret_to_user r1, lr + ct_user_enter restore_user_regs fast = 1, offset = S_OFF UNWIND(.fnend ) @@ -76,6 +77,7 @@ no_work_pending: #endif /* perform architecture specific actions before user return */ arch_ret_to_user r1, lr + ct_user_enter save = 0 restore_user_regs fast = 0, offset = 0 ENDPROC(ret_to_user_from_irq) @@ -394,6 +396,7 @@ ENTRY(vector_swi) mcr p15, 0, ip, c1, c0 @ update control register #endif enable_irq + ct_user_exit get_thread_info tsk adr tbl, sys_call_table @ load syscall table pointer diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S index 9a8531eadd3d..782a94956286 100644 --- a/arch/arm/kernel/entry-header.S +++ b/arch/arm/kernel/entry-header.S @@ -164,6 +164,34 @@ #endif /* !CONFIG_THUMB2_KERNEL */ /* + * Context tracking subsystem. Used to instrument transitions + * between user and kernel mode. + */ + .macro ct_user_exit, save = 1 +#ifdef CONFIG_CONTEXT_TRACKING + .if \save + stmdb sp!, {r0-r3, ip, lr} + bl user_exit + ldmia sp!, {r0-r3, ip, lr} + .else + bl user_exit + .endif +#endif + .endm + + .macro ct_user_enter, save = 1 +#ifdef CONFIG_CONTEXT_TRACKING + .if \save + stmdb sp!, {r0-r3, ip, lr} + bl user_enter + ldmia sp!, {r0-r3, ip, lr} + .else + bl user_enter + .endif +#endif + .endm + +/* * These are the registers used in the syscall handler, and allow us to * have in theory up to 7 arguments to a function - r0 to r6. * |