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| author | Mark Rutland <mark.rutland@arm.com> | 2016-01-05 20:33:34 +0300 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2016-01-06 18:40:38 +0300 |
| commit | ee03353bc04f8e460cc4e3da80d9721d9ecb89f1 (patch) | |
| tree | 7079b34f326357afdc3aff8af868f327684ac31f /arch/arm64/kernel | |
| parent | 39b5be9b4233a9f212b98242bddf008f379b5122 (diff) | |
| download | linux-ee03353bc04f8e460cc4e3da80d9721d9ecb89f1.tar.xz | |
arm64: entry: remove pointless SPSR mode check
In work_pending, we may skip work if the stacked SPSR value represents
anything other than an EL0 context. We then immediately invoke the
kernel_exit 0 macro as part of ret_to_user, assuming a return to EL0.
This is somewhat confusing.
We use work_pending as part of the ret_to_user/ret_fast_syscall state
machine. We only use ret_fast_syscall in the return from an SVC issued
from EL0. We use ret_to_user for return from EL0 exception handlers and
also for return from ret_from_fork in the case the task was not a kernel
thread (i.e. it is a user task).
Thus in all cases the stacked SPSR value must represent an EL0 context,
and the check is redundant. This patch removes it, along with the now
unused no_work_pending label.
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/entry.S | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index c0db321db7e1..1f7f5a2b61bf 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -676,10 +676,7 @@ ret_fast_syscall_trace: work_pending: tbnz x1, #TIF_NEED_RESCHED, work_resched /* TIF_SIGPENDING, TIF_NOTIFY_RESUME or TIF_FOREIGN_FPSTATE case */ - ldr x2, [sp, #S_PSTATE] mov x0, sp // 'regs' - tst x2, #PSR_MODE_MASK // user mode regs? - b.ne no_work_pending // returning to kernel enable_irq // enable interrupts for do_notify_resume() bl do_notify_resume b ret_to_user @@ -698,7 +695,6 @@ ret_to_user: and x2, x1, #_TIF_WORK_MASK cbnz x2, work_pending enable_step_tsk x1, x2 -no_work_pending: kernel_exit 0 ENDPROC(ret_to_user) |