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Diffstat (limited to 'arch/arm64/kernel/process.c')
-rw-r--r--arch/arm64/kernel/process.c84
1 files changed, 43 insertions, 41 deletions
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index aacf2f5559a8..5369e649fa79 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -40,6 +40,7 @@
#include <linux/percpu.h>
#include <linux/thread_info.h>
#include <linux/prctl.h>
+#include <linux/stacktrace.h>
#include <asm/alternative.h>
#include <asm/compat.h>
@@ -439,34 +440,26 @@ static void entry_task_switch(struct task_struct *next)
/*
* ARM erratum 1418040 handling, affecting the 32bit view of CNTVCT.
- * Assuming the virtual counter is enabled at the beginning of times:
- *
- * - disable access when switching from a 64bit task to a 32bit task
- * - enable access when switching from a 32bit task to a 64bit task
+ * Ensure access is disabled when switching to a 32bit task, ensure
+ * access is enabled when switching to a 64bit task.
*/
-static void erratum_1418040_thread_switch(struct task_struct *prev,
- struct task_struct *next)
+static void erratum_1418040_thread_switch(struct task_struct *next)
{
- bool prev32, next32;
- u64 val;
-
- if (!IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040))
- return;
-
- prev32 = is_compat_thread(task_thread_info(prev));
- next32 = is_compat_thread(task_thread_info(next));
-
- if (prev32 == next32 || !this_cpu_has_cap(ARM64_WORKAROUND_1418040))
+ if (!IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040) ||
+ !this_cpu_has_cap(ARM64_WORKAROUND_1418040))
return;
- val = read_sysreg(cntkctl_el1);
-
- if (!next32)
- val |= ARCH_TIMER_USR_VCT_ACCESS_EN;
+ if (is_compat_thread(task_thread_info(next)))
+ sysreg_clear_set(cntkctl_el1, ARCH_TIMER_USR_VCT_ACCESS_EN, 0);
else
- val &= ~ARCH_TIMER_USR_VCT_ACCESS_EN;
+ sysreg_clear_set(cntkctl_el1, 0, ARCH_TIMER_USR_VCT_ACCESS_EN);
+}
- write_sysreg(val, cntkctl_el1);
+static void erratum_1418040_new_exec(void)
+{
+ preempt_disable();
+ erratum_1418040_thread_switch(current);
+ preempt_enable();
}
/*
@@ -490,7 +483,8 @@ void update_sctlr_el1(u64 sctlr)
/*
* Thread switching.
*/
-__notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
+__notrace_funcgraph __sched
+struct task_struct *__switch_to(struct task_struct *prev,
struct task_struct *next)
{
struct task_struct *last;
@@ -501,7 +495,7 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
contextidr_thread_switch(next);
entry_task_switch(next);
ssbs_thread_switch(next);
- erratum_1418040_thread_switch(prev, next);
+ erratum_1418040_thread_switch(next);
ptrauth_thread_switch_user(next);
/*
@@ -528,30 +522,37 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
return last;
}
+struct wchan_info {
+ unsigned long pc;
+ int count;
+};
+
+static bool get_wchan_cb(void *arg, unsigned long pc)
+{
+ struct wchan_info *wchan_info = arg;
+
+ if (!in_sched_functions(pc)) {
+ wchan_info->pc = pc;
+ return false;
+ }
+ return wchan_info->count++ < 16;
+}
+
unsigned long __get_wchan(struct task_struct *p)
{
- struct stackframe frame;
- unsigned long stack_page, ret = 0;
- int count = 0;
+ struct wchan_info wchan_info = {
+ .pc = 0,
+ .count = 0,
+ };
- stack_page = (unsigned long)try_get_task_stack(p);
- if (!stack_page)
+ if (!try_get_task_stack(p))
return 0;
- start_backtrace(&frame, thread_saved_fp(p), thread_saved_pc(p));
-
- do {
- if (unwind_frame(p, &frame))
- goto out;
- if (!in_sched_functions(frame.pc)) {
- ret = frame.pc;
- goto out;
- }
- } while (count++ < 16);
+ arch_stack_walk(get_wchan_cb, &wchan_info, p, NULL);
-out:
put_task_stack(p);
- return ret;
+
+ return wchan_info.pc;
}
unsigned long arch_align_stack(unsigned long sp)
@@ -611,6 +612,7 @@ void arch_setup_new_exec(void)
current->mm->context.flags = mmflags;
ptrauth_thread_init_user();
mte_thread_init_user();
+ erratum_1418040_new_exec();
if (task_spec_ssb_noexec(current)) {
arch_prctl_spec_ctrl_set(current, PR_SPEC_STORE_BYPASS,