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-rw-r--r--arch/arm/include/asm/assembler.h10
-rw-r--r--arch/arm/include/asm/spectre.h32
-rw-r--r--arch/arm/include/asm/vmlinux.lds.h35
-rw-r--r--arch/arm/kernel/Makefile2
-rw-r--r--arch/arm/kernel/entry-armv.S79
-rw-r--r--arch/arm/kernel/entry-common.S24
-rw-r--r--arch/arm/kernel/spectre.c71
-rw-r--r--arch/arm/kernel/traps.c65
-rw-r--r--arch/arm/mm/Kconfig11
-rw-r--r--arch/arm/mm/proc-v7-bugs.c207
10 files changed, 481 insertions, 55 deletions
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index 6fe67963ba5a..b50cc0169d5c 100644
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -107,6 +107,16 @@
.endm
#endif
+#if __LINUX_ARM_ARCH__ < 7
+ .macro dsb, args
+ mcr p15, 0, r0, c7, c10, 4
+ .endm
+
+ .macro isb, args
+ mcr p15, 0, r0, c7, r5, 4
+ .endm
+#endif
+
.macro asm_trace_hardirqs_off, save=1
#if defined(CONFIG_TRACE_IRQFLAGS)
.if \save
diff --git a/arch/arm/include/asm/spectre.h b/arch/arm/include/asm/spectre.h
new file mode 100644
index 000000000000..d1fa5607d3aa
--- /dev/null
+++ b/arch/arm/include/asm/spectre.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __ASM_SPECTRE_H
+#define __ASM_SPECTRE_H
+
+enum {
+ SPECTRE_UNAFFECTED,
+ SPECTRE_MITIGATED,
+ SPECTRE_VULNERABLE,
+};
+
+enum {
+ __SPECTRE_V2_METHOD_BPIALL,
+ __SPECTRE_V2_METHOD_ICIALLU,
+ __SPECTRE_V2_METHOD_SMC,
+ __SPECTRE_V2_METHOD_HVC,
+ __SPECTRE_V2_METHOD_LOOP8,
+};
+
+enum {
+ SPECTRE_V2_METHOD_BPIALL = BIT(__SPECTRE_V2_METHOD_BPIALL),
+ SPECTRE_V2_METHOD_ICIALLU = BIT(__SPECTRE_V2_METHOD_ICIALLU),
+ SPECTRE_V2_METHOD_SMC = BIT(__SPECTRE_V2_METHOD_SMC),
+ SPECTRE_V2_METHOD_HVC = BIT(__SPECTRE_V2_METHOD_HVC),
+ SPECTRE_V2_METHOD_LOOP8 = BIT(__SPECTRE_V2_METHOD_LOOP8),
+};
+
+void spectre_v2_update_state(unsigned int state, unsigned int methods);
+
+int spectre_bhb_update_vectors(unsigned int method);
+
+#endif
diff --git a/arch/arm/include/asm/vmlinux.lds.h b/arch/arm/include/asm/vmlinux.lds.h
index 4a91428c324d..0ef21bfae9f6 100644
--- a/arch/arm/include/asm/vmlinux.lds.h
+++ b/arch/arm/include/asm/vmlinux.lds.h
@@ -26,6 +26,11 @@
#define ARM_MMU_DISCARD(x) x
#endif
+/* Set start/end symbol names to the LMA for the section */
+#define ARM_LMA(sym, section) \
+ sym##_start = LOADADDR(section); \
+ sym##_end = LOADADDR(section) + SIZEOF(section)
+
#define PROC_INFO \
. = ALIGN(4); \
__proc_info_begin = .; \
@@ -110,19 +115,31 @@
* only thing that matters is their relative offsets
*/
#define ARM_VECTORS \
- __vectors_start = .; \
- .vectors 0xffff0000 : AT(__vectors_start) { \
- *(.vectors) \
+ __vectors_lma = .; \
+ OVERLAY 0xffff0000 : NOCROSSREFS AT(__vectors_lma) { \
+ .vectors { \
+ *(.vectors) \
+ } \
+ .vectors.bhb.loop8 { \
+ *(.vectors.bhb.loop8) \
+ } \
+ .vectors.bhb.bpiall { \
+ *(.vectors.bhb.bpiall) \
