@@ -278,6 +278,7 @@ extern void e500_idle(void);
extern void power4_idle(void);
extern void power4_cpu_offline_powersave(void);
extern void ppc6xx_idle(void);
+extern void book3e_idle(void);
/*
* ppc_md contains a copy of the machine description structure for the
@@ -37,7 +37,7 @@ obj-$(CONFIG_PPC64) += setup_64.o sys_ppc32.o \
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
obj-$(CONFIG_PPC_BOOK3S_64) += cpu_setup_ppc970.o cpu_setup_pa6t.o
obj64-$(CONFIG_RELOCATABLE) += reloc_64.o
-obj-$(CONFIG_PPC_BOOK3E_64) += exceptions-64e.o
+obj-$(CONFIG_PPC_BOOK3E_64) += exceptions-64e.o idle_book3e.o
obj-$(CONFIG_PPC64) += vdso64/
obj-$(CONFIG_ALTIVEC) += vecemu.o
obj-$(CONFIG_PPC_970_NAP) += idle_power4.o
@@ -204,11 +204,30 @@ exc_##n##_bad_stack: \
lis r,TSR_FIS@h; \
mtspr SPRN_TSR,r
+/* Used by asynchronous interrupt that may happen in the idle loop.
+ *
+ * This check if the thread was in the idle loop, and if yes, returns
+ * to the caller rather than the PC. This is to avoid a race if
+ * interrupts happen before the wait instruction.
+ */
+#define CHECK_NAPPING() \
+ clrrdi r11,r1,THREAD_SHIFT; \
+ ld r10,TI_LOCAL_FLAGS(r11); \
+ andi. r9,r10,_TLF_NAPPING; \
+ beq+ 1f; \
+ ld r8,_LINK(r1); \
+ rlwinm r7,r10,0,~_TLF_NAPPING; \
+ std r8,_NIP(r1); \
+ std r7,TI_LOCAL_FLAGS(r11); \
+1:
+
+
#define MASKABLE_EXCEPTION(trapnum, label, hdlr, ack) \
START_EXCEPTION(label); \
NORMAL_EXCEPTION_PROLOG(trapnum, PROLOG_ADDITION_MASKABLE) \
EXCEPTION_COMMON(trapnum, PACA_EXGEN, INTS_DISABLE_ALL) \
ack(r8); \
+ CHECK_NAPPING(); \
addi r3,r1,STACK_FRAME_OVERHEAD; \
bl hdlr; \
b .ret_from_except_lite;
@@ -257,6 +276,7 @@ interrupt_end_book3e:
CRIT_EXCEPTION_PROLOG(0x100, PROLOG_ADDITION_NONE)
// EXCEPTION_COMMON(0x100, PACA_EXCRIT, INTS_DISABLE_ALL)
// bl special_reg_save_crit
+// CHECK_NAPPING();
// addi r3,r1,STACK_FRAME_OVERHEAD
// bl .critical_exception
// b ret_from_crit_except
@@ -268,6 +288,7 @@ interrupt_end_book3e:
// EXCEPTION_COMMON(0x200, PACA_EXMC, INTS_DISABLE_ALL)
// bl special_reg_save_mc
// addi r3,r1,STACK_FRAME_OVERHEAD
+// CHECK_NAPPING();
// bl .machine_check_exception
// b ret_from_mc_except
b .
