1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
|
From ca1e6f4491981432c3e88441131c8e25067da95e Mon Sep 17 00:00:00 2001
From: Samuel Holland <samuel@sholland.org>
Date: Sat, 9 Oct 2021 22:00:22 -0500
Subject: [PATCH 26/90] sunxi: psci: Avoid hanging when CPU 0 is hot-unplugged
Do not try to send an SGI from CPU 0 to itself. Since FIQs are masked
when entering monitor mode, this will hang. Plus, CPU 0 cannot fully
power itself off anyway. Instead, have it turn FIQs back on and continue
servicing SGIs from other cores.
Signed-off-by: Samuel Holland <samuel@sholland.org>
---
arch/arm/cpu/armv7/sunxi/psci.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
--- a/arch/arm/cpu/armv7/sunxi/psci.c
+++ b/arch/arm/cpu/armv7/sunxi/psci.c
@@ -38,6 +38,15 @@
#define SUN8I_R40_PWR_CLAMP(cpu) (0x120 + (cpu) * 0x4)
#define SUN8I_R40_SRAMC_SOFT_ENTRY_REG0 (0xbc)
+static inline u32 __secure cp15_read_mpidr(void)
+{
+ u32 val;
+
+ asm volatile ("mrc p15, 0, %0, c0, c0, 5" : "=r" (val));
+
+ return val;
+}
+
static void __secure cp15_write_cntp_tval(u32 tval)
{
asm volatile ("mcr p15, 0, %0, c14, c2, 0" : : "r" (tval));
@@ -281,9 +290,14 @@ s32 __secure psci_cpu_off(void)
{
psci_cpu_off_common();
- /* Ask CPU0 via SGI15 to pull the rug... */
- writel(BIT(16) | 15, GICD_BASE + GICD_SGIR);
- dsb();
+ if (cp15_read_mpidr() & 3) {
+ /* Ask CPU0 via SGI15 to pull the rug... */
+ writel(BIT(16) | 15, GICD_BASE + GICD_SGIR);
+ dsb();
+ } else {
+ /* Unmask FIQs to service SGI15. */
+ asm volatile ("cpsie f");
+ }
/* Wait to be turned off */
while (1)
|