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authorLinus Torvalds <torvalds@linux-foundation.org>2015-12-16 10:57:24 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-12-16 10:57:24 -0800
commita5e90b1b075f89f084047628d4ef181aded0bbfb (patch)
treeda0010e547be7bf0f3b2bac9d7c74015e5e8662f /arch/arm/mm/context.c
parentedb42dc7bc0da0125ceacab810a553ce1f0cac8d (diff)
parent34bfbae33ae84107d0c257edd6c6a8689a09be26 (diff)
downloadlinux-a5e90b1b075f89f084047628d4ef181aded0bbfb.tar.bz2
Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
Pull ARM fixes from Russell King: "Further ARM fixes: - Anson Huang noticed that we were corrupting a register we shouldn't be during suspend on some CPUs. - Shengjiu Wang spotted a bug in the 'swp' instruction emulation. - Will Deacon fixed a bug in the ASID allocator. - Laura Abbott fixed the kernel permission protection to apply to all threads running in the system. - I've fixed two bugs with the domain access control register handling, one to do with printing an appropriate value at oops time, and the other to further fix the uaccess_with_memcpy code" * 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: ARM: 8475/1: SWP emulation: Restore original *data when failed ARM: 8471/1: need to save/restore arm register(r11) when it is corrupted ARM: fix uaccess_with_memcpy() with SW_DOMAIN_PAN ARM: report proper DACR value in oops dumps ARM: 8464/1: Update all mm structures with section adjustments ARM: 8465/1: mm: keep reserved ASIDs in sync with mm after multiple rollovers
Diffstat (limited to 'arch/arm/mm/context.c')
-rw-r--r--arch/arm/mm/context.c38
1 files changed, 26 insertions, 12 deletions
diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c
index 845769e41332..c8c8b9ed02e0 100644
--- a/arch/arm/mm/context.c
+++ b/arch/arm/mm/context.c
@@ -165,13 +165,28 @@ static void flush_context(unsigned int cpu)
__flush_icache_all();
}
-static int is_reserved_asid(u64 asid)
+static bool check_update_reserved_asid(u64 asid, u64 newasid)
{
int cpu;
- for_each_possible_cpu(cpu)
- if (per_cpu(reserved_asids, cpu) == asid)
- return 1;
- return 0;
+ bool hit = false;
+
+ /*
+ * Iterate over the set of reserved ASIDs looking for a match.
+ * If we find one, then we can update our mm to use newasid
+ * (i.e. the same ASID in the current generation) but we can't
+ * exit the loop early, since we need to ensure that all copies
+ * of the old ASID are updated to reflect the mm. Failure to do
+ * so could result in us missing the reserved ASID in a future
+ * generation.
+ */
+ for_each_possible_cpu(cpu) {
+ if (per_cpu(reserved_asids, cpu) == asid) {
+ hit = true;
+ per_cpu(reserved_asids, cpu) = newasid;
+ }
+ }
+
+ return hit;
}
static u64 new_context(struct mm_struct *mm, unsigned int cpu)
@@ -181,12 +196,14 @@ static u64 new_context(struct mm_struct *mm, unsigned int cpu)
u64 generation = atomic64_read(&asid_generation);
if (asid != 0) {
+ u64 newasid = generation | (asid & ~ASID_MASK);
+
/*
* If our current ASID was active during a rollover, we
* can continue to use it and this was just a false alarm.
*/
- if (is_reserved_asid(asid))
- return generation | (asid & ~ASID_MASK);
+ if (check_update_reserved_asid(asid, newasid))
+ return newasid;
/*
* We had a valid ASID in a previous life, so try to re-use
@@ -194,7 +211,7 @@ static u64 new_context(struct mm_struct *mm, unsigned int cpu)
*/
asid &= ~ASID_MASK;
if (!__test_and_set_bit(asid, asid_map))
- goto bump_gen;
+ return newasid;
}
/*
@@ -216,11 +233,8 @@ static u64 new_context(struct mm_struct *mm, unsigned int cpu)
__set_bit(asid, asid_map);
cur_idx = asid;
-
-bump_gen:
- asid |= generation;
cpumask_clear(mm_cpumask(mm));
- return asid;
+ return asid | generation;
}
void check_and_switch_context(struct mm_struct *mm, struct task_struct *tsk)