@@ -65,6 +65,9 @@
#define __write_sysreg(v, r, w, c, t) asm volatile(w " " c : : "r" ((t)(v)))
#define write_sysreg(v, ...) __write_sysreg(v, __VA_ARGS__)
+#define BPIALL __ACCESS_CP15(c7, 0, c5, 6)
+#define ICIALLU __ACCESS_CP15(c7, 0, c5, 0)
+
extern unsigned long cr_alignment; /* defined in entry-armv.S */
static inline unsigned long get_cr(void)
@@ -8,6 +8,7 @@
#include <linux/linkage.h>
#include <linux/irqflags.h>
#include <linux/reboot.h>
+#include <linux/percpu.h>
extern void cpu_init(void);
@@ -15,6 +16,20 @@ void soft_restart(unsigned long);
extern void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
extern void (*arm_pm_idle)(void);
+#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
+typedef void (*harden_branch_predictor_fn_t)(void);
+DECLARE_PER_CPU(harden_branch_predictor_fn_t, harden_branch_predictor_fn);
+static inline void harden_branch_predictor(void)
+{
+ harden_branch_predictor_fn_t fn = per_cpu(harden_branch_predictor_fn,
+ smp_processor_id());
+ if (fn)
+ fn();
+}
+#else
+#define harden_branch_predictor() do { } while (0)
+#endif
+
#define UDBG_UNDEFINED (1 << 0)
#define UDBG_SYSCALL (1 << 1)
#define UDBG_BADABORT (1 << 2)
@@ -164,6 +164,9 @@ __do_user_fault(struct task_struct *tsk, unsigned long addr,
{
struct siginfo si;
+ if (addr > TASK_SIZE)
+ harden_branch_predictor();
+
#ifdef CONFIG_DEBUG_USER
if (((user_debug & UDBG_SEGV) && (sig == SIGSEGV)) ||
((user_debug & UDBG_BUS) && (sig == SIGBUS))) {
@@ -2,7 +2,61 @@
#include <linux/kernel.h>
#include <linux/smp.h>
-static __maybe_unused void cpu_v7_check_auxcr_set(bool *warned,
+#include <asm/cp15.h>
+#include <asm/cputype.h>
+#include <asm/system_misc.h>
+
+#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
+DEFINE_PER_CPU(harden_branch_predictor_fn_t, harden_branch_predictor_fn);
+
+static void harden_branch_predictor_bpiall(void)
+{
+ write_sysreg(0, BPIALL);
+}
+
+static void harden_branch_predictor_iciallu(void)
+{
+ write_sysreg(0, ICIALLU);
+}
+
+static void cpu_v7_spectre_init(void)
+{
+ const char *spectre_v2_method = NULL;
+ int cpu = smp_processor_id();
+
+ if (per_cpu(harden_branch_predictor_fn, cpu))
+ return;
+
+ switch (read_cpuid_part()) {
+ case ARM_CPU_PART_CORTEX_A8:
+ case ARM_CPU_PART_CORTEX_A9:
+ case ARM_CPU_PART_CORTEX_A12:
+ 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";
+ 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";
+ break;
+ }
+ if (spectre_v2_method)
+ pr_info("CPU%u: Spectre v2: using %s workaround\n",
+ smp_processor_id(), spectre_v2_method);
+}
+#else
+static void cpu_v7_spectre_init(void)
+{
+}
+#endif
+
+static __maybe_unused bool cpu_v7_check_auxcr_set(bool *warned,
u32 mask, const char *msg)
{
u32 aux_cr;
@@ -13,24 +67,33 @@ static __maybe_unused void cpu_v7_check_auxcr_set(bool *warned,
if (!*warned)
pr_err("CPU%u: %s", smp_processor_id(), msg);
*warned = true;
+ return false;
}
+ return true;
}
static DEFINE_PER_CPU(bool, spectre_warned);
-static void check_spectre_auxcr(bool *warned, u32 bit)
+static bool check_spectre_auxcr(bool *warned, u32 bit)
{
- if (IS_ENABLED(CONFIG_HARDEN_BRANCH_PREDICTOR) &&
+ return IS_ENABLED(CONFIG_HARDEN_BRANCH_PREDICTOR) &&
cpu_v7_check_auxcr_set(warned, bit,
"Spectre v2: firmware did not set auxiliary control register IBE bit, system vulnerable\n");
}
void cpu_v7_ca8_ibe(void)
{
- check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(6));
+ if (check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(6)))
+ cpu_v7_spectre_init();
}
void cpu_v7_ca15_ibe(void)
{
- check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(0));
+ if (check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(0)))
+ cpu_v7_spectre_init();
+}
+
+void cpu_v7_bugs_init(void)
+{
+ cpu_v7_spectre_init();
}
@@ -532,8 +532,10 @@ __v7_setup_stack:
__INITDATA
+ .weak cpu_v7_bugs_init
+
@ define struct processor (see <asm/proc-fns.h> and proc-macros.S)
- define_processor_functions v7, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
+ define_processor_functions v7, dabort=v7_early_abort, pabort=v7_pabort, suspend=1, bugs=cpu_v7_bugs_init
#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
@ generic v7 bpiall on context switch
@@ -548,7 +550,7 @@ __v7_setup_stack:
globl_equ cpu_v7_bpiall_do_suspend, cpu_v7_do_suspend
globl_equ cpu_v7_bpiall_do_resume, cpu_v7_do_resume
#endif
- define_processor_functions v7_bpiall, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
+ define_processor_functions v7_bpiall, dabort=v7_early_abort, pabort=v7_pabort, suspend=1, bugs=cpu_v7_bugs_init
#define HARDENED_BPIALL_PROCESSOR_FUNCTIONS v7_bpiall_processor_functions
#else
@@ -584,7 +586,7 @@ __v7_setup_stack:
globl_equ cpu_ca9mp_switch_mm, cpu_v7_switch_mm
#endif
globl_equ cpu_ca9mp_set_pte_ext, cpu_v7_set_pte_ext
- define_processor_functions ca9mp, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
+ define_processor_functions ca9mp, dabort=v7_early_abort, pabort=v7_pabort, suspend=1, bugs=cpu_v7_bugs_init
#endif
@ Cortex-A15 - needs iciallu switch_mm for hardening