Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'x86-urgent-2020-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner:
"A set of x86 fixes:
- Use SYM_FUNC_START_WEAK in the mem* ASM functions instead of a
combination of .weak and SYM_FUNC_START_LOCAL which makes LLVMs
integrated assembler upset
- Correct the mitigation selection logic which prevented the related
prctl to work correctly
- Make the UV5 hubless system work correctly by fixing up the
malformed table entries and adding the missing ones"
* tag 'x86-urgent-2020-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/platform/uv: Recognize UV5 hubless system identifier
x86/platform/uv: Remove spaces from OEM IDs
x86/platform/uv: Fix missing OEM_TABLE_ID
x86/speculation: Allow IBPB to be conditionally enabled on CPUs with always-on STIBP
x86/lib: Change .weak to SYM_FUNC_START_WEAK for arch/x86/lib/mem*_64.S
+54
-32
+18
-5
arch/x86/kernel/apic/x2apic_uv_x.c
+18
-5
arch/x86/kernel/apic/x2apic_uv_x.c
···
290
290
{
291
291
/* Relies on 'to' being NULL chars so result will be NULL terminated */
292
292
strncpy(to, from, len-1);
293
+
294
+
/* Trim trailing spaces */
295
+
(void)strim(to);
293
296
}
294
297
295
298
/* Find UV arch type entry in UVsystab */
···
369
366
return ret;
370
367
}
371
368
372
-
static int __init uv_set_system_type(char *_oem_id)
369
+
static int __init uv_set_system_type(char *_oem_id, char *_oem_table_id)
373
370
{
374
371
/* Save OEM_ID passed from ACPI MADT */
375
372
uv_stringify(sizeof(oem_id), oem_id, _oem_id);
···
389
386
/* (Not hubless), not a UV */
390
387
return 0;
391
388
389
+
/* Is UV hubless system */
390
+
uv_hubless_system = 0x01;
391
+
392
+
/* UV5 Hubless */
393
+
if (strncmp(uv_archtype, "NSGI5", 5) == 0)
394
+
uv_hubless_system |= 0x20;
395
+
392
396
/* UV4 Hubless: CH */
393
-
if (strncmp(uv_archtype, "NSGI4", 5) == 0)
394
-
uv_hubless_system = 0x11;
397
+
else if (strncmp(uv_archtype, "NSGI4", 5) == 0)
398
+
uv_hubless_system |= 0x10;
395
399
396
400
/* UV3 Hubless: UV300/MC990X w/o hub */
397
401
else
398
-
uv_hubless_system = 0x9;
402
+
uv_hubless_system |= 0x8;
403
+
404
+
/* Copy APIC type */
405
+
uv_stringify(sizeof(oem_table_id), oem_table_id, _oem_table_id);
399
406
400
407
pr_info("UV: OEM IDs %s/%s, SystemType %d, HUBLESS ID %x\n",
401
408
oem_id, oem_table_id, uv_system_type, uv_hubless_system);
···
469
456
uv_cpu_info->p_uv_hub_info = &uv_hub_info_node0;
470
457
471
458
/* If not UV, return. */
472
-
if (likely(uv_set_system_type(_oem_id) == 0))
459
+
if (uv_set_system_type(_oem_id, _oem_table_id) == 0)
473
460
return 0;
474
461
475
462
/* Save and Decode OEM Table ID */
+33
-18
arch/x86/kernel/cpu/bugs.c
+33
-18
arch/x86/kernel/cpu/bugs.c
···
1254
1254
return 0;
1255
1255
}
1256
1256
1257
+
static bool is_spec_ib_user_controlled(void)
1258
+
{
1259
+
return spectre_v2_user_ibpb == SPECTRE_V2_USER_PRCTL ||
1260
+
spectre_v2_user_ibpb == SPECTRE_V2_USER_SECCOMP ||
1261
+
spectre_v2_user_stibp == SPECTRE_V2_USER_PRCTL ||
1262
+
spectre_v2_user_stibp == SPECTRE_V2_USER_SECCOMP;
1263
+
}
1264
+
1257
1265
static int ib_prctl_set(struct task_struct *task, unsigned long ctrl)
1258
1266
{
1259
1267
switch (ctrl) {
···
1269
1261
if (spectre_v2_user_ibpb == SPECTRE_V2_USER_NONE &&
1270
1262
spectre_v2_user_stibp == SPECTRE_V2_USER_NONE)
1271
1263
return 0;
1264
+
1272
1265
/*
1273
-
* Indirect branch speculation is always disabled in strict
1274
-
* mode. It can neither be enabled if it was force-disabled
1275
-
* by a previous prctl call.
1266
+
* With strict mode for both IBPB and STIBP, the instruction
1267
+
* code paths avoid checking this task flag and instead,
1268
+
* unconditionally run the instruction. However, STIBP and IBPB
1269
+
* are independent and either can be set to conditionally
1270
+
* enabled regardless of the mode of the other.
