[PATCH V2 00/20] perf tools and x86 PTI entry trampolines

[PATCH V2 00/20] perf tools and x86 PTI entry trampolines

[Adrian Hunter]

Hi

Here is V2 of patches to support x86 PTI entry trampolines in perf tools.

Patches also here:

	http://git.infradead.org/users/ahunter/linux-perf.git/shortlog/refs/heads/perf-tools-kpti-v2

	git://git.infradead.org/users/ahunter/linux-perf.git perf-tools-kpti-v2

V1 patches also here:

	http://git.infradead.org/users/ahunter/linux-perf.git/shortlog/refs/heads/perf-tools-kpti-v1

	git://git.infradead.org/users/ahunter/linux-perf.git perf-tools-kpti-v1



Changes Since V1:

	perf tools: Use the _stest symbol to identify the kernel map when loading kcore
		Dropped because it has been applied

	perf tools: Add machine__is() to identify machine arch
		New patch

	perf tools: Fix kernel_start for PTI on x86
		Moved definition of machine__is() to a separate patch

	perf tools: Add machine__nr_cpus_avail()
		New patch

	perf tools: Workaround missing maps for x86 PTI entry trampolines
		Use machine__nr_cpus_avail()

	perf tools: Create maps for x86 PTI entry trampolines
		Re-based

Changes Since RFC:

	Change description 'x86_64 KPTI' to 'x86 PTI'

	Rename 'special' kernel map to 'extra' kernel map etc

	kallsyms: Simplify update_iter_mod()
		Expand commit message

	perf tools: Fix kernel_start for PTI on x86
		Amend machine__is() to check if machine is NULL

	perf tools: Workaround missing maps for x86 PTI entry trampolines
		Simplify find_entry_trampoline()
		Add comment before struct extra_kernel_map /* Kernel-space
		maps for symbols that are outside the main kernel map and
		module maps */

	perf tools: Create maps for x86 PTI entry trampolines
		Move code presently only used by x86_64 into arch

	perf tools: Synthesize and process mmap events for x86 PTI entry
	trampolines
		Fix spelling 'kernal' -> 'kernel'
		Rename 'special' kernel map to 'extra' kernel map etc
		Move code presently only used by x86_64 into arch

	perf buildid-cache: kcore_copy: Keep phdr data in a list
		Expand commit message
		Rename 'list' -> 'node'

	perf buildid-cache: kcore_copy: Get rid of kernel_map
		Expand commit message
		Add phdr_data__new()
		Rename 'kcore_copy__new_phdr' -> 'kcore_copy_info__addnew'


Original Cover email:

Perf tools do not know about x86 PTI entry trampolines - see example
below.  These patches add a workaround, namely "perf tools: Workaround
missing maps for x86 PTI entry trampolines", which has the limitation
that it hard codes the addresses.  Note that the workaround will work for
old kernels and old perf.data files, but not for future kernels if the
trampoline addresses are ever changed.

At present, perf tools uses /proc/kallsyms to construct a memory map for
the kernel.  Recording such a map in the perf.data file is necessary to
deal with kernel relocation and KASLR.

While it is reasonable on its own terms, to add symbols for the trampolines
to /proc/kallsyms, the motivation here is to have perf tools use them to
create memory maps in the same fashion as is done for the kernel text.

So the first 2 patches add symbols to /proc/kallsyms for the trampolines:

      kallsyms: Simplify update_iter_mod()
      kallsyms, x86: Export addresses of syscall trampolines

perf tools have the ability to use /proc/kcore (in conjunction with
/proc/kallsyms) as the kernel image. So the next 2 patches add program
headers for the trampolines to the kcore ELF:

      x86: Add entry trampolines to kcore
      x86: kcore: Give entry trampolines all the same offset in kcore

It is worth noting that, with the kcore changes alone, perf tools require
no changes to recognise the trampolines when using /proc/kcore.

Similarly, if perf tools are used with a matching kallsyms only (by denying
access to /proc/kcore or a vmlinux image), then the kallsyms patches are
sufficient to recognise the trampolines with no changes needed to the
tools.

However, in the general case, when using vmlinux or dealing with
relocations, perf tools needs memory maps for the trampolines.  Because the
kernel text map is constructed as a special case, using the same approach
for the trampolines means treating them as a special case also, which
requires a number of changes to perf tools, and the remaining patches deal
with that.


Example: make a program that does lots of small syscalls e.g.

	$ cat uname_x_n.c

	#include <sys/utsname.h>
	#include <stdlib.h>

	int main(int argc, char *argv[])
	{
		long n = argc > 1 ? strtol(argv[1], NULL, 0) : 0;
		struct utsname u;

		while (n--)
			uname(&u);

		return 0;
	}

and then:

	sudo perf record uname_x_n 100000
	sudo perf report --stdio

Before the changes, there are unknown symbols:

 # Overhead  Command    Shared Object     Symbol
 # ........  .........  ................  ..................................
 #
    41.91%  uname_x_n  [kernel.vmlinux]  [k] syscall_return_via_sysret
    19.22%  uname_x_n  [kernel.vmlinux]  [k] copy_user_enhanced_fast_string
    18.70%  uname_x_n  [unknown]         [k] 0xfffffe00000e201b
     4.09%  uname_x_n  libc-2.19.so      [.] __GI___uname
     3.08%  uname_x_n  [kernel.vmlinux]  [k] do_syscall_64
     3.02%  uname_x_n  [unknown]         [k] 0xfffffe00000e2025
     2.32%  uname_x_n  [kernel.vmlinux]  [k] down_read
     2.27%  uname_x_n  ld-2.19.so        [.] _dl_start
     1.97%  uname_x_n  [unknown]         [k] 0xfffffe00000e201e
     1.25%  uname_x_n  [kernel.vmlinux]  [k] up_read
     1.02%  uname_x_n  [unknown]         [k] 0xfffffe00000e200c
     0.99%  uname_x_n  [kernel.vmlinux]  [k] entry_SYSCALL_64
     0.16%  uname_x_n  [kernel.vmlinux]  [k] flush_signal_handlers
     0.01%  perf       [kernel.vmlinux]  [k] native_sched_clock
     0.00%  perf       [kernel.vmlinux]  [k] native_write_msr

After the changes there are not:

 # Overhead  Command    Shared Object     Symbol
 # ........  .........  ................  ..................................
 #
    41.91%  uname_x_n  [kernel.vmlinux]  [k] syscall_return_via_sysret
    24.70%  uname_x_n  [kernel.vmlinux]  [k] entry_SYSCALL_64_trampoline
    19.22%  uname_x_n  [kernel.vmlinux]  [k] copy_user_enhanced_fast_string
     4.09%  uname_x_n  libc-2.19.so      [.] __GI___uname
     3.08%  uname_x_n  [kernel.vmlinux]  [k] do_syscall_64
     2.32%  uname_x_n  [kernel.vmlinux]  [k] down_read
     2.27%  uname_x_n  ld-2.19.so        [.] _dl_start
     1.25%  uname_x_n  [kernel.vmlinux]  [k] up_read
     0.99%  uname_x_n  [kernel.vmlinux]  [k] entry_SYSCALL_64
     0.16%  uname_x_n  [kernel.vmlinux]  [k] flush_signal_handlers
     0.01%  perf       [kernel.vmlinux]  [k] native_sched_clock
     0.00%  perf       [kernel.vmlinux]  [k] native_write_msr


Adrian Hunter (18):
      kallsyms: Simplify update_iter_mod()
      x86: kcore: Give entry trampolines all the same offset in kcore
      perf tools: Add machine__is() to identify machine arch
      perf tools: Fix kernel_start for PTI on x86
      perf tools: Add machine__nr_cpus_avail()
      perf tools: Workaround missing maps for x86 PTI entry trampolines
      perf tools: Fix map_groups__split_kallsyms() for entry trampoline symbols
      perf tools: Allow for extra kernel maps
      perf tools: Create maps for x86 PTI entry trampolines
      perf tools: Synthesize and process mmap events for x86 PTI entry trampolines
      perf buildid-cache: kcore_copy: Keep phdr data in a list
      perf buildid-cache: kcore_copy: Keep a count of phdrs
      perf buildid-cache: kcore_copy: Calculate offset from phnum
      perf buildid-cache: kcore_copy: Layout sections
      perf buildid-cache: kcore_copy: Iterate phdrs
      perf buildid-cache: kcore_copy: Get rid of kernel_map
      perf buildid-cache: kcore_copy: Copy x86 PTI entry trampoline sections
      perf buildid-cache: kcore_copy: Amend the offset of sections that remap kernel text

Alexander Shishkin (2):
      kallsyms, x86: Export addresses of syscall trampolines
      x86: Add entry trampolines to kcore

 arch/x86/mm/cpu_entry_area.c       |  28 +++++
 fs/proc/kcore.c                    |   7 +-
 include/linux/kcore.h              |  13 +++
 kernel/kallsyms.c                  |  46 +++++---
 tools/perf/arch/x86/util/Build     |   2 +
 tools/perf/arch/x86/util/event.c   |  76 +++++++++++++
 tools/perf/arch/x86/util/machine.c | 103 +++++++++++++++++
 tools/perf/util/env.c              |  31 ++++++
 tools/perf/util/env.h              |   3 +
 tools/perf/util/event.c            |  36 ++++--
 tools/perf/util/event.h            |   8 ++
 tools/perf/util/machine.c          | 191 ++++++++++++++++++++++++++++++--
 tools/perf/util/machine.h          |  25 +++++
 tools/perf/util/map.c              |  22 +++-
 tools/perf/util/map.h              |  15 ++-
 tools/perf/util/symbol-elf.c       | 219 +++++++++++++++++++++++++++++++------
 tools/perf/util/symbol.c           |  49 +++++++--
 17 files changed, 794 insertions(+), 80 deletions(-)
 create mode 100644 tools/perf/arch/x86/util/event.c
 create mode 100644 tools/perf/arch/x86/util/machine.c


Regards
Adrian

[PATCH V2 01/20] kallsyms: Simplify update_iter_mod()

[Adrian Hunter]

The logic in update_iter_mod() is overcomplicated and gets worse every time
another get_ksymbol_* function is added.

In preparation for adding another get_ksymbol_* function, simplify logic in
update_iter_mod().

