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authorHugh Dickins <hughd@google.com>2017-12-04 15:07:50 +0100
committerIngo Molnar <mingo@kernel.org>2017-12-23 21:13:00 +0100
commitc1961a4631daef4aeabee8e368b1b13e8f173c91 (patch)
treee27322eb539ad6c6f8ddbfa6503f61b81f80264d
parent10043e02db7f8a4161f76434931051e7d797a5f6 (diff)
downloadop-kernel-dev-c1961a4631daef4aeabee8e368b1b13e8f173c91.zip
op-kernel-dev-c1961a4631daef4aeabee8e368b1b13e8f173c91.tar.gz
x86/events/intel/ds: Map debug buffers in cpu_entry_area
The BTS and PEBS buffers both have their virtual addresses programmed into the hardware. This means that any access to them is performed via the page tables. The times that the hardware accesses these are entirely dependent on how the performance monitoring hardware events are set up. In other words, there is no way for the kernel to tell when the hardware might access these buffers. To avoid perf crashes, place 'debug_store' allocate pages and map them into the cpu_entry_area. The PEBS fixup buffer does not need this treatment. [ tglx: Got rid of the kaiser_add_mapping() complication ] Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Laight <David.Laight@aculab.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Eduardo Valentin <eduval@amazon.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: keescook@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--arch/x86/events/intel/ds.c125
-rw-r--r--arch/x86/events/perf_event.h2
2 files changed, 82 insertions, 45 deletions
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 6522f02..8f0aace 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -3,6 +3,7 @@
#include <linux/types.h>
#include <linux/slab.h>
+#include <asm/cpu_entry_area.h>
#include <asm/perf_event.h>
#include <asm/insn.h>
@@ -280,17 +281,52 @@ void fini_debug_store_on_cpu(int cpu)
static DEFINE_PER_CPU(void *, insn_buffer);
-static int alloc_pebs_buffer(int cpu)
+static void ds_update_cea(void *cea, void *addr, size_t size, pgprot_t prot)
{
- struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+ phys_addr_t pa;
+ size_t msz = 0;
+
+ pa = virt_to_phys(addr);
+ for (; msz < size; msz += PAGE_SIZE, pa += PAGE_SIZE, cea += PAGE_SIZE)
+ cea_set_pte(cea, pa, prot);
+}
+
+static void ds_clear_cea(void *cea, size_t size)
+{
+ size_t msz = 0;
+
+ for (; msz < size; msz += PAGE_SIZE, cea += PAGE_SIZE)
+ cea_set_pte(cea, 0, PAGE_NONE);
+}
+
+static void *dsalloc_pages(size_t size, gfp_t flags, int cpu)
+{
+ unsigned int order = get_order(size);
int node = cpu_to_node(cpu);
- int max;
- void *buffer, *ibuffer;
+ struct page *page;
+
+ page = __alloc_pages_node(node, flags | __GFP_ZERO, order);
+ return page ? page_address(page) : NULL;
+}
+
+static void dsfree_pages(const void *buffer, size_t size)
+{
+ if (buffer)
+ free_pages((unsigned long)buffer, get_order(size));
+}
+
+static int alloc_pebs_buffer(int cpu)
+{
+ struct cpu_hw_events *hwev = per_cpu_ptr(&cpu_hw_events, cpu);
+ struct debug_store *ds = hwev->ds;
+ size_t bsiz = x86_pmu.pebs_buffer_size;
+ int max, node = cpu_to_node(cpu);
+ void *buffer, *ibuffer, *cea;
if (!x86_pmu.pebs)
return 0;
- buffer = kzalloc_node(x86_pmu.pebs_buffer_size, GFP_KERNEL, node);
+ buffer = dsalloc_pages(bsiz, GFP_KERNEL, cpu);
if (unlikely(!buffer))
return -ENOMEM;
@@ -301,25 +337,27 @@ static int alloc_pebs_buffer(int cpu)
if (x86_pmu.intel_cap.pebs_format < 2) {
ibuffer = kzalloc_node(PEBS_FIXUP_SIZE, GFP_KERNEL, node);
if (!ibuffer) {
- kfree(buffer);
+ dsfree_pages(buffer, bsiz);
return -ENOMEM;
}
per_cpu(insn_buffer, cpu) = ibuffer;
}
-
- max = x86_pmu.pebs_buffer_size / x86_pmu.pebs_record_size;
-
- ds->pebs_buffer_base = (u64)(unsigned long)buffer;
+ hwev->ds_pebs_vaddr = buffer;
+ /* Update the cpu entry area mapping */
+ cea = &get_cpu_entry_area(cpu)->cpu_debug_buffers.pebs_buffer;
