Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 2328af0c authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARC: [SMP] Enable icache coherency 



icaches are not snooped hence not cohrent in SMP setups which means
kernel has to do cross core calls to ensure the same.

The leaf routine __ic_line_inv_vaddr() now does cross core calls.

__sync_icache_dcache() is affected due to this:

* local dcache line flushed ahead of remote icache inv requests
* can't disable interrupts anymore, since
      __ic_line_inv_vaddr()->on_each_cpu() can deadlock.

| WARNING: CPU: 0 PID: 1 at kernel/smp.c:374
| smp_call_function_many+0x25a/0x2c4()
|
|  init_kprobes+0x90/0xc8
|     register_kprobe+0x1d6/0x510
|	__sync_icache_dcache+0x28/0x80
|
|	    DISABLE IRQ
|
|	    __ic_line_inv_vaddr
|		on_each_cpu
|		     smp_call_function_many+0x25a/0x2c4   --> WARN
|			__ic_line_inv_vaddr_local
|	    __dc_line_op

* TODO: Needs to use mask of relevant CPUs to avoid broadcasting

Signed-off-by: default avatarNoam Camus <noamc@ezchip.com>
Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent 7e512219

arch/arc/mm/cache_arc700.c

+19 −6
Original line number Diff line number Diff line
@@ -389,7 +389,7 @@ static inline void __dc_line_op(unsigned long paddr, unsigned long vaddr, 
/***********************************************************

 * Machine specific helper for per line I-Cache invalidate.

 */

static void __ic_line_inv_vaddr(unsigned long paddr, unsigned long vaddr,

static void __ic_line_inv_vaddr_local(unsigned long paddr, unsigned long vaddr,

				unsigned long sz)

{

	unsigned long flags;
@@ -405,6 +405,23 @@ static inline void __ic_entire_inv(void) 
	read_aux_reg(ARC_REG_IC_CTRL);	/* blocks */

}



struct ic_line_inv_vaddr_ipi {

	unsigned long paddr, vaddr;

	int sz;

};



static void __ic_line_inv_vaddr_helper(void *info)

{

        struct ic_line_inv_vaddr_ipi *ic_inv = (struct ic_line_inv_vaddr_ipi*) info;

        __ic_line_inv_vaddr_local(ic_inv->paddr, ic_inv->vaddr, ic_inv->sz);

}



static void __ic_line_inv_vaddr(unsigned long paddr, unsigned long vaddr,

				unsigned long sz)

{

	struct ic_line_inv_vaddr_ipi ic_inv = { paddr, vaddr , sz};

	on_each_cpu(__ic_line_inv_vaddr_helper, &ic_inv, 1);

}

#else



#define __ic_entire_inv()
@@ -553,12 +570,8 @@ void flush_icache_range(unsigned long kstart, unsigned long kend) 
 */

void __sync_icache_dcache(unsigned long paddr, unsigned long vaddr, int len)

{

	unsigned long flags;



	local_irq_save(flags);

	__ic_line_inv_vaddr(paddr, vaddr, len);

	__dc_line_op(paddr, vaddr, len, OP_FLUSH_N_INV);

	local_irq_restore(flags);

	__ic_line_inv_vaddr(paddr, vaddr, len);

}



/* wrapper to compile time eliminate alignment checks in flush loop */