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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 04/20] x86: kcore: Give entry trampolines all the same offset in kcore
Date: Thu, 17 May 2018 12:21:52 +0300	[thread overview]
Message-ID: <1526548928-20790-5-git-send-email-adrian.hunter@intel.com> (raw)
In-Reply-To: <1526548928-20790-1-git-send-email-adrian.hunter@intel.com>

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

  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 ` [PATCH V2 02/20] kallsyms, x86: Export addresses of syscall trampolines Adrian Hunter
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 ` Adrian Hunter [this message]
2018-05-17 17:54   ` [PATCH V2 04/20] x86: kcore: Give entry trampolines all the same offset in kcore 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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