+ } \
} \
- . = __vectors_start + SIZEOF(.vectors); \
- __vectors_end = .; \
+ ARM_LMA(__vectors, .vectors); \
+ ARM_LMA(__vectors_bhb_loop8, .vectors.bhb.loop8); \
+ ARM_LMA(__vectors_bhb_bpiall, .vectors.bhb.bpiall); \
+ . = __vectors_lma + SIZEOF(.vectors) + \
+ SIZEOF(.vectors.bhb.loop8) + \
+ SIZEOF(.vectors.bhb.bpiall); \
\
- __stubs_start = .; \
- .stubs ADDR(.vectors) + 0x1000 : AT(__stubs_start) { \
+ __stubs_lma = .; \
+ .stubs ADDR(.vectors) + 0x1000 : AT(__stubs_lma) { \
*(.stubs) \
} \
- . = __stubs_start + SIZEOF(.stubs); \
- __stubs_end = .; \
+ ARM_LMA(__stubs, .stubs); \
+ . = __stubs_lma + SIZEOF(.stubs); \
\
PROVIDE(vector_fiq_offset = vector_fiq - ADDR(.vectors));
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index ae295a3bcfef..6ef3b535b7bf 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -106,4 +106,6 @@ endif
obj-$(CONFIG_HAVE_ARM_SMCCC) += smccc-call.o
+obj-$(CONFIG_GENERIC_CPU_VULNERABILITIES) += spectre.o
+
extra-y := $(head-y) vmlinux.lds
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 5cd057859fe9..676703cbfe4b 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -1002,12 +1002,11 @@ vector_\name:
sub lr, lr, #\correction
.endif
- @
- @ Save r0, lr_<exception> (parent PC) and spsr_<exception>
- @ (parent CPSR)
- @
+ @ Save r0, lr_<exception> (parent PC)
stmia sp, {r0, lr} @ save r0, lr
- mrs lr, spsr
+
+ @ Save spsr_<exception> (parent CPSR)
+2: mrs lr, spsr
str lr, [sp, #8] @ save spsr
@
@@ -1028,6 +1027,44 @@ vector_\name:
movs pc, lr @ branch to handler in SVC mode
ENDPROC(vector_\name)
+#ifdef CONFIG_HARDEN_BRANCH_HISTORY
+ .subsection 1
+ .align 5
+vector_bhb_loop8_\name:
+ .if \correction
+ sub lr, lr, #\correction
+ .endif
+
+ @ Save r0, lr_<exception> (parent PC)
+ stmia sp, {r0, lr}
+
+ @ bhb workaround
+ mov r0, #8
+1: b . + 4
+ subs r0, r0, #1
+ bne 1b
+ dsb
+ isb
+ b 2b
+ENDPROC(vector_bhb_loop8_\name)
+
+vector_bhb_bpiall_\name:
+ .if \correction
+ sub lr, lr, #\correction
+ .endif
+
+ @ Save r0, lr_<exception> (parent PC)
+ stmia sp, {r0, lr}
+
+ @ bhb workaround
+ mcr p15, 0, r0, c7, c5, 6 @ BPIALL
+ @ isb not needed due to "movs pc, lr" in the vector stub
+ @ which gives a "context synchronisation".
+ b 2b
+ENDPROC(vector_bhb_bpiall_\name)
+ .previous
+#endif
+
.align 2
@ handler addresses follow this label
1:
@@ -1036,6 +1073,10 @@ ENDPROC(vector_\name)
.section .stubs, "ax", %progbits
@ This must be the first word
.word vector_swi
+#ifdef CONFIG_HARDEN_BRANCH_HISTORY
+ .word vector_bhb_loop8_swi
+ .word vector_bhb_bpiall_swi
+#endif
vector_rst:
ARM( swi SYS_ERROR0 )
@@ -1150,8 +1191,10 @@ vector_addrexcptn:
* FIQ "NMI" handler
*-----------------------------------------------------------------------------
* Handle a FIQ using the SVC stack allowing FIQ act like NMI on x86
- * systems.
