diff options
Diffstat (limited to 'arch/arc/include/asm')
| -rw-r--r-- | arch/arc/include/asm/entry.h | 95 | ||||
| -rw-r--r-- | arch/arc/include/asm/irqflags.h | 6 |
2 files changed, 100 insertions, 1 deletions
diff --git a/arch/arc/include/asm/entry.h b/arch/arc/include/asm/entry.h index 716f4f7b5cd..23ef2de1e09 100644 --- a/arch/arc/include/asm/entry.h +++ b/arch/arc/include/asm/entry.h @@ -5,6 +5,12 @@ * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * + * Vineetg: March 2009 (Supporting 2 levels of Interrupts) + * Stack switching code can no longer reliably rely on the fact that + * if we are NOT in user mode, stack is switched to kernel mode. + * e.g. L2 IRQ interrupted a L1 ISR which had not yet completed + * it's prologue including stack switching from user mode + * * Vineetg: Aug 28th 2008: Bug #94984 * -Zero Overhead Loop Context shd be cleared when entering IRQ/EXcp/Trap * Normally CPU does this automatically, however when doing FAKE rtie, @@ -268,6 +274,33 @@ * assume SP is kernel mode SP. _NO_ need to do any stack switching */ +#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS + /* However.... + * If Level 2 Interrupts enabled, we may end up with a corner case: + * 1. User Task executing + * 2. L1 IRQ taken, ISR starts (CPU auto-switched to KERNEL mode) + * 3. But before it could switch SP from USER to KERNEL stack + * a L2 IRQ "Interrupts" L1 + * Thay way although L2 IRQ happened in Kernel mode, stack is still + * not switched. + * To handle this, we may need to switch stack even if in kernel mode + * provided SP has values in range of USER mode stack ( < 0x7000_0000 ) + */ + brlo sp, VMALLOC_START, 88f + + /* TODO: vineetg: + * We need to be a bit more cautious here. What if a kernel bug in + * L1 ISR, caused SP to go whaco (some small value which looks like + * USER stk) and then we take L2 ISR. + * Above brlo alone would treat it as a valid L1-L2 sceanrio + * instead of shouting alound + * The only feasible way is to make sure this L2 happened in + * L1 prelogue ONLY i.e. ilink2 is less than a pre-set marker in + * L1 ISR before it switches stack + */ + +#endif + /* Save Pre Intr/Exception KERNEL MODE SP on kernel stack * safe-keeping not really needed, but it keeps the epilogue code * (SP restore) simpler/uniform. @@ -503,6 +536,42 @@ sub sp, sp, 4 .endm +.macro SAVE_ALL_INT2 + + /* TODO-vineetg: SMP we can't use global nor can we use + * SCRATCH0 as we do for int1 because while int1 is using + * it, int2 can come + */ + /* retsore original r9 , saved in sys_saved_r9 */ + ld r9, [@int2_saved_reg] + + /* now we are ready to save the remaining context :) */ + st orig_r8_IS_IRQ2, [sp, 8] /* Event Type */ + st 0, [sp, 4] /* orig_r0 , N/A for IRQ */ + SAVE_CALLER_SAVED + st.a r26, [sp, -4] /* gp */ + st.a fp, [sp, -4] + st.a blink, [sp, -4] + st.a ilink2, [sp, -4] + lr r9, [status32_l2] + st.a r9, [sp, -4] + st.a lp_count, [sp, -4] + lr r9, [lp_end] + st.a r9, [sp, -4] + lr r9, [lp_start] + st.a r9, [sp, -4] + lr r9, [bta_l2] + st.a r9, [sp, -4] + +#ifdef PT_REGS_CANARY + mov r9, 0xdeadbee2 + st r9, [sp, -4] +#endif + + /* move up by 1 word to "create" pt_regs->"stack_place_holder" */ + sub sp, sp, 4 +.endm + /*-------------------------------------------------------------- * Restore all registers used by interrupt handlers. * @@ -537,6 +606,32 @@ /* orig_r0 and orig_r8 skipped automatically */ .endm +.macro RESTORE_ALL_INT2 + add sp, sp, 4 /* hop over unused "pt_regs->stack_place_holder" */ + + ld.ab r9, [sp, 4] + sr r9, [bta_l2] + ld.ab r9, [sp, 4] + sr r9, [lp_start] + ld.ab r9, [sp, 4] + sr r9, [lp_end] + ld.ab r9, [sp, 4] + mov lp_count, r9 + ld.ab r9, [sp, 4] + sr r9, [status32_l2] + ld.ab r9, [sp, 4] + mov ilink2, r9 + ld.ab blink, [sp, 4] + ld.ab fp, [sp, 4] + ld.ab r26, [sp, 4] /* gp */ + RESTORE_CALLER_SAVED + + ld sp, [sp] /* restore original sp */ + /* orig_r0 and orig_r8 skipped automatically */ + +.endm + + /* Get CPU-ID of this core */ .macro GET_CPU_ID reg lr \reg, [identity] diff --git a/arch/arc/include/asm/irqflags.h b/arch/arc/include/asm/irqflags.h index 5cc1080d7c2..ccd84806b62 100644 --- a/arch/arc/include/asm/irqflags.h +++ b/arch/arc/include/asm/irqflags.h @@ -95,7 +95,11 @@ static inline long arch_local_save_flags(void) */ static inline int arch_irqs_disabled_flags(unsigned long flags) { - return !(flags & (STATUS_E1_MASK)); + return !(flags & (STATUS_E1_MASK +#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS + | STATUS_E2_MASK +#endif + )); } static inline int arch_irqs_disabled(void) |