*/
#include <linux/bitops.h>
+#include <linux/cpu.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/prctl.h>
#include <asm/ptrace.h>
#include <asm/sysreg.h>
-u64 gcr_kernel_excl __ro_after_init;
-
-static bool report_fault_once = true;
+static DEFINE_PER_CPU_READ_MOSTLY(u64, mte_tcf_preferred);
#ifdef CONFIG_KASAN_HW_TAGS
/* Whether the MTE asynchronous mode is enabled. */
return ret;
}
-void mte_init_tags(u64 max_tag)
-{
- static bool gcr_kernel_excl_initialized;
-
- if (!gcr_kernel_excl_initialized) {
- /*
- * The format of the tags in KASAN is 0xFF and in MTE is 0xF.
- * This conversion extracts an MTE tag from a KASAN tag.
- */
- u64 incl = GENMASK(FIELD_GET(MTE_TAG_MASK >> MTE_TAG_SHIFT,
- max_tag), 0);
-
- gcr_kernel_excl = ~incl & SYS_GCR_EL1_EXCL_MASK;
- gcr_kernel_excl_initialized = true;
- }
-
- /* Enable the kernel exclude mask for random tags generation. */
- write_sysreg_s(SYS_GCR_EL1_RRND | gcr_kernel_excl, SYS_GCR_EL1);
-}
-
static inline void __mte_enable_kernel(const char *mode, unsigned long tcf)
{
/* Enable MTE Sync Mode for EL1. */
}
#endif
-void mte_set_report_once(bool state)
-{
- WRITE_ONCE(report_fault_once, state);
-}
-
-bool mte_report_once(void)
-{
- return READ_ONCE(report_fault_once);
-}
-
#ifdef CONFIG_KASAN_HW_TAGS
void mte_check_tfsr_el1(void)
{
}
#endif
-static void set_gcr_el1_excl(u64 excl)
+static void mte_update_sctlr_user(struct task_struct *task)
{
- current->thread.gcr_user_excl = excl;
-
/*
- * SYS_GCR_EL1 will be set to current->thread.gcr_user_excl value
- * by mte_set_user_gcr() in kernel_exit,
+ * This must be called with preemption disabled and can only be called
+ * on the current or next task since the CPU must match where the thread
+ * is going to run. The caller is responsible for calling
+ * update_sctlr_el1() later in the same preemption disabled block.
*/
+ unsigned long sctlr = task->thread.sctlr_user;
+ unsigned long mte_ctrl = task->thread.mte_ctrl;
+ unsigned long pref, resolved_mte_tcf;
+
+ pref = __this_cpu_read(mte_tcf_preferred);
+ resolved_mte_tcf = (mte_ctrl & pref) ? pref : mte_ctrl;
+ sctlr &= ~SCTLR_EL1_TCF0_MASK;
+ if (resolved_mte_tcf & MTE_CTRL_TCF_ASYNC)
+ sctlr |= SCTLR_EL1_TCF0_ASYNC;
+ else if (resolved_mte_tcf & MTE_CTRL_TCF_SYNC)
+ sctlr |= SCTLR_EL1_TCF0_SYNC;
+ task->thread.sctlr_user = sctlr;
}
void mte_thread_init_user(void)
dsb(ish);
write_sysreg_s(0, SYS_TFSRE0_EL1);
clear_thread_flag(TIF_MTE_ASYNC_FAULT);
- /* disable tag checking */
- set_task_sctlr_el1((current->thread.sctlr_user & ~SCTLR_EL1_TCF0_MASK) |
- SCTLR_EL1_TCF0_NONE);
- /* reset tag generation mask */
- set_gcr_el1_excl(SYS_GCR_EL1_EXCL_MASK);
+ /* disable tag checking and reset tag generation mask */
+ set_mte_ctrl(current, 0);
}
void mte_thread_switch(struct task_struct *next)
{
+ mte_update_sctlr_user(next);
+
/*
* Check if an async tag exception occurred at EL1.
