* Added allocation and initialization of the irq stacks. We limit the
stacks to be in lowmem for ppc32.
* Implemented ppc32 versions of call_do_softirq() and call_handle_irq()
to switch the stack pointers
* Reworked how we do stack overflow detection. We now keep around the
limit of the stack in the thread_struct and compare against the limit
to see if we've overflowed. We can now use this on ppc64 if desired.
Signed-off-by: Kumar Gala <[EMAIL PROTECTED]>
---
arch/powerpc/Kconfig.debug | 1 -
arch/powerpc/kernel/asm-offsets.c | 1 +
arch/powerpc/kernel/entry_32.S | 4 ++--
arch/powerpc/kernel/irq.c | 10 +++++++++-
arch/powerpc/kernel/misc_32.S | 25 +++++++++++++++++++++++++
arch/powerpc/kernel/process.c | 2 ++
arch/powerpc/kernel/setup_32.c | 21 +++++++++++++++++++++
include/asm-powerpc/processor.h | 6 ++++++
8 files changed, 66 insertions(+), 4 deletions(-)
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/asm-offsets.c
b/arch/powerpc/kernel/asm-offsets.c
index adf1d09..0ef4d41 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -64,6 +64,7 @@ int main(void)
#endif /* CONFIG_PPC64 */
DEFINE(KSP, offsetof(struct thread_struct, ksp));
+ DEFINE(KSP_LIMIT, offsetof(struct thread_struct, ksp_limit));
DEFINE(PT_REGS, offsetof(struct thread_struct, regs));
DEFINE(THREAD_FPEXC_MODE, offsetof(struct thread_struct, fpexc_mode));
DEFINE(THREAD_FPR0, offsetof(struct thread_struct, fpr[0]));
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 84c8686..f33c1fe 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -137,8 +137,8 @@ transfer_to_handler:
2: /* if from kernel, check interrupted DOZE/NAP mode and
* check for stack overflow
*/
- lwz r9,THREAD_INFO-THREAD(r12)
- cmplw r1,r9 /* if r1 <= current->thread_info */
+ lwz r9,KSP_LIMIT(r12)
+ cmplw r1,r9 /* if r1 <= ksp_limit */
ble- stack_ovf /* then the kernel stack overflowed */
5:
#ifdef CONFIG_6xx
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 425616f..7378c98 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -307,6 +307,7 @@ void do_IRQ(struct pt_regs *regs)
if (curtp != irqtp) {
struct irq_desc *desc = irq_desc + irq;
void *handler = desc->handle_irq;
+ unsigned long saved_sp_limit =
current->thread.ksp_limit;
if (handler == NULL)
handler = &__do_IRQ;
irqtp->task = curtp->task;
@@ -319,7 +320,10 @@ void do_IRQ(struct pt_regs *regs)
(irqtp->preempt_count & ~SOFTIRQ_MASK) |
(curtp->preempt_count & SOFTIRQ_MASK);
+ current->thread.ksp_limit = (unsigned long)irqtp +
+ _ALIGN_UP(sizeof(struct thread_info), 16);
call_handle_irq(irq, desc, irqtp, handler);
+ current->thread.ksp_limit = saved_sp_limit;
irqtp->task = NULL;
@@ -352,7 +356,7 @@ void __init init_IRQ(void)
{
if (ppc_md.init_IRQ)
ppc_md.init_IRQ();
-#ifdef CONFIG_PPC64
+#ifdef CONFIG_IRQSTACKS
irq_ctx_init();
#endif
}
@@ -383,11 +387,15 @@ void irq_ctx_init(void)
static inline void do_softirq_onstack(void)
{
struct thread_info *curtp, *irqtp;
+ unsigned long saved_sp_limit = current->thread.ksp_limit;
curtp = current_thread_info();
irqtp = softirq_ctx[smp_processor_id()];
irqtp->task = curtp->task;
+ current->thread.ksp_limit = (unsigned long)irqtp +
+ _ALIGN_UP(sizeof(struct thread_info), 16);
call_do_softirq(irqtp);
+ current->thread.ksp_limit = saved_sp_limit;
irqtp->task = NULL;
}
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/process.c b/arch/powerpc/kernel/process.c
index 6caad17..7de41c3 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -589,6 +589,8 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned
long usp,
kregs = (struct pt_regs *) sp;
sp -= STACK_FRAME_OVERHEAD;
p->thread.ksp = sp;
+ p->thread.ksp_limit = (unsigned long)task_stack_page(p) +
+ _ALIGN_UP(sizeof(struct thread_info), 16);
#ifdef CONFIG_PPC64
if (cpu_has_feature(CPU_FTR_SLB)) {
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index 36f6779..5112a4a 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 +230,24 @@ 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 in lowmem, we get that for free on ppc32
+ * as the lmb is limited to lowmem by LMB_REAL_LIMIT */
+ for_each_possible_cpu(i) {
+ softirq_ctx[i] = (struct thread_info *)
+ __va(lmb_alloc(THREAD_SIZE, THREAD_SIZE));
+ hardirq_ctx[i] = (struct thread_info *)
+ __va(lmb_alloc(THREAD_SIZE, THREAD_SIZE));
+ }
+}
+#else
+#define irqstack_early_init()
+#endif
+
/* Warning, IO base is not yet inited */
void __init setup_arch(char **cmdline_p)
{
@@ -286,6 +305,8 @@ 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);
diff --git a/include/asm-powerpc/processor.h b/include/asm-powerpc/processor.h
index fd98ca9..cf83f2d 100644
--- a/include/asm-powerpc/processor.h
+++ b/include/asm-powerpc/processor.h
@@ -138,6 +138,8 @@ typedef struct {
struct thread_struct {
unsigned long ksp; /* Kernel stack pointer */
+ unsigned long ksp_limit; /* if ksp <= ksp_limit stack overflow */
+
#ifdef CONFIG_PPC64
unsigned long ksp_vsid;
#endif
@@ -182,11 +184,14 @@ struct thread_struct {
#define ARCH_MIN_TASKALIGN 16
#define INIT_SP (sizeof(init_stack) + (unsigned long)
&init_stack)
+#define INIT_SP_LIMIT \
+ (_ALIGN_UP(sizeof(init_thread_info), 16) + (unsigned long) &init_stack)
#ifdef CONFIG_PPC32
#define INIT_THREAD { \
.ksp = INIT_SP, \
+ .ksp_limit = INIT_SP_LIMIT, \
.fs = KERNEL_DS, \
.pgdir = swapper_pg_dir, \
.fpexc_mode = MSR_FE0 | MSR_FE1, \
@@ -194,6 +199,7 @@ struct thread_struct {
#else
#define INIT_THREAD { \
.ksp = INIT_SP, \
+ .ksp_limit = INIT_SP_LIMIT, \
.regs = (struct pt_regs *)INIT_SP - 1, /* XXX bogus, I think */ \
.fs = KERNEL_DS, \
.fpr = {0}, \
--
1.5.4.1
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