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arm64 fixes: 

- switch_mm() fix where init_mm.pgd ends up in the user TTBR0;
   swapper_pg_dir is not suitable for user mappings
 - this_cpu accessors fix for preemption safety
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Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull two arm64 fixes from Catalin Marinas:

 - switch_mm() fix where init_mm.pgd ends up in the user TTBR0;
   swapper_pg_dir is not suitable for user mappings

 - this_cpu accessors fix for preemption safety

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: percpu: Make this_cpu accessors pre-empt safe
  arm64: Use the reserved TTBR0 if context switching to the init_mm
This commit is contained in:
Linus Torvalds 2015-03-24 17:27:18 -07:00
parent a55feeb103 f3eab7184d
commit c875f42109
3 changed files with 66 additions and 19 deletions
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30
arch/arm64/include/asm/cmpxchg.h
View File

@ -246,14 +246,30 @@ static inline unsigned long __cmpxchg_mb(volatile void *ptr, unsigned long old,
__ret; \
})
#define this_cpu_cmpxchg_1(ptr, o, n) cmpxchg_local(raw_cpu_ptr(&(ptr)), o, n)
#define this_cpu_cmpxchg_2(ptr, o, n) cmpxchg_local(raw_cpu_ptr(&(ptr)), o, n)
#define this_cpu_cmpxchg_4(ptr, o, n) cmpxchg_local(raw_cpu_ptr(&(ptr)), o, n)
#define this_cpu_cmpxchg_8(ptr, o, n) cmpxchg_local(raw_cpu_ptr(&(ptr)), o, n)
#define _protect_cmpxchg_local(pcp, o, n) \
({ \
typeof(*raw_cpu_ptr(&(pcp))) __ret; \
preempt_disable(); \
__ret = cmpxchg_local(raw_cpu_ptr(&(pcp)), o, n); \
preempt_enable(); \
__ret; \
})
#define this_cpu_cmpxchg_double_8(ptr1, ptr2, o1, o2, n1, n2) \
cmpxchg_double_local(raw_cpu_ptr(&(ptr1)), raw_cpu_ptr(&(ptr2)), \
o1, o2, n1, n2)
#define this_cpu_cmpxchg_1(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
#define this_cpu_cmpxchg_2(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
#define this_cpu_cmpxchg_4(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
#define this_cpu_cmpxchg_8(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
#define this_cpu_cmpxchg_double_8(ptr1, ptr2, o1, o2, n1, n2) \
({ \
int __ret; \
preempt_disable(); \
__ret = cmpxchg_double_local( raw_cpu_ptr(&(ptr1)), \
raw_cpu_ptr(&(ptr2)), \
o1, o2, n1, n2); \
preempt_enable(); \
__ret; \
})
#define cmpxchg64(ptr,o,n) cmpxchg((ptr),(o),(n))
#define cmpxchg64_local(ptr,o,n) cmpxchg_local((ptr),(o),(n))

9
arch/arm64/include/asm/mmu_context.h
View File

@ -151,6 +151,15 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next,
{
unsigned int cpu = smp_processor_id();
/*
* init_mm.pgd does not contain any user mappings and it is always
* active for kernel addresses in TTBR1. Just set the reserved TTBR0.
*/
if (next == &init_mm) {
cpu_set_reserved_ttbr0();
return;
}
if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next)
check_and_switch_context(next, tsk);
}

46
arch/arm64/include/asm/percpu.h
View File

@ -204,25 +204,47 @@ static inline unsigned long __percpu_xchg(void *ptr, unsigned long val,
return ret;
}
#define _percpu_add(pcp, val) \
__percpu_add(raw_cpu_ptr(&(pcp)), val, sizeof(pcp))
#define _percpu_read(pcp) \
({ \
typeof(pcp) __retval; \
preempt_disable(); \
__retval = (typeof(pcp))__percpu_read(raw_cpu_ptr(&(pcp)), \
sizeof(pcp)); \
preempt_enable(); \
__retval; \
})
#define _percpu_add_return(pcp, val) (typeof(pcp)) (_percpu_add(pcp, val))
#define _percpu_write(pcp, val) \
do { \
preempt_disable(); \
__percpu_write(raw_cpu_ptr(&(pcp)), (unsigned long)(val), \
sizeof(pcp)); \
preempt_enable(); \
} while(0) \
#define _pcp_protect(operation, pcp, val) \
({ \
typeof(pcp) __retval; \
preempt_disable(); \
__retval = (typeof(pcp))operation(raw_cpu_ptr(&(pcp)), \
(val), sizeof(pcp)); \
preempt_enable(); \
__retval; \
})
#define _percpu_add(pcp, val) \
_pcp_protect(__percpu_add, pcp, val)
#define _percpu_add_return(pcp, val) _percpu_add(pcp, val)
#define _percpu_and(pcp, val) \
__percpu_and(raw_cpu_ptr(&(pcp)), val, sizeof(pcp))
_pcp_protect(__percpu_and, pcp, val)
#define _percpu_or(pcp, val) \
__percpu_or(raw_cpu_ptr(&(pcp)), val, sizeof(pcp))
#define _percpu_read(pcp) (typeof(pcp)) \
(__percpu_read(raw_cpu_ptr(&(pcp)), sizeof(pcp)))
#define _percpu_write(pcp, val) \
__percpu_write(raw_cpu_ptr(&(pcp)), (unsigned long)(val), sizeof(pcp))
_pcp_protect(__percpu_or, pcp, val)
#define _percpu_xchg(pcp, val) (typeof(pcp)) \
(__percpu_xchg(raw_cpu_ptr(&(pcp)), (unsigned long)(val), sizeof(pcp)))
_pcp_protect(__percpu_xchg, pcp, (unsigned long)(val))
#define this_cpu_add_1(pcp, val) _percpu_add(pcp, val)
#define this_cpu_add_2(pcp, val) _percpu_add(pcp, val)