Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'x86_urgent_for_v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:
- Fix build error on RHEL where -Werror=maybe-uninitialized is set.
- Restore the firmware's IDT when calling EFI boot services and before
ExitBootServices() has been called. This fixes a boot failure on what
appears to be a tablet with 32-bit UEFI running a 64-bit kernel.
* tag 'x86_urgent_for_v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/resctrl: Fix a maybe-uninitialized build warning treated as error
x86/efi: Restore Firmware IDT before calling ExitBootServices()
+30
-9
+21
-9
arch/x86/boot/compressed/efi_thunk_64.S
+21
-9
arch/x86/boot/compressed/efi_thunk_64.S
···
5
5
* Early support for invoking 32-bit EFI services from a 64-bit kernel.
6
6
*
7
7
* Because this thunking occurs before ExitBootServices() we have to
8
-
* restore the firmware's 32-bit GDT before we make EFI service calls,
9
-
* since the firmware's 32-bit IDT is still currently installed and it
10
-
* needs to be able to service interrupts.
8
+
* restore the firmware's 32-bit GDT and IDT before we make EFI service
9
+
* calls.
11
10
*
12
11
* On the plus side, we don't have to worry about mangling 64-bit
13
12
* addresses into 32-bits because we're executing with an identity
···
38
39
/*
39
40
* Convert x86-64 ABI params to i386 ABI
40
41
*/
41
-
subq $32, %rsp
42
+
subq $64, %rsp
42
43
movl %esi, 0x0(%rsp)
43
44
movl %edx, 0x4(%rsp)
44
45
movl %ecx, 0x8(%rsp)
···
48
49
leaq 0x14(%rsp), %rbx
49
50
sgdt (%rbx)
50
51
52
+
addq $16, %rbx
53
+
sidt (%rbx)
54
+
51
55
/*
52
-
* Switch to gdt with 32-bit segments. This is the firmware GDT
53
-
* that was installed when the kernel started executing. This
54
-
* pointer was saved at the EFI stub entry point in head_64.S.
56
+
* Switch to IDT and GDT with 32-bit segments. This is the firmware GDT
57
+
* and IDT that was installed when the kernel started executing. The
58
+
* pointers were saved at the EFI stub entry point in head_64.S.
55
59
*
56
60
* Pass the saved DS selector to the 32-bit code, and use far return to
57
61
* restore the saved CS selector.
58
62
*/
63
+
leaq efi32_boot_idt(%rip), %rax
64
+
lidt (%rax)
59
65
leaq efi32_boot_gdt(%rip), %rax
60
66
lgdt (%rax)
61
67
···
71
67
pushq %rax
72
68
lretq
73
69
74
-
1: addq $32, %rsp
70
+
1: addq $64, %rsp
75
71
movq %rdi, %rax
76
72
77
73
pop %rbx
···
132
128
133
129
/*
134
130
* Some firmware will return with interrupts enabled. Be sure to
135
-
* disable them before we switch GDTs.
131
+
* disable them before we switch GDTs and IDTs.
136
132
*/
137
133
cli
134
+
135
+
lidtl (%ebx)
136
+
subl $16, %ebx
138
137
139
138
lgdtl (%ebx)
140
139
···
172
165
.word 0
173
166
.quad 0
174
167
SYM_DATA_END(efi32_boot_gdt)
168
+
169
+
SYM_DATA_START(efi32_boot_idt)
170
+
.word 0
171
+
.quad 0
172
+
SYM_DATA_END(efi32_boot_idt)
175
173
176
174
SYM_DATA_START(efi32_boot_cs)
177
175
.word 0
+3
arch/x86/boot/compressed/head_64.S
+3
arch/x86/boot/compressed/head_64.S
+6
arch/x86/kernel/cpu/resctrl/monitor.c
+6
arch/x86/kernel/cpu/resctrl/monitor.c
···
304
304
case QOS_L3_MBM_LOCAL_EVENT_ID:
305
305
m = &rr->d->mbm_local[rmid];
306
306
break;
307
+
default:
308
+
/*
309
+
* Code would never reach here because an invalid
310
+
* event id would fail the __rmid_read.
311
+
*/
312
+
return RMID_VAL_ERROR;
307
313
}
308
314
309
315
if (rr->first) {