Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Will Deacon:
"Three arm64 fixes for -rc8/final.
The MTE and stolen time fixes have been doing the rounds for a little
while, but review and testing feedback was ongoing until earlier this
week. The kexec fix showed up on Monday and addresses a failure
observed under Qemu.
Summary:
- Add missing write barrier to publish MTE tags before a pte update
- Fix kexec relocation clobbering its own data structures
- Fix stolen time crash if a timer IRQ fires during CPU hotplug"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: mte: Ensure the cleared tags are visible before setting the PTE
arm64: kexec: load from kimage prior to clobbering
arm64: paravirt: Use RCU read locks to guard stolen_time
+39
-15
+3
arch/arm64/kernel/mte.c
+3
arch/arm64/kernel/mte.c
+21
-8
arch/arm64/kernel/paravirt.c
+21
-8
arch/arm64/kernel/paravirt.c
···
35
35
DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock);
36
36
37
37
struct pv_time_stolen_time_region {
38
-
struct pvclock_vcpu_stolen_time *kaddr;
38
+
struct pvclock_vcpu_stolen_time __rcu *kaddr;
39
39
};
40
40
41
41
static DEFINE_PER_CPU(struct pv_time_stolen_time_region, stolen_time_region);
···
52
52
/* return stolen time in ns by asking the hypervisor */
53
53
static u64 para_steal_clock(int cpu)
54
54
{
55
+
struct pvclock_vcpu_stolen_time *kaddr = NULL;
55
56
struct pv_time_stolen_time_region *reg;
57
+
u64 ret = 0;
56
58
57
59
reg = per_cpu_ptr(&stolen_time_region, cpu);
58
60
···
63
61
* online notification callback runs. Until the callback
64
62
* has run we just return zero.
65
63
*/
66
-
if (!reg->kaddr)
64
+
rcu_read_lock();
65
+
kaddr = rcu_dereference(reg->kaddr);
66
+
if (!kaddr) {
67
+
rcu_read_unlock();
67
68
return 0;
69
+
}
68
70
69
-
return le64_to_cpu(READ_ONCE(reg->kaddr->stolen_time));
71
+
ret = le64_to_cpu(READ_ONCE(kaddr->stolen_time));
72
+
rcu_read_unlock();
73
+
return ret;
70
74
}
71
75
72
76
static int stolen_time_cpu_down_prepare(unsigned int cpu)
73
77
{
78
+
struct pvclock_vcpu_stolen_time *kaddr = NULL;
74
79
struct pv_time_stolen_time_region *reg;
75
80
76
81
reg = this_cpu_ptr(&stolen_time_region);
77
82
if (!reg->kaddr)
78
83
return 0;
79
84
80
-
memunmap(reg->kaddr);
81
-
memset(reg, 0, sizeof(*reg));
85
+
kaddr = rcu_replace_pointer(reg->kaddr, NULL, true);
86
+
synchronize_rcu();
87
+
memunmap(kaddr);
82
88
83
89
return 0;
84
90
}
85
91
86
92
static int stolen_time_cpu_online(unsigned int cpu)
87
93
{
94
+
struct pvclock_vcpu_stolen_time *kaddr = NULL;
88
95
struct pv_time_stolen_time_region *reg;
89
96
struct arm_smccc_res res;
90
97
···
104
93
if (res.a0 == SMCCC_RET_NOT_SUPPORTED)
105
94
return -EINVAL;
106
95
107
-
reg->kaddr = memremap(res.a0,
96
+
kaddr = memremap(res.a0,
108
97
sizeof(struct pvclock_vcpu_stolen_time),
109
98
MEMREMAP_WB);
99
+
100
+
rcu_assign_pointer(reg->kaddr, kaddr);
110
101
111
102
if (!reg->kaddr) {
112
103
pr_warn("Failed to map stolen time data structure\n");
113
104
return -ENOMEM;
114
105
}
115
106
116
-
if (le32_to_cpu(reg->kaddr->revision) != 0 ||
117
-
le32_to_cpu(reg->kaddr->attributes) != 0) {
107
+
if (le32_to_cpu(kaddr->revision) != 0 ||
108
+
le32_to_cpu(kaddr->attributes) != 0) {
118
109
pr_warn_once("Unexpected revision or attributes in stolen time data\n");
119
110
return -ENXIO;
120
111
}
+15
-7
arch/arm64/kernel/relocate_kernel.S
+15
-7
arch/arm64/kernel/relocate_kernel.S
···
37
37
* safe memory that has been set up to be preserved during the copy operation.
38
38
*/
39
39
SYM_CODE_START(arm64_relocate_new_kernel)
40
+
/*
41
+
* The kimage structure isn't allocated specially and may be clobbered
42
+
* during relocation. We must load any values we need from it prior to
43
+
* any relocation occurring.
44
+
*/
45
+
ldr x28, [x0, #KIMAGE_START]
46
+
ldr x27, [x0, #KIMAGE_ARCH_EL2_VECTORS]
47
+
ldr x26, [x0, #KIMAGE_ARCH_DTB_MEM]
48
+
40
49
/* Setup the list loop variables. */
41
50
ldr x18, [x0, #KIMAGE_ARCH_ZERO_PAGE] /* x18 = zero page for BBM */
42
51
ldr x17, [x0, #KIMAGE_ARCH_TTBR1] /* x17 = linear map copy */
···
81
72
ic iallu
82
73
dsb nsh
83
74
isb
84
-
ldr x4, [x0, #KIMAGE_START] /* relocation start */
85
-
ldr x1, [x0, #KIMAGE_ARCH_EL2_VECTORS] /* relocation start */
86
-
ldr x0, [x0, #KIMAGE_ARCH_DTB_MEM] /* dtb address */
87
75
turn_off_mmu x12, x13
88
76
89
77
/* Start new image. */
90
-
cbz x1, .Lel1
91
-
mov x1, x4 /* relocation start */
92
-
mov x2, x0 /* dtb address */
78
+
cbz x27, .Lel1
79
+
mov x1, x28 /* kernel entry point */
80
+
mov x2, x26 /* dtb address */
93
81
mov x3, xzr
94
82
mov x4, xzr
95
83
mov x0, #HVC_SOFT_RESTART
96
84
hvc #0 /* Jumps from el2 */
97
85
.Lel1:
86
+
mov x0, x26 /* dtb address */
87
+
mov x1, xzr
98
88
mov x2, xzr
99
89
mov x3, xzr
100
-
br x4 /* Jumps from el1 */
90
+
br x28 /* Jumps from el1 */
101
91
SYM_CODE_END(arm64_relocate_new_kernel)