@@ -338,6 +359,7 @@ interrupt_end_book3e:
CRIT_EXCEPTION_PROLOG(0x9f0, PROLOG_ADDITION_NONE)
// EXCEPTION_COMMON(0x9f0, PACA_EXCRIT, INTS_DISABLE_ALL)
// bl special_reg_save_crit
+// CHECK_NAPPING();
// addi r3,r1,STACK_FRAME_OVERHEAD
// bl .unknown_exception
// b ret_from_crit_except
@@ -434,6 +456,7 @@ kernel_dbg_exc:
CRIT_EXCEPTION_PROLOG(0x2080, PROLOG_ADDITION_NONE)
// EXCEPTION_COMMON(0x2080, PACA_EXCRIT, INTS_DISABLE_ALL)
// bl special_reg_save_crit
+// CHECK_NAPPING();
// addi r3,r1,STACK_FRAME_OVERHEAD
// bl .doorbell_critical_exception
// b ret_from_crit_except
new file mode 100644
@@ -0,0 +1,86 @@
+/*
+ * Copyright 2010 IBM Corp, Benjamin Herrenschmidt <benh@kernel.crashing.org>
+ *
+ * Generic idle routine for Book3E processors
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/threads.h>
+#include <asm/reg.h>
+#include <asm/ppc_asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/ppc-opcode.h>
+#include <asm/processor.h>
+#include <asm/thread_info.h>
+
+/* 64-bit version only for now */
+#ifdef CONFIG_PPC64
+
+_GLOBAL(book3e_idle)
+ /* Save LR for later */
+ mflr r0
+ std r0,16(r1)
+
+ /* Hard disable interrupts */
+ wrteei 0
+
+ /* Now check if an interrupt came in while we were soft disabled
+ * since we may otherwise lose it (doorbells etc...). We know
+ * that since PACAHARDIRQEN will have been cleared in that case.
+ */
+ lbz r3,PACAHARDIRQEN(r13)
+ cmpwi cr0,r3,0
+ beqlr
+
+ /* Now we are going to mark ourselves as soft and hard enables in
+ * order to be able to take interrupts while asleep. We inform lockdep
+ * of that. We don't actually turn interrupts on just yet tho.
+ */
+#ifdef CONFIG_TRACE_IRQFLAGS
+ stdu r1,-128(r1)
+ bl .trace_hardirqs_on
+#endif
+ li r0,1
+ stb r0,PACASOFTIRQEN(r13)
+ stb r0,PACAHARDIRQEN(r13)
+
+ /* Interrupts will make use return to LR, so get something we want
+ * in there
+ */
+ bl 1f
+
+ /* Hard disable interrupts again */
+ wrteei 0
+
+ /* Mark them off again in the PACA as well */
+ li r0,0
+ stb r0,PACASOFTIRQEN(r13)
+ stb r0,PACAHARDIRQEN(r13)
+
+ /* Tell lockdep about it */
+#ifdef CONFIG_TRACE_IRQFLAGS
+ bl .trace_hardirqs_off
+ addi r1,r1,128
+#endif
+ ld r0,16(r1)
+ mtlr r0
+ blr
+
+1: /* Let's set the _TLF_NAPPING flag so interrupts make us return
+ * to the right spot
+ */
+ clrrdi r11,r1,THREAD_SHIFT
+ ld r10,TI_LOCAL_FLAGS(r11)
+ ori r10,r10,_TLF_NAPPING
+ std r10,TI_LOCAL_FLAGS(r11)
+
+ /* We can now re-enable hard interrupts and go to sleep */
+ wrteei 1
+1: PPC_WAIT(0)
+ b 1b
+
+#endif /* CONFIG_PPC64 */
We use a similar technique to ppc32: We set a thread local flag to indicate that we are about to enter or have entered the stop state, and have fixup code in the async interrupt entry code that reacts to this flag to make us return to a different location (sets NIP to LINK in our case). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> -- v2. Fix lockdep bug Re-mask interrupts when coming back from idle --- arch/powerpc/include/asm/machdep.h | 1 + arch/powerpc/kernel/Makefile | 2 +- arch/powerpc/kernel/exceptions-64e.S | 23 +++++++++ arch/powerpc/kernel/idle_book3e.S | 86 ++++++++++++++++++++++++++++++++++ 4 files changed, 111 insertions(+), 1 deletions(-) create mode 100644 arch/powerpc/kernel/idle_book3e.S