linux-kernel - [PATCH AUTOSEL 4.4 39/60] powerpc/ps3: Fix kexec shutdown hang

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Date:   Wed, 17 Jun 2020 21:29:43 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Geoff Levand <geoff@...radead.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Sasha Levin <sashal@...nel.org>, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH AUTOSEL 4.4 39/60] powerpc/ps3: Fix kexec shutdown hang

From: Geoff Levand <geoff@...radead.org>

[ Upstream commit 126554465d93b10662742128918a5fc338cda4aa ]

The ps3_mm_region_destroy() and ps3_mm_vas_destroy() routines
are called very late in the shutdown via kexec's mmu_cleanup_all
routine.  By the time mmu_cleanup_all runs it is too late to use
udbg_printf, and calling it will cause PS3 systems to hang.

Remove all debugging statements from ps3_mm_region_destroy() and
ps3_mm_vas_destroy() and replace any error reporting with calls
to lv1_panic.

With this change builds with 'DEBUG' defined will not cause kexec
reboots to hang, and builds with 'DEBUG' defined or not will end
in lv1_panic if an error is encountered.

Signed-off-by: Geoff Levand <geoff@...radead.org>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Link: https://lore.kernel.org/r/7325c4af2b4c989c19d6a26b90b1fec9c0615ddf.1589049250.git.geoff@infradead.org
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/powerpc/platforms/ps3/mm.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/platforms/ps3/mm.c b/arch/powerpc/platforms/ps3/mm.c
index b0f34663b1ae..19bae78b1f25 100644
--- a/arch/powerpc/platforms/ps3/mm.c
+++ b/arch/powerpc/platforms/ps3/mm.c
@@ -212,13 +212,14 @@ void ps3_mm_vas_destroy(void)
 {
 	int result;
 
-	DBG("%s:%d: map.vas_id    = %llu\n", __func__, __LINE__, map.vas_id);
-
 	if (map.vas_id) {
 		result = lv1_select_virtual_address_space(0);
-		BUG_ON(result);
-		result = lv1_destruct_virtual_address_space(map.vas_id);
-		BUG_ON(result);
+		result += lv1_destruct_virtual_address_space(map.vas_id);
+
+		if (result) {
+			lv1_panic(0);
+		}
+
 		map.vas_id = 0;
 	}
 }
@@ -316,19 +317,20 @@ static void ps3_mm_region_destroy(struct mem_region *r)
 	int result;
 
 	if (!r->destroy) {
-		pr_info("%s:%d: Not destroying high region: %llxh %llxh\n",
-			__func__, __LINE__, r->base, r->size);
 		return;
 	}
 
-	DBG("%s:%d: r->base = %llxh\n", __func__, __LINE__, r->base);
-
 	if (r->base) {
 		result = lv1_release_memory(r->base);
-		BUG_ON(result);
+
+		if (result) {
+			lv1_panic(0);
+		}
+
 		r->size = r->base = r->offset = 0;
 		map.total = map.rm.size;
 	}
+
 	ps3_mm_set_repository_highmem(NULL);
 }
 
-- 
2.25.1