Posting this to get any review and suggestions on the functionality of the
patch.
Questions/issues:
* what to do about the stack_ovf check in entry_32.S
* do we really have any constraints on ppc32 (beyond being in lowmem) on
the locations of the stacks [see irqstack_early_init()]
- k
diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index a86d8d8..2cf72d2 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -118,7 +118,6 @@ config XMON_DISASSEMBLY
config IRQSTACKS
bool "Use separate kernel stacks when processing interrupts"
- depends on PPC64
help
If you say Y here the kernel will use separate kernel stacks
for handling hard and soft interrupts. This can help avoid
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 425616f..ad40eb4 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -352,7 +352,7 @@ void __init init_IRQ(void)
{
if (ppc_md.init_IRQ)
ppc_md.init_IRQ();
-#ifdef CONFIG_PPC64
+#ifdef CONFIG_IRQSTACKS
irq_ctx_init();
#endif
}
diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
index 92ccc6f..89aaaa6 100644
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -32,6 +32,31 @@
.text
+#ifdef CONFIG_IRQSTACKS
+_GLOBAL(call_do_softirq)
+ mflr r0
+ stw r0,4(r1)
+ stwu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r3)
+ mr r1,r3
+ bl __do_softirq
+ lwz r1,0(r1)
+ lwz r0,4(r1)
+ mtlr r0
+ blr
+
+_GLOBAL(call_handle_irq)
+ mflr r0
+ stw r0,4(r1)
+ mtctr r6
+ stwu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r5)
+ mr r1,r5
+ bctrl
+ lwz r1,0(r1)
+ lwz r0,4(r1)
+ mtlr r0
+ blr
+#endif /* CONFIG_IRQSTACKS */
+
/*
* This returns the high 64 bits of the product of two 64-bit numbers.
*/
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index 36f6779..ebd1b1d 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -16,6 +16,7 @@
#include <linux/root_dev.h>
#include <linux/cpu.h>
#include <linux/console.h>
+#include <linux/lmb.h>
#include <asm/io.h>
#include <asm/prom.h>
@@ -229,6 +230,28 @@ int __init ppc_init(void)
arch_initcall(ppc_init);
+#ifdef CONFIG_IRQSTACKS
+static void __init irqstack_early_init(void)
+{
+ unsigned int i;
+
+ /*
+ * interrupt stacks must be under 256MB, we cannot afford to take
+ * SLB misses on them.
+ */
+ for_each_possible_cpu(i) {
+ softirq_ctx[i] = (struct thread_info *)
+ __va(lmb_alloc_base(THREAD_SIZE,
+ THREAD_SIZE, 0x10000000));
+ hardirq_ctx[i] = (struct thread_info *)
+ __va(lmb_alloc_base(THREAD_SIZE,
+ THREAD_SIZE, 0x10000000));
+ }
+}
+#else
+#define irqstack_early_init()
+#endif
+
/* Warning, IO base is not yet inited */
void __init setup_arch(char **cmdline_p)
{
@@ -286,6 +309,8 @@ void __init setup_arch(char **cmdline_p)
init_mm.end_data = (unsigned long) _edata;
init_mm.brk = klimit;
+ irqstack_early_init();
+
/* set up the bootmem stuff with available memory */
do_init_bootmem();
if ( ppc_md.progress ) ppc_md.progress("setup_arch: bootmem", 0x3eab);
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