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 kernel/kallsyms.c | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index a23e21ada81b..eda4b0222dab 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -510,23 +510,15 @@ static int update_iter_mod(struct kallsym_iter *iter, loff_t pos)
 {
 	iter->pos = pos;
 
-	if (iter->pos_ftrace_mod_end > 0 &&
-	    iter->pos_ftrace_mod_end < iter->pos)
-		return get_ksymbol_bpf(iter);
-
-	if (iter->pos_mod_end > 0 &&
-	    iter->pos_mod_end < iter->pos) {
-		if (!get_ksymbol_ftrace_mod(iter))
-			return get_ksymbol_bpf(iter);
+	if ((!iter->pos_mod_end || iter->pos_mod_end > pos) &&
+	    get_ksymbol_mod(iter))
 		return 1;
-	}
 
-	if (!get_ksymbol_mod(iter)) {
-		if (!get_ksymbol_ftrace_mod(iter))
-			return get_ksymbol_bpf(iter);
-	}
+	if ((!iter->pos_ftrace_mod_end || iter->pos_ftrace_mod_end > pos) &&
+	    get_ksymbol_ftrace_mod(iter))
+		return 1;
 
-	return 1;
+	return get_ksymbol_bpf(iter);
 }
 
 /* Returns false if pos at or past end of file. */
-- 
1.9.1

[PATCH V2 02/20] kallsyms, x86: Export addresses of syscall trampolines

[Adrian Hunter]

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

[PATCH V2 03/20] x86: Add entry trampolines to kcore

[Adrian Hunter]

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 | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c
index d1da5cf4b2de..fb1fbc8538fa 100644
--- a/arch/x86/mm/cpu_entry_area.c
+++ b/arch/x86/mm/cpu_entry_area.c
@@ -3,6 +3,7 @@
 #include <linux/spinlock.h>
 #include <linux/percpu.h>
 #include <linux/kallsyms.h>
+#include <linux/kcore.h>
 
 #include <asm/cpu_entry_area.h>
 #include <asm/pgtable.h>
@@ -14,6 +15,7 @@
 #ifdef CONFIG_X86_64
 static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
 	[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]);
+static DEFINE_PER_CPU(struct kcore_list, kcore_entry_trampoline);
 #endif
 
 struct cpu_entry_area *get_cpu_entry_area(int cpu)
@@ -147,6 +149,9 @@ static void __init setup_cpu_entry_area(int cpu)
 
 	cea_set_pte(&get_cpu_entry_area(cpu)->entry_trampoline,
 		     __pa_symbol(_entry_trampoline), PAGE_KERNEL_RX);
+	kclist_add(&per_cpu(kcore_entry_trampoline, cpu),
+		   &get_cpu_entry_area(cpu)->entry_trampoline, PAGE_SIZE,
+		   KCORE_TEXT);
 #endif
 	percpu_setup_debug_store(cpu);
 }
-- 
1.9.1

[PATCH V2 04/20] x86: kcore: Give entry trampolines all the same offset in kcore

[Adrian Hunter]

Entry trampolines all map to the same page.  Represent that by giving the
corresponding program headers in kcore the same offset.

This has the benefit that, when perf tools uses /proc/kcore as a source for
kernel object code, samples from different CPU trampolines are aggregated
together.  Note, such aggregation is normal for profiling i.e. people want
to profile the object code, not every different virtual address the object
code might be mapped to (across different processes for example).

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 arch/x86/mm/cpu_entry_area.c |  6 +++---
 fs/proc/kcore.c              |  7 +++++--
 include/linux/kcore.h        | 13 +++++++++++++
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c
index fb1fbc8538fa..faea80e9bbd2 100644
--- a/arch/x86/mm/cpu_entry_area.c
+++ b/arch/x86/mm/cpu_entry_area.c
@@ -149,9 +149,9 @@ static void __init setup_cpu_entry_area(int cpu)
 
 	cea_set_pte(&get_cpu_entry_area(cpu)->entry_trampoline,
 		     __pa_symbol(_entry_trampoline), PAGE_KERNEL_RX);
-	kclist_add(&per_cpu(kcore_entry_trampoline, cpu),
-		   &get_cpu_entry_area(cpu)->entry_trampoline, PAGE_SIZE,
-		   KCORE_TEXT);
+	kclist_add_remap(&per_cpu(kcore_entry_trampoline, cpu),
+			 _entry_trampoline,
+			 &get_cpu_entry_area(cpu)->entry_trampoline, PAGE_SIZE);
 #endif
 	percpu_setup_debug_store(cpu);
 }
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index e64ecb9f2720..00282f134336 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -383,8 +383,11 @@ static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff)
 		phdr->p_type	= PT_LOAD;
 		phdr->p_flags	= PF_R|PF_W|PF_X;
 		phdr->p_offset	= kc_vaddr_to_offset(m->addr) + dataoff;
-		phdr->p_vaddr	= (size_t)m->addr;
-		if (m->type == KCORE_RAM || m->type == KCORE_TEXT)
+		if (m->type == KCORE_REMAP)
+			phdr->p_vaddr	= (size_t)m->vaddr;
+		else
+			phdr->p_vaddr	= (size_t)m->addr;
+		if (m->type == KCORE_RAM || m->type == KCORE_TEXT || m->type == KCORE_REMAP)
 			phdr->p_paddr	= __pa(m->addr);
 		else
 			phdr->p_paddr	= (elf_addr_t)-1;
diff --git a/include/linux/kcore.h b/include/linux/kcore.h
index 80db19d3a505..3a11ce51e137 100644
--- a/include/linux/kcore.h
+++ b/include/linux/kcore.h
@@ -12,11 +12,13 @@ enum kcore_type {
 	KCORE_VMEMMAP,
 	KCORE_USER,
 	KCORE_OTHER,
+	KCORE_REMAP,
 };
 
 struct kcore_list {
 	struct list_head list;
 	unsigned long addr;
+	unsigned long vaddr;
 	size_t size;
 	int type;
 };
@@ -30,11 +32,22 @@ struct vmcore {
 
 #ifdef CONFIG_PROC_KCORE
 extern void kclist_add(struct kcore_list *, void *, size_t, int type);
+static inline
+void kclist_add_remap(struct kcore_list *m, void *addr, void *vaddr, size_t sz)
+{
+	m->vaddr = (unsigned long)vaddr;
+	kclist_add(m, addr, sz, KCORE_REMAP);
+}
 #else
 static inline
 void kclist_add(struct kcore_list *new, void *addr, size_t size, int type)
 {
 }
+
+static inline
+void kclist_add_remap(struct kcore_list *m, void *addr, void *vaddr, size_t sz)
+{
+}
 #endif
 
 #endif /* _LINUX_KCORE_H */
-- 
1.9.1

[PATCH V2 05/20] perf tools: Add machine__is() to identify machine arch

[Adrian Hunter]

Add a function to identify the machine architecture.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/env.c     | 18 ++++++++++++++++++
 tools/perf/util/env.h     |  2 ++
 tools/perf/util/machine.c |  9 +++++++++
 tools/perf/util/machine.h |  2 ++
 4 files changed, 31 insertions(+)

diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
index 4c842762e3f2..319fb0a0d05e 100644
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -93,6 +93,24 @@ int perf_env__read_cpu_topology_map(struct perf_env *env)
 	return 0;
 }
 
+static int perf_env__read_arch(struct perf_env *env)
+{
+	struct utsname uts;
+
+	if (env->arch)
+		return 0;
+
+	if (!uname(&uts))
+		env->arch = strdup(uts.machine);
+
+	return env->arch ? 0 : -ENOMEM;
+}
+
+const char *perf_env__raw_arch(struct perf_env *env)
+{
+	return env && !perf_env__read_arch(env) ? env->arch : "unknown";
+}
+
 void cpu_cache_level__free(struct cpu_cache_level *cache)
 {
 	free(cache->type);
diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
index c4ef2e523367..62e193948608 100644
--- a/tools/perf/util/env.h
+++ b/tools/perf/util/env.h
@@ -76,4 +76,6 @@ struct perf_env {
 void cpu_cache_level__free(struct cpu_cache_level *cache);
 
 const char *perf_env__arch(struct perf_env *env);
+const char *perf_env__raw_arch(struct perf_env *env);
+
 #endif /* __PERF_ENV_H */
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 72a351613d85..dcdf78ddc470 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2296,6 +2296,15 @@ int machine__set_current_tid(struct machine *machine, int cpu, pid_t pid,
 	return 0;
 }
 
+/*
+ * Compares the raw arch string. N.B. see instead perf_env__arch() if a
+ * normalized arch is needed.
+ */
+bool machine__is(struct machine *machine, const char *arch)
+{
+	return machine && !strcmp(perf_env__raw_arch(machine->env), arch);
+}
+
 int machine__get_kernel_start(struct machine *machine)
 {
 	struct map *map = machine__kernel_map(machine);
diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
index 388fb4741c54..b31d33b5aa2a 100644
--- a/tools/perf/util/machine.h
+++ b/tools/perf/util/machine.h
@@ -188,6 +188,8 @@ static inline bool machine__is_host(struct machine *machine)
 	return machine ? machine->pid == HOST_KERNEL_ID : false;
 }
 
+bool machine__is(struct machine *machine, const char *arch);
+
 struct thread *__machine__findnew_thread(struct machine *machine, pid_t pid, pid_t tid);
 struct thread *machine__findnew_thread(struct machine *machine, pid_t pid, pid_t tid);
 
-- 
1.9.1

[PATCH V2 06/20] perf tools: Fix kernel_start for PTI on x86

[Adrian Hunter]

On x86_64, PTI entry trampolines are less than the start of kernel text,
but still above 2^63. So leave kernel_start = 1ULL << 63 for x86_64.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/machine.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index dcdf78ddc470..4281a9b65aba 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2321,7 +2321,12 @@ int machine__get_kernel_start(struct machine *machine)
 	machine->kernel_start = 1ULL << 63;
 	if (map) {
 		err = map__load(map);
-		if (!err)
+		/*
+		 * On x86_64, PTI entry trampolines are less than the
+		 * start of kernel text, but still above 2^63. So leave
+		 * kernel_start = 1ULL << 63 for x86_64.
+		 */
+		if (!err && !machine__is(machine, "x86_64"))
 			machine->kernel_start = map->start;
 	}
 	return err;
-- 
1.9.1

[PATCH V2 07/20] perf tools: Add machine__nr_cpus_avail()

[Adrian Hunter]