*
mte_check_tfsr_el1();
}
-void mte_suspend_exit(void)
-{
- if (!system_supports_mte())
- return;
-
- sysreg_clear_set_s(SYS_GCR_EL1, SYS_GCR_EL1_EXCL_MASK, gcr_kernel_excl);
- isb();
-}
-
long set_mte_ctrl(struct task_struct *task, unsigned long arg)
{
- u64 sctlr = task->thread.sctlr_user & ~SCTLR_EL1_TCF0_MASK;
- u64 gcr_excl = ~((arg & PR_MTE_TAG_MASK) >> PR_MTE_TAG_SHIFT) &
- SYS_GCR_EL1_EXCL_MASK;
+ u64 mte_ctrl = (~((arg & PR_MTE_TAG_MASK) >> PR_MTE_TAG_SHIFT) &
+ SYS_GCR_EL1_EXCL_MASK) << MTE_CTRL_GCR_USER_EXCL_SHIFT;
if (!system_supports_mte())
return 0;
- switch (arg & PR_MTE_TCF_MASK) {
- case PR_MTE_TCF_NONE:
- sctlr |= SCTLR_EL1_TCF0_NONE;
- break;
- case PR_MTE_TCF_SYNC:
- sctlr |= SCTLR_EL1_TCF0_SYNC;
- break;
- case PR_MTE_TCF_ASYNC:
- sctlr |= SCTLR_EL1_TCF0_ASYNC;
- break;
- default:
- return -EINVAL;
- }
-
- if (task != current) {
- task->thread.sctlr_user = sctlr;
- task->thread.gcr_user_excl = gcr_excl;
- } else {
- set_task_sctlr_el1(sctlr);
- set_gcr_el1_excl(gcr_excl);
+ if (arg & PR_MTE_TCF_ASYNC)
+ mte_ctrl |= MTE_CTRL_TCF_ASYNC;
+ if (arg & PR_MTE_TCF_SYNC)
+ mte_ctrl |= MTE_CTRL_TCF_SYNC;
+
+ task->thread.mte_ctrl = mte_ctrl;
+ if (task == current) {
+ preempt_disable();
+ mte_update_sctlr_user(task);
+ update_sctlr_el1(task->thread.sctlr_user);
+ preempt_enable();
}
return 0;
long get_mte_ctrl(struct task_struct *task)
{
unsigned long ret;
- u64 incl = ~task->thread.gcr_user_excl & SYS_GCR_EL1_EXCL_MASK;
+ u64 mte_ctrl = task->thread.mte_ctrl;
+ u64 incl = (~mte_ctrl >> MTE_CTRL_GCR_USER_EXCL_SHIFT) &
+ SYS_GCR_EL1_EXCL_MASK;
if (!system_supports_mte())
return 0;
ret = incl << PR_MTE_TAG_SHIFT;
-
- switch (task->thread.sctlr_user & SCTLR_EL1_TCF0_MASK) {
- case SCTLR_EL1_TCF0_NONE:
- ret |= PR_MTE_TCF_NONE;
- break;
- case SCTLR_EL1_TCF0_SYNC:
- ret |= PR_MTE_TCF_SYNC;
- break;
- case SCTLR_EL1_TCF0_ASYNC:
+ if (mte_ctrl & MTE_CTRL_TCF_ASYNC)
ret |= PR_MTE_TCF_ASYNC;
- break;
- }
+ if (mte_ctrl & MTE_CTRL_TCF_SYNC)
+ ret |= PR_MTE_TCF_SYNC;
return ret;
}
return ret;
}
+
+static ssize_t mte_tcf_preferred_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ switch (per_cpu(mte_tcf_preferred, dev->id)) {
+ case MTE_CTRL_TCF_ASYNC:
+ return sysfs_emit(buf, "async\n");
+ case MTE_CTRL_TCF_SYNC:
+ return sysfs_emit(buf, "sync\n");
+ default:
+ return sysfs_emit(buf, "???\n");
+ }
+}
+
+static ssize_t mte_tcf_preferred_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ u64 tcf;
+
+ if (sysfs_streq(buf, "async"))
+ tcf = MTE_CTRL_TCF_ASYNC;
+ else if (sysfs_streq(buf, "sync"))
+ tcf = MTE_CTRL_TCF_SYNC;
+ else
+ return -EINVAL;
+
+ device_lock(dev);
+ per_cpu(mte_tcf_preferred, dev->id) = tcf;
+ device_unlock(dev);
+
+ return count;
+}
+static DEVICE_ATTR_RW(mte_tcf_preferred);
+
+static int register_mte_tcf_preferred_sysctl(void)
+{
+ unsigned int cpu;
+
+ if (!system_supports_mte())
+ return 0;
+
+ for_each_possible_cpu(cpu) {
+ per_cpu(mte_tcf_preferred, cpu) = MTE_CTRL_TCF_ASYNC;
+ device_create_file(get_cpu_device(cpu),
+ &dev_attr_mte_tcf_preferred);
+ }
+
+ return 0;
+}
+subsys_initcall(register_mte_tcf_preferred_sysctl);
projects / linux-2.6-microblaze.git / blobdiff