+ * systems. This must be the last vector stub, so lets place it in its own
+ * subsection.
*/
+ .subsection 2
vector_stub fiq, FIQ_MODE, 4
.long __fiq_usr @ 0 (USR_26 / USR_32)
@@ -1184,6 +1227,30 @@ vector_addrexcptn:
W(b) vector_irq
W(b) vector_fiq
+#ifdef CONFIG_HARDEN_BRANCH_HISTORY
+ .section .vectors.bhb.loop8, "ax", %progbits
+.L__vectors_bhb_loop8_start:
+ W(b) vector_rst
+ W(b) vector_bhb_loop8_und
+ W(ldr) pc, .L__vectors_bhb_loop8_start + 0x1004
+ W(b) vector_bhb_loop8_pabt
+ W(b) vector_bhb_loop8_dabt
+ W(b) vector_addrexcptn
+ W(b) vector_bhb_loop8_irq
+ W(b) vector_bhb_loop8_fiq
+
+ .section .vectors.bhb.bpiall, "ax", %progbits
+.L__vectors_bhb_bpiall_start:
+ W(b) vector_rst
+ W(b) vector_bhb_bpiall_und
+ W(ldr) pc, .L__vectors_bhb_bpiall_start + 0x1008
+ W(b) vector_bhb_bpiall_pabt
+ W(b) vector_bhb_bpiall_dabt
+ W(b) vector_addrexcptn
+ W(b) vector_bhb_bpiall_irq
+ W(b) vector_bhb_bpiall_fiq
+#endif
+
.data
.align 2
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index ac86c34682bb..dbc1913ee30b 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -154,12 +154,36 @@ ENDPROC(ret_from_fork)
*/
.align 5
+#ifdef CONFIG_HARDEN_BRANCH_HISTORY
+ENTRY(vector_bhb_loop8_swi)
+ sub sp, sp, #PT_REGS_SIZE
+ stmia sp, {r0 - r12}
+ mov r8, #8
+1: b 2f
+2: subs r8, r8, #1
+ bne 1b
+ dsb
+ isb
+ b 3f
+ENDPROC(vector_bhb_loop8_swi)
+
+ .align 5
+ENTRY(vector_bhb_bpiall_swi)
+ sub sp, sp, #PT_REGS_SIZE
+ stmia sp, {r0 - r12}
+ mcr p15, 0, r8, c7, c5, 6 @ BPIALL
+ isb
+ b 3f
+ENDPROC(vector_bhb_bpiall_swi)
+#endif
+ .align 5
ENTRY(vector_swi)
#ifdef CONFIG_CPU_V7M
v7m_exception_entry
#else
sub sp, sp, #PT_REGS_SIZE
stmia sp, {r0 - r12} @ Calling r0 - r12
+3:
ARM( add r8, sp, #S_PC )
ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
THUMB( mov r8, sp )
diff --git a/arch/arm/kernel/spectre.c b/arch/arm/kernel/spectre.c
new file mode 100644
index 000000000000..e7fea962d632
--- /dev/null
+++ b/arch/arm/kernel/spectre.c
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/bpf.h>
+#include <linux/cpu.h>
+#include <linux/device.h>
+
+#include <asm/spectre.h>
+
+static bool _unprivileged_ebpf_enabled(void)
+{
+#ifdef CONFIG_BPF_SYSCALL
+ return !sysctl_unprivileged_bpf_disabled;
+#else
+ return false
+#endif
+}
+
+ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "Mitigation: __user pointer sanitization\n");
+}
+
+static unsigned int spectre_v2_state;
+static unsigned int spectre_v2_methods;
+
+void spectre_v2_update_state(unsigned int state, unsigned int method)
+{
+ if (state > spectre_v2_state)
+ spectre_v2_state = state;
+ spectre_v2_methods |= method;
+}
+
+ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ const char *method;
+
+ if (spectre_v2_state == SPECTRE_UNAFFECTED)
+ return sprintf(buf, "%s\n", "Not affected");
+
+ if (spectre_v2_state != SPECTRE_MITIGATED)