Add a function to return the number of the machine's available CPUs.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/env.c     | 13 +++++++++++++
 tools/perf/util/env.h     |  1 +
 tools/perf/util/machine.c |  5 +++++
 tools/perf/util/machine.h |  1 +
 4 files changed, 20 insertions(+)

diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
index 319fb0a0d05e..59f38c7693f8 100644
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -106,11 +106,24 @@ static int perf_env__read_arch(struct perf_env *env)
 	return env->arch ? 0 : -ENOMEM;
 }
 
+static int perf_env__read_nr_cpus_avail(struct perf_env *env)
+{
+	if (env->nr_cpus_avail == 0)
+		env->nr_cpus_avail = cpu__max_present_cpu();
+
+	return env->nr_cpus_avail ? 0 : -ENOENT;
+}
+
 const char *perf_env__raw_arch(struct perf_env *env)
 {
 	return env && !perf_env__read_arch(env) ? env->arch : "unknown";
 }
 
+int perf_env__nr_cpus_avail(struct perf_env *env)
+{
+	return env && !perf_env__read_nr_cpus_avail(env) ? env->nr_cpus_avail : 0;
+}
+
 void cpu_cache_level__free(struct cpu_cache_level *cache)
 {
 	free(cache->type);
diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
index 62e193948608..1f3ccc368530 100644
--- a/tools/perf/util/env.h
+++ b/tools/perf/util/env.h
@@ -77,5 +77,6 @@ struct perf_env {
 
 const char *perf_env__arch(struct perf_env *env);
 const char *perf_env__raw_arch(struct perf_env *env);
+int perf_env__nr_cpus_avail(struct perf_env *env);
 
 #endif /* __PERF_ENV_H */
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 4281a9b65aba..10a440025174 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2305,6 +2305,11 @@ bool machine__is(struct machine *machine, const char *arch)
 	return machine && !strcmp(perf_env__raw_arch(machine->env), arch);
 }
 
+int machine__nr_cpus_avail(struct machine *machine)
+{
+	return machine ? perf_env__nr_cpus_avail(machine->env) : 0;
+}
+
 int machine__get_kernel_start(struct machine *machine)
 {
 	struct map *map = machine__kernel_map(machine);
diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
index b31d33b5aa2a..2d2b092ba753 100644
--- a/tools/perf/util/machine.h
+++ b/tools/perf/util/machine.h
@@ -189,6 +189,7 @@ static inline bool machine__is_host(struct machine *machine)
 }
 
 bool machine__is(struct machine *machine, const char *arch);
+int machine__nr_cpus_avail(struct machine *machine);
 
 struct thread *__machine__findnew_thread(struct machine *machine, pid_t pid, pid_t tid);
 struct thread *machine__findnew_thread(struct machine *machine, pid_t pid, pid_t tid);
-- 
1.9.1

[PATCH V2 08/20] perf tools: Workaround missing maps for x86 PTI entry trampolines

[Adrian Hunter]

On x86_64 the PTI entry trampolines are not in the kernel map created by
perf tools. That results in the addresses having no symbols and prevents
annotation. It also causes Intel PT to have decoding errors at the
trampoline addresses. Workaround that by creating maps for the trampolines.
At present the kernel does not export information revealing where the
trampolines are. Until that happens, the addresses are hardcoded.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/machine.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/machine.h |  3 ++
 tools/perf/util/symbol.c  | 12 +++---
 3 files changed, 106 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 10a440025174..13fb283635ad 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -851,6 +851,102 @@ static int machine__get_running_kernel_start(struct machine *machine,
 	return 0;
 }
 
+/* Kernel-space maps for symbols that are outside the main kernel map and module maps */
+struct extra_kernel_map {
+	u64 start;
+	u64 end;
+	u64 pgoff;
+};
+
+static int machine__create_extra_kernel_map(struct machine *machine,
+					    struct dso *kernel,
+					    struct extra_kernel_map *xm)
+{
+	struct kmap *kmap;
+	struct map *map;
+
+	map = map__new2(xm->start, kernel);
+	if (!map)
+		return -1;
+
+	map->end   = xm->end;
+	map->pgoff = xm->pgoff;
+
+	kmap = map__kmap(map);
+
+	kmap->kmaps = &machine->kmaps;
+
+	map_groups__insert(&machine->kmaps, map);
+
+	pr_debug2("Added extra kernel map %" PRIx64 "-%" PRIx64 "\n",
+		  map->start, map->end);
+
+	map__put(map);
+
+	return 0;
+}
+
+static u64 find_entry_trampoline(struct dso *dso)
+{
+	/* Duplicates are removed so lookup all aliases */
+	const char *syms[] = {
+		"_entry_trampoline",
+		"__entry_trampoline_start",
+		"entry_SYSCALL_64_trampoline",
+	};
+	struct symbol *sym = dso__first_symbol(dso);
+	unsigned int i;
+
+	for (; sym; sym = dso__next_symbol(sym)) {
+		if (sym->binding != STB_GLOBAL)
+			continue;
+		for (i = 0; i < ARRAY_SIZE(syms); i++) {
+			if (!strcmp(sym->name, syms[i]))
+				return sym->start;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * These values can be used for kernels that do not have symbols for the entry
+ * trampolines in kallsyms.
+ */
+#define X86_64_CPU_ENTRY_AREA_PER_CPU	0xfffffe0000000000ULL
+#define X86_64_CPU_ENTRY_AREA_SIZE	0x2c000
+#define X86_64_ENTRY_TRAMPOLINE		0x6000
+
+/* Map x86_64 PTI entry trampolines */
+int machine__map_x86_64_entry_trampolines(struct machine *machine,
+					  struct dso *kernel)
+{
+	u64 pgoff = find_entry_trampoline(kernel);
+	int nr_cpus_avail, cpu;
+
+	if (!pgoff)
+		return 0;
+
+	nr_cpus_avail = machine__nr_cpus_avail(machine);
+
+	/* Add a 1 page map for each CPU's entry trampoline */
+	for (cpu = 0; cpu < nr_cpus_avail; cpu++) {
+		u64 va = X86_64_CPU_ENTRY_AREA_PER_CPU +
+			 cpu * X86_64_CPU_ENTRY_AREA_SIZE +
+			 X86_64_ENTRY_TRAMPOLINE;
+		struct extra_kernel_map xm = {
+			.start = va,
+			.end   = va + page_size,
+			.pgoff = pgoff,
+		};
+
+		if (machine__create_extra_kernel_map(machine, kernel, &xm) < 0)
+			return -1;
+	}
+
+	return 0;
+}
+
 static int
 __machine__create_kernel_maps(struct machine *machine, struct dso *kernel)
 {
diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
index 2d2b092ba753..b6a1c3eb3d65 100644
--- a/tools/perf/util/machine.h
+++ b/tools/perf/util/machine.h
@@ -268,4 +268,7 @@ int machine__set_current_tid(struct machine *machine, int cpu, pid_t pid,
  */
 char *machine__resolve_kernel_addr(void *vmachine, unsigned long long *addrp, char **modp);
 
+int machine__map_x86_64_entry_trampolines(struct machine *machine,
+					  struct dso *kernel);
+
 #endif /* __PERF_MACHINE_H */
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 4a39f4d0a174..701144094183 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1490,20 +1490,22 @@ int dso__load(struct dso *dso, struct map *map)
 		goto out;
 	}
 
+	if (map->groups && map->groups->machine)
+		machine = map->groups->machine;
+	else
+		machine = NULL;
+
 	if (dso->kernel) {
 		if (dso->kernel == DSO_TYPE_KERNEL)
 			ret = dso__load_kernel_sym(dso, map);
 		else if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
 			ret = dso__load_guest_kernel_sym(dso, map);
 
+		if (machine__is(machine, "x86_64"))
+			machine__map_x86_64_entry_trampolines(machine, dso);
 		goto out;
 	}
 
-	if (map->groups && map->groups->machine)
-		machine = map->groups->machine;
-	else
-		machine = NULL;
-
 	dso->adjust_symbols = 0;
 
 	if (perfmap) {
-- 
1.9.1

[PATCH V2 09/20] perf tools: Fix map_groups__split_kallsyms() for entry trampoline symbols

[Adrian Hunter]

When kernel symbols are derived from /proc/kallsyms only (not using vmlinux
or /proc/kcore) map_groups__split_kallsyms() is used. However that function
makes assumptions that are not true with entry trampoline symbols. For now,
remove the entry trampoline symbols at that point, as they are no longer
needed at that point.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/map.h    |  8 ++++++++
 tools/perf/util/symbol.c | 13 +++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index f1afe1ab6ff7..fafcc375ed37 100644
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -8,6 +8,7 @@
 #include <linux/rbtree.h>
 #include <pthread.h>
 #include <stdio.h>
+#include <string.h>
 #include <stdbool.h>
 #include <linux/types.h>
 #include "rwsem.h"
@@ -239,4 +240,11 @@ static inline bool __map__is_kmodule(const struct map *map)
 
 bool map__has_symbols(const struct map *map);
 
+#define ENTRY_TRAMPOLINE_NAME "__entry_SYSCALL_64_trampoline"
+
+static inline bool is_entry_trampoline(const char *name)
+{
+	return !strcmp(name, ENTRY_TRAMPOLINE_NAME);
+}
+
 #endif /* __PERF_MAP_H */
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 701144094183..929058da6727 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -737,12 +737,15 @@ static int map_groups__split_kallsyms(struct map_groups *kmaps, struct dso *dso,
 	struct rb_root *root = &dso->symbols;
 	struct rb_node *next = rb_first(root);
 	int kernel_range = 0;
+	bool x86_64;
 
 	if (!kmaps)
 		return -1;
 
 	machine = kmaps->machine;
 
+	x86_64 = machine__is(machine, "x86_64");
+
 	while (next) {
 		char *module;
 
@@ -790,6 +793,16 @@ static int map_groups__split_kallsyms(struct map_groups *kmaps, struct dso *dso,
 			 */
 			pos->start = curr_map->map_ip(curr_map, pos->start);
 			pos->end   = curr_map->map_ip(curr_map, pos->end);
+		} else if (x86_64 && is_entry_trampoline(pos->name)) {
+			/*
+			 * These symbols are not needed anymore since the
+			 * trampoline maps refer to the text section and it's
+			 * symbols instead. Avoid having to deal with
+			 * relocations, and the assumption that the first symbol
+			 * is the start of kernel text, by simply removing the
+			 * symbols at this point.
+			 */
+			goto discard_symbol;
 		} else if (curr_map != initial_map) {
 			char dso_name[PATH_MAX];
 			struct dso *ndso;
-- 
1.9.1

