From: Adrian Hunter <adrian.hunter@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>, Andi Kleen <ak@linux.intel.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Joerg Roedel <joro@8bytes.org>, Jiri Olsa <jolsa@redhat.com>,
linux-kernel@vger.kernel.org, x86@kernel.org
Subject: [PATCH RFC 02/19] kallsyms, x86: Export addresses of syscall trampolines
Date: Wed, 9 May 2018 14:43:31 +0300 [thread overview]
Message-ID: <1525866228-30321-3-git-send-email-adrian.hunter@intel.com> (raw)
In-Reply-To: <1525866228-30321-1-git-send-email-adrian.hunter@intel.com>
From: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.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..d1da5cf4b2de 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;
+
+ if (symnum >= num_possible_cpus())
+ return -EINVAL;
+
+ for (cpu = cpumask_first(cpu_possible_mask), ncpu = 0;
+ cpu < num_possible_cpus() && ncpu < symnum;
+ cpu = cpumask_next(cpu, cpu_possible_mask), ncpu++)
+ ;
+
+ *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 eda4b0222dab..ebe6befac47e 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;
}
@@ -510,6 +532,10 @@ 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;
--
1.9.1
next prev parent reply other threads:[~2018-05-09 11:49 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-09 11:43 [PATCH RFC 00/19] perf tools and x86_64 KPTI entry trampolines Adrian Hunter
2018-05-09 11:43 ` [PATCH RFC 01/19] kallsyms: Simplify update_iter_mod() Adrian Hunter
2018-05-10 13:01 ` Jiri Olsa
2018-05-10 17:02 ` Hunter, Adrian
2018-05-14 17:55 ` Arnaldo Carvalho de Melo
2018-05-09 11:43 ` Adrian Hunter [this message]
2018-05-09 11:43 ` [PATCH RFC 03/19] x86: Add entry trampolines to kcore Adrian Hunter
2018-05-09 11:43 ` [PATCH RFC 04/19] x86: kcore: Give entry trampolines all the same offset in kcore Adrian Hunter
2018-05-09 11:43 ` [PATCH RFC 05/19] perf tools: Use the _stest symbol to identify the kernel map when loading kcore Adrian Hunter
2018-05-16 18:04 ` [tip:perf/core] perf tools: Use the "_stest" " tip-bot for Adrian Hunter
2018-05-09 11:43 ` [PATCH RFC 06/19] perf tools: Fix kernel_start for KPTI on x86_64 Adrian Hunter
2018-05-09 17:08 ` Arnaldo Carvalho de Melo
2018-05-09 11:43 ` [PATCH RFC 07/19] perf tools: Workaround missing maps for x86_64 KPTI entry trampolines Adrian Hunter
2018-05-09 17:07 ` Arnaldo Carvalho de Melo
2018-05-10 19:08 ` Hunter, Adrian
2018-05-10 20:15 ` Arnaldo Carvalho de Melo
2018-05-10 20:19 ` Arnaldo Carvalho de Melo
2018-05-10 20:47 ` Arnaldo Carvalho de Melo
2018-05-11 11:18 ` Adrian Hunter
2018-05-11 14:45 ` Arnaldo Carvalho de Melo
2018-05-14 13:02 ` Adrian Hunter
2018-05-11 11:15 ` Adrian Hunter
2018-05-15 10:30 ` Jiri Olsa
2018-05-15 10:40 ` Adrian Hunter
2018-05-09 11:43 ` [PATCH RFC 08/19] perf tools: Fix map_groups__split_kallsyms() for entry trampoline symbols Adrian Hunter
2018-05-09 11:43 ` [PATCH RFC 09/19] perf tools: Allow for special kernel maps Adrian Hunter
2018-05-09 11:43 ` [PATCH RFC 10/19] perf tools: Create maps for x86_64 KPTI entry trampolines Adrian Hunter
2018-05-14 8:32 ` Ingo Molnar
2018-05-09 11:43 ` [PATCH RFC 11/19] perf tools: Synthesize and process mmap events " Adrian Hunter
2018-05-15 10:49 ` Jiri Olsa
2018-05-09 11:43 ` [PATCH RFC 12/19] perf buildid-cache: kcore_copy: Keep phdr data in a list Adrian Hunter
2018-05-09 11:43 ` [PATCH RFC 13/19] perf buildid-cache: kcore_copy: Keep a count of phdrs Adrian Hunter
2018-05-09 11:43 ` [PATCH RFC 14/19] perf buildid-cache: kcore_copy: Calculate offset from phnum Adrian Hunter
2018-05-09 11:43 ` [PATCH RFC 15/19] perf buildid-cache: kcore_copy: Layout sections Adrian Hunter
2018-05-09 11:43 ` [PATCH RFC 16/19] perf buildid-cache: kcore_copy: Iterate phdrs Adrian Hunter
2018-05-09 11:43 ` [PATCH RFC 17/19] perf buildid-cache: kcore_copy: Get rid of kernel_map Adrian Hunter
2018-05-09 11:43 ` [PATCH RFC 18/19] perf buildid-cache: kcore_copy: Copy x86_64 entry trampoline sections Adrian Hunter
2018-05-09 11:43 ` [PATCH RFC 19/19] perf buildid-cache: kcore_copy: Amend the offset of sections that remap kernel text Adrian Hunter
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