1271
+
*
1272
+
* If either is set to conditional, allow the task flag to be
1273
+
* updated, unless it was force-disabled by a previous prctl
1274
+
* call. Currently, this is possible on an AMD CPU which has the
1275
+
* feature X86_FEATURE_AMD_STIBP_ALWAYS_ON. In this case, if the
1276
+
* kernel is booted with 'spectre_v2_user=seccomp', then
1277
+
* spectre_v2_user_ibpb == SPECTRE_V2_USER_SECCOMP and
1278
+
* spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED.
1276
1279
*/
1277
-
if (spectre_v2_user_ibpb == SPECTRE_V2_USER_STRICT ||
1278
-
spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT ||
1279
-
spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED ||
1280
+
if (!is_spec_ib_user_controlled() ||
1280
1281
task_spec_ib_force_disable(task))
1281
1282
return -EPERM;
1283
+
1282
1284
task_clear_spec_ib_disable(task);
1283
1285
task_update_spec_tif(task);
1284
1286
break;
···
1301
1283
if (spectre_v2_user_ibpb == SPECTRE_V2_USER_NONE &&
1302
1284
spectre_v2_user_stibp == SPECTRE_V2_USER_NONE)
1303
1285
return -EPERM;
1304
-
if (spectre_v2_user_ibpb == SPECTRE_V2_USER_STRICT ||
1305
-
spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT ||
1306
-
spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED)
1286
+
1287
+
if (!is_spec_ib_user_controlled())
1307
1288
return 0;
1289
+
1308
1290
task_set_spec_ib_disable(task);
1309
1291
if (ctrl == PR_SPEC_FORCE_DISABLE)
1310
1292
task_set_spec_ib_force_disable(task);
···
1369
1351
if (spectre_v2_user_ibpb == SPECTRE_V2_USER_NONE &&
1370
1352
spectre_v2_user_stibp == SPECTRE_V2_USER_NONE)
1371
1353
return PR_SPEC_ENABLE;
1372
-
else if (spectre_v2_user_ibpb == SPECTRE_V2_USER_STRICT ||
1373
-
spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT ||
1374
-
spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED)
1375
-
return PR_SPEC_DISABLE;
1376
-
else if (spectre_v2_user_ibpb == SPECTRE_V2_USER_PRCTL ||
1377
-
spectre_v2_user_ibpb == SPECTRE_V2_USER_SECCOMP ||
1378
-
spectre_v2_user_stibp == SPECTRE_V2_USER_PRCTL ||
1379
-
spectre_v2_user_stibp == SPECTRE_V2_USER_SECCOMP) {
1354
+
else if (is_spec_ib_user_controlled()) {
1380
1355
if (task_spec_ib_force_disable(task))
1381
1356
return PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE;
1382
1357
if (task_spec_ib_disable(task))
1383
1358
return PR_SPEC_PRCTL | PR_SPEC_DISABLE;
1384
1359
return PR_SPEC_PRCTL | PR_SPEC_ENABLE;
1385
-
} else
1360
+
} else if (spectre_v2_user_ibpb == SPECTRE_V2_USER_STRICT ||
1361
+
spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT ||
1362
+
spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED)
1363
+
return PR_SPEC_DISABLE;
1364
+
else
1386
1365
return PR_SPEC_NOT_AFFECTED;
1387
1366
}
1388
1367
+1
-3
arch/x86/lib/memcpy_64.S
+1
-3
arch/x86/lib/memcpy_64.S
···
16
16
* to a jmp to memcpy_erms which does the REP; MOVSB mem copy.
17
17
*/
18
18
19
-
.weak memcpy
20
-
21
19
/*
22
20
* memcpy - Copy a memory block.
23
21
*
···
28
30
* rax original destination
29
31
*/
30
32
SYM_FUNC_START_ALIAS(__memcpy)
31
-
SYM_FUNC_START_LOCAL(memcpy)
33
+
SYM_FUNC_START_WEAK(memcpy)
32
34
ALTERNATIVE_2 "jmp memcpy_orig", "", X86_FEATURE_REP_GOOD, \
33
35
"jmp memcpy_erms", X86_FEATURE_ERMS
34
36
+1
-3
arch/x86/lib/memmove_64.S
+1
-3
arch/x86/lib/memmove_64.S
+1
-3
arch/x86/lib/memset_64.S
+1
-3
arch/x86/lib/memset_64.S
···
6
6
#include <asm/alternative-asm.h>
7
7
#include <asm/export.h>
8
8
9
-
.weak memset
10
-
11
9
/*
12
10
* ISO C memset - set a memory block to a byte value. This function uses fast
13
11
* string to get better performance than the original function. The code is
···
17
19
*
18
20
* rax original destination
19
21
*/
20
-
SYM_FUNC_START_ALIAS(memset)
22
+
SYM_FUNC_START_WEAK(memset)
21
23
SYM_FUNC_START(__memset)
22
24
/*
23
25
* Some CPUs support enhanced REP MOVSB/STOSB feature. It is recommended