[PATCH V2 10/20] perf tools: Allow for extra kernel maps

[Adrian Hunter]

Identify extra kernel maps by name so that they can be distinguished from
the kernel map and module maps.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/event.c   |  2 +-
 tools/perf/util/machine.c |  8 ++++++--
 tools/perf/util/map.c     | 22 ++++++++++++++++++----
 tools/perf/util/map.h     |  7 ++++++-
 tools/perf/util/symbol.c  |  7 +++----
 5 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 244135b5ea43..aafa9878465f 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -487,7 +487,7 @@ int perf_event__synthesize_modules(struct perf_tool *tool,
 	for (pos = maps__first(maps); pos; pos = map__next(pos)) {
 		size_t size;
 
-		if (__map__is_kernel(pos))
+		if (!__map__is_kmodule(pos))
 			continue;
 
 		size = PERF_ALIGN(pos->dso->long_name_len + 1, sizeof(u64));
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 13fb283635ad..fb609f5e31e2 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -856,6 +856,7 @@ struct extra_kernel_map {
 	u64 start;
 	u64 end;
 	u64 pgoff;
+	char name[KMAP_NAME_LEN];
 };
 
 static int machine__create_extra_kernel_map(struct machine *machine,
@@ -875,11 +876,12 @@ static int machine__create_extra_kernel_map(struct machine *machine,
 	kmap = map__kmap(map);
 
 	kmap->kmaps = &machine->kmaps;
+	strlcpy(kmap->name, xm->name, KMAP_NAME_LEN);
 
 	map_groups__insert(&machine->kmaps, map);
 
-	pr_debug2("Added extra kernel map %" PRIx64 "-%" PRIx64 "\n",
-		  map->start, map->end);
+	pr_debug2("Added extra kernel map %s %" PRIx64 "-%" PRIx64 "\n",
+		  kmap->name, map->start, map->end);
 
 	map__put(map);
 
@@ -940,6 +942,8 @@ int machine__map_x86_64_entry_trampolines(struct machine *machine,
 			.pgoff = pgoff,
 		};
 
+		strlcpy(xm.name, ENTRY_TRAMPOLINE_NAME, KMAP_NAME_LEN);
+
 		if (machine__create_extra_kernel_map(machine, kernel, &xm) < 0)
 			return -1;
 	}
diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index c8fe836e4c3c..6ae97eda370b 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -252,6 +252,13 @@ bool __map__is_kernel(const struct map *map)
 	return machine__kernel_map(map->groups->machine) == map;
 }
 
+bool __map__is_extra_kernel_map(const struct map *map)
+{
+	struct kmap *kmap = __map__kmap((struct map *)map);
+
+	return kmap && kmap->name[0];
+}
+
 bool map__has_symbols(const struct map *map)
 {
 	return dso__has_symbols(map->dso);
@@ -846,15 +853,22 @@ struct map *map__next(struct map *map)
 	return NULL;
 }
 
-struct kmap *map__kmap(struct map *map)
+struct kmap *__map__kmap(struct map *map)
 {
-	if (!map->dso || !map->dso->kernel) {
-		pr_err("Internal error: map__kmap with a non-kernel map\n");
+	if (!map->dso || !map->dso->kernel)
 		return NULL;
-	}
 	return (struct kmap *)(map + 1);
 }
 
+struct kmap *map__kmap(struct map *map)
+{
+	struct kmap *kmap = __map__kmap(map);
+
+	if (!kmap)
+		pr_err("Internal error: map__kmap with a non-kernel map\n");
+	return kmap;
+}
+
 struct map_groups *map__kmaps(struct map *map)
 {
 	struct kmap *kmap = map__kmap(map);
diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index fafcc375ed37..97e2a063bd65 100644
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -47,9 +47,12 @@ struct map {
 	refcount_t		refcnt;
 };
 
+#define KMAP_NAME_LEN 256
+
 struct kmap {
 	struct ref_reloc_sym	*ref_reloc_sym;
 	struct map_groups	*kmaps;
+	char			name[KMAP_NAME_LEN];
 };
 
 struct maps {
@@ -76,6 +79,7 @@ static inline struct map_groups *map_groups__get(struct map_groups *mg)
 
 void map_groups__put(struct map_groups *mg);
 
+struct kmap *__map__kmap(struct map *map);
 struct kmap *map__kmap(struct map *map);
 struct map_groups *map__kmaps(struct map *map);
 
@@ -232,10 +236,11 @@ int map_groups__fixup_overlappings(struct map_groups *mg, struct map *map,
 struct map *map_groups__find_by_name(struct map_groups *mg, const char *name);
 
 bool __map__is_kernel(const struct map *map);
+bool __map__is_extra_kernel_map(const struct map *map);
 
 static inline bool __map__is_kmodule(const struct map *map)
 {
-	return !__map__is_kernel(map);
+	return !__map__is_kernel(map) && !__map__is_extra_kernel_map(map);
 }
 
 bool map__has_symbols(const struct map *map);
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 929058da6727..cdddae67f40c 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1030,7 +1030,7 @@ struct map *map_groups__first(struct map_groups *mg)
 	return maps__first(&mg->maps);
 }
 
-static int do_validate_kcore_modules(const char *filename, struct map *map,
+static int do_validate_kcore_modules(const char *filename,
 				  struct map_groups *kmaps)
 {
 	struct rb_root modules = RB_ROOT;
@@ -1046,8 +1046,7 @@ static int do_validate_kcore_modules(const char *filename, struct map *map,
 		struct map *next = map_groups__next(old_map);
 		struct module_info *mi;
 
-		if (old_map == map || old_map->start == map->start) {
-			/* The kernel map */
+		if (!__map__is_kmodule(old_map)) {
 			old_map = next;
 			continue;
 		}
@@ -1104,7 +1103,7 @@ static int validate_kcore_modules(const char *kallsyms_filename,
 					     kallsyms_filename))
 		return -EINVAL;
 
-	if (do_validate_kcore_modules(modules_filename, map, kmaps))
+	if (do_validate_kcore_modules(modules_filename, kmaps))
 		return -EINVAL;
 
 	return 0;
-- 
1.9.1

[PATCH V2 11/20] perf tools: Create maps for x86 PTI entry trampolines

[Adrian Hunter]

Create maps for x86 PTI entry trampolines, based on symbols found in
kallsyms. It is also necessary to keep track of whether the trampolines
have been mapped particularly when the kernel dso is kcore.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/arch/x86/util/Build     |   1 +
 tools/perf/arch/x86/util/machine.c | 103 +++++++++++++++++++++++++++++++++++++
 tools/perf/util/machine.c          |  66 +++++++++++++++++-------
 tools/perf/util/machine.h          |  19 +++++++
 tools/perf/util/symbol.c           |  17 ++++++
 5 files changed, 187 insertions(+), 19 deletions(-)
 create mode 100644 tools/perf/arch/x86/util/machine.c

diff --git a/tools/perf/arch/x86/util/Build b/tools/perf/arch/x86/util/Build
index f95e6f46ef0d..aa1ce5f6cc00 100644
--- a/tools/perf/arch/x86/util/Build
+++ b/tools/perf/arch/x86/util/Build
@@ -4,6 +4,7 @@ libperf-y += pmu.o
 libperf-y += kvm-stat.o
 libperf-y += perf_regs.o
 libperf-y += group.o
+libperf-y += machine.o
 
 libperf-$(CONFIG_DWARF) += dwarf-regs.o
 libperf-$(CONFIG_BPF_PROLOGUE) += dwarf-regs.o
diff --git a/tools/perf/arch/x86/util/machine.c b/tools/perf/arch/x86/util/machine.c
new file mode 100644
index 000000000000..50dd6d0426a9
--- /dev/null
+++ b/tools/perf/arch/x86/util/machine.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/types.h>
+#include <linux/string.h>
+#include <stdlib.h>
+
+#include "../../util/machine.h"
+#include "../../util/map.h"
+#include "../../util/symbol.h"
+#include "../../util/sane_ctype.h"
+
+#include <symbol/kallsyms.h>
+
+#if defined(__x86_64__)
+
+struct extra_kernel_map_info {
+	int cnt;
+	int max_cnt;
+	struct extra_kernel_map *maps;
+	bool get_entry_trampolines;
+	u64 entry_trampoline;
+};
+
+static int add_extra_kernel_map(struct extra_kernel_map_info *mi, u64 start,
+				u64 end, u64 pgoff, const char *name)
+{
+	if (mi->cnt >= mi->max_cnt) {
+		void *buf;
+		size_t sz;
+
+		mi->max_cnt = mi->max_cnt ? mi->max_cnt * 2 : 32;
+		sz = sizeof(struct extra_kernel_map) * mi->max_cnt;
+		buf = realloc(mi->maps, sz);
+		if (!buf)
+			return -1;
+		mi->maps = buf;
+	}
+
+	mi->maps[mi->cnt].start = start;
+	mi->maps[mi->cnt].end   = end;
+	mi->maps[mi->cnt].pgoff = pgoff;
+	strlcpy(mi->maps[mi->cnt].name, name, KMAP_NAME_LEN);
+
+	mi->cnt += 1;
+
+	return 0;
+}
+
+static int find_extra_kernel_maps(void *arg, const char *name, char type,
+				  u64 start)
+{
+	struct extra_kernel_map_info *mi = arg;
+
+	if (!mi->entry_trampoline && kallsyms2elf_binding(type) == STB_GLOBAL &&
+	    !strcmp(name, "_entry_trampoline")) {
+		mi->entry_trampoline = start;
+		return 0;
+	}
+
+	if (is_entry_trampoline(name)) {
+		u64 end = start + page_size;
+
+		return add_extra_kernel_map(mi, start, end, 0, name);
+	}
+
+	return 0;
+}
+
+int machine__create_extra_kernel_maps(struct machine *machine,
+				      struct dso *kernel)
+{
+	struct extra_kernel_map_info mi = {0};
+	char filename[PATH_MAX];
+	int ret;
+	int i;
+
+	machine__get_kallsyms_filename(machine, filename, PATH_MAX);
+
+	if (symbol__restricted_filename(filename, "/proc/kallsyms"))
+		return 0;
+
+	ret = kallsyms__parse(filename, &mi, find_extra_kernel_maps);
+	if (ret)
+		goto out_free;
+
+	if (!mi.entry_trampoline)
+		goto out_free;
+
+	for (i = 0; i < mi.cnt; i++) {
+		struct extra_kernel_map *xm = &mi.maps[i];
+
+		xm->pgoff = mi.entry_trampoline;
+		ret = machine__create_extra_kernel_map(machine, kernel, xm);
+		if (ret)
+			goto out_free;
+	}
+
+	machine->trampolines_mapped = mi.cnt;
+out_free:
+	free(mi.maps);
+	return ret;
+}
+
+#endif
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index fb609f5e31e2..a23aecc7328a 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -807,8 +807,8 @@ struct process_args {
 	u64 start;
 };
 
