[PATCH -next] irq-chip/gic-v3-its: Fixed an issue where the ITS executes the residual commands in the queue again when the ITS wakes up from sleep mode.

[Xu Qiang]

On my platform, ITS_FLAGS_SAVE_SUSPEND_STATE is not set,thus do nothing
in its suspend and resuse function.On the other hand,firmware stores
GITS_CTRL,GITS_CBASER,GITS_CWRITER and GITS_BASER<n> in the suspend,
and restores these registers in the resume. As a result, the ITS executes
the residual commands in the queue.

Memory corruption may occur in the following scenarios:

The kernel sends three commands in the following sequence:
1.mapd(deviceA, ITT_addr1, valid:1)
2.mapti(deviceA):ITS write ITT_addr1 memory;
3.mapd(deviceA, ITT_addr1, valid:0) and kfree(ITT_addr1);
4.mapd(deviceA, ITT_addr2, valid:1);
5.mapti(deviceA):ITS write ITT_addr2 memory;

To solve this problem,dropping the checks for ITS_FLAGS_SAVE_SUSPEND_STATE.

Signed-off-by: Xu Qiang <xuqiang36@xxxxxxxxxx>
---
 drivers/irqchip/irq-gic-v3-its.c | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 0fec31931e11..06f2c1c252b9 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -42,7 +42,6 @@
 #define ITS_FLAGS_CMDQ_NEEDS_FLUSHING		(1ULL << 0)
 #define ITS_FLAGS_WORKAROUND_CAVIUM_22375	(1ULL << 1)
 #define ITS_FLAGS_WORKAROUND_CAVIUM_23144	(1ULL << 2)
-#define ITS_FLAGS_SAVE_SUSPEND_STATE		(1ULL << 3)
 
 #define RDIST_FLAGS_PROPBASE_NEEDS_FLUSHING	(1 << 0)
 #define RDIST_FLAGS_RD_TABLES_PREALLOCATED	(1 << 1)
@@ -4741,9 +4740,6 @@ static int its_save_disable(void)
 	list_for_each_entry(its, &its_nodes, entry) {
 		void __iomem *base;
 
-		if (!(its->flags & ITS_FLAGS_SAVE_SUSPEND_STATE))
-			continue;
-
 		base = its->base;
 		its->ctlr_save = readl_relaxed(base + GITS_CTLR);
 		err = its_force_quiescent(base);
@@ -4762,9 +4758,6 @@ static int its_save_disable(void)
 		list_for_each_entry_continue_reverse(its, &its_nodes, entry) {
 			void __iomem *base;
 
-			if (!(its->flags & ITS_FLAGS_SAVE_SUSPEND_STATE))
-				continue;
-
 			base = its->base;
 			writel_relaxed(its->ctlr_save, base + GITS_CTLR);
 		}
@@ -4784,9 +4777,6 @@ static void its_restore_enable(void)
 		void __iomem *base;
 		int i;
 
-		if (!(its->flags & ITS_FLAGS_SAVE_SUSPEND_STATE))
-			continue;
-
 		base = its->base;
 
 		/*
@@ -5074,9 +5064,6 @@ static int __init its_probe_one(struct resource *res,
 		ctlr |= GITS_CTLR_ImDe;
 	writel_relaxed(ctlr, its->base + GITS_CTLR);
 
-	if (GITS_TYPER_HCC(typer))
-		its->flags |= ITS_FLAGS_SAVE_SUSPEND_STATE;
-
 	err = its_init_domain(handle, its);
 	if (err)
 		goto out_free_tables;
-- 
2.25.0