+ return sprintf(buf, "%s\n", "Vulnerable");
+
+ if (_unprivileged_ebpf_enabled())
+ return sprintf(buf, "Vulnerable: Unprivileged eBPF enabled\n");
+
+ switch (spectre_v2_methods) {
+ case SPECTRE_V2_METHOD_BPIALL:
+ method = "Branch predictor hardening";
+ break;
+
+ case SPECTRE_V2_METHOD_ICIALLU:
+ method = "I-cache invalidation";
+ break;
+
+ case SPECTRE_V2_METHOD_SMC:
+ case SPECTRE_V2_METHOD_HVC:
+ method = "Firmware call";
+ break;
+
+ case SPECTRE_V2_METHOD_LOOP8:
+ method = "History overwrite";
+ break;
+
+ default:
+ method = "Multiple mitigations";
+ break;
+ }
+
+ return sprintf(buf, "Mitigation: %s\n", method);
+}
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index da04ed85855a..cae4a748811f 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -30,6 +30,7 @@
#include <linux/atomic.h>
#include <asm/cacheflush.h>
#include <asm/exception.h>
+#include <asm/spectre.h>
#include <asm/unistd.h>
#include <asm/traps.h>
#include <asm/ptrace.h>
@@ -789,10 +790,59 @@ static inline void __init kuser_init(void *vectors)
}
#endif
+#ifndef CONFIG_CPU_V7M
+static void copy_from_lma(void *vma, void *lma_start, void *lma_end)
+{
+ memcpy(vma, lma_start, lma_end - lma_start);
+}
+
+static void flush_vectors(void *vma, size_t offset, size_t size)
+{
+ unsigned long start = (unsigned long)vma + offset;
+ unsigned long end = start + size;
+
+ flush_icache_range(start, end);
+}
+
+#ifdef CONFIG_HARDEN_BRANCH_HISTORY
+int spectre_bhb_update_vectors(unsigned int method)
+{
+ extern char __vectors_bhb_bpiall_start[], __vectors_bhb_bpiall_end[];
+ extern char __vectors_bhb_loop8_start[], __vectors_bhb_loop8_end[];
+ void *vec_start, *vec_end;
+
+ if (system_state >= SYSTEM_FREEING_INITMEM) {
+ pr_err("CPU%u: Spectre BHB workaround too late - system vulnerable\n",
+ smp_processor_id());
+ return SPECTRE_VULNERABLE;
+ }
+
+ switch (method) {
+ case SPECTRE_V2_METHOD_LOOP8:
+ vec_start = __vectors_bhb_loop8_start;
+ vec_end = __vectors_bhb_loop8_end;
+ break;
+
+ case SPECTRE_V2_METHOD_BPIALL:
+ vec_start = __vectors_bhb_bpiall_start;
+ vec_end = __vectors_bhb_bpiall_end;
+ break;
+
+ default:
+ pr_err("CPU%u: unknown Spectre BHB state %d\n",
+ smp_processor_id(), method);
+ return SPECTRE_VULNERABLE;
+ }
+
+ copy_from_lma(vectors_page, vec_start, vec_end);
+ flush_vectors(vectors_page, 0, vec_end - vec_start);
+
+ return SPECTRE_MITIGATED;
+}
+#endif
+
void __init early_trap_init(void *vectors_base)
{
-#ifndef CONFIG_CPU_V7M
- unsigned long vectors = (unsigned long)vectors_base;
extern char __stubs_start[], __stubs_end[];
extern char __vectors_start[], __vectors_end[];
unsigned i;
@@ -813,17 +863,20 @@ void __init early_trap_init(void *vectors_base)
* into the vector page, mapped at 0xffff0000, and ensure these
* are visible to the instruction stream.