-static void machine__get_kallsyms_filename(struct machine *machine, char *buf,
-					   size_t bufsz)
+void machine__get_kallsyms_filename(struct machine *machine, char *buf,
+				    size_t bufsz)
 {
 	if (machine__is_default_guest(machine))
 		scnprintf(buf, bufsz, "%s", symbol_conf.default_guest_kallsyms);
@@ -851,17 +851,9 @@ static int machine__get_running_kernel_start(struct machine *machine,
 	return 0;
 }
 
-/* Kernel-space maps for symbols that are outside the main kernel map and module maps */
-struct extra_kernel_map {
-	u64 start;
-	u64 end;
-	u64 pgoff;
-	char name[KMAP_NAME_LEN];
-};
-
-static int machine__create_extra_kernel_map(struct machine *machine,
-					    struct dso *kernel,
-					    struct extra_kernel_map *xm)
+int machine__create_extra_kernel_map(struct machine *machine,
+				     struct dso *kernel,
+				     struct extra_kernel_map *xm)
 {
 	struct kmap *kmap;
 	struct map *map;
@@ -923,9 +915,33 @@ static u64 find_entry_trampoline(struct dso *dso)
 int machine__map_x86_64_entry_trampolines(struct machine *machine,
 					  struct dso *kernel)
 {
-	u64 pgoff = find_entry_trampoline(kernel);
+	struct map_groups *kmaps = &machine->kmaps;
+	struct maps *maps = &kmaps->maps;
 	int nr_cpus_avail, cpu;
+	bool found = false;
+	struct map *map;
+	u64 pgoff;
+
+	/*
+	 * In the vmlinux case, pgoff is a virtual address which must now be
+	 * mapped to a vmlinux offset.
+	 */
+	for (map = maps__first(maps); map; map = map__next(map)) {
+		struct kmap *kmap = __map__kmap(map);
+		struct map *dest_map;
+
+		if (!kmap || !is_entry_trampoline(kmap->name))
+			continue;
+
+		dest_map = map_groups__find(kmaps, map->pgoff);
+		if (dest_map != map)
+			map->pgoff = dest_map->map_ip(dest_map, map->pgoff);
+		found = true;
+	}
+	if (found || machine->trampolines_mapped)
+		return 0;
 
+	pgoff = find_entry_trampoline(kernel);
 	if (!pgoff)
 		return 0;
 
@@ -948,6 +964,14 @@ int machine__map_x86_64_entry_trampolines(struct machine *machine,
 			return -1;
 	}
 
+	machine->trampolines_mapped = nr_cpus_avail;
+
+	return 0;
+}
+
+int __weak machine__create_extra_kernel_maps(struct machine *machine __maybe_unused,
+					     struct dso *kernel __maybe_unused)
+{
 	return 0;
 }
 
@@ -1306,9 +1330,8 @@ int machine__create_kernel_maps(struct machine *machine)
 		return -1;
 
 	ret = __machine__create_kernel_maps(machine, kernel);
-	dso__put(kernel);
 	if (ret < 0)
-		return -1;
+		goto out_put;
 
 	if (symbol_conf.use_modules && machine__create_modules(machine) < 0) {
 		if (machine__is_host(machine))
@@ -1323,7 +1346,8 @@ int machine__create_kernel_maps(struct machine *machine)
 		if (name &&
 		    map__set_kallsyms_ref_reloc_sym(machine->vmlinux_map, name, addr)) {
 			machine__destroy_kernel_maps(machine);
-			return -1;
+			ret = -1;
+			goto out_put;
 		}
 
 		/* we have a real start address now, so re-order the kmaps */
@@ -1339,12 +1363,16 @@ int machine__create_kernel_maps(struct machine *machine)
 		map__put(map);
 	}
 
+	if (machine__create_extra_kernel_maps(machine, kernel))
+		pr_debug("Problems creating extra kernel maps, continuing anyway...\n");
+
 	/* update end address of the kernel map using adjacent module address */
 	map = map__next(machine__kernel_map(machine));
 	if (map)
 		machine__set_kernel_mmap(machine, addr, map->start);
-
-	return 0;
+out_put:
+	dso__put(kernel);
+	return ret;
 }
 
 static bool machine__uses_kcore(struct machine *machine)
diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
index b6a1c3eb3d65..1de7660d93e9 100644
--- a/tools/perf/util/machine.h
+++ b/tools/perf/util/machine.h
@@ -56,6 +56,7 @@ struct machine {
 		void	  *priv;
 		u64	  db_id;
 	};
+	bool		  trampolines_mapped;
 };
 
 static inline struct threads *machine__threads(struct machine *machine, pid_t tid)
@@ -268,6 +269,24 @@ int machine__set_current_tid(struct machine *machine, int cpu, pid_t pid,
  */
 char *machine__resolve_kernel_addr(void *vmachine, unsigned long long *addrp, char **modp);
 
+void machine__get_kallsyms_filename(struct machine *machine, char *buf,
+				    size_t bufsz);
+
+int machine__create_extra_kernel_maps(struct machine *machine,
+				      struct dso *kernel);
+
+/* Kernel-space maps for symbols that are outside the main kernel map and module maps */
+struct extra_kernel_map {
+	u64 start;
+	u64 end;
+	u64 pgoff;
+	char name[KMAP_NAME_LEN];
+};
+
+int machine__create_extra_kernel_map(struct machine *machine,
+				     struct dso *kernel,
+				     struct extra_kernel_map *xm);
+
 int machine__map_x86_64_entry_trampolines(struct machine *machine,
 					  struct dso *kernel);
 
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index cdddae67f40c..8c84437f2a10 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1158,6 +1158,7 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
 	struct map_groups *kmaps = map__kmaps(map);
 	struct kcore_mapfn_data md;
 	struct map *old_map, *new_map, *replacement_map = NULL;
+	struct machine *machine;
 	bool is_64_bit;
 	int err, fd;
 	char kcore_filename[PATH_MAX];
@@ -1166,6 +1167,8 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
 	if (!kmaps)
 		return -EINVAL;
 
+	machine = kmaps->machine;
+
 	/* This function requires that the map is the kernel map */
 	if (!__map__is_kernel(map))
 		return -EINVAL;
@@ -1209,6 +1212,7 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
 			map_groups__remove(kmaps, old_map);
 		old_map = next;
 	}
+	machine->trampolines_mapped = false;
 
 	/* Find the kernel map using the '_stext' symbol */
 	if (!kallsyms__get_function_start(kallsyms_filename, "_stext", &stext)) {
@@ -1245,6 +1249,19 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
 		map__put(new_map);
 	}
 
+	if (machine__is(machine, "x86_64")) {
+		u64 addr;
+
+		/*
+		 * If one of the corresponding symbols is there, assume the
+		 * entry trampoline maps are too.
+		 */
+		if (!kallsyms__get_function_start(kallsyms_filename,
+						  ENTRY_TRAMPOLINE_NAME,
+						  &addr))
+			machine->trampolines_mapped = true;
+	}
+
 	/*
 	 * Set the data type and long name so that kcore can be read via
 	 * dso__data_read_addr().
-- 
1.9.1

[PATCH V2 12/20] perf tools: Synthesize and process mmap events for x86 PTI entry trampolines

[Adrian Hunter]

Like the kernel text, the location of x86 PTI entry trampolines must be
recorded in the perf.data file. Like the kernel, synthesize a mmap event
for that, and add processing for it.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/arch/x86/util/Build   |  1 +
 tools/perf/arch/x86/util/event.c | 76 ++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/event.c          | 34 ++++++++++++++----
 tools/perf/util/event.h          |  8 +++++
 tools/perf/util/machine.c        | 28 +++++++++++++++
 5 files changed, 140 insertions(+), 7 deletions(-)
 create mode 100644 tools/perf/arch/x86/util/event.c

diff --git a/tools/perf/arch/x86/util/Build b/tools/perf/arch/x86/util/Build
index aa1ce5f6cc00..844b8f335532 100644
--- a/tools/perf/arch/x86/util/Build
+++ b/tools/perf/arch/x86/util/Build
@@ -5,6 +5,7 @@ libperf-y += kvm-stat.o
 libperf-y += perf_regs.o
 libperf-y += group.o
 libperf-y += machine.o
+libperf-y += event.o
 
 libperf-$(CONFIG_DWARF) += dwarf-regs.o
 libperf-$(CONFIG_BPF_PROLOGUE) += dwarf-regs.o
diff --git a/tools/perf/arch/x86/util/event.c b/tools/perf/arch/x86/util/event.c
new file mode 100644
index 000000000000..675a0213044d
--- /dev/null
+++ b/tools/perf/arch/x86/util/event.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/types.h>
+#include <linux/string.h>
+
+#include "../../util/machine.h"
+#include "../../util/tool.h"
+#include "../../util/map.h"
+#include "../../util/util.h"
+#include "../../util/debug.h"
+
+#if defined(__x86_64__)
+
+int perf_event__synthesize_extra_kmaps(struct perf_tool *tool,
+				       perf_event__handler_t process,
+				       struct machine *machine)
+{
+	int rc = 0;
+	struct map *pos;
+	struct map_groups *kmaps = &machine->kmaps;
+	struct maps *maps = &kmaps->maps;
+	union perf_event *event = zalloc(sizeof(event->mmap) +
+					 machine->id_hdr_size);
+
+	if (!event) {
+		pr_debug("Not enough memory synthesizing mmap event "
+			 "for extra kernel maps\n");
+		return -1;
+	}
+
+	for (pos = maps__first(maps); pos; pos = map__next(pos)) {
+		struct kmap *kmap;
+		size_t size;
+
+		if (!__map__is_extra_kernel_map(pos))
+			continue;
+
+		kmap = map__kmap(pos);
+
+		size = sizeof(event->mmap) - sizeof(event->mmap.filename) +
+		       PERF_ALIGN(strlen(kmap->name) + 1, sizeof(u64)) +
+		       machine->id_hdr_size;
+
+		memset(event, 0, size);
+
+		event->mmap.header.type = PERF_RECORD_MMAP;
+
+		/*
+		 * kernel uses 0 for user space maps, see kernel/perf_event.c
+		 * __perf_event_mmap
+		 */
+		if (machine__is_host(machine))
+			event->header.misc = PERF_RECORD_MISC_KERNEL;
+		else
+			event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
+
+		event->mmap.header.size = size;
+
+		event->mmap.start = pos->start;
+		event->mmap.len   = pos->end - pos->start;
+		event->mmap.pgoff = pos->pgoff;
+		event->mmap.pid   = machine->pid;
+
+		strlcpy(event->mmap.filename, kmap->name, PATH_MAX);
+
+		if (perf_tool__process_synth_event(tool, event, machine,
+						   process) != 0) {
+			rc = -1;
+			break;
+		}
+	}
+
+	free(event);
+	return rc;
+}
+
+#endif
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index aafa9878465f..0c8ecf0c78a4 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -88,10 +88,10 @@ static const char *perf_ns__name(unsigned int id)
 	return perf_ns__names[id];
 }
 
