From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Clark Williams <williams@redhat.com>,
linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H . Peter Anvin" <hpa@zytor.com>, Jiri Olsa <jolsa@redhat.com>,
Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, Arnaldo Carvalho de Melo <acme@redhat.com>
Subject: [PATCH 34/35] kallsyms, x86: Export addresses of PTI entry trampolines
Date: Wed, 15 Aug 2018 12:06:10 -0300 [thread overview]
Message-ID: <20180815150611.32080-35-acme@kernel.org> (raw)
In-Reply-To: <20180815150611.32080-1-acme@kernel.org>
From: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Currently, the addresses of PTI entry trampolines are not exported to
user space. Kernel profiling tools need these addresses to identify the
kernel code, so add a symbol and address for each CPU's PTI entry
trampoline.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/1528289651-4113-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
arch/x86/mm/cpu_entry_area.c | 23 +++++++++++++++++++++++
kernel/kallsyms.c | 28 +++++++++++++++++++++++++++-
2 files changed, 50 insertions(+), 1 deletion(-)
diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c
index b45f5aaefd74..fab49fd5190f 100644
--- a/arch/x86/mm/cpu_entry_area.c
+++ b/arch/x86/mm/cpu_entry_area.c
@@ -2,6 +2,7 @@
#include <linux/spinlock.h>
#include <linux/percpu.h>
+#include <linux/kallsyms.h>
#include <asm/cpu_entry_area.h>
#include <asm/pgtable.h>
@@ -150,6 +151,28 @@ static void __init setup_cpu_entry_area(int cpu)
percpu_setup_debug_store(cpu);
}
+#ifdef CONFIG_X86_64
+int arch_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
+ char *name)
+{
+ unsigned int cpu, ncpu = 0;
+
+ if (symnum >= num_possible_cpus())
+ return -EINVAL;
+
+ for_each_possible_cpu(cpu) {
+ if (ncpu++ >= symnum)
+ break;
+ }
+
+ *value = (unsigned long)&get_cpu_entry_area(cpu)->entry_trampoline;
+ *type = 't';
+ strlcpy(name, "__entry_SYSCALL_64_trampoline", KSYM_NAME_LEN);
+
+ return 0;
+}
+#endif
+
static __init void setup_cpu_entry_area_ptes(void)
{
#ifdef CONFIG_X86_32
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index aa31aa07f2ef..02a0b01380d8 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -432,6 +432,7 @@ int sprint_backtrace(char *buffer, unsigned long address)
/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
struct kallsym_iter {
loff_t pos;
+ loff_t pos_arch_end;
loff_t pos_mod_end;
loff_t pos_ftrace_mod_end;
unsigned long value;
@@ -443,9 +444,29 @@ struct kallsym_iter {
int show_value;
};
+int __weak arch_get_kallsym(unsigned int symnum, unsigned long *value,
+ char *type, char *name)
+{
+ return -EINVAL;
+}
+
+static int get_ksymbol_arch(struct kallsym_iter *iter)
+{
+ int ret = arch_get_kallsym(iter->pos - kallsyms_num_syms,
+ &iter->value, &iter->type,
+ iter->name);
+
+ if (ret < 0) {
+ iter->pos_arch_end = iter->pos;
+ return 0;
+ }
+
+ return 1;
+}
+
static int get_ksymbol_mod(struct kallsym_iter *iter)
{
- int ret = module_get_kallsym(iter->pos - kallsyms_num_syms,
+ int ret = module_get_kallsym(iter->pos - iter->pos_arch_end,
&iter->value, &iter->type,
iter->name, iter->module_name,
&iter->exported);
@@ -501,6 +522,7 @@ static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
iter->nameoff = get_symbol_offset(new_pos);
iter->pos = new_pos;
if (new_pos == 0) {
+ iter->pos_arch_end = 0;
iter->pos_mod_end = 0;
iter->pos_ftrace_mod_end = 0;
}
@@ -515,6 +537,10 @@ static int update_iter_mod(struct kallsym_iter *iter, loff_t pos)
{
iter->pos = pos;
+ if ((!iter->pos_arch_end || iter->pos_arch_end > pos) &&
+ get_ksymbol_arch(iter))
+ return 1;
+
if ((!iter->pos_mod_end || iter->pos_mod_end > pos) &&
get_ksymbol_mod(iter))
return 1;
--
2.14.4