*/
- memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);
- memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);
+ copy_from_lma(vectors_base, __vectors_start, __vectors_end);
+ copy_from_lma(vectors_base + 0x1000, __stubs_start, __stubs_end);
kuser_init(vectors_base);
- flush_icache_range(vectors, vectors + PAGE_SIZE * 2);
+ flush_vectors(vectors_base, 0, PAGE_SIZE * 2);
+}
#else /* ifndef CONFIG_CPU_V7M */
+void __init early_trap_init(void *vectors_base)
+{
/*
* on V7-M there is no need to copy the vector table to a dedicated
* memory area. The address is configurable and so a table in the kernel
* image can be used.
*/
-#endif
}
+#endif
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index 58afba346729..9724c16e9076 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -830,6 +830,7 @@ config CPU_BPREDICT_DISABLE
config CPU_SPECTRE
bool
+ select GENERIC_CPU_VULNERABILITIES
config HARDEN_BRANCH_PREDICTOR
bool "Harden the branch predictor against aliasing attacks" if EXPERT
@@ -850,6 +851,16 @@ config HARDEN_BRANCH_PREDICTOR
If unsure, say Y.
+config HARDEN_BRANCH_HISTORY
+ bool "Harden Spectre style attacks against branch history" if EXPERT
+ depends on CPU_SPECTRE
+ default y
+ help
+ Speculation attacks against some high-performance processors can
+ make use of branch history to influence future speculation. When
+ taking an exception, a sequence of branches overwrites the branch
+ history, or branch history is invalidated.
+
config TLS_REG_EMUL
bool
select NEED_KUSER_HELPERS
diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c
index 114c05ab4dd9..c226feab2457 100644
--- a/arch/arm/mm/proc-v7-bugs.c
+++ b/arch/arm/mm/proc-v7-bugs.c
@@ -6,8 +6,35 @@
#include <asm/cp15.h>
#include <asm/cputype.h>
#include <asm/proc-fns.h>
+#include <asm/spectre.h>
#include <asm/system_misc.h>
+#ifdef CONFIG_ARM_PSCI
+static int __maybe_unused spectre_v2_get_cpu_fw_mitigation_state(void)
+{
+ struct arm_smccc_res res;
+
+ arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
+ ARM_SMCCC_ARCH_WORKAROUND_1, &res);
+
+ switch ((int)res.a0) {
+ case SMCCC_RET_SUCCESS:
+ return SPECTRE_MITIGATED;
+
+ case SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED:
+ return SPECTRE_UNAFFECTED;
+
+ default:
+ return SPECTRE_VULNERABLE;
+ }
+}
+#else
+static int __maybe_unused spectre_v2_get_cpu_fw_mitigation_state(void)
+{
+ return SPECTRE_VULNERABLE;
+}
+#endif
+
#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
DEFINE_PER_CPU(harden_branch_predictor_fn_t, harden_branch_predictor_fn);
@@ -36,13 +63,60 @@ static void __maybe_unused call_hvc_arch_workaround_1(void)
arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL);
}
-static void cpu_v7_spectre_init(void)
+static unsigned int spectre_v2_install_workaround(unsigned int method)
{
const char *spectre_v2_method = NULL;
int cpu = smp_processor_id();