-static int perf_tool__process_synth_event(struct perf_tool *tool,
-					  union perf_event *event,
-					  struct machine *machine,
-					  perf_event__handler_t process)
+int perf_tool__process_synth_event(struct perf_tool *tool,
+				   union perf_event *event,
+				   struct machine *machine,
+				   perf_event__handler_t process)
 {
 	struct perf_sample synth_sample = {
 	.pid	   = -1,
@@ -888,9 +888,16 @@ int kallsyms__get_function_start(const char *kallsyms_filename,
 	return 0;
 }
 
-int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
-				       perf_event__handler_t process,
-				       struct machine *machine)
+int __weak perf_event__synthesize_extra_kmaps(struct perf_tool *tool __maybe_unused,
+					      perf_event__handler_t process __maybe_unused,
+					      struct machine *machine __maybe_unused)
+{
+	return 0;
+}
+
+static int __perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
+						perf_event__handler_t process,
+						struct machine *machine)
 {
 	size_t size;
 	struct map *map = machine__kernel_map(machine);
@@ -943,6 +950,19 @@ int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
 	return err;
 }
 
+int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
+				       perf_event__handler_t process,
+				       struct machine *machine)
+{
+	int err;
+
+	err = __perf_event__synthesize_kernel_mmap(tool, process, machine);
+	if (err < 0)
+		return err;
+
+	return perf_event__synthesize_extra_kmaps(tool, process, machine);
+}
+
 int perf_event__synthesize_thread_map2(struct perf_tool *tool,
 				      struct thread_map *threads,
 				      perf_event__handler_t process,
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 0f794744919c..bfa60bcafbde 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -750,6 +750,10 @@ int perf_event__process_exit(struct perf_tool *tool,
 			     union perf_event *event,
 			     struct perf_sample *sample,
 			     struct machine *machine);
+int perf_tool__process_synth_event(struct perf_tool *tool,
+				   union perf_event *event,
+				   struct machine *machine,
+				   perf_event__handler_t process);
 int perf_event__process(struct perf_tool *tool,
 			union perf_event *event,
 			struct perf_sample *sample,
@@ -796,6 +800,10 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
 				       bool mmap_data,
 				       unsigned int proc_map_timeout);
 
+int perf_event__synthesize_extra_kmaps(struct perf_tool *tool,
+				       perf_event__handler_t process,
+				       struct machine *machine);
+
 size_t perf_event__fprintf_comm(union perf_event *event, FILE *fp);
 size_t perf_event__fprintf_mmap(union perf_event *event, FILE *fp);
 size_t perf_event__fprintf_mmap2(union perf_event *event, FILE *fp);
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index a23aecc7328a..775889ae05b7 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1387,6 +1387,32 @@ static bool machine__uses_kcore(struct machine *machine)
 	return false;
 }
 
+static bool perf_event__is_extra_kernel_mmap(struct machine *machine,
+					     union perf_event *event)
+{
+	return machine__is(machine, "x86_64") &&
+	       is_entry_trampoline(event->mmap.filename);
+}
+
+static int machine__process_extra_kernel_map(struct machine *machine,
+					     union perf_event *event)
+{
+	struct map *kernel_map = machine__kernel_map(machine);
+	struct dso *kernel = kernel_map ? kernel_map->dso : NULL;
+	struct extra_kernel_map xm = {
+		.start = event->mmap.start,
+		.end   = event->mmap.start + event->mmap.len,
+		.pgoff = event->mmap.pgoff,
+	};
+
+	if (kernel == NULL)
+		return -1;
+
+	strlcpy(xm.name, event->mmap.filename, KMAP_NAME_LEN);
+
+	return machine__create_extra_kernel_map(machine, kernel, &xm);
+}
+
 static int machine__process_kernel_mmap_event(struct machine *machine,
 					      union perf_event *event)
 {
@@ -1490,6 +1516,8 @@ static int machine__process_kernel_mmap_event(struct machine *machine,
 			 */
 			dso__load(kernel, machine__kernel_map(machine));
 		}
+	} else if (perf_event__is_extra_kernel_mmap(machine, event)) {
+		return machine__process_extra_kernel_map(machine, event);
 	}
 	return 0;
 out_problem:
-- 
1.9.1

[PATCH V2 13/20] perf buildid-cache: kcore_copy: Keep phdr data in a list

[Adrian Hunter]

Currently, kcore_copy makes 2 program headers, one for the kernel text
(namely kernel_map) and one for the modules (namely modules_map). Now more
program headers are needed, but treating each program header as a special
case results in much more code.

Instead, in preparation to add more program headers, change to keep program
header data (phdr_data) in a list.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/symbol-elf.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 48943b834f11..b13873a6f368 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1388,6 +1388,7 @@ struct phdr_data {
 	off_t offset;
 	u64 addr;
 	u64 len;
+	struct list_head node;
 };
 
 struct kcore_copy_info {
@@ -1399,6 +1400,7 @@ struct kcore_copy_info {
 	u64 last_module_symbol;
 	struct phdr_data kernel_map;
 	struct phdr_data modules_map;
+	struct list_head phdrs;
 };
 
 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
@@ -1510,6 +1512,11 @@ static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
 	if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
 		return -1;
 
+	if (kci->kernel_map.len)
+		list_add_tail(&kci->kernel_map.node, &kci->phdrs);
+	if (kci->modules_map.len)
+		list_add_tail(&kci->modules_map.node, &kci->phdrs);
+
 	return 0;
 }
 
@@ -1678,6 +1685,8 @@ int kcore_copy(const char *from_dir, const char *to_dir)
 	char kcore_filename[PATH_MAX];
 	char extract_filename[PATH_MAX];
 
+	INIT_LIST_HEAD(&kci.phdrs);
+
 	if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
 		return -1;
 
-- 
1.9.1

[PATCH V2 14/20] perf buildid-cache: kcore_copy: Keep a count of phdrs

[Adrian Hunter]

In preparation to add more program headers, keep a count of phdrs.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/symbol-elf.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index b13873a6f368..4e7b71e8ac0e 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1398,6 +1398,7 @@ struct kcore_copy_info {
 	u64 last_symbol;
 	u64 first_module;
 	u64 last_module_symbol;
+	size_t phnum;
 	struct phdr_data kernel_map;
 	struct phdr_data modules_map;
 	struct list_head phdrs;
@@ -1517,6 +1518,8 @@ static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
 	if (kci->modules_map.len)
 		list_add_tail(&kci->modules_map.node, &kci->phdrs);
 
+	kci->phnum = !!kci->kernel_map.len + !!kci->modules_map.len;
+
 	return 0;
 }
 
@@ -1678,7 +1681,6 @@ int kcore_copy(const char *from_dir, const char *to_dir)
 {
 	struct kcore kcore;
 	struct kcore extract;
-	size_t count = 2;
 	int idx = 0, err = -1;
 	off_t offset = page_size, sz, modules_offset = 0;
 	struct kcore_copy_info kci = { .stext = 0, };
@@ -1705,10 +1707,7 @@ int kcore_copy(const char *from_dir, const char *to_dir)
 	if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
 		goto out_kcore_close;
 
-	if (!kci.modules_map.addr)
-		count -= 1;
-
-	if (kcore__copy_hdr(&kcore, &extract, count))
+	if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
 		goto out_extract_close;
 
 	if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
-- 
1.9.1

[PATCH V2 15/20] perf buildid-cache: kcore_copy: Calculate offset from phnum

[Adrian Hunter]

In preparation to add more program headers, calculate offset from the
number of phdrs.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/symbol-elf.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 4e7b71e8ac0e..4aec12102e19 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1682,7 +1682,7 @@ int kcore_copy(const char *from_dir, const char *to_dir)
 	struct kcore kcore;
 	struct kcore extract;
 	int idx = 0, err = -1;
-	off_t offset = page_size, sz, modules_offset = 0;
+	off_t offset, sz, modules_offset = 0;
 	struct kcore_copy_info kci = { .stext = 0, };
 	char kcore_filename[PATH_MAX];
 	char extract_filename[PATH_MAX];
@@ -1710,6 +1710,10 @@ int kcore_copy(const char *from_dir, const char *to_dir)
 	if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
 		goto out_extract_close;
 
+	offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
+		 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
+	offset = round_up(offset, page_size);
+
 	if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
 			    kci.kernel_map.len))
 		goto out_extract_close;
-- 
1.9.1

[PATCH V2 16/20] perf buildid-cache: kcore_copy: Layout sections

[Adrian Hunter]

In preparation to add more program headers, layout the relative offset of
each section.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/symbol-elf.c | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 4aec12102e19..3e76a0efd15c 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1386,6 +1386,7 @@ static off_t kcore__write(struct kcore *kcore)
 
 struct phdr_data {
 	off_t offset;
+	off_t rel;
 	u64 addr;
 	u64 len;
 	struct list_head node;
@@ -1404,6 +1405,9 @@ struct kcore_copy_info {
 	struct list_head phdrs;
 };
 
+#define kcore_copy__for_each_phdr(k, p) \
+	list_for_each_entry((p), &(k)->phdrs, node)
+
 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
 					u64 start)
 {
@@ -1518,11 +1522,21 @@ static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
 	if (kci->modules_map.len)
 		list_add_tail(&kci->modules_map.node, &kci->phdrs);
 
