diff options
Diffstat (limited to 'arch/arc')
| -rw-r--r-- | arch/arc/kernel/entry-arcv2.S | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/arch/arc/kernel/entry-arcv2.S b/arch/arc/kernel/entry-arcv2.S index cbfec79137bf..b17830294706 100644 --- a/arch/arc/kernel/entry-arcv2.S +++ b/arch/arc/kernel/entry-arcv2.S @@ -211,7 +211,11 @@ debug_marker_syscall: ; (since IRQ NOT allowed in DS in ARCv2, this can only happen if orig ; entry was via Exception in DS which got preempted in kernel). ; -; IRQ RTIE won't reliably restore DE bit and/or BTA, needs handling +; IRQ RTIE won't reliably restore DE bit and/or BTA, needs workaround +; +; Solution is return from Intr w/o any delay slot quirks into a kernel trampoline +; and from pure kernel mode return to delay slot which handles DS bit/BTA correctly + .Lintr_ret_to_delay_slot: debug_marker_ds: @@ -222,18 +226,23 @@ debug_marker_ds: ld r2, [sp, PT_ret] ld r3, [sp, PT_status32] + ; STAT32 for Int return created from scratch + ; (No delay dlot, disable Further intr in trampoline) + bic r0, r3, STATUS_U_MASK|STATUS_DE_MASK|STATUS_IE_MASK|STATUS_L_MASK st r0, [sp, PT_status32] mov r1, .Lintr_ret_to_delay_slot_2 st r1, [sp, PT_ret] + ; Orig exception PC/STAT32 safekept @orig_r0 and @event stack slots st r2, [sp, 0] st r3, [sp, 4] b .Lisr_ret_fast_path .Lintr_ret_to_delay_slot_2: + ; Trampoline to restore orig exception PC/STAT32/BTA/AUX_USER_SP sub sp, sp, SZ_PT_REGS st r9, [sp, -4] @@ -243,11 +252,19 @@ debug_marker_ds: ld r9, [sp, 4] sr r9, [erstatus] + ; restore AUX_USER_SP if returning to U mode + bbit0 r9, STATUS_U_BIT, 1f + ld r9, [sp, PT_sp] + sr r9, [AUX_USER_SP] + +1: ld r9, [sp, 8] sr r9, [erbta] ld r9, [sp, -4] add sp, sp, SZ_PT_REGS + + ; return from pure kernel mode to delay slot rtie END(ret_from_exception) |