next prev parent reply other threads:[~2018-08-15 15:08 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-15 15:05 [GIT PULL 00/35] perf/core improvements and fixes Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 01/35] perf probe powerpc: Fix trace event post-processing Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 02/35] tools lib traceevent, perf tools: Rename struct pevent to struct tep_handle Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 03/35] tools lib traceevent, perf tools: Rename 'struct pevent_record' to 'struct tep_record' Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 04/35] tools lib traceevent, perf tools: Rename pevent plugin related APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 05/35] tools lib traceevent, perf tools: Rename pevent alloc / free APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 06/35] tools lib traceevent, perf tools: Rename pevent find APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 07/35] tools lib traceevent, perf tools: Rename pevent parse APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 08/35] tools lib traceevent, perf tools: Rename pevent print APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 09/35] tools lib traceevent, perf tools: Rename pevent_read_number_* APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 10/35] tools lib traceevent, perf tools: Rename pevent_register_* APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 11/35] tools lib traceevent, perf tools: Rename pevent_set_* APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 12/35] tools lib traceevent, perf tools: Rename traceevent_* APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 13/35] tools lib traceevent, perf tools: Rename 'enum pevent_flag' to 'enum tep_flag' Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 14/35] tools lib traceevent, tools lib lockdep: Rename 'enum pevent_errno' to 'enum tep_errno' Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 15/35] tools lib traceevent: Rename pevent_function* APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 16/35] tools lib traceevent, perf tools: Rename traceevent_plugin_* APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 17/35] tools lib traceevent: Rename pevent_filter* APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 18/35] tools lib traceevent: Rename pevent_register / unregister APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 19/35] tools lib traceevent: Rename pevent_data_ APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 20/35] tools lib traceevent: Rename pevent field APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 21/35] tools lib traceevent: Rename pevent_find_* APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 22/35] tools lib traceevent: Rename various pevent get/set/is APIs Arnaldo Carvalho de Melo
2018-08-15 15:05 ` [PATCH 23/35] tools lib traceevent: Rename internal parser related APIs Arnaldo Carvalho de Melo
2018-08-15 15:06 ` [PATCH 24/35] tools lib traceevent: Rename various pevent APIs Arnaldo Carvalho de Melo
2018-08-15 15:06 ` [PATCH 25/35] tools lib traceevent: Rename static variables and functions in event-parse.c Arnaldo Carvalho de Melo
2018-08-15 15:06 ` [PATCH 26/35] perf tools: Check for null when copying nsinfo Arnaldo Carvalho de Melo
2018-08-15 15:06 ` [PATCH 27/35] perf tools: Fix check-headers.sh AND list path of execution Arnaldo Carvalho de Melo
2018-08-15 15:06 ` [PATCH 28/35] perf tools: Make check-headers.sh check based on kernel dir Arnaldo Carvalho de Melo
2018-08-15 15:06 ` [PATCH 29/35] perf tools: Move syscall_64.tbl check into check-headers.sh Arnaldo Carvalho de Melo
2018-08-15 15:06 ` [PATCH 30/35] perf arm spe: Fix uninitialized record error variable Arnaldo Carvalho de Melo
2018-08-15 15:06 ` [PATCH 31/35] perf python: Remove -mcet and -fcf-protection when building with clang Arnaldo Carvalho de Melo
2018-08-15 15:06 ` [PATCH 32/35] perf auxtrace: Fix queue resize Arnaldo Carvalho de Melo
2018-08-15 15:06 ` [PATCH 33/35] kallsyms: Simplify update_iter_mod() Arnaldo Carvalho de Melo
2018-08-15 15:06 ` Arnaldo Carvalho de Melo [this message]
2018-08-15 15:06 ` [PATCH 35/35] x86: Add entry trampolines to kcore Arnaldo Carvalho de Melo
2018-08-15 15:21 ` [GIT PULL 00/35] perf/core improvements and fixes Andy Lutomirski
2018-08-18 11:17 ` Ingo Molnar
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