[MIPS] R2: Implement shadow register allocation without spinlock. (193dd2ce) · Commits · e / devices / android_kernel_xiaomi_markw

arch/mips/kernel/traps.c

+18 −23

Original line number	Diff line number	Diff line
		@@ -961,15 +961,19 @@ void set_except_vector(int n, void addr)

		#ifdef CONFIG_CPU_MIPSR2
		/*
		* Shadow register allocation
		* MIPSR2 shadow register set allocation
		* FIXME: SMP...
		*/

		/* MIPSR2 shadow register sets */
		struct shadow_registers {
		spinlock_t sr_lock; /* */
		int sr_supported; /* Number of shadow register sets supported */
		int sr_allocated; /* Bitmap of allocated shadow registers */
		static struct shadow_registers {
		/*
		* Number of shadow register sets supported
		*/
		unsigned long sr_supported;
		/*
		* Bitmap of allocated shadow registers
		*/
		unsigned long sr_allocated;
		} shadow_registers;

		void mips_srs_init(void)
		@@ -980,7 +984,6 @@ void mips_srs_init(void)
		shadow_registers.sr_supported);
		#endif
		shadow_registers.sr_allocated = 1; /* Set 0 used by kernel */
		spin_lock_init(&shadow_registers.sr_lock);
		}

		int mips_srs_max(void)
		@@ -991,32 +994,24 @@ int mips_srs_max(void)
		int mips_srs_alloc(void)
		{
		struct shadow_registers *sr = &shadow_registers;
		unsigned long flags;
		int set;

		spin_lock_irqsave(&sr->sr_lock, flags);
		again:
		set = find_first_zero_bit(&sr->sr_allocated, sr->sr_supported);
		if (set >= sr->sr_supported)
		return -1;

		if (test_and_set_bit(set, &sr->sr_allocated))
		goto again;

		for (set = 0; set < sr->sr_supported; set++) {
		if ((sr->sr_allocated & (1 << set)) == 0) {
		sr->sr_allocated \|= 1 << set;
		spin_unlock_irqrestore(&sr->sr_lock, flags);
		return set;
		}
		}

		/* None available */
		spin_unlock_irqrestore(&sr->sr_lock, flags);
		return -1;
		}

		void mips_srs_free (int set)
		{
		struct shadow_registers *sr = &shadow_registers;
		unsigned long flags;

		spin_lock_irqsave(&sr->sr_lock, flags);
		sr->sr_allocated &= ~(1 << set);
		spin_unlock_irqrestore(&sr->sr_lock, flags);
		clear_bit(set, &sr->sr_allocated);
		}

		static void set_vi_srs_handler(int n, void addr, int srs)