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From: Alexander Duyck <alexander.h.duyck@intel.com>
To: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, andi@firstfloor.org
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
	Steven Rostedt <rostedt@goodmis.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Alexander Duyck <alexander.h.duyck@intel.com>
Subject: [PATCH v3 5/8] x86/ftrace: Use __pa_symbol instead of __pa on C visible symbols
Date: Mon, 05 Nov 2012 11:05:53 -0800	[thread overview]
Message-ID: <20121105190547.10205.29226.stgit@gitlad.jf.intel.com> (raw)
In-Reply-To: <20121105185657.10205.27419.stgit@gitlad.jf.intel.com>

Instead of using __pa which is meant to be a general function for converting
virtual addresses to physical addresses we can use __pa_symbol which is the
preferred way of decoding kernel text virtual addresses to physical addresses.

In this case we are not directly converting C visible symbols however if we
know that the instruction pointer is somewhere between _text and _etext we
know that we are going to be translating an address form the kernel text
space.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---

 arch/x86/kernel/ftrace.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 1d41402..42a392a 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -89,7 +89,7 @@ do_ftrace_mod_code(unsigned long ip, const void *new_code)
 	 * kernel identity mapping to modify code.
 	 */
 	if (within(ip, (unsigned long)_text, (unsigned long)_etext))
-		ip = (unsigned long)__va(__pa(ip));
+		ip = (unsigned long)__va(__pa_symbol(ip));
 
 	return probe_kernel_write((void *)ip, new_code, MCOUNT_INSN_SIZE);
 }
@@ -279,7 +279,7 @@ static int ftrace_write(unsigned long ip, const char *val, int size)
 	 * kernel identity mapping to modify code.
 	 */
 	if (within(ip, (unsigned long)_text, (unsigned long)_etext))
-		ip = (unsigned long)__va(__pa(ip));
+		ip = (unsigned long)__va(__pa_symbol(ip));
 
 	return probe_kernel_write((void *)ip, val, size);
 }


  parent reply	other threads:[~2012-11-05 19:05 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-05 19:03 [PATCH v3 0/8] Improve performance of VM translation on x86_64 Alexander Duyck
2012-11-05 19:04 ` [PATCH v3 1/8] x86: Improve __phys_addr performance by making use of carry flags and inlining Alexander Duyck
2012-11-05 20:24   ` Kirill A. Shutemov
2012-11-05 21:56     ` Alexander Duyck
2012-11-05 22:08       ` Kirill A. Shutemov
2012-11-16 19:35         ` Alexander Duyck
2012-11-05 19:04 ` [PATCH v3 2/8] x86: Make it so that __pa_symbol can only process kernel symbols on x86_64 Alexander Duyck
2012-11-05 19:04 ` [PATCH v3 3/8] x86: Drop 4 unnecessary calls to __pa_symbol Alexander Duyck
2012-11-05 19:05 ` [PATCH v3 4/8] x86: Use __pa_symbol instead of __pa on C visible symbols Alexander Duyck
2012-11-05 19:05 ` Alexander Duyck [this message]
2012-11-05 19:06 ` [PATCH v3 6/8] x86/xen: " Alexander Duyck
2012-11-06 15:45   ` Konrad Rzeszutek Wilk
2012-11-05 19:06 ` [PATCH v3 7/8] x86/acpi: " Alexander Duyck
2012-11-05 19:06 ` [PATCH v3 8/8] x86/lguest: " Alexander Duyck
2012-11-06  1:11   ` Rusty Russell

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