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Revert "arm64: initialize per-cpu offsets earlier"

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This reverts commit 353e228eb3.

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: Qian Cai <cai@redhat.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Will Deacon 2020-10-09 11:24:17 +01:00
parent a82e4ef041
commit d13027bb35
4 changed files with 11 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm64/include/asm/cpu.h
View File

@ -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 */

3
arch/arm64/kernel/head.S
View File

@ -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)

12
arch/arm64/kernel/setup.c
View File

@ -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;

13
arch/arm64/kernel/smp.c
View File

@ -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();
/*