-	kci->phnum = !!kci->kernel_map.len + !!kci->modules_map.len;
-
 	return 0;
 }
 
+static void kcore_copy__layout(struct kcore_copy_info *kci)
+{
+	struct phdr_data *p;
+	off_t rel = 0;
+
+	kcore_copy__for_each_phdr(kci, p) {
+		p->rel = rel;
+		rel += p->len;
+		kci->phnum += 1;
+	}
+}
+
 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
 				 Elf *elf)
 {
@@ -1558,7 +1572,12 @@ static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
 	if (kci->first_module && !kci->last_module_symbol)
 		return -1;
 
-	return kcore_copy__read_maps(kci, elf);
+	if (kcore_copy__read_maps(kci, elf))
+		return -1;
+
+	kcore_copy__layout(kci);
+
+	return 0;
 }
 
 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
-- 
1.9.1

[PATCH V2 17/20] perf buildid-cache: kcore_copy: Iterate phdrs

[Adrian Hunter]

In preparation to add more program headers, iterate phdrs instead of
assuming there is only one for the kernel text and one for the modules.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/symbol-elf.c | 25 ++++++++++---------------
 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 3e76a0efd15c..91b8cfb045ec 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1701,10 +1701,11 @@ int kcore_copy(const char *from_dir, const char *to_dir)
 	struct kcore kcore;
 	struct kcore extract;
 	int idx = 0, err = -1;
-	off_t offset, sz, modules_offset = 0;
+	off_t offset, sz;
 	struct kcore_copy_info kci = { .stext = 0, };
 	char kcore_filename[PATH_MAX];
 	char extract_filename[PATH_MAX];
+	struct phdr_data *p;
 
 	INIT_LIST_HEAD(&kci.phdrs);
 
@@ -1733,14 +1734,10 @@ int kcore_copy(const char *from_dir, const char *to_dir)
 		 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
 	offset = round_up(offset, page_size);
 
-	if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
-			    kci.kernel_map.len))
-		goto out_extract_close;
+	kcore_copy__for_each_phdr(&kci, p) {
+		off_t offs = p->rel + offset;
 
-	if (kci.modules_map.addr) {
-		modules_offset = offset + kci.kernel_map.len;
-		if (kcore__add_phdr(&extract, idx, modules_offset,
-				    kci.modules_map.addr, kci.modules_map.len))
+		if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
 			goto out_extract_close;
 	}
 
@@ -1748,14 +1745,12 @@ int kcore_copy(const char *from_dir, const char *to_dir)
 	if (sz < 0 || sz > offset)
 		goto out_extract_close;
 
-	if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
-		       kci.kernel_map.len))
-		goto out_extract_close;
+	kcore_copy__for_each_phdr(&kci, p) {
+		off_t offs = p->rel + offset;
 
-	if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
-					 extract.fd, modules_offset,
-					 kci.modules_map.len))
-		goto out_extract_close;
+		if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
+			goto out_extract_close;
+	}
 
 	if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
 		goto out_extract_close;
-- 
1.9.1

[PATCH V2 18/20] perf buildid-cache: kcore_copy: Get rid of kernel_map

[Adrian Hunter]

In preparation to add more program headers, get rid of kernel_map and
modules_map by moving ->kernel_map and ->modules_map to newly allocated
entries in the ->phdrs list.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/symbol-elf.c | 70 ++++++++++++++++++++++++++++++++------------
 1 file changed, 52 insertions(+), 18 deletions(-)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 91b8cfb045ec..37d9324c277c 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1400,14 +1400,47 @@ struct kcore_copy_info {
 	u64 first_module;
 	u64 last_module_symbol;
 	size_t phnum;
-	struct phdr_data kernel_map;
-	struct phdr_data modules_map;
 	struct list_head phdrs;
 };
 
 #define kcore_copy__for_each_phdr(k, p) \
 	list_for_each_entry((p), &(k)->phdrs, node)
 
+static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
+{
+	struct phdr_data *p = zalloc(sizeof(*p));
+
+	if (p) {
+		p->addr   = addr;
+		p->len    = len;
+		p->offset = offset;
+	}
+
+	return p;
+}
+
+static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
+						 u64 addr, u64 len,
+						 off_t offset)
+{
+	struct phdr_data *p = phdr_data__new(addr, len, offset);
+
+	if (p)
+		list_add_tail(&p->node, &kci->phdrs);
+
+	return p;
+}
+
+static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
+{
+	struct phdr_data *p, *tmp;
+
+	list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
+		list_del(&p->node);
+		free(p);
+	}
+}
+
 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
 					u64 start)
 {
@@ -1487,15 +1520,18 @@ static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
 	return 0;
 }
 
-static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
-			    u64 s, u64 e)
+static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
+			   u64 pgoff, u64 s, u64 e)
 {
-	if (p->addr || s < start || s >= end)
-		return;
+	u64 len, offset;
+
+	if (s < start || s >= end)
+		return 0;
 
-	p->addr = s;
-	p->offset = (s - start) + pgoff;
-	p->len = e < end ? e - s : end - s;
+	offset = (s - start) + pgoff;
+	len = e < end ? e - s : end - s;
+
+	return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
 }
 
 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
@@ -1503,11 +1539,12 @@ static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
 	struct kcore_copy_info *kci = data;
 	u64 end = start + len;
 
-	kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
-			kci->etext);
+	if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
+		return -1;
 
-	kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
-			kci->last_module_symbol);
+	if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
+			    kci->last_module_symbol))
+		return -1;
 
 	return 0;
 }
@@ -1517,11 +1554,6 @@ static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
 	if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
 		return -1;
 
-	if (kci->kernel_map.len)
-		list_add_tail(&kci->kernel_map.node, &kci->phdrs);
-	if (kci->modules_map.len)
-		list_add_tail(&kci->modules_map.node, &kci->phdrs);
-
 	return 0;
 }
 
@@ -1773,6 +1805,8 @@ int kcore_copy(const char *from_dir, const char *to_dir)
 	if (err)
 		kcore_copy__unlink(to_dir, "kallsyms");
 
+	kcore_copy__free_phdrs(&kci);
+
 	return err;
 }
 
-- 
1.9.1

[PATCH V2 19/20] perf buildid-cache: kcore_copy: Copy x86 PTI entry trampoline sections

[Adrian Hunter]

Identify and copy any sections for x86 PTI entry trampolines.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/symbol-elf.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 37d9324c277c..584966913aeb 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1392,6 +1392,11 @@ struct phdr_data {
 	struct list_head node;
 };
 
+struct sym_data {
+	u64 addr;
+	struct list_head node;
+};
+
 struct kcore_copy_info {
 	u64 stext;
 	u64 etext;
@@ -1401,6 +1406,7 @@ struct kcore_copy_info {
 	u64 last_module_symbol;
 	size_t phnum;
 	struct list_head phdrs;
+	struct list_head syms;
 };
 
 #define kcore_copy__for_each_phdr(k, p) \
@@ -1441,6 +1447,29 @@ static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
 	}
 }
 
+static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
+					    u64 addr)
+{
+	struct sym_data *s = zalloc(sizeof(*s));
+
+	if (s) {
+		s->addr = addr;
+		list_add_tail(&s->node, &kci->syms);
+	}
+
+	return s;
+}
+
+static void kcore_copy__free_syms(struct kcore_copy_info *kci)
+{
+	struct sym_data *s, *tmp;
+
+	list_for_each_entry_safe(s, tmp, &kci->syms, node) {
+		list_del(&s->node);
+		free(s);
+	}
+}
+
 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
 					u64 start)
 {
@@ -1471,6 +1500,9 @@ static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
 		return 0;
 	}
 
+	if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
+		return -1;
+
 	return 0;
 }
 
@@ -1538,6 +1570,7 @@ static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
 {
 	struct kcore_copy_info *kci = data;
 	u64 end = start + len;
+	struct sym_data *sdat;
 
 	if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
 		return -1;
@@ -1546,6 +1579,13 @@ static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
 			    kci->last_module_symbol))
 		return -1;
 
+	list_for_each_entry(sdat, &kci->syms, node) {
+		u64 s = round_down(sdat->addr, page_size);
+
+		if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
+			return -1;
+	}
+
 	return 0;
 }
 
@@ -1740,6 +1780,7 @@ int kcore_copy(const char *from_dir, const char *to_dir)
 	struct phdr_data *p;
 
 	INIT_LIST_HEAD(&kci.phdrs);
+	INIT_LIST_HEAD(&kci.syms);
 
 	if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
 		return -1;
@@ -1806,6 +1847,7 @@ int kcore_copy(const char *from_dir, const char *to_dir)
 		kcore_copy__unlink(to_dir, "kallsyms");
 
 	kcore_copy__free_phdrs(&kci);
+	kcore_copy__free_syms(&kci);
 
 	return err;
 }
-- 
1.9.1

[PATCH V2 20/20] perf buildid-cache: kcore_copy: Amend the offset of sections that remap kernel text

[Adrian Hunter]

x86 PTI entry trampolines all map to the same physical page. If that is
reflected in the program headers of /proc/kcore, then do the same for the
copy of kcore.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/symbol-elf.c | 53 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 51 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 584966913aeb..29770ea61768 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1390,6 +1390,7 @@ struct phdr_data {
 	u64 addr;
 	u64 len;
 	struct list_head node;
+	struct phdr_data *remaps;
 };
 
 struct sym_data {
@@ -1597,16 +1598,62 @@ static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
 	return 0;
 }
 
+static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
+{
+	struct phdr_data *p, *k = NULL;
+	u64 kend;
+
+	if (!kci->stext)
+		return;
+
+	/* Find phdr that corresponds to the kernel map (contains stext) */
+	kcore_copy__for_each_phdr(kci, p) {
+		u64 pend = p->addr + p->len - 1;
+
+		if (p->addr <= kci->stext && pend >= kci->stext) {
+			k = p;
+			break;
+		}
+	}
+
+	if (!k)
+		return;
+
+	kend = k->offset + k->len;
+
+	/* Find phdrs that remap the kernel */
+	kcore_copy__for_each_phdr(kci, p) {
+		u64 pend = p->offset + p->len;
+
+		if (p == k)
+			continue;
+
+		if (p->offset >= k->offset && pend <= kend)
+			p->remaps = k;
+	}
+}
+
 static void kcore_copy__layout(struct kcore_copy_info *kci)
 {
 	struct phdr_data *p;
 	off_t rel = 0;
 
+	kcore_copy__find_remaps(kci);
+
 	kcore_copy__for_each_phdr(kci, p) {
-		p->rel = rel;
-		rel += p->len;
+		if (!p->remaps) {
+			p->rel = rel;
+			rel += p->len;
+		}
 		kci->phnum += 1;
 	}
+
+	kcore_copy__for_each_phdr(kci, p) {
+		struct phdr_data *k = p->remaps;
+
+		if (k)
+			p->rel = p->offset - k->offset + k->rel;
+	}
 }
 
 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
@@ -1821,6 +1868,8 @@ int kcore_copy(const char *from_dir, const char *to_dir)
 	kcore_copy__for_each_phdr(&kci, p) {
 		off_t offs = p->rel + offset;
 
+		if (p->remaps)
+			continue;
 		if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
 			goto out_extract_close;
 	}
-- 
1.9.1

Re: [PATCH V2 03/20] x86: Add entry trampolines to kcore

[Dave Hansen]

On 05/17/2018 02:21 AM, Adrian Hunter wrote:
> From: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> 
> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>

For the benefit of the poor souls looking at this code in the decades to
come, could you please take a few minutes to write a couple of sentences
about why this is being done?

> diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c
> index d1da5cf4b2de..fb1fbc8538fa 100644
> --- a/arch/x86/mm/cpu_entry_area.c
> +++ b/arch/x86/mm/cpu_entry_area.c
> @@ -3,6 +3,7 @@
>  #include <linux/spinlock.h>
>  #include <linux/percpu.h>
>  #include <linux/kallsyms.h>
> +#include <linux/kcore.h>
>  
>  #include <asm/cpu_entry_area.h>
>  #include <asm/pgtable.h>
> @@ -14,6 +15,7 @@
>  #ifdef CONFIG_X86_64
>  static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
>  	[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]);
> +static DEFINE_PER_CPU(struct kcore_list, kcore_entry_trampoline);
>  #endif
>  
>  struct cpu_entry_area *get_cpu_entry_area(int cpu)
> @@ -147,6 +149,9 @@ static void __init setup_cpu_entry_area(int cpu)
>  
>  	cea_set_pte(&get_cpu_entry_area(cpu)->entry_trampoline,
>  		     __pa_symbol(_entry_trampoline), PAGE_KERNEL_RX);
> +	kclist_add(&per_cpu(kcore_entry_trampoline, cpu),
> +		   &get_cpu_entry_area(cpu)->entry_trampoline, PAGE_SIZE,
> +		   KCORE_TEXT);
>  #endif

Any reason not to add a comment like:

/*
 * The cpu_entry_area alias addresses are not in the kernel binary
 * so they do not show up in /proc/kcore normally.  This adds entries
 * for them manually.
 */

Re: [PATCH V2 04/20] x86: kcore: Give entry trampolines all the same offset in kcore

[Dave Hansen]

On 05/17/2018 02:21 AM, Adrian Hunter wrote:
> @@ -149,9 +149,9 @@ static void __init setup_cpu_entry_area(int cpu)
>  
>  	cea_set_pte(&get_cpu_entry_area(cpu)->entry_trampoline,
>  		     __pa_symbol(_entry_trampoline), PAGE_KERNEL_RX);
> -	kclist_add(&per_cpu(kcore_entry_trampoline, cpu),
> -		   &get_cpu_entry_area(cpu)->entry_trampoline, PAGE_SIZE,
> -		   KCORE_TEXT);
> +	kclist_add_remap(&per_cpu(kcore_entry_trampoline, cpu),
> +			 _entry_trampoline,
> +			 &get_cpu_entry_area(cpu)->entry_trampoline, PAGE_SIZE);
>  #endif
>  	percpu_setup_debug_store(cpu);
>  }

Why do you bother adding then immediately removing this code?

Re: [PATCH V2 03/20] x86: Add entry trampolines to kcore

[Arnaldo Carvalho de Melo]

Em Thu, May 17, 2018 at 10:52:30AM -0700, Dave Hansen escreveu:
> On 05/17/2018 02:21 AM, Adrian Hunter wrote:
> > From: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> > 
> > Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> 
> For the benefit of the poor souls looking at this code in the decades to
> come, could you please take a few minutes to write a couple of sentences
> about why this is being done?

Hey, for the poor souls reading in _this_ decade as well! ;-)

- Arnaldo
 
> > diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c
> > index d1da5cf4b2de..fb1fbc8538fa 100644
> > --- a/arch/x86/mm/cpu_entry_area.c
> > +++ b/arch/x86/mm/cpu_entry_area.c
> > @@ -3,6 +3,7 @@
> >  #include <linux/spinlock.h>
> >  #include <linux/percpu.h>
> >  #include <linux/kallsyms.h>
> > +#include <linux/kcore.h>
> >  
> >  #include <asm/cpu_entry_area.h>
> >  #include <asm/pgtable.h>
> > @@ -14,6 +15,7 @@
> >  #ifdef CONFIG_X86_64
> >  static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
> >  	[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]);
> > +static DEFINE_PER_CPU(struct kcore_list, kcore_entry_trampoline);
> >  #endif
> >  
> >  struct cpu_entry_area *get_cpu_entry_area(int cpu)
> > @@ -147,6 +149,9 @@ static void __init setup_cpu_entry_area(int cpu)
> >  
> >  	cea_set_pte(&get_cpu_entry_area(cpu)->entry_trampoline,
> >  		     __pa_symbol(_entry_trampoline), PAGE_KERNEL_RX);
> > +	kclist_add(&per_cpu(kcore_entry_trampoline, cpu),
> > +		   &get_cpu_entry_area(cpu)->entry_trampoline, PAGE_SIZE,
> > +		   KCORE_TEXT);
> >  #endif
> 
> Any reason not to add a comment like:
> 
> /*
>  * The cpu_entry_area alias addresses are not in the kernel binary
>  * so they do not show up in /proc/kcore normally.  This adds entries
>  * for them manually.
>  */

[tip:perf/core] perf machine: Add machine__is() to identify machine arch

[tip-bot for Adrian Hunter]

Commit-ID:  dbbd34a666ee117d0e39e71a47f38f02c4a5c698
Gitweb:     https://git.kernel.org/tip/dbbd34a666ee117d0e39e71a47f38f02c4a5c698
Author:     Adrian Hunter <adrian.hunter@intel.com>
AuthorDate: Thu, 17 May 2018 12:21:53 +0300
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Sat, 19 May 2018 06:42:50 -0300

perf machine: Add machine__is() to identify machine arch

Add a function to identify the machine architecture.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/1526548928-20790-6-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/env.c     | 18 ++++++++++++++++++
 tools/perf/util/env.h     |  2 ++
 tools/perf/util/machine.c |  9 +++++++++
 tools/perf/util/machine.h |  2 ++
 4 files changed, 31 insertions(+)

diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
index 4c842762e3f2..319fb0a0d05e 100644
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -93,6 +93,24 @@ int perf_env__read_cpu_topology_map(struct perf_env *env)
 	return 0;
 }
 
+static int perf_env__read_arch(struct perf_env *env)
+{
+	struct utsname uts;
+
+	if (env->arch)
+		return 0;
+
+	if (!uname(&uts))
+		env->arch = strdup(uts.machine);
+
+	return env->arch ? 0 : -ENOMEM;
+}
+
+const char *perf_env__raw_arch(struct perf_env *env)
+{
+	return env && !perf_env__read_arch(env) ? env->arch : "unknown";
+}
+
 void cpu_cache_level__free(struct cpu_cache_level *cache)
 {
 	free(cache->type);
diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
index c4ef2e523367..62e193948608 100644
--- a/tools/perf/util/env.h
+++ b/tools/perf/util/env.h
@@ -76,4 +76,6 @@ int perf_env__read_cpu_topology_map(struct perf_env *env);
 void cpu_cache_level__free(struct cpu_cache_level *cache);
 
 const char *perf_env__arch(struct perf_env *env);
+const char *perf_env__raw_arch(struct perf_env *env);
+
 #endif /* __PERF_ENV_H */
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 7c777cb32806..107bae7676b1 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2296,6 +2296,15 @@ int machine__set_current_tid(struct machine *machine, int cpu, pid_t pid,
 	return 0;
 }
 
+/*
+ * Compares the raw arch string. N.B. see instead perf_env__arch() if a
+ * normalized arch is needed.
+ */
+bool machine__is(struct machine *machine, const char *arch)
+{
+	return machine && !strcmp(perf_env__raw_arch(machine->env), arch);
+}
+
 int machine__get_kernel_start(struct machine *machine)
 {
 	struct map *map = machine__kernel_map(machine);
diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
index 388fb4741c54..b31d33b5aa2a 100644
--- a/tools/perf/util/machine.h
+++ b/tools/perf/util/machine.h
@@ -188,6 +188,8 @@ static inline bool machine__is_host(struct machine *machine)
 	return machine ? machine->pid == HOST_KERNEL_ID : false;
 }
 
+bool machine__is(struct machine *machine, const char *arch);
+
 struct thread *__machine__findnew_thread(struct machine *machine, pid_t pid, pid_t tid);
 struct thread *machine__findnew_thread(struct machine *machine, pid_t pid, pid_t tid);
 

[tip:perf/core] perf tools: Fix kernel_start for PTI on x86

[tip-bot for Adrian Hunter]

Commit-ID:  19422a9f2a3be7f3a046285ffae4cbb571aa853a
Gitweb:     https://git.kernel.org/tip/19422a9f2a3be7f3a046285ffae4cbb571aa853a
Author:     Adrian Hunter <adrian.hunter@intel.com>
AuthorDate: Thu, 17 May 2018 12:21:54 +0300
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Sat, 19 May 2018 06:42:51 -0300

perf tools: Fix kernel_start for PTI on x86

Opickn x86_64, PTI entry trampolines are less than the start of kernel text,
but still above 2^63. So leave kernel_start = 1ULL << 63 for x86_64.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/1526548928-20790-7-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/machine.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 107bae7676b1..e011a7160380 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2321,7 +2321,12 @@ int machine__get_kernel_start(struct machine *machine)
 	machine->kernel_start = 1ULL << 63;
 	if (map) {
 		err = map__load(map);
-		if (!err)
+		/*
+		 * On x86_64, PTI entry trampolines are less than the
+		 * start of kernel text, but still above 2^63. So leave
+		 * kernel_start = 1ULL << 63 for x86_64.
+		 */
+		if (!err && !machine__is(machine, "x86_64"))
 			machine->kernel_start = map->start;
 	}
 	return err;