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From: tip-bot for Borislav Petkov <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, jpoimboe@redhat.com,
	mingo@kernel.org, peterz@infradead.org, luto@amacapital.net,
	hpa@zytor.com, torvalds@linux-foundation.org, bp@suse.de,
	tglx@linutronix.de
Subject: [tip:x86/cleanups] x86/dumpstack: Remove code_bytes
Date: Thu, 26 Apr 2018 07:18:46 -0700	[thread overview]
Message-ID: <tip-5d12f0424edf01ccd8abbcba1c7d45fe0b23c779@git.kernel.org> (raw)
In-Reply-To: <20180417161124.5294-2-bp@alien8.de>

Commit-ID:  5d12f0424edf01ccd8abbcba1c7d45fe0b23c779
Gitweb:     https://git.kernel.org/tip/5d12f0424edf01ccd8abbcba1c7d45fe0b23c779
Author:     Borislav Petkov <bp@suse.de>
AuthorDate: Tue, 17 Apr 2018 18:11:16 +0200
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 26 Apr 2018 16:15:25 +0200

x86/dumpstack: Remove code_bytes

This was added by

  86c418374223 ("[PATCH] i386: add option to show more code in oops reports")

long time ago but experience shows that 64 instruction bytes are plenty
when deciphering an oops. So get rid of it.

Removing it will simplify further enhancements to the opcodes dumping
machinery coming in the following patches.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Link: https://lkml.kernel.org/r/20180417161124.5294-2-bp@alien8.de

---
 Documentation/admin-guide/kernel-parameters.txt |  5 -----
 arch/x86/kernel/dumpstack.c                     | 27 ++++---------------------
 2 files changed, 4 insertions(+), 28 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 11fc28ecdb6d..47aa554e41b7 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -587,11 +587,6 @@
 			Sets the size of memory pool for coherent, atomic dma
 			allocations, by default set to 256K.
 
-	code_bytes	[X86] How many bytes of object code to print
-			in an oops report.
-			Range: 0 - 8192
-			Default: 64
-
 	com20020=	[HW,NET] ARCnet - COM20020 chipset
 			Format:
 			<io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 18fa9d74c182..593db796374d 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -22,9 +22,10 @@
 #include <asm/stacktrace.h>
 #include <asm/unwind.h>
 
+#define OPCODE_BUFSIZE 64
+
 int panic_on_unrecovered_nmi;
 int panic_on_io_nmi;
-static unsigned int code_bytes = 64;
 static int die_counter;
 
 bool in_task_stack(unsigned long *stack, struct task_struct *task,
@@ -356,26 +357,6 @@ void die(const char *str, struct pt_regs *regs, long err)
 	oops_end(flags, regs, sig);
 }
 
-static int __init code_bytes_setup(char *s)
-{
-	ssize_t ret;
-	unsigned long val;
-
-	if (!s)
-		return -EINVAL;
-
-	ret = kstrtoul(s, 0, &val);
-	if (ret)
-		return ret;
-
-	code_bytes = val;
-	if (code_bytes > 8192)
-		code_bytes = 8192;
-
-	return 1;
-}
-__setup("code_bytes=", code_bytes_setup);
-
 void show_regs(struct pt_regs *regs)
 {
 	bool all = true;
@@ -393,8 +374,8 @@ void show_regs(struct pt_regs *regs)
 	 * time of the fault..
 	 */
 	if (!user_mode(regs)) {
-		unsigned int code_prologue = code_bytes * 43 / 64;
-		unsigned int code_len = code_bytes;
+		unsigned int code_prologue = OPCODE_BUFSIZE * 43 / 64;
+		unsigned int code_len = OPCODE_BUFSIZE;
 		unsigned char c;
 		u8 *ip;
 

  reply	other threads:[~2018-04-26 14:19 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-17 16:11 [PATCH 0/9] x86/dumpstack: Cleanups and user opcode bytes Code: section, v3 Borislav Petkov
2018-04-17 16:11 ` [PATCH 1/9] x86/dumpstack: Remove code_bytes Borislav Petkov
2018-04-26 14:18   ` tip-bot for Borislav Petkov [this message]
2018-04-17 16:11 ` [PATCH 2/9] x86/dumpstack: Unexport oops_begin() Borislav Petkov
2018-04-26 14:19   ` [tip:x86/cleanups] " tip-bot for Borislav Petkov
2018-04-17 16:11 ` [PATCH 3/9] x86/dumpstack: Carve out Code: dumping into a function Borislav Petkov
2018-04-26 14:19   ` [tip:x86/cleanups] x86/dumpstack: Carve out code-dumping " tip-bot for Borislav Petkov
2018-04-17 16:11 ` [PATCH 4/9] x86/dumpstack: Improve opcodes dumping in the Code: section Borislav Petkov
2018-04-26 14:20   ` [tip:x86/cleanups] x86/dumpstack: Improve opcodes dumping in the code section tip-bot for Borislav Petkov
2018-04-17 16:11 ` [PATCH 5/9] x86/dumpstack: Add loglevel argument to show_opcodes() Borislav Petkov
2018-04-26 14:20   ` [tip:x86/cleanups] " tip-bot for Borislav Petkov
2018-04-17 16:11 ` [PATCH 6/9] x86/fault: Dump user opcode bytes on fatal faults Borislav Petkov
2018-04-26 14:21   ` [tip:x86/cleanups] " tip-bot for Borislav Petkov
2018-04-17 16:11 ` [PATCH 7/9] x86/dumpstack: Add a show_ip() function Borislav Petkov
2018-04-26 14:21   ` [tip:x86/cleanups] " tip-bot for Borislav Petkov
2018-04-17 16:11 ` [PATCH 8/9] x86/dumpstack: Save first regs set for the executive summary Borislav Petkov
2018-04-26 14:22   ` [tip:x86/cleanups] " tip-bot for Borislav Petkov
2018-04-17 16:11 ` [PATCH 9/9] x86/dumpstack: Explain the reasoning for the prologue and buffer size Borislav Petkov
2018-04-26 14:22   ` [tip:x86/cleanups] " tip-bot for Borislav Petkov

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