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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 V2 02/20] kallsyms, x86: Export addresses of syscall trampolines
Date: Thu, 17 May 2018 12:21:50 +0300	[thread overview]
Message-ID: <1526548928-20790-3-git-send-email-adrian.hunter@intel.com> (raw)
In-Reply-To: <1526548928-20790-1-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

  parent reply	other threads:[~2018-05-17  9:23 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-17  9:21 [PATCH V2 00/20] perf tools and x86 PTI entry trampolines Adrian Hunter
2018-05-17  9:21 ` [PATCH V2 01/20] kallsyms: Simplify update_iter_mod() Adrian Hunter
2018-05-17  9:21 ` Adrian Hunter [this message]
2018-05-17  9:21 ` [PATCH V2 03/20] x86: Add entry trampolines to kcore Adrian Hunter
2018-05-17 17:52   ` Dave Hansen
2018-05-17 18:09     ` Arnaldo Carvalho de Melo
2018-05-17  9:21 ` [PATCH V2 04/20] x86: kcore: Give entry trampolines all the same offset in kcore Adrian Hunter
2018-05-17 17:54   ` Dave Hansen
2018-05-17  9:21 ` [PATCH V2 05/20] perf tools: Add machine__is() to identify machine arch Adrian Hunter
2018-05-19 11:47   ` [tip:perf/core] perf machine: " tip-bot for Adrian Hunter
2018-05-17  9:21 ` [PATCH V2 06/20] perf tools: Fix kernel_start for PTI on x86 Adrian Hunter
2018-05-19 11:48   ` [tip:perf/core] " tip-bot for Adrian Hunter
2018-05-17  9:21 ` [PATCH V2 07/20] perf tools: Add machine__nr_cpus_avail() Adrian Hunter
2018-05-17  9:21 ` [PATCH V2 08/20] perf tools: Workaround missing maps for x86 PTI entry trampolines Adrian Hunter
2018-05-17  9:21 ` [PATCH V2 09/20] perf tools: Fix map_groups__split_kallsyms() for entry trampoline symbols Adrian Hunter
2018-05-17  9:21 ` [PATCH V2 10/20] perf tools: Allow for extra kernel maps Adrian Hunter
2018-05-17  9:21 ` [PATCH V2 11/20] perf tools: Create maps for x86 PTI entry trampolines Adrian Hunter
2018-05-17  9:22 ` [PATCH V2 12/20] perf tools: Synthesize and process mmap events " Adrian Hunter
2018-05-17  9:22 ` [PATCH V2 13/20] perf buildid-cache: kcore_copy: Keep phdr data in a list Adrian Hunter
2018-05-17  9:22 ` [PATCH V2 14/20] perf buildid-cache: kcore_copy: Keep a count of phdrs Adrian Hunter
2018-05-17  9:22 ` [PATCH V2 15/20] perf buildid-cache: kcore_copy: Calculate offset from phnum Adrian Hunter
2018-05-17  9:22 ` [PATCH V2 16/20] perf buildid-cache: kcore_copy: Layout sections Adrian Hunter
2018-05-17  9:22 ` [PATCH V2 17/20] perf buildid-cache: kcore_copy: Iterate phdrs Adrian Hunter
2018-05-17  9:22 ` [PATCH V2 18/20] perf buildid-cache: kcore_copy: Get rid of kernel_map Adrian Hunter
2018-05-17  9:22 ` [PATCH V2 19/20] perf buildid-cache: kcore_copy: Copy x86 PTI entry trampoline sections Adrian Hunter
2018-05-17  9:22 ` [PATCH V2 20/20] perf buildid-cache: kcore_copy: Amend the offset of sections that remap kernel text Adrian Hunter

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