Commit 18928e7f authored by Andrew Boie's avatar Andrew Boie Committed by Anas Nashif
Browse files

nios2: fix irq_lock/unlock ordering bug 



Memory accesses could be reordered before an irq_lock() or
after an irq_unlock() without the memory barriers.

See commit 15bc5377 for the
ARM fix for a complete description of the issue and fix.

Change-Id: I1d96fe0088d90150f0888c2893d017155fc0a0a7
Signed-off-by: default avatarAndrew Boie <andrew.p.boie@intel.com>
(cherry picked from commit bba445b3)
parent d39e0a92

include/arch/nios2/arch.h

+21 −14
Original line number Diff line number Diff line
@@ -94,10 +94,15 @@ typedef unsigned int vaddr_t; 


static ALWAYS_INLINE unsigned int _arch_irq_lock(void)

{

	unsigned int key;

	unsigned int key, tmp;



	key = _nios2_creg_read(NIOS2_CR_STATUS);

	_nios2_creg_write(NIOS2_CR_STATUS, key & ~NIOS2_STATUS_PIE_MSK);

	__asm__ volatile (

	    "rdctl %[key], status\n\t"

	    "movi %[tmp], -2\n\t"

	    "and %[tmp], %[key], %[tmp]\n\t"

	    "wrctl status, %[tmp]\n\t"

	    : [key] "=r" (key), [tmp] "=r" (tmp)

	    : : "memory");



	return key;

}
@@ -117,18 +122,20 @@ static ALWAYS_INLINE void _arch_irq_unlock(unsigned int key) 
		(defined ALT_CPU_EIC_PRESENT) || \

		(defined ALT_CPU_MMU_PRESENT) || \

		(defined ALT_CPU_MPU_PRESENT)

	uint32_t status_reg;



	/* Interrupts were already locked when irq_lock() was called,

	 * so don't do anything

	 */

	if (!(key & NIOS2_STATUS_PIE_MSK))

		return;



	status_reg = _nios2_creg_read(NIOS2_CR_STATUS);

	_nios2_creg_write(NIOS2_CR_STATUS, status_reg | NIOS2_STATUS_PIE_MSK);

	__asm__ volatile (

	    "andi %[key], %[key], 1\n\t"

	    "beq %[key], zero, 1f\n\t"

	    "rdctl %[key], status\n\t"

	    "ori %[key], %[key], 1\n\t"

	    "wrctl status, %[key]\n\t"

	    "1:\n\t"

	    : [key] "+r" (key)

	    : : "memory");

#else

	_nios2_creg_write(NIOS2_CR_STATUS, key);

	__asm__ volatile (

	    "wrctl status, %[key]"

	    : : [key] "r" (key)

	    : "memory");

#endif

}

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