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-rw-r--r--arch/arm64/mm/context.c28
-rw-r--r--arch/arm64/mm/dump.c2
-rw-r--r--arch/arm64/mm/fault.c5
-rw-r--r--arch/arm64/mm/init.c3
-rw-r--r--arch/arm64/mm/pgd.c2
5 files changed, 22 insertions, 18 deletions
diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c
index ab9f5f0fb2c7..6f4017046323 100644
--- a/arch/arm64/mm/context.c
+++ b/arch/arm64/mm/context.c
@@ -96,12 +96,6 @@ static void flush_context(unsigned int cpu)
set_reserved_asid_bits();
- /*
- * Ensure the generation bump is observed before we xchg the
- * active_asids.
- */
- smp_wmb();
-
for_each_possible_cpu(i) {
asid = atomic64_xchg_relaxed(&per_cpu(active_asids, i), 0);
/*
@@ -117,7 +111,10 @@ static void flush_context(unsigned int cpu)
per_cpu(reserved_asids, i) = asid;
}
- /* Queue a TLB invalidate and flush the I-cache if necessary. */
+ /*
+ * Queue a TLB invalidation for each CPU to perform on next
+ * context-switch
+ */
cpumask_setall(&tlb_flush_pending);
}
@@ -202,11 +199,18 @@ void check_and_switch_context(struct mm_struct *mm, unsigned int cpu)
asid = atomic64_read(&mm->context.id);
/*
- * The memory ordering here is subtle. We rely on the control
- * dependency between the generation read and the update of
- * active_asids to ensure that we are synchronised with a
- * parallel rollover (i.e. this pairs with the smp_wmb() in
- * flush_context).
+ * The memory ordering here is subtle.
+ * If our ASID matches the current generation, then we update
+ * our active_asids entry with a relaxed xchg. Racing with a
+ * concurrent rollover means that either:
+ *
+ * - We get a zero back from the xchg and end up waiting on the
+ * lock. Taking the lock synchronises with the rollover and so
+ * we are forced to see the updated generation.
+ *
+ * - We get a valid ASID back from the xchg, which means the
+ * relaxed xchg in flush_context will treat us as reserved
+ * because atomic RmWs are totally ordered for a given location.
*/
if (!((asid ^ atomic64_read(&asid_generation)) >> asid_bits)
&& atomic64_xchg_relaxed(&per_cpu(active_asids, cpu), asid))
diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c
index ca74a2aace42..7b60d62ac593 100644
--- a/arch/arm64/mm/dump.c
+++ b/arch/arm64/mm/dump.c
@@ -389,7 +389,7 @@ void ptdump_check_wx(void)
.check_wx = true,
};
- walk_pgd(&st, &init_mm, 0);
+ walk_pgd(&st, &init_mm, VA_START);
note_page(&st, 0, 0, 0);
if (st.wx_pages || st.uxn_pages)
pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found, %lu non-UXN pages found\n",
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 22168cd0dde7..9b7f89df49db 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -574,7 +574,6 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
{
struct siginfo info;
const struct fault_info *inf;
- int ret = 0;
inf = esr_to_fault_info(esr);
pr_err("Synchronous External Abort: %s (0x%08x) at 0x%016lx\n",
@@ -589,7 +588,7 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
if (interrupts_enabled(regs))
nmi_enter();
- ret = ghes_notify_sea();
+ ghes_notify_sea();
if (interrupts_enabled(regs))
nmi_exit();
@@ -604,7 +603,7 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
info.si_addr = (void __user *)addr;
arm64_notify_die("", regs, &info, esr);
- return ret;
+ return 0;
}
static const struct fault_info fault_info[] = {
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 5960bef0170d..00e7b900ca41 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -476,6 +476,8 @@ void __init arm64_memblock_init(void)
reserve_elfcorehdr();
+ high_memory = __va(memblock_end_of_DRAM() - 1) + 1;
+
dma_contiguous_reserve(arm64_dma_phys_limit);
memblock_allow_resize();
@@ -502,7 +504,6 @@ void __init bootmem_init(void)
sparse_init();
zone_sizes_init(min, max);
- high_memory = __va((max << PAGE_SHIFT) - 1) + 1;
memblock_dump_all();
}
diff --git a/arch/arm64/mm/pgd.c b/arch/arm64/mm/pgd.c
index 371c5f03a170..051e71ec3335 100644
--- a/arch/arm64/mm/pgd.c
+++ b/arch/arm64/mm/pgd.c
@@ -26,7 +26,7 @@
#include <asm/page.h>
#include <asm/tlbflush.h>
-static struct kmem_cache *pgd_cache;
+static struct kmem_cache *pgd_cache __ro_after_init;
pgd_t *pgd_alloc(struct mm_struct *mm)
{