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authorLinus Torvalds <torvalds@linux-foundation.org>2020-11-08 10:09:36 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-11-08 10:09:36 -0800
commit40be821d627c61ee5beb51d265af372ab29804e4 (patch)
tree06a3212cfd92c4aa0fd5745000183c69a33afb64 /arch
parent100e38914a025a2fc797aa887efee15d812e9f83 (diff)
parent801284f9737883a2b2639bd494455a72c82fdedf (diff)
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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
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/apic/x2apic_uv_x.c23
-rw-r--r--arch/x86/kernel/cpu/bugs.c51
-rw-r--r--arch/x86/lib/memcpy_64.S4
-rw-r--r--arch/x86/lib/memmove_64.S4
-rw-r--r--arch/x86/lib/memset_64.S4
5 files changed, 54 insertions, 32 deletions
diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index 714233cee0b5..3115caa7d7d0 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -290,6 +290,9 @@ static void __init uv_stringify(int len, char *to, char *from)
{
/* Relies on 'to' being NULL chars so result will be NULL terminated */
strncpy(to, from, len-1);
+
+ /* Trim trailing spaces */
+ (void)strim(to);
}
/* Find UV arch type entry in UVsystab */
@@ -366,7 +369,7 @@ static int __init early_get_arch_type(void)
return ret;
}
-static int __init uv_set_system_type(char *_oem_id)
+static int __init uv_set_system_type(char *_oem_id, char *_oem_table_id)
{
/* Save OEM_ID passed from ACPI MADT */
uv_stringify(sizeof(oem_id), oem_id, _oem_id);
@@ -386,13 +389,23 @@ static int __init uv_set_system_type(char *_oem_id)
/* (Not hubless), not a UV */
return 0;
+ /* Is UV hubless system */
+ uv_hubless_system = 0x01;
+
+ /* UV5 Hubless */
+ if (strncmp(uv_archtype, "NSGI5", 5) == 0)
+ uv_hubless_system |= 0x20;
+
/* UV4 Hubless: CH */
- if (strncmp(uv_archtype, "NSGI4", 5) == 0)
- uv_hubless_system = 0x11;
+ else if (strncmp(uv_archtype, "NSGI4", 5) == 0)
+ uv_hubless_system |= 0x10;
/* UV3 Hubless: UV300/MC990X w/o hub */
else
- uv_hubless_system = 0x9;
+ uv_hubless_system |= 0x8;
+
+ /* Copy APIC type */
+ uv_stringify(sizeof(oem_table_id), oem_table_id, _oem_table_id);
pr_info("UV: OEM IDs %s/%s, SystemType %d, HUBLESS ID %x\n",
oem_id, oem_table_id, uv_system_type, uv_hubless_system);
@@ -456,7 +469,7 @@ static int __init uv_acpi_madt_oem_check(char *_oem_id, char *_oem_table_id)
uv_cpu_info->p_uv_hub_info = &uv_hub_info_node0;
/* If not UV, return. */
- if (likely(uv_set_system_type(_oem_id) == 0))
+ if (uv_set_system_type(_oem_id, _oem_table_id) == 0)
return 0;
/* Save and Decode OEM Table ID */
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index d3f0db463f96..581fb7223ad0 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1254,6 +1254,14 @@ static int ssb_prctl_set(struct task_struct *task, unsigned long ctrl)
return 0;
}
+static bool is_spec_ib_user_controlled(void)
+{
+ return spectre_v2_user_ibpb == SPECTRE_V2_USER_PRCTL ||
+ spectre_v2_user_ibpb == SPECTRE_V2_USER_SECCOMP ||
+ spectre_v2_user_stibp == SPECTRE_V2_USER_PRCTL ||
+ spectre_v2_user_stibp == SPECTRE_V2_USER_SECCOMP;
+}
+
static int ib_prctl_set(struct task_struct *task, unsigned long ctrl)
{
switch (ctrl) {
@@ -1261,16 +1269,26 @@ static int ib_prctl_set(struct task_struct *task, unsigned long ctrl)
if (spectre_v2_user_ibpb == SPECTRE_V2_USER_NONE &&
spectre_v2_user_stibp == SPECTRE_V2_USER_NONE)
return 0;
+
/*
- * Indirect branch speculation is always disabled in strict
- * mode. It can neither be enabled if it was force-disabled
- * by a previous prctl call.
+ * With strict mode for both IBPB and STIBP, the instruction
+ * code paths avoid checking this task flag and instead,
+ * unconditionally run the instruction. However, STIBP and IBPB
+ * are independent and either can be set to conditionally
+ * enabled regardless of the mode of the other.
+ *
+ * If either is set to conditional, allow the task flag to be
+ * updated, unless it was force-disabled by a previous prctl
+ * call. Currently, this is possible on an AMD CPU which has the
+ * feature X86_FEATURE_AMD_STIBP_ALWAYS_ON. In this case, if the
+ * kernel is booted with 'spectre_v2_user=seccomp', then
+ * spectre_v2_user_ibpb == SPECTRE_V2_USER_SECCOMP and
+ * spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED.
