Commit d13027bb authored by Will Deacon's avatar Will Deacon
Browse files

Revert "arm64: initialize per-cpu offsets earlier" 

This reverts commit 353e228e.

Qian Cai reports that TX2 no longer boots with his .config as it appears
that task_cpu() gets instrumented and used before KASAN has been
initialised.

Although Mark has a proposed fix, let's take the safe option of reverting
this for now and sorting it out properly later.

Link: https://lore.kernel.org/r/711bc57a314d8d646b41307008db2845b7537b3d.camel@redhat.com


Reported-by: default avatarQian Cai <cai@redhat.com>
Tested-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent a82e4ef0

arch/arm64/include/asm/cpu.h

+0 −2
Original line number Diff line number Diff line
@@ -68,6 +68,4 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info); 
void update_cpu_features(int cpu, struct cpuinfo_arm64 *info,

				 struct cpuinfo_arm64 *boot);



void init_this_cpu_offset(void);



#endif /* __ASM_CPU_H */

arch/arm64/kernel/head.S

+0 −3
Original line number Diff line number Diff line
@@ -448,8 +448,6 @@ SYM_FUNC_START_LOCAL(__primary_switched) 
	bl	__pi_memset

	dsb	ishst				// Make zero page visible to PTW



	bl	init_this_cpu_offset



#ifdef CONFIG_KASAN

	bl	kasan_early_init

#endif
@@ -756,7 +754,6 @@ SYM_FUNC_START_LOCAL(__secondary_switched) 
	ptrauth_keys_init_cpu x2, x3, x4, x5

#endif



	bl	init_this_cpu_offset

	b	secondary_start_kernel

SYM_FUNC_END(__secondary_switched)

arch/arm64/kernel/setup.c

+6 −6
Original line number Diff line number Diff line
@@ -87,6 +87,12 @@ void __init smp_setup_processor_id(void) 
	u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK;

	set_cpu_logical_map(0, mpidr);



	/*

	 * clear __my_cpu_offset on boot CPU to avoid hang caused by

	 * using percpu variable early, for example, lockdep will

	 * access percpu variable inside lock_release

	 */

	set_my_cpu_offset(0);

	pr_info("Booting Linux on physical CPU 0x%010lx [0x%08x]\n",

		(unsigned long)mpidr, read_cpuid_id());

}
@@ -276,12 +282,6 @@ u64 cpu_logical_map(int cpu) 
}

EXPORT_SYMBOL_GPL(cpu_logical_map);



void noinstr init_this_cpu_offset(void)

{

	unsigned int cpu = task_cpu(current);

	set_my_cpu_offset(per_cpu_offset(cpu));

}



void __init __no_sanitize_address setup_arch(char **cmdline_p)

{

	init_mm.start_code = (unsigned long) _text;

arch/arm64/kernel/smp.c

+5 −8
Original line number Diff line number Diff line
@@ -192,7 +192,10 @@ asmlinkage notrace void secondary_start_kernel(void) 
	u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK;

	struct mm_struct *mm = &init_mm;

	const struct cpu_operations *ops;

	unsigned int cpu = smp_processor_id();

	unsigned int cpu;



	cpu = task_cpu(current);

	set_my_cpu_offset(per_cpu_offset(cpu));



	/*

	 * All kernel threads share the same mm context; grab a
@@ -432,13 +435,7 @@ void __init smp_cpus_done(unsigned int max_cpus) 


void __init smp_prepare_boot_cpu(void)

{

	/*

	 * Now that setup_per_cpu_areas() has allocated the runtime per-cpu

	 * areas it is only safe to read the CPU0 boot-time area, and we must

	 * reinitialize the offset to point to the runtime area.

	 */

	init_this_cpu_offset();



	set_my_cpu_offset(per_cpu_offset(smp_processor_id()));

	cpuinfo_store_boot_cpu();



	/*

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