Merge tag 'loongarch-fixes-6.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

Pull LoongArch fixes from Huacai Chen:
 "Fix some bugs in kernel-fpu, cpu idle function, hibernation and
  uprobes"

* tag 'loongarch-fixes-6.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
  LoongArch: uprobes: Remove redundant code about resume_era
  LoongArch: uprobes: Remove user_{en,dis}able_single_step()
  LoongArch: Save and restore CSR.CNTC for hibernation
  LoongArch: Move __arch_cpu_idle() to .cpuidle.text section
  LoongArch: Fix MAX_REG_OFFSET calculation
  LoongArch: Prevent cond_resched() occurring within kernel-fpu

Author: torvalds

arch/loongarch/include/asm/ptrace.h

@@ -55,7 +55,7 @@ static inline void instruction_pointer_set(struct pt_regs *regs, unsigned long v
 
 /* Query offset/name of register from its name/offset */
 extern int regs_query_register_offset(const char *name);
-#define MAX_REG_OFFSET (offsetof(struct pt_regs, __last))
+#define MAX_REG_OFFSET (offsetof(struct pt_regs, __last) - sizeof(unsigned long))
 
 /**
  * regs_get_register() - get register value from its offset

arch/loongarch/include/asm/uprobes.h

@@ -15,7 +15,6 @@ typedef u32 uprobe_opcode_t;
 #define UPROBE_XOLBP_INSN	__emit_break(BRK_UPROBE_XOLBP)
 
 struct arch_uprobe {
-	unsigned long	resume_era;
 	u32	insn[2];
 	u32	ixol[2];
 	bool	simulate;

arch/loongarch/kernel/genex.S

@@ -16,6 +16,7 @@
 #include <asm/stackframe.h>
 #include <asm/thread_info.h>
 
+	.section .cpuidle.text, "ax"
 	.align	5
 SYM_FUNC_START(__arch_cpu_idle)
 	/* start of idle interrupt region */
@@ -31,14 +32,16 @@ SYM_FUNC_START(__arch_cpu_idle)
 	 */
 	idle	0
 	/* end of idle interrupt region */
-1:	jr	ra
+idle_exit:
+	jr	ra
 SYM_FUNC_END(__arch_cpu_idle)
+	.previous
 
 SYM_CODE_START(handle_vint)
 	UNWIND_HINT_UNDEFINED
 	BACKUP_T0T1
 	SAVE_ALL
-	la_abs	t1, 1b
+	la_abs	t1, idle_exit
 	LONG_L	t0, sp, PT_ERA
 	/* 3 instructions idle interrupt region */
 	ori	t0, t0, 0b1100

arch/loongarch/kernel/kfpu.c

@@ -18,11 +18,28 @@ static unsigned int euen_mask = CSR_EUEN_FPEN;
 static DEFINE_PER_CPU(bool, in_kernel_fpu);
 static DEFINE_PER_CPU(unsigned int, euen_current);
 
+static inline void fpregs_lock(void)
+{
+	if (IS_ENABLED(CONFIG_PREEMPT_RT))
+		preempt_disable();
+	else
+		local_bh_disable();
+}
+
+static inline void fpregs_unlock(void)
+{
+	if (IS_ENABLED(CONFIG_PREEMPT_RT))
+		preempt_enable();
+	else
+		local_bh_enable();
+}
+
 void kernel_fpu_begin(void)
 {
 	unsigned int *euen_curr;
 
-	preempt_disable();
+	if (!irqs_disabled())
+		fpregs_lock();
 
 	WARN_ON(this_cpu_read(in_kernel_fpu));
 
@@ -73,7 +90,8 @@ void kernel_fpu_end(void)
 
 	this_cpu_write(in_kernel_fpu, false);
 
-	preempt_enable();
+	if (!irqs_disabled())
+		fpregs_unlock();
 }
 EXPORT_SYMBOL_GPL(kernel_fpu_end);
 

arch/loongarch/kernel/time.c

@@ -111,7 +111,7 @@ static unsigned long __init get_loops_per_jiffy(void)
 	return lpj;
 }
 
-static long init_offset __nosavedata;
+static long init_offset;
 
 void save_counter(void)
 {

arch/loongarch/kernel/uprobes.c

@@ -42,7 +42,6 @@ int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 	utask->autask.saved_trap_nr = current->thread.trap_nr;
 	current->thread.trap_nr = UPROBE_TRAP_NR;
 	instruction_pointer_set(regs, utask->xol_vaddr);
-	user_enable_single_step(current);
 
 	return 0;
 }
@@ -53,13 +52,7 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 
 	WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR);
 	current->thread.trap_nr = utask->autask.saved_trap_nr;
-
-	if (auprobe->simulate)
-		instruction_pointer_set(regs, auprobe->resume_era);
-	else
-		instruction_pointer_set(regs, utask->vaddr + LOONGARCH_INSN_SIZE);
-
-	user_disable_single_step(current);
+	instruction_pointer_set(regs, utask->vaddr + LOONGARCH_INSN_SIZE);
 
 	return 0;
 }
@@ -70,7 +63,6 @@ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 
 	current->thread.trap_nr = utask->autask.saved_trap_nr;
 	instruction_pointer_set(regs, utask->vaddr);
-	user_disable_single_step(current);
 }
 
 bool arch_uprobe_xol_was_trapped(struct task_struct *t)
@@ -90,7 +82,6 @@ bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
 
 	insn.word = auprobe->insn[0];
 	arch_simulate_insn(insn, regs);
-	auprobe->resume_era = regs->csr_era;
 
 	return true;
 }

arch/loongarch/power/hibernate.c

@@ -2,6 +2,7 @@
 #include <asm/fpu.h>
 #include <asm/loongson.h>
 #include <asm/sections.h>
+#include <asm/time.h>
 #include <asm/tlbflush.h>
 #include <linux/suspend.h>
 
@@ -14,6 +15,7 @@ struct pt_regs saved_regs;
 
 void save_processor_state(void)
 {
+	save_counter();
 	saved_crmd = csr_read32(LOONGARCH_CSR_CRMD);
 	saved_prmd = csr_read32(LOONGARCH_CSR_PRMD);
 	saved_euen = csr_read32(LOONGARCH_CSR_EUEN);
@@ -26,6 +28,7 @@ void save_processor_state(void)
 
 void restore_processor_state(void)
 {
+	sync_counter();
 	csr_write32(saved_crmd, LOONGARCH_CSR_CRMD);
 	csr_write32(saved_prmd, LOONGARCH_CSR_PRMD);
 	csr_write32(saved_euen, LOONGARCH_CSR_EUEN);