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Subject[PATCH v5 09/17] powerpc/32: Use vmapped stacks for interrupts
Date
In order to also catch overflows on IRQ stacks, use vmapped stacks.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/kernel/irq.c | 22 ++++++++++++++++++++++
arch/powerpc/kernel/setup_32.c | 3 +++
2 files changed, 25 insertions(+)

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index add67498c126..5c9b11878555 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -50,6 +50,7 @@
#include <linux/debugfs.h>
#include <linux/of.h>
#include <linux/of_irq.h>
+#include <linux/vmalloc.h>

#include <linux/uaccess.h>
#include <asm/io.h>
@@ -664,8 +665,29 @@ void do_IRQ(struct pt_regs *regs)
set_irq_regs(old_regs);
}

+static void *__init alloc_vm_stack(void)
+{
+ return __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN, VMALLOC_START,
+ VMALLOC_END, THREADINFO_GFP, PAGE_KERNEL,
+ 0, NUMA_NO_NODE, (void*)_RET_IP_);
+}
+
+static void __init vmap_irqstack_init(void)
+{
+ int i;
+
+ for_each_possible_cpu(i) {
+ softirq_ctx[i] = alloc_vm_stack();
+ hardirq_ctx[i] = alloc_vm_stack();
+ }
+}
+
+
void __init init_IRQ(void)
{
+ if (IS_ENABLED(CONFIG_VMAP_STACK))
+ vmap_irqstack_init();
+
if (ppc_md.init_IRQ)
ppc_md.init_IRQ();
}
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index a55b4d9ab824..5b49b26eb154 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -153,6 +153,9 @@ void __init irqstack_early_init(void)
{
unsigned int i;

+ if (IS_ENABLED(CONFIG_VMAP_STACK))
+ return;
+
/* interrupt stacks must be in lowmem, we get that for free on ppc32
* as the memblock is limited to lowmem by default */
for_each_possible_cpu(i) {
--
2.13.3
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