+ ds->pebs_buffer_base = (unsigned long) cea;
+ ds_update_cea(cea, buffer, bsiz, PAGE_KERNEL);
ds->pebs_index = ds->pebs_buffer_base;
- ds->pebs_absolute_maximum = ds->pebs_buffer_base +
- max * x86_pmu.pebs_record_size;
-
+ max = x86_pmu.pebs_record_size * (bsiz / x86_pmu.pebs_record_size);
+ ds->pebs_absolute_maximum = ds->pebs_buffer_base + max;
return 0;
}
static void release_pebs_buffer(int cpu)
{
- struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+ struct cpu_hw_events *hwev = per_cpu_ptr(&cpu_hw_events, cpu);
+ struct debug_store *ds = hwev->ds;
+ void *cea;
if (!ds || !x86_pmu.pebs)
return;
@@ -327,73 +365,70 @@ static void release_pebs_buffer(int cpu)
kfree(per_cpu(insn_buffer, cpu));
per_cpu(insn_buffer, cpu) = NULL;
- kfree((void *)(unsigned long)ds->pebs_buffer_base);
+ /* Clear the fixmap */
+ cea = &get_cpu_entry_area(cpu)->cpu_debug_buffers.pebs_buffer;
+ ds_clear_cea(cea, x86_pmu.pebs_buffer_size);
ds->pebs_buffer_base = 0;
+ dsfree_pages(hwev->ds_pebs_vaddr, x86_pmu.pebs_buffer_size);
+ hwev->ds_pebs_vaddr = NULL;
}
static int alloc_bts_buffer(int cpu)
{
- struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
- int node = cpu_to_node(cpu);
- int max, thresh;
- void *buffer;
+ struct cpu_hw_events *hwev = per_cpu_ptr(&cpu_hw_events, cpu);
+ struct debug_store *ds = hwev->ds;
+ void *buffer, *cea;
+ int max;
if (!x86_pmu.bts)
return 0;
- buffer = kzalloc_node(BTS_BUFFER_SIZE, GFP_KERNEL | __GFP_NOWARN, node);
+ buffer = dsalloc_pages(BTS_BUFFER_SIZE, GFP_KERNEL | __GFP_NOWARN, cpu);
if (unlikely(!buffer)) {
WARN_ONCE(1, "%s: BTS buffer allocation failure\n", __func__);
return -ENOMEM;
}
-
- max = BTS_BUFFER_SIZE / BTS_RECORD_SIZE;
- thresh = max / 16;
-
- ds->bts_buffer_base = (u64)(unsigned long)buffer;
+ hwev->ds_bts_vaddr = buffer;
+ /* Update the fixmap */
+ cea = &get_cpu_entry_area(cpu)->cpu_debug_buffers.bts_buffer;
+ ds->bts_buffer_base = (unsigned long) cea;
+ ds_update_cea(cea, buffer, BTS_BUFFER_SIZE, PAGE_KERNEL);
ds->bts_index = ds->bts_buffer_base;
- ds->bts_absolute_maximum = ds->bts_buffer_base +
- max * BTS_RECORD_SIZE;
- ds->bts_interrupt_threshold = ds->bts_absolute_maximum -
- thresh * BTS_RECORD_SIZE;
-
+ max = BTS_RECORD_SIZE * (BTS_BUFFER_SIZE / BTS_RECORD_SIZE);
+ ds->bts_absolute_maximum = ds->bts_buffer_base + max;
+ ds->bts_interrupt_threshold = ds->bts_absolute_maximum - (max / 16);
return 0;
}
static void release_bts_buffer(int cpu)
{
- struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+ struct cpu_hw_events *hwev = per_cpu_ptr(&cpu_hw_events, cpu);
+ struct debug_store *ds = hwev->ds;
+ void *cea;
if (!ds || !x86_pmu.bts)
return;
- kfree((void *)(unsigned long)ds->bts_buffer_base);
+ /* Clear the fixmap */
+ cea = &get_cpu_entry_area(cpu)->cpu_debug_buffers.bts_buffer;
+ ds_clear_cea(cea, BTS_BUFFER_SIZE);
ds->bts_buffer_base = 0;
+ dsfree_pages(hwev->ds_bts_vaddr, BTS_BUFFER_SIZE);
+ hwev->ds_bts_vaddr = NULL;
}
static int alloc_ds_buffer(int cpu)
{
- int node = cpu_to_node(cpu);
- struct debug_store *ds;
-
- ds = kzalloc_node(sizeof(*ds), GFP_KERNEL, node);
- if (unlikely(!ds))
- return -ENOMEM;
+ struct debug_store *ds = &get_cpu_entry_area(cpu)->cpu_debug_store;
+ memset(ds, 0, sizeof(*ds));
per_cpu(cpu_hw_events, cpu).ds = ds;
-
return 0;
}
static void release_ds_buffer(int cpu)
{
- struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
-
- if (!ds)
- return;
-
per_cpu(cpu_hw_events, cpu).ds = NULL;
- kfree(ds);
}
void release_ds_buffers(void)
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 373f9ed..8e4ea143 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -199,6 +199,8 @@ struct cpu_hw_events {
* Intel DebugStore bits
*/
struct debug_store *ds;
+ void *ds_pebs_vaddr;
+ void *ds_bts_vaddr;
u64 pebs_enabled;
int n_pebs;
int n_large_pebs;
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