if (per_cpu(harden_branch_predictor_fn, cpu))
- return;
+ return SPECTRE_MITIGATED;
+
+ switch (method) {
+ case SPECTRE_V2_METHOD_BPIALL:
+ per_cpu(harden_branch_predictor_fn, cpu) =
+ harden_branch_predictor_bpiall;
+ spectre_v2_method = "BPIALL";
+ break;
+
+ case SPECTRE_V2_METHOD_ICIALLU:
+ per_cpu(harden_branch_predictor_fn, cpu) =
+ harden_branch_predictor_iciallu;
+ spectre_v2_method = "ICIALLU";
+ break;
+
+ case SPECTRE_V2_METHOD_HVC:
+ per_cpu(harden_branch_predictor_fn, cpu) =
+ call_hvc_arch_workaround_1;
+ cpu_do_switch_mm = cpu_v7_hvc_switch_mm;
+ spectre_v2_method = "hypervisor";
+ break;
+
+ case SPECTRE_V2_METHOD_SMC:
+ per_cpu(harden_branch_predictor_fn, cpu) =
+ call_smc_arch_workaround_1;
+ cpu_do_switch_mm = cpu_v7_smc_switch_mm;
+ spectre_v2_method = "firmware";
+ break;
+ }
+
+ if (spectre_v2_method)
+ pr_info("CPU%u: Spectre v2: using %s workaround\n",
+ smp_processor_id(), spectre_v2_method);
+
+ return SPECTRE_MITIGATED;
+}
+#else
+static unsigned int spectre_v2_install_workaround(unsigned int method)
+{
+ pr_info("CPU%u: Spectre V2: workarounds disabled by configuration\n");
+
+ return SPECTRE_VULNERABLE;
+}
+#endif
+
+static void cpu_v7_spectre_v2_init(void)
+{
+ unsigned int state, method = 0;
switch (read_cpuid_part()) {
case ARM_CPU_PART_CORTEX_A8:
@@ -51,69 +125,133 @@ static void cpu_v7_spectre_init(void)
case ARM_CPU_PART_CORTEX_A17:
case ARM_CPU_PART_CORTEX_A73:
case ARM_CPU_PART_CORTEX_A75:
- per_cpu(harden_branch_predictor_fn, cpu) =
- harden_branch_predictor_bpiall;
- spectre_v2_method = "BPIALL";
+ state = SPECTRE_MITIGATED;
+ method = SPECTRE_V2_METHOD_BPIALL;
break;
case ARM_CPU_PART_CORTEX_A15:
case ARM_CPU_PART_BRAHMA_B15:
- per_cpu(harden_branch_predictor_fn, cpu) =
- harden_branch_predictor_iciallu;
- spectre_v2_method = "ICIALLU";
+ state = SPECTRE_MITIGATED;
+ method = SPECTRE_V2_METHOD_ICIALLU;
break;
-#ifdef CONFIG_ARM_PSCI
case ARM_CPU_PART_BRAHMA_B53:
/* Requires no workaround */
+ state = SPECTRE_UNAFFECTED;
break;
+
default:
/* Other ARM CPUs require no workaround */
- if (read_cpuid_implementor() == ARM_CPU_IMP_ARM)
+ if (read_cpuid_implementor() == ARM_CPU_IMP_ARM) {
+ state = SPECTRE_UNAFFECTED;
break;
+ }
+
fallthrough;
- /* Cortex A57/A72 require firmware workaround */
- case ARM_CPU_PART_CORTEX_A57:
- case ARM_CPU_PART_CORTEX_A72: {
- struct arm_smccc_res res;
- arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
- ARM_SMCCC_ARCH_WORKAROUND_1, &res);
- if ((int)res.a0 != 0)
- return;
+ /* Cortex A57/A72 require firmware workaround */
+ case ARM_CPU_PART_CORTEX_A57:
+ case ARM_CPU_PART_CORTEX_A72:
+ state = spectre_v2_get_cpu_fw_mitigation_state();
+ if (state != SPECTRE_MITIGATED)
+ break;
switch (arm_smccc_1_1_get_conduit()) {
case SMCCC_CONDUIT_HVC:
- per_cpu(harden_branch_predictor_fn, cpu) =
- call_hvc_arch_workaround_1;
- cpu_do_switch_mm = cpu_v7_hvc_switch_mm;