*/
- if (spectre_v2_user_ibpb == SPECTRE_V2_USER_STRICT ||
- spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT ||
- spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED ||
+ if (!is_spec_ib_user_controlled() ||
task_spec_ib_force_disable(task))
return -EPERM;
+
task_clear_spec_ib_disable(task);
task_update_spec_tif(task);
break;
@@ -1283,10 +1301,10 @@ static int ib_prctl_set(struct task_struct *task, unsigned long ctrl)
if (spectre_v2_user_ibpb == SPECTRE_V2_USER_NONE &&
spectre_v2_user_stibp == SPECTRE_V2_USER_NONE)
return -EPERM;
- if (spectre_v2_user_ibpb == SPECTRE_V2_USER_STRICT ||
- spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT ||
- spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED)
+
+ if (!is_spec_ib_user_controlled())
return 0;
+
task_set_spec_ib_disable(task);
if (ctrl == PR_SPEC_FORCE_DISABLE)
task_set_spec_ib_force_disable(task);
@@ -1351,20 +1369,17 @@ static int ib_prctl_get(struct task_struct *task)
if (spectre_v2_user_ibpb == SPECTRE_V2_USER_NONE &&
spectre_v2_user_stibp == SPECTRE_V2_USER_NONE)
return PR_SPEC_ENABLE;
- else if (spectre_v2_user_ibpb == SPECTRE_V2_USER_STRICT ||
- spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT ||
- spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED)
- return PR_SPEC_DISABLE;
- else if (spectre_v2_user_ibpb == SPECTRE_V2_USER_PRCTL ||
- spectre_v2_user_ibpb == SPECTRE_V2_USER_SECCOMP ||
- spectre_v2_user_stibp == SPECTRE_V2_USER_PRCTL ||
- spectre_v2_user_stibp == SPECTRE_V2_USER_SECCOMP) {
+ else if (is_spec_ib_user_controlled()) {
if (task_spec_ib_force_disable(task))
return PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE;
if (task_spec_ib_disable(task))
return PR_SPEC_PRCTL | PR_SPEC_DISABLE;
return PR_SPEC_PRCTL | PR_SPEC_ENABLE;
- } else
+ } else if (spectre_v2_user_ibpb == SPECTRE_V2_USER_STRICT ||
+ spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT ||
+ spectre_v2_user_stibp == SPECTRE_V2_USER_STRICT_PREFERRED)
+ return PR_SPEC_DISABLE;
+ else
return PR_SPEC_NOT_AFFECTED;
}
diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S
index 037faac46b0c..1e299ac73c86 100644
--- a/arch/x86/lib/memcpy_64.S
+++ b/arch/x86/lib/memcpy_64.S
@@ -16,8 +16,6 @@
* to a jmp to memcpy_erms which does the REP; MOVSB mem copy.
*/
-.weak memcpy
-
/*
* memcpy - Copy a memory block.
*
@@ -30,7 +28,7 @@
* rax original destination
*/
SYM_FUNC_START_ALIAS(__memcpy)
-SYM_FUNC_START_LOCAL(memcpy)
+SYM_FUNC_START_WEAK(memcpy)
ALTERNATIVE_2 "jmp memcpy_orig", "", X86_FEATURE_REP_GOOD, \
"jmp memcpy_erms", X86_FEATURE_ERMS
diff --git a/arch/x86/lib/memmove_64.S b/arch/x86/lib/memmove_64.S
index 7ff00ea64e4f..41902fe8b859 100644
--- a/arch/x86/lib/memmove_64.S
+++ b/arch/x86/lib/memmove_64.S
@@ -24,9 +24,7 @@
* Output:
* rax: dest
*/
-.weak memmove
-
-SYM_FUNC_START_ALIAS(memmove)
+SYM_FUNC_START_WEAK(memmove)
SYM_FUNC_START(__memmove)
mov %rdi, %rax
diff --git a/arch/x86/lib/memset_64.S b/arch/x86/lib/memset_64.S
index 9ff15ee404a4..0bfd26e4ca9e 100644
--- a/arch/x86/lib/memset_64.S
+++ b/arch/x86/lib/memset_64.S
@@ -6,8 +6,6 @@
#include <asm/alternative-asm.h>
#include <asm/export.h>
-.weak memset
-
/*
* ISO C memset - set a memory block to a byte value. This function uses fast
* string to get better performance than the original function. The code is
@@ -19,7 +17,7 @@
*
* rax original destination
*/
-SYM_FUNC_START_ALIAS(memset)
+SYM_FUNC_START_WEAK(memset)
SYM_FUNC_START(__memset)
/*
* Some CPUs support enhanced REP MOVSB/STOSB feature. It is recommended