FreeCalypso > hg > fc-tourmaline

annotate src/cs/system/main/gcc/irqfiq.S @ 268:f2e52cab0a73

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
abb_inth.c: check all interrupt causes, not just one The original code used if - else if - else if etc constructs, thus the first detected interrupt was the only one handled. However, Iota ITSTATREG is a clear-on-read register, thus if we only handle the first detected interrupt and skip checking the others, then the other interrupts will be lost, if more than one interrupt happened to occur in one ABB interrupt handling cycle - a form of rare race condition. Change the code to check all interrupts that were read in this cycle.
author Mychaela Falconia <falcon@freecalypso.org>
date Sun, 13 Jun 2021 18:17:53 +0000
parents 4e78acac3d88
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
0
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
1 /*
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
2 * This module contains the assembly shells for IRQ and FIQ, separated
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
3 * from the architectured vectors only by some simple unconditional
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
4 * branch instructions.
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
5 *
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
6 * Note that TI's way of handling interrupts sacrifices Nucleus' ability
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
7 * to nest interrupts and minimize the IRQ-disabled window: if my (Falcon's)
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
8 * understanding is correct, TI's code leaves all further IRQs disabled
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
9 * for the full execution duration of an IRQ handler. (IRQ handlers are
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
10 * really LISRs, but TI's GSM fw does not use Nucleus' LISR framework.)
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
11 */
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
12
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
13 .text
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
14 .code 32
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
15
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
16 .globl _INT_IRQ
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
17 _INT_IRQ:
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
18 STMDB sp!,{r0-r4} @ used to be a1-a4
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
19
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
20 /*
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
21 * Thanks to TI for discovering and documenting this apparent ARM7TDMI bug:
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
22
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
23 BUG correction 1st part -------------------
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
24 It looks like there is an issue with ARM7 IRQ masking in the CPSR register
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
25 which leads to crashes in Nucleus+ scheduler.
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
26 Basically the code below (correct as LOCKOUT = 0xC0) is used in many places by N+ but do not
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
27 prevent from having an interrupt after the execution of the third line (I mean execution, not
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
28 fetch).
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
29 MRS a1,CPSR ; Pickup current CPSR
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
30 ORR a1,a1,#LOCKOUT ; Build interrupt lockout value
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
31 MSR CPSR,a1 ; Lockout interrupts
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
32 * IRQ INTERRUPT ! *
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
33 Next instructions...
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
34
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
35 SW workaround:
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
36 When a task is interrupted at this point an interrupted context is stored on its task and will
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
37 be resumed later on at the next instruction but to make a long story short it leads to some
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
38 problem as the OS does not expect to be interrupted there.
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
39 Further testing tends to show that the CPSR *seems* to be loaded with the proper masking value
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
40 but that the IRQ is still triggered (has been hardwarewise requested during the instruction
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
41 exectution by the ARM7 core?)
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
42 */
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
43
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
44 MRS a1,spsr @ check for the IRQ bug:
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
45 TST a1,#0x80 @ if the I - flag is set,
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
46 BNE IRQBUG @ then postpone execution of this IRQ
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
47 /* Bug correction 1st part end --------------- */
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
48
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
49 SUB r4,lr,#4 @ Save IRQ's lr (return address)
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
50 BL TCT_Interrupt_Context_Save @ Call context save routine
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
51
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
52 BL IQ_IRQ_isr @ Call int. service routine
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
53
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
54 /* IRQ interrupt processing is complete. Restore context- Never
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
55 returns! */
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
56 B TCT_Interrupt_Context_Restore
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
57
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
58 /* BUG correction 2nd part ------------------ */
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
59 IRQBUG: LDMFD sp!,{r0-r4} @ return from interrupt
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
60 SUBS pc,r14,#4
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
61 /* BUG correction 2nd part end -------------- */
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
62
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
63 .globl _INT_FIQ
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
64 _INT_FIQ:
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
65 STMDB sp!,{r0-r4} @ used to be a1-a4
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
66 SUB r4,lr,#4 @ Save FIQ's lr (return address)
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
67 BL TCT_Interrupt_Context_Save @ Call context save routine
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
68
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
69 BL IQ_FIQ_isr @ Call the FIQ ISR
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
70
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
71 /* FIQ interrupt processing is complete. Restore context- Never
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
72 returns! */
4e78acac3d88 src/{condat,cs,gpf,nucleus}: import from Selenite
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
73 B TCT_Interrupt_Context_Restore