- spectre_v2_method = "hypervisor";
+ method = SPECTRE_V2_METHOD_HVC;
break;
case SMCCC_CONDUIT_SMC:
- per_cpu(harden_branch_predictor_fn, cpu) =
- call_smc_arch_workaround_1;
- cpu_do_switch_mm = cpu_v7_smc_switch_mm;
- spectre_v2_method = "firmware";
+ method = SPECTRE_V2_METHOD_SMC;
break;
default:
+ state = SPECTRE_VULNERABLE;
break;
}
}
-#endif
+
+ if (state == SPECTRE_MITIGATED)
+ state = spectre_v2_install_workaround(method);
+
+ spectre_v2_update_state(state, method);
+}
+
+#ifdef CONFIG_HARDEN_BRANCH_HISTORY
+static int spectre_bhb_method;
+
+static const char *spectre_bhb_method_name(int method)
+{
+ switch (method) {
+ case SPECTRE_V2_METHOD_LOOP8:
+ return "loop";
+
+ case SPECTRE_V2_METHOD_BPIALL:
+ return "BPIALL";
+
+ default:
+ return "unknown";
}
+}
- if (spectre_v2_method)
- pr_info("CPU%u: Spectre v2: using %s workaround\n",
- smp_processor_id(), spectre_v2_method);
+static int spectre_bhb_install_workaround(int method)
+{
+ if (spectre_bhb_method != method) {
+ if (spectre_bhb_method) {
+ pr_err("CPU%u: Spectre BHB: method disagreement, system vulnerable\n",
+ smp_processor_id());
+
+ return SPECTRE_VULNERABLE;
+ }
+
+ if (spectre_bhb_update_vectors(method) == SPECTRE_VULNERABLE)
+ return SPECTRE_VULNERABLE;
+
+ spectre_bhb_method = method;
+ }
+
+ pr_info("CPU%u: Spectre BHB: using %s workaround\n",
+ smp_processor_id(), spectre_bhb_method_name(method));
+
+ return SPECTRE_MITIGATED;
}
#else
-static void cpu_v7_spectre_init(void)
+static int spectre_bhb_install_workaround(int method)
{
+ return SPECTRE_VULNERABLE;
}
#endif
+static void cpu_v7_spectre_bhb_init(void)
+{
+ unsigned int state, method = 0;
+
+ switch (read_cpuid_part()) {
+ case ARM_CPU_PART_CORTEX_A15:
+ case ARM_CPU_PART_BRAHMA_B15:
+ case ARM_CPU_PART_CORTEX_A57:
+ case ARM_CPU_PART_CORTEX_A72:
+ state = SPECTRE_MITIGATED;
+ method = SPECTRE_V2_METHOD_LOOP8;
+ break;
+
+ case ARM_CPU_PART_CORTEX_A73:
+ case ARM_CPU_PART_CORTEX_A75:
+ state = SPECTRE_MITIGATED;
+ method = SPECTRE_V2_METHOD_BPIALL;
+ break;
+
+ default:
+ state = SPECTRE_UNAFFECTED;
+ break;
+ }
+
+ if (state == SPECTRE_MITIGATED)
+ state = spectre_bhb_install_workaround(method);
+
+ spectre_v2_update_state(state, method);
+}
+
static __maybe_unused bool cpu_v7_check_auxcr_set(bool *warned,
u32 mask, const char *msg)
{
@@ -142,16 +280,17 @@ static bool check_spectre_auxcr(bool *warned, u32 bit)
void cpu_v7_ca8_ibe(void)
{
if (check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(6)))
- cpu_v7_spectre_init();
+ cpu_v7_spectre_v2_init();
}
void cpu_v7_ca15_ibe(void)
{
if (check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(0)))
- cpu_v7_spectre_init();
+ cpu_v7_spectre_v2_init();
}
void cpu_v7_bugs_init(void)
{
- cpu_v7_spectre_init();
+ cpu_v7_spectre_v2_init();
+ cpu_v7_spectre_bhb_init();
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-01 18:51:05 +0000