Dear RT folks!
I'm pleased to announce the v6.6-rt14 patch set.
Changes since v6.6-rt13:
- The kernel test robot reported a compile warning in the !PRINTK
case. Patch by John Ogness.
- The PREEMPT_RT patch can be enabled on RiscV. It has been reported
by a few people that it works without any warnings. Tests by a wider
user base is appreciated.
Known issues
Pierre Gondois reported crashes on ARM64 together with "rtla timerlat
hist" as trigger. It is not yet understood. The report is at
https://lore.kernel.org/70c08728-3d4f-47a6-8a3e-114e4877d120@xxxxxxx
The delta patch against v6.6-rt13 is appended below and can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/6.6/incr/patch-6.6-rt13-rt14.patch.xz
You can get this release via the git tree at:
https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v6.6-rt14
The RT patch against v6.6 can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patch-6.6-rt14.patch.xz
The split quilt queue is available at:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6-rt14.tar.xz
Sebastian
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 9c48fecc67191..ecf9db99a9272 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -48,6 +48,7 @@ config RISCV
select ARCH_SUPPORTS_HUGETLBFS if MMU
select ARCH_SUPPORTS_PAGE_TABLE_CHECK if MMU
select ARCH_SUPPORTS_PER_VMA_LOCK if MMU
+ select ARCH_SUPPORTS_RT
select ARCH_USE_MEMTEST
select ARCH_USE_QUEUED_RWLOCKS
select ARCH_USES_CFI_TRAPS if CFI_CLANG
@@ -135,6 +136,7 @@ config RISCV
select HAVE_PERF_USER_STACK_DUMP
select HAVE_POSIX_CPU_TIMERS_TASK_WORK
select HAVE_PREEMPT_DYNAMIC_KEY if !XIP_KERNEL
+ select HAVE_PREEMPT_AUTO
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_RETHOOK if !XIP_KERNEL
select HAVE_RSEQ
diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
index d0345bd659c94..23fed53b88157 100644
--- a/arch/riscv/include/asm/cpufeature.h
+++ b/arch/riscv/include/asm/cpufeature.h
@@ -30,6 +30,4 @@ DECLARE_PER_CPU(long, misaligned_access_speed);
/* Per-cpu ISA extensions. */
extern struct riscv_isainfo hart_isa[NR_CPUS];
-void check_unaligned_access(int cpu);
-
#endif
diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h
index 1833beb00489c..c5aebcdafd7b2 100644
--- a/arch/riscv/include/asm/thread_info.h
+++ b/arch/riscv/include/asm/thread_info.h
@@ -85,6 +85,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
* - pending work-to-be-done flags are in lowest half-word
* - other flags in upper half-word(s)
*/
+#define TIF_ARCH_RESCHED_LAZY 0 /* Lazy rescheduling */
#define TIF_NOTIFY_RESUME 1 /* callback before returning to user */
#define TIF_SIGPENDING 2 /* signal pending */
#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
@@ -99,6 +100,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
#define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
#define _TIF_UPROBE (1 << TIF_UPROBE)
+#define _TIF_ARCH_RESCHED_LAZY (1 << TIF_ARCH_RESCHED_LAZY)
#define _TIF_WORK_MASK \
(_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NEED_RESCHED | \
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 1cfbba65d11ae..07c7baac014db 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -8,6 +8,7 @@
#include <linux/acpi.h>
#include <linux/bitmap.h>
+#include <linux/cpuhotplug.h>
#include <linux/ctype.h>
#include <linux/log2.h>
#include <linux/memory.h>
@@ -29,6 +30,7 @@
#define MISALIGNED_ACCESS_JIFFIES_LG2 1
#define MISALIGNED_BUFFER_SIZE 0x4000
+#define MISALIGNED_BUFFER_ORDER get_order(MISALIGNED_BUFFER_SIZE)
#define MISALIGNED_COPY_SIZE ((MISALIGNED_BUFFER_SIZE / 2) - 0x80)
unsigned long elf_hwcap __read_mostly;
@@ -556,24 +558,19 @@ unsigned long riscv_get_elf_hwcap(void)
return hwcap;
}
-void check_unaligned_access(int cpu)
+static int check_unaligned_access(void *param)
{
+ int cpu = smp_processor_id();
u64 start_cycles, end_cycles;
u64 word_cycles;
u64 byte_cycles;
int ratio;
unsigned long start_jiffies, now;
- struct page *page;
+ struct page *page = param;
void *dst;
void *src;
long speed = RISCV_HWPROBE_MISALIGNED_SLOW;
- page = alloc_pages(GFP_NOWAIT, get_order(MISALIGNED_BUFFER_SIZE));
- if (!page) {
- pr_warn("Can't alloc pages to measure memcpy performance");
- return;
- }
-
/* Make an unaligned destination buffer. */
dst = (void *)((unsigned long)page_address(page) | 0x1);
/* Unalign src as well, but differently (off by 1 + 2 = 3). */
@@ -626,7 +623,7 @@ void check_unaligned_access(int cpu)
pr_warn("cpu%d: rdtime lacks granularity needed to measure unaligned access speed\n",
cpu);
- goto out;
+ return 0;
}
if (word_cycles < byte_cycles)
@@ -640,18 +637,83 @@ void check_unaligned_access(int cpu)
(speed == RISCV_HWPROBE_MISALIGNED_FAST) ? "fast" : "slow");
per_cpu(misaligned_access_speed, cpu) = speed;
-
-out:
- __free_pages(page, get_order(MISALIGNED_BUFFER_SIZE));
-}
-
-static int check_unaligned_access_boot_cpu(void)
-{
- check_unaligned_access(0);
return 0;
}
-arch_initcall(check_unaligned_access_boot_cpu);
+static void check_unaligned_access_nonboot_cpu(void *param)
+{
+ unsigned int cpu = smp_processor_id();
+ struct page **pages = param;
+
+ if (smp_processor_id() != 0)
+ check_unaligned_access(pages[cpu]);
+}
+
+static int riscv_online_cpu(unsigned int cpu)
+{
+ static struct page *buf;
+
+ /* We are already set since the last check */
+ if (per_cpu(misaligned_access_speed, cpu) != RISCV_HWPROBE_MISALIGNED_UNKNOWN)
+ return 0;
+
+ buf = alloc_pages(GFP_KERNEL, MISALIGNED_BUFFER_ORDER);
+ if (!buf) {
+ pr_warn("Allocation failure, not measuring misaligned performance\n");
+ return -ENOMEM;
+ }
+
+ check_unaligned_access(buf);
+ __free_pages(buf, MISALIGNED_BUFFER_ORDER);
+ return 0;
+}
+
+/* Measure unaligned access on all CPUs present at boot in parallel. */
+static int check_unaligned_access_all_cpus(void)
+{
+ unsigned int cpu;
+ unsigned int cpu_count = num_possible_cpus();
+ struct page **bufs = kzalloc(cpu_count * sizeof(struct page *),
+ GFP_KERNEL);
+
+ if (!bufs) {
+ pr_warn("Allocation failure, not measuring misaligned performance\n");
+ return 0;
+ }
+
+ /*
+ * Allocate separate buffers for each CPU so there's no fighting over
+ * cache lines.
+ */
+ for_each_cpu(cpu, cpu_online_mask) {
+ bufs[cpu] = alloc_pages(GFP_KERNEL, MISALIGNED_BUFFER_ORDER);
+ if (!bufs[cpu]) {
+ pr_warn("Allocation failure, not measuring misaligned performance\n");
+ goto out;
+ }
+ }
+
+ /* Check everybody except 0, who stays behind to tend jiffies. */
+ on_each_cpu(check_unaligned_access_nonboot_cpu, bufs, 1);
+
+ /* Check core 0. */
+ smp_call_on_cpu(0, check_unaligned_access, bufs[0], true);
+
+ /* Setup hotplug callback for any new CPUs that come online. */
+ cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "riscv:online",
+ riscv_online_cpu, NULL);
+
+out:
+ for_each_cpu(cpu, cpu_online_mask) {
+ if (bufs[cpu])
+ __free_pages(bufs[cpu], MISALIGNED_BUFFER_ORDER);
+ }
+
+ kfree(bufs);
+ return 0;
+}
+
+arch_initcall(check_unaligned_access_all_cpus);
#ifdef CONFIG_RISCV_ALTERNATIVE
/*
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 1b8da4e40a4d6..2cb5e651412cb 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -246,7 +246,6 @@ asmlinkage __visible void smp_callin(void)
numa_add_cpu(curr_cpuid);
set_cpu_online(curr_cpuid, 1);
- check_unaligned_access(curr_cpuid);
if (has_vector()) {
if (riscv_v_setup_vsize())
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index db8329091bb82..a3ae0710346cd 100644
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -178,7 +178,7 @@ static inline void nbcon_seq_force(struct console *con, u64 seq) { }
static inline bool nbcon_alloc(struct console *con) { return false; }
static inline void nbcon_init(struct console *con) { }
static inline void nbcon_free(struct console *con) { }
-enum nbcon_prio nbcon_get_default_prio(void) { return NBCON_PRIO_NONE; }
+static inline enum nbcon_prio nbcon_get_default_prio(void) { return NBCON_PRIO_NONE; }
static inline void nbcon_atomic_flush_all(void) { }
static bool nbcon_atomic_emit_next_record(struct console *con) { return false; }
diff --git a/localversion-rt b/localversion-rt
index 9f7d0bdbffb18..08b3e75841adc 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt13
+-rt14
