This allows platforms to provide their own cpu wakeup routines
as well as IPI send / clear backends, while allowing a SMP kernel w/o
any such backend to build/boot
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Caveats about cache flush on ARCv2 based cores
- dcache is PIPT so paddr is sufficient for cache maintenance ops (no
need to setup PTAG reg
- icache is still VIPT but only aliasing configs need PTAG setup
So basically this is departure from MMU-v3 which always need vaddr in
line ops registers (DC_IVDL, DC_FLDL, IC_IVIL) but paddr in DC_PTAG,
IC_PTAG respectively.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
The issue was, on HS when interrupt is taken, IRQ_ACT is set and that is
NOT cleared unless we do RTIE (or manually clear it). Linux interrupt
handling has top and bottom halves. Latter lead to softirqs (which can
reschedule) AND expect interrupts to be REALLY re-enabled which was NOT
happening for us since we only SETI, dont clear IRQ_ACT
So we can have a state when both cores have taken interrupt (IRQ_ACT set),
get rescheduled, both send IPI and wait in CSD lock which will never be
cleared as cores can't take the pending IPI IRQ due to existing IRQ_ACT
set.
So local_irq_enable() now drops the IRQ_ACT.act bit to re-enable IRQs.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Reported by Anton as LTP:munmap01 failing with Illegal Instruction
Exception.
--------------------->8--------------------------------------
mmap2(NULL, 24576, PROT_READ|PROT_WRITE, MAP_SHARED, 3, 0) = 0x200d2000
munmap(0x200d2000, 24576) = 0
--- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=0x200d2000}
---
potentially unexpected fatal signal 4.
Path: /munmap01
CPU: 0 PID: 61 Comm: munmap01 Not tainted 3.13.0-g5d5c46d9a556 #8
task: 9f1a8000 ti: 9f154000 task.ti: 9f154000
[ECR ]: 0x00020100 => Illegal Insn
[EFA ]: 0x0001354c
[BLINK ]: 0x200515d4
[ERET ]: 0x1354c
@off 0x1354c in [/munmap01]
VMA: 0x00010000 to 0x00018000
[STAT32]: 0x800802c0
...
--------------------->8--------------------------------------
The issue was
1. munmap01 accessed unmapped memory (on purpose) with signal handler
installed for SIGSEGV
2. The faulting instruction happened to be in Delay Slot
00011864 <main>:
11908: bl.d 13284 <tst_resm>
1190c: stb r16,[r2]
3. kernel sets up the reg file for signal handler and correctly clears
the DE bit in pt_regs->status32 placeholder
4. However RESTORE_CALLEE_SAVED_USER macro is not adjusted for ARCv2,
and it over-writes the above with orig/stale value of status32
5. After RTIE, userspace signal handler executes a non branch
instruction with DE bit set, triggering Illegal Instruction Exception.
Reported-by: Anton Kolesov <akolesov@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
These have been register compatible so far. However ARCv2 mandates
different pt_regs layout (due to h/w auto save). To keep pt_regs same
for both, we start by removing the assumption - used mainly for block
copies between the 2 structs in signal handling and ptrace
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Previously this macro was overloaded with stack switching, saving SP at right
slot in pt_regs, saving/setup of r25 and setting SP baseline to where
pt_regs->sp is saved (vs. bottom of pt_regs)
Now it only does SP switch, and leaves SP pointing to bottom of pt_regs.
r25 saving is no longer done here to allow for future reordering of
regfile in pt_regs w/o touching this macro
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Returning from pure kernel mode and exception mode use the same code
anyways. Remove one the duplicate blocks
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Elide the need to re-read ECR in Trap handler by ensuring that
EXCEPTION_PROLOGUE does that at the very end just before returning
to Trap handler
ARCv2 EXCEPTION_PROLOGUE already did that, so same for ARcompact and the
common trap handler adjusted to use cached ECR
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This fixes the possible link/relo errors, since restore_regs will be
provided by ISA code, but called from ARC common code.
The .L prefix reassures binutils that it will be in same compilation
unit.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Vineet Gupta
Claudiu Zissulescu