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Commit 7bbb7940 authored by Russell King's avatar Russell King Committed by Russell King
Browse files

[ARM] Fix SMP initialisation oops 



A change to the SMP initialisation caused the following oops:

 CPU1: Booted secondary processor
 CPU1: D VIPT write-back cache
 CPU1: I cache: 32768 bytes, associativity 4, 32 byte lines, 256 sets
 CPU1: D cache: 32768 bytes, associativity 4, 32 byte lines, 256 sets
 <7>Calibrating delay loop... 83.14 BogoMIPS (lpj=415744)
 <1>Unable to handle kernel NULL pointer dereference at virtual address 0000001c
 ...
 PC is at enqueue_task+0x1c/0x64
 LR is at activate_task+0xcc/0xe4

SMP initialisation now requires cpu_possible_map to be initialised in
setup_arch().  Move this from smp_prepare_cpus() to smp_init_cpus()
and call it from our setup_arch() if CONFIG_SMP is enabled.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent ba09cf2b

arch/arm/kernel/setup.c

+5 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#include <linux/root_dev.h>

#include <linux/cpu.h>

#include <linux/interrupt.h>

#include <linux/smp.h>



#include <asm/cpu.h>

#include <asm/elf.h>
@@ -771,6 +772,10 @@ void __init setup_arch(char **cmdline_p) 
	paging_init(&meminfo, mdesc);

	request_standard_resources(&meminfo, mdesc);



#ifdef CONFIG_SMP

	smp_init_cpus();

#endif



	cpu_init();



	/*

arch/arm/kernel/smp.c

+0 −1
Original line number Diff line number Diff line
@@ -338,7 +338,6 @@ void __init smp_prepare_boot_cpu(void) 


	per_cpu(cpu_data, cpu).idle = current;



	cpu_set(cpu, cpu_possible_map);

	cpu_set(cpu, cpu_present_map);

	cpu_set(cpu, cpu_online_map);

}

arch/arm/mach-integrator/platsmp.c

+15 −6
Original line number Diff line number Diff line
@@ -140,6 +140,18 @@ static void __init poke_milo(void) 
	mb();

}



/*

 * Initialise the CPU possible map early - this describes the CPUs

 * which may be present or become present in the system.

 */

void __init smp_init_cpus(void)

{

	unsigned int i, ncores = get_core_count();



	for (i = 0; i < ncores; i++)

		cpu_set(i, cpu_possible_map);

}



void __init smp_prepare_cpus(unsigned int max_cpus)

{

	unsigned int ncores = get_core_count();
@@ -176,14 +188,11 @@ void __init smp_prepare_cpus(unsigned int max_cpus) 
		max_cpus = ncores;



	/*

	 * Initialise the possible/present maps.

	 * cpu_possible_map describes the set of CPUs which may be present

	 * cpu_present_map describes the set of CPUs populated

	 * Initialise the present map, which describes the set of CPUs

	 * actually populated at the present time.

	 */

	for (i = 0; i < max_cpus; i++) {

		cpu_set(i, cpu_possible_map);

	for (i = 0; i < max_cpus; i++)

		cpu_set(i, cpu_present_map);

	}



	/*

	 * Do we need any more CPUs? If so, then let them know where

arch/arm/mach-realview/platsmp.c

+15 −6
Original line number Diff line number Diff line
@@ -143,6 +143,18 @@ static void __init poke_milo(void) 
	mb();

}



/*

 * Initialise the CPU possible map early - this describes the CPUs

 * which may be present or become present in the system.

 */

void __init smp_init_cpus(void)

{

	unsigned int i, ncores = get_core_count();



	for (i = 0; i < ncores; i++)

		cpu_set(i, cpu_possible_map);

}



void __init smp_prepare_cpus(unsigned int max_cpus)

{

	unsigned int ncores = get_core_count();
@@ -179,14 +191,11 @@ void __init smp_prepare_cpus(unsigned int max_cpus) 
	local_timer_setup(cpu);



	/*

	 * Initialise the possible/present maps.

	 * cpu_possible_map describes the set of CPUs which may be present

	 * cpu_present_map describes the set of CPUs populated

	 * Initialise the present map, which describes the set of CPUs

	 * actually populated at the present time.

	 */

	for (i = 0; i < max_cpus; i++) {

		cpu_set(i, cpu_possible_map);

	for (i = 0; i < max_cpus; i++)

		cpu_set(i, cpu_present_map);

	}



	/*

	 * Do we need any more CPUs? If so, then let them know where

include/asm-arm/smp.h

+5 −0
Original line number Diff line number Diff line
@@ -41,6 +41,11 @@ extern void show_ipi_list(struct seq_file *p); 
 */

asmlinkage void do_IPI(struct pt_regs *regs);



/*

 * Setup the SMP cpu_possible_map

 */

extern void smp_init_cpus(void);



/*

 * Move global